Example #1
0
def dict_of_branch_powers(branches, buses):
    """
    Create a dictionary of the branch powers
    (with subkeys pf, qf, pt, qt)
    """
    branch_powers = dict()
    branch_powers['pf'] = dict()
    branch_powers['qf'] = dict()
    branch_powers['pt'] = dict()
    branch_powers['qt'] = dict()
    for branch_name, branch in branches.items():
        from_bus = buses[branch['from_bus']]
        to_bus = buses[branch['to_bus']]
        pf = 0
        qf = 0
        pt = 0
        qt = 0
        if branch['in_service'] \
            and from_bus['vm'] is not None and from_bus['va'] is not None \
            and to_bus['vm'] is not None and to_bus['va'] is not None:
            # we have all the information we need
            y_matrix = tx_calc.calculate_y_matrix_from_branch(branch)
            vfr = tx_calc.calculate_vr_from_vm_va_degrees(
                from_bus['vm'], from_bus['va'])
            vfj = tx_calc.calculate_vj_from_vm_va_degrees(
                from_bus['vm'], from_bus['va'])
            vtr = tx_calc.calculate_vr_from_vm_va_degrees(
                to_bus['vm'], to_bus['va'])
            vtj = tx_calc.calculate_vj_from_vm_va_degrees(
                to_bus['vm'], to_bus['va'])
            ifr = tx_calc.calculate_ifr(vfr, vfj, vtr, vtj, y_matrix)
            ifj = tx_calc.calculate_ifj(vfr, vfj, vtr, vtj, y_matrix)
            itr = tx_calc.calculate_itr(vfr, vfj, vtr, vtj, y_matrix)
            itj = tx_calc.calculate_itj(vfr, vfj, vtr, vtj, y_matrix)
            pf = tx_calc.calculate_p(ifr, ifj, vfr, vfj)
            qf = tx_calc.calculate_q(ifr, ifj, vfr, vfj)
            pt = tx_calc.calculate_p(itr, itj, vtr, vtj)
            qt = tx_calc.calculate_q(itr, itj, vtr, vtj)
        branch_powers['pf'][branch_name] = pf
        branch_powers['qf'][branch_name] = qf
        branch_powers['pt'][branch_name] = pt
        branch_powers['qt'][branch_name] = qt
    return branch_powers
Example #2
0
def create_psv_acopf_model(model_data, include_feasibility_slack=False):
    md = model_data.clone_in_service()
    tx_utils.scale_ModelData_to_pu(md, inplace=True)

    gens = dict(md.elements(element_type='generator'))
    buses = dict(md.elements(element_type='bus'))
    branches = dict(md.elements(element_type='branch'))
    loads = dict(md.elements(element_type='load'))
    shunts = dict(md.elements(element_type='shunt'))

    gen_attrs = md.attributes(element_type='generator')
    bus_attrs = md.attributes(element_type='bus')
    branch_attrs = md.attributes(element_type='branch')
    load_attrs = md.attributes(element_type='load')
    shunt_attrs = md.attributes(element_type='shunt')

    inlet_branches_by_bus, outlet_branches_by_bus = \
        tx_utils.inlet_outlet_branches_by_bus(branches, buses)
    gens_by_bus = tx_utils.gens_by_bus(buses, gens)

    model = pe.ConcreteModel()

    ### declare (and fix) the loads at the buses
    bus_p_loads, bus_q_loads = tx_utils.dict_of_bus_loads(buses, loads)

    libbus.declare_var_pl(model, bus_attrs['names'], initialize=bus_p_loads)
    libbus.declare_var_ql(model, bus_attrs['names'], initialize=bus_q_loads)
    model.pl.fix()
    model.ql.fix()

    ### declare the fixed shunts at the buses
    bus_bs_fixed_shunts, bus_gs_fixed_shunts = tx_utils.dict_of_bus_fixed_shunts(
        buses, shunts)

    ### declare the polar voltages
    libbus.declare_var_vm(model,
                          bus_attrs['names'],
                          initialize=bus_attrs['vm'],
                          bounds=zip_items(bus_attrs['v_min'],
                                           bus_attrs['v_max']))

    libbus.declare_expr_vmsq(model=model,
                             index_set=bus_attrs['names'],
                             coordinate_type=CoordinateType.POLAR)

    va_bounds = {k: (-pi, pi) for k in bus_attrs['va']}
    libbus.declare_var_va(model,
                          bus_attrs['names'],
                          initialize=bus_attrs['va'],
                          bounds=va_bounds)

    ### include the feasibility slack for the bus balances
    p_rhs_kwargs = {}
    q_rhs_kwargs = {}
    if include_feasibility_slack:
        p_rhs_kwargs, q_rhs_kwargs, penalty_expr = _include_feasibility_slack(
            model, bus_attrs, gen_attrs, bus_p_loads, bus_q_loads)

    ### fix the reference bus
    ref_bus = md.data['system']['reference_bus']
    ref_angle = md.data['system']['reference_bus_angle']
    model.va[ref_bus].fix(radians(ref_angle))

    ### declare the generator real and reactive power
    pg_init = {
        k: (gen_attrs['p_min'][k] + gen_attrs['p_max'][k]) / 2.0
        for k in gen_attrs['pg']
    }
    libgen.declare_var_pg(model,
                          gen_attrs['names'],
                          initialize=pg_init,
                          bounds=zip_items(gen_attrs['p_min'],
                                           gen_attrs['p_max']))

    qg_init = {
        k: (gen_attrs['q_min'][k] + gen_attrs['q_max'][k]) / 2.0
        for k in gen_attrs['qg']
    }
    libgen.declare_var_qg(model,
                          gen_attrs['names'],
                          initialize=qg_init,
                          bounds=zip_items(gen_attrs['q_min'],
                                           gen_attrs['q_max']))

    ### declare the current flows in the branches
    vr_init = {
        k: bus_attrs['vm'][k] * pe.cos(bus_attrs['va'][k])
        for k in bus_attrs['vm']
    }
    vj_init = {
        k: bus_attrs['vm'][k] * pe.sin(bus_attrs['va'][k])
        for k in bus_attrs['vm']
    }
    s_max = {k: branches[k]['rating_long_term'] for k in branches.keys()}
    s_lbub = dict()
    for k in branches.keys():
        if s_max[k] is None:
            s_lbub[k] = (None, None)
        else:
            s_lbub[k] = (-s_max[k], s_max[k])
    pf_bounds = s_lbub
    pt_bounds = s_lbub
    qf_bounds = s_lbub
    qt_bounds = s_lbub
    pf_init = dict()
    pt_init = dict()
    qf_init = dict()
    qt_init = dict()
    for branch_name, branch in branches.items():
        from_bus = branch['from_bus']
        to_bus = branch['to_bus']
        y_matrix = tx_calc.calculate_y_matrix_from_branch(branch)
        ifr_init = tx_calc.calculate_ifr(vr_init[from_bus], vj_init[from_bus],
                                         vr_init[to_bus], vj_init[to_bus],
                                         y_matrix)
        ifj_init = tx_calc.calculate_ifj(vr_init[from_bus], vj_init[from_bus],
                                         vr_init[to_bus], vj_init[to_bus],
                                         y_matrix)
        itr_init = tx_calc.calculate_itr(vr_init[from_bus], vj_init[from_bus],
                                         vr_init[to_bus], vj_init[to_bus],
                                         y_matrix)
        itj_init = tx_calc.calculate_itj(vr_init[from_bus], vj_init[from_bus],
                                         vr_init[to_bus], vj_init[to_bus],
                                         y_matrix)
        pf_init[branch_name] = tx_calc.calculate_p(ifr_init, ifj_init,
                                                   vr_init[from_bus],
                                                   vj_init[from_bus])
        pt_init[branch_name] = tx_calc.calculate_p(itr_init, itj_init,
                                                   vr_init[to_bus],
                                                   vj_init[to_bus])
        qf_init[branch_name] = tx_calc.calculate_q(ifr_init, ifj_init,
                                                   vr_init[from_bus],
                                                   vj_init[from_bus])
        qt_init[branch_name] = tx_calc.calculate_q(itr_init, itj_init,
                                                   vr_init[to_bus],
                                                   vj_init[to_bus])

    libbranch.declare_var_pf(model=model,
                             index_set=branch_attrs['names'],
                             initialize=pf_init,
                             bounds=pf_bounds)
    libbranch.declare_var_pt(model=model,
                             index_set=branch_attrs['names'],
                             initialize=pt_init,
                             bounds=pt_bounds)
    libbranch.declare_var_qf(model=model,
                             index_set=branch_attrs['names'],
                             initialize=qf_init,
                             bounds=qf_bounds)
    libbranch.declare_var_qt(model=model,
                             index_set=branch_attrs['names'],
                             initialize=qt_init,
                             bounds=qt_bounds)

    ### declare the branch power flow constraints
    bus_pairs = zip_items(branch_attrs['from_bus'], branch_attrs['to_bus'])
    unique_bus_pairs = list(
        OrderedDict((val, None) for idx, val in bus_pairs.items()).keys())
    libbranch.declare_expr_c(model=model,
                             index_set=unique_bus_pairs,
                             coordinate_type=CoordinateType.POLAR)
    libbranch.declare_expr_s(model=model,
                             index_set=unique_bus_pairs,
                             coordinate_type=CoordinateType.POLAR)
    libbranch.declare_eq_branch_power(model=model,
                                      index_set=branch_attrs['names'],
                                      branches=branches)

    ### declare the pq balances
    libbus.declare_eq_p_balance(model=model,
                                index_set=bus_attrs['names'],
                                bus_p_loads=bus_p_loads,
                                gens_by_bus=gens_by_bus,
                                bus_gs_fixed_shunts=bus_gs_fixed_shunts,
                                inlet_branches_by_bus=inlet_branches_by_bus,
                                outlet_branches_by_bus=outlet_branches_by_bus,
                                **p_rhs_kwargs)

    libbus.declare_eq_q_balance(model=model,
                                index_set=bus_attrs['names'],
                                bus_q_loads=bus_q_loads,
                                gens_by_bus=gens_by_bus,
                                bus_bs_fixed_shunts=bus_bs_fixed_shunts,
                                inlet_branches_by_bus=inlet_branches_by_bus,
                                outlet_branches_by_bus=outlet_branches_by_bus,
                                **q_rhs_kwargs)

    ### declare the thermal limits
    libbranch.declare_ineq_s_branch_thermal_limit(
        model=model,
        index_set=branch_attrs['names'],
        branches=branches,
        s_thermal_limits=s_max,
        flow_type=FlowType.POWER)

    ### declare the voltage min and max inequalities
    libbus.declare_ineq_vm_bus_lbub(model=model,
                                    index_set=bus_attrs['names'],
                                    buses=buses,
                                    coordinate_type=CoordinateType.POLAR)

    ### declare angle difference limits on interconnected buses
    libbranch.declare_ineq_angle_diff_branch_lbub(
        model=model,
        index_set=branch_attrs['names'],
        branches=branches,
        coordinate_type=CoordinateType.POLAR)

    ### declare the generator cost objective
    libgen.declare_expression_pgqg_operating_cost(model=model,
                                                  index_set=gen_attrs['names'],
                                                  p_costs=gen_attrs['p_cost'],
                                                  q_costs=gen_attrs.get(
                                                      'q_cost', None))

    obj_expr = sum(model.pg_operating_cost[gen_name]
                   for gen_name in model.pg_operating_cost)
    if include_feasibility_slack:
        obj_expr += penalty_expr
    if hasattr(model, 'qg_operating_cost'):
        obj_expr += sum(model.qg_operating_cost[gen_name]
                        for gen_name in model.qg_operating_cost)

    model.obj = pe.Objective(expr=obj_expr)

    return model, md
Example #3
0
def solve_acopf(model_data,
                solver,
                timelimit=None,
                solver_tee=True,
                symbolic_solver_labels=False,
                options=None,
                acopf_model_generator=create_psv_acopf_model,
                return_model=False,
                return_results=False,
                **kwargs):
    '''
    Create and solve a new acopf model

    Parameters
    ----------
    model_data : egret.data.ModelData
        An egret ModelData object with the appropriate data loaded.
    solver : str or pyomo.opt.base.solvers.OptSolver
        Either a string specifying a pyomo solver name, or an instantiated pyomo solver
    timelimit : float (optional)
        Time limit for dcopf run. Default of None results in no time
        limit being set.
    solver_tee : bool (optional)
        Display solver log. Default is True.
    symbolic_solver_labels : bool (optional)
        Use symbolic solver labels. Useful for debugging; default is False.
    options : dict (optional)
        Other options to pass into the solver. Default is dict().
    acopf_model_generator : function (optional)
        Function for generating the acopf model. Default is
        egret.models.acopf.create_psv_acopf_model
    return_model : bool (optional)
        If True, returns the pyomo model object
    return_results : bool (optional)
        If True, returns the pyomo results object
    kwargs : dictionary (optional)
        Additional arguments for building model
    '''

    import pyomo.environ as pe
    from pyomo.environ import value
    from egret.common.solver_interface import _solve_model
    from egret.model_library.transmission.tx_utils import \
        scale_ModelData_to_pu, unscale_ModelData_to_pu

    m, md = acopf_model_generator(model_data, **kwargs)

    m.dual = pe.Suffix(direction=pe.Suffix.IMPORT)

    m, results = _solve_model(m,
                              solver,
                              timelimit=timelimit,
                              solver_tee=solver_tee,
                              symbolic_solver_labels=symbolic_solver_labels,
                              options=options)

    # save results data to ModelData object
    gens = dict(md.elements(element_type='generator'))
    buses = dict(md.elements(element_type='bus'))
    branches = dict(md.elements(element_type='branch'))

    md.data['system']['total_cost'] = value(m.obj)

    for g, g_dict in gens.items():
        g_dict['pg'] = value(m.pg[g])
        g_dict['qg'] = value(m.qg[g])

    for b, b_dict in buses.items():
        b_dict['lmp'] = value(m.dual[m.eq_p_balance[b]])
        b_dict['qlmp'] = value(m.dual[m.eq_q_balance[b]])
        b_dict['pl'] = value(m.pl[b])
        if hasattr(m, 'vj'):
            b_dict['vm'] = tx_calc.calculate_vm_from_vj_vr(
                value(m.vj[b]), value(m.vr[b]))
            b_dict['va'] = tx_calc.calculate_va_from_vj_vr(
                value(m.vj[b]), value(m.vr[b]))
        else:
            b_dict['vm'] = value(m.vm[b])
            b_dict['va'] = value(m.va[b])

    for k, k_dict in branches.items():
        if hasattr(m, 'pf'):
            k_dict['pf'] = value(m.pf[k])
            k_dict['pt'] = value(m.pt[k])
            k_dict['qf'] = value(m.qf[k])
            k_dict['qt'] = value(m.qt[k])
        if hasattr(m, 'irf'):
            b = k_dict['from_bus']
            k_dict['pf'] = value(
                tx_calc.calculate_p(value(m.ifr[k]), value(m.ifj[k]),
                                    value(m.vr[b]), value(m.vj[b])))
            k_dict['qf'] = value(
                tx_calc.calculate_q(value(m.ifr[k]), value(m.ifj[k]),
                                    value(m.vr[b]), value(m.vj[b])))
            b = k_dict['to_bus']
            k_dict['pt'] = value(
                tx_calc.calculate_p(value(m.itr[k]), value(m.itj[k]),
                                    value(m.vr[b]), value(m.vj[b])))
            k_dict['qt'] = value(
                tx_calc.calculate_q(value(m.itr[k]), value(m.itj[k]),
                                    value(m.vr[b]), value(m.vj[b])))

    unscale_ModelData_to_pu(md, inplace=True)

    if return_model and return_results:
        return md, m, results
    elif return_model:
        return md, m
    elif return_results:
        return md, results
    return md
Example #4
0
def create_ptdf_dcopf_model(model_data, include_feasibility_slack=False,base_point=BasePointType.FLATSTART):
    md = model_data.clone_in_service()
    tx_utils.scale_ModelData_to_pu(md, inplace = True)

    data_utils.create_dicts_of_ptdf(md,base_point=base_point)

    gens = dict(md.elements(element_type='generator'))
    buses = dict(md.elements(element_type='bus'))
    branches = dict(md.elements(element_type='branch'))
    loads = dict(md.elements(element_type='load'))
    shunts = dict(md.elements(element_type='shunt'))

    gen_attrs = md.attributes(element_type='generator')
    bus_attrs = md.attributes(element_type='bus')
    branch_attrs = md.attributes(element_type='branch')
    load_attrs = md.attributes(element_type='load')
    shunt_attrs = md.attributes(element_type='shunt')

    inlet_branches_by_bus, outlet_branches_by_bus = \
        tx_utils.inlet_outlet_branches_by_bus(branches, buses)
    gens_by_bus = tx_utils.gens_by_bus(buses, gens)

    model = pe.ConcreteModel()

    ### declare (and fix) the loads at the buses
    bus_p_loads, _ = tx_utils.dict_of_bus_loads(buses, loads)

    libbus.declare_var_pl(model, bus_attrs['names'], initialize=bus_p_loads)
    model.pl.fix()

    ### declare the fixed shunts at the buses
    _, bus_gs_fixed_shunts = tx_utils.dict_of_bus_fixed_shunts(buses, shunts)

    ### declare the generator real power
    pg_init = {k: (gen_attrs['p_min'][k] + gen_attrs['p_max'][k]) / 2.0 for k in gen_attrs['pg']}
    libgen.declare_var_pg(model, gen_attrs['names'], initialize=pg_init,
                          bounds=zip_items(gen_attrs['p_min'], gen_attrs['p_max'])
                          )

    ### include the feasibility slack for the system balance
    p_rhs_kwargs = {}
    if include_feasibility_slack:
        p_rhs_kwargs, penalty_expr = _include_system_feasibility_slack(model, gen_attrs, bus_p_loads)

    ### declare the current flows in the branches
    vr_init = {k: bus_attrs['vm'][k] * pe.cos(bus_attrs['va'][k]) for k in bus_attrs['vm']}
    vj_init = {k: bus_attrs['vm'][k] * pe.sin(bus_attrs['va'][k]) for k in bus_attrs['vm']}
    p_max = {k: branches[k]['rating_long_term'] for k in branches.keys()}
    p_lbub = {k: (-p_max[k],p_max[k]) for k in branches.keys()}
    pf_bounds = p_lbub
    pf_init = dict()
    for branch_name, branch in branches.items():
        from_bus = branch['from_bus']
        to_bus = branch['to_bus']
        y_matrix = tx_calc.calculate_y_matrix_from_branch(branch)
        ifr_init = tx_calc.calculate_ifr(vr_init[from_bus], vj_init[from_bus], vr_init[to_bus],
                                         vj_init[to_bus], y_matrix)
        ifj_init = tx_calc.calculate_ifj(vr_init[from_bus], vj_init[from_bus], vr_init[to_bus],
                                         vj_init[to_bus], y_matrix)
        pf_init[branch_name] = tx_calc.calculate_p(ifr_init, ifj_init, vr_init[from_bus], vj_init[from_bus])

    libbranch.declare_var_pf(model=model,
                             index_set=branch_attrs['names'],
                             initialize=pf_init,
                             bounds=pf_bounds
                             )

    ### declare the branch power flow approximation constraints
    libbranch.declare_eq_branch_power_ptdf_approx(model=model,
                                                  index_set=branch_attrs['names'],
                                                  branches=branches,
                                                  buses=buses,
                                                  bus_p_loads=bus_p_loads,
                                                  gens_by_bus=gens_by_bus,
                                                  bus_gs_fixed_shunts=bus_gs_fixed_shunts
                                                  )

    ### declare the p balance
    libbus.declare_eq_p_balance_ed(model=model,
                                   index_set=bus_attrs['names'],
                                   bus_p_loads=bus_p_loads,
                                   gens_by_bus=gens_by_bus,
                                   bus_gs_fixed_shunts=bus_gs_fixed_shunts,
                                   **p_rhs_kwargs
                                   )

    ### declare the real power flow limits
    libbranch.declare_ineq_p_branch_thermal_lbub(model=model,
                                                 index_set=branch_attrs['names'],
                                                 branches=branches,
                                                 p_thermal_limits=p_max,
                                                 approximation_type=ApproximationType.PTDF
                                                 )

    ### declare the generator cost objective
    libgen.declare_expression_pgqg_operating_cost(model=model,
                                                  index_set=gen_attrs['names'],
                                                  p_costs=gen_attrs['p_cost']
                                                  )

    obj_expr = sum(model.pg_operating_cost[gen_name] for gen_name in model.pg_operating_cost)
    if include_feasibility_slack:
        obj_expr += penalty_expr

    model.obj = pe.Objective(expr=obj_expr)

    return model, md
def create_gdp_subproblem(model, model_data, include_angle_diff_limits=False):
    md = model_data
    tx_utils.scale_ModelData_to_pu(md, inplace=True)

    gens = dict(md.elements(element_type='generator'))
    buses = dict(md.elements(element_type='bus'))
    branches = dict(md.elements(element_type='branch'))
    loads = dict(md.elements(element_type='load'))
    shunts = dict(md.elements(element_type='shunt'))

    gen_attrs = md.attributes(element_type='generator')
    bus_attrs = md.attributes(element_type='bus')
    branch_attrs = md.attributes(element_type='branch')

    inlet_branches_by_bus, outlet_branches_by_bus = \
        tx_utils.inlet_outlet_branches_by_bus(branches, buses)
    gens_by_bus = tx_utils.gens_by_bus(buses, gens)

    model.subproblem = bi.SubModel(fixed=(model.u, model.v, model.w))

    ### declare (and fix) the loads at the buses
    bus_p_loads, _ = tx_utils.dict_of_bus_loads(buses, loads)
    buses_with_loads = list(k for k in bus_p_loads.keys()
                            if bus_p_loads[k] != 0.)

    libbus.declare_var_pl(model.subproblem,
                          bus_attrs['names'],
                          initialize=bus_p_loads)
    model.subproblem.pl.fix()

    ### declare the fixed shunts at the buses
    _, bus_gs_fixed_shunts = tx_utils.dict_of_bus_fixed_shunts(buses, shunts)

    ### declare the polar voltages
    va_bounds = {k: (-pi, pi) for k in bus_attrs['va']}
    libbus.declare_var_va(model.subproblem,
                          bus_attrs['names'],
                          initialize=tx_utils.radians_from_degrees_dict(
                              bus_attrs['va']),
                          bounds=va_bounds)

    ### fix the reference bus
    ref_bus = md.data['system']['reference_bus']
    ref_angle = md.data['system']['reference_bus_angle']
    model.subproblem.va[ref_bus].fix(radians(ref_angle))

    ### declare the generator real power
    pg_init = {
        k: (gen_attrs['p_min'][k] + gen_attrs['p_max'][k]) / 2.0
        for k in gen_attrs['pg']
    }
    libgen.declare_var_pg(model.subproblem,
                          gen_attrs['names'],
                          initialize=pg_init,
                          bounds=zip_items(gen_attrs['p_min'],
                                           gen_attrs['p_max']))

    ### declare the current flows in the branches
    vr_init = {
        k: bus_attrs['vm'][k] * pe.cos(radians(bus_attrs['va'][k]))
        for k in bus_attrs['vm']
    }
    vj_init = {
        k: bus_attrs['vm'][k] * pe.sin(radians(bus_attrs['va'][k]))
        for k in bus_attrs['vm']
    }
    p_max = {k: branches[k]['rating_long_term'] for k in branches.keys()}
    p_lbub = {k: (-p_max[k], p_max[k]) for k in branches.keys()}
    pf_bounds = p_lbub
    pf_init = dict()
    for branch_name, branch in branches.items():
        from_bus = branch['from_bus']
        to_bus = branch['to_bus']
        y_matrix = tx_calc.calculate_y_matrix_from_branch(branch)
        ifr_init = tx_calc.calculate_ifr(vr_init[from_bus], vj_init[from_bus],
                                         vr_init[to_bus], vj_init[to_bus],
                                         y_matrix)
        ifj_init = tx_calc.calculate_ifj(vr_init[from_bus], vj_init[from_bus],
                                         vr_init[to_bus], vj_init[to_bus],
                                         y_matrix)
        pf_init[branch_name] = tx_calc.calculate_p(ifr_init, ifj_init,
                                                   vr_init[from_bus],
                                                   vj_init[from_bus])

    libbranch.declare_var_pf(model=model.subproblem,
                             index_set=branch_attrs['names'],
                             initialize=pf_init,
                             bounds=pf_bounds)

    # need to include variable references on subproblem to variables, which exist on the master block
    bi.components.varref(model.subproblem)

    ### declare the branch power flow disjuncts (LHS is status quo, RHS is compromised)
    libbranch.declare_eq_branch_power_btheta_approx(
        model=model.subproblem,
        index_set=branch_attrs['names'],
        branches=branches)
    subcons.declare_eq_branch_power_off(model=model.subproblem,
                                        index_set=branch_attrs['names'],
                                        branches=branches)
    subcons.disjunctify(model=model.subproblem,
                        indicator_name='pf_branch_indicator',
                        disjunct_name='pf_branch_disjunct',
                        LHS_disjunct_set=model.subproblem.eq_pf_branch,
                        RHS_disjunct_set=model.subproblem.eq_pf_branch_off)

    ### declare the load shed disjuncts (LHS is status quo, RHS is compromised)
    subcons.declare_ineq_load_shed_ub(model=model.subproblem,
                                      index_set=buses_with_loads)
    subcons.declare_ineq_load_shed_lb(model=model.subproblem,
                                      index_set=buses_with_loads)
    subcons.declare_ineq_load_shed_lb_off(model=model.subproblem,
                                          index_set=buses_with_loads)
    subcons.disjunctify(
        model=model.subproblem,
        indicator_name='load_shed_indicator',
        disjunct_name='load_shed_disjunct',
        LHS_disjunct_set=model.subproblem.ineq_load_shed_lb,
        RHS_disjunct_set=model.subproblem.ineq_load_shed_lb_off)

    ### declare the generator disjuncts (LHS is status quo, RHS is compromised)
    subcons.declare_ineq_gen_on(model=model.subproblem,
                                index_set=gen_attrs['names'],
                                gens=gens)
    subcons.declare_ineq_gen_off(model=model.subproblem,
                                 index_set=gen_attrs['names'],
                                 gens=gens)
    subcons.disjunctify(model=model.subproblem,
                        indicator_name='gen_indicator',
                        disjunct_name='gen_disjunct',
                        LHS_disjunct_set=model.subproblem.ineq_gen,
                        RHS_disjunct_set=model.subproblem.ineq_gen_off)

    ### declare the p balance
    rhs_kwargs = {'include_feasibility_slack_neg': 'load_shed'}
    libbus.declare_eq_p_balance_dc_approx(
        model=model.subproblem,
        index_set=bus_attrs['names'],
        bus_p_loads=bus_p_loads,
        gens_by_bus=gens_by_bus,
        bus_gs_fixed_shunts=bus_gs_fixed_shunts,
        inlet_branches_by_bus=inlet_branches_by_bus,
        outlet_branches_by_bus=outlet_branches_by_bus,
        approximation_type=ApproximationType.BTHETA,
        **rhs_kwargs)

    ### declare the real power flow limits
    libbranch.declare_ineq_p_branch_thermal_lbub(
        model=model.subproblem,
        index_set=branch_attrs['names'],
        branches=branches,
        p_thermal_limits=p_max,
        approximation_type=ApproximationType.BTHETA)

    ### declare angle difference limits on interconnected buses
    if include_angle_diff_limits:
        libbranch.declare_ineq_angle_diff_branch_lbub(
            model=model.subproblem,
            index_set=branch_attrs['names'],
            branches=branches,
            coordinate_type=CoordinateType.POLAR)

    model.subproblem.obj = pe.Objective(expr=sum(model.load_shed[l]
                                                 for l in buses_with_loads),
                                        sense=pe.minimize)

    return model, md
Example #6
0
def create_explicit_subproblem(model,
                               subproblem,
                               model_data,
                               include_angle_diff_limits=False,
                               include_bigm=False):
    ### power system data
    md = model_data

    ### create dictionaries of object sets
    gens = dict(md.elements(element_type='generator'))
    buses = dict(md.elements(element_type='bus'))
    branches = dict(md.elements(element_type='branch'))
    loads = dict(md.elements(element_type='load'))
    shunts = dict(md.elements(element_type='shunt'))

    ### create dictionaries across object attributes for an object of the same set type
    gen_attrs = md.attributes(element_type='generator')
    bus_attrs = md.attributes(element_type='bus')
    branch_attrs = md.attributes(element_type='branch')

    inlet_branches_by_bus, outlet_branches_by_bus = \
        tx_utils.inlet_outlet_branches_by_bus(branches, buses)
    gens_by_bus = tx_utils.gens_by_bus(buses, gens)

    ### declare (and fix) the loads at the buses
    bus_p_loads, _ = tx_utils.dict_of_bus_loads(buses, loads)
    buses_with_loads = list(k for k in bus_p_loads.keys()
                            if bus_p_loads[k] != 0.)

    ### declare load shed variables
    decl.declare_var('load_shed',
                     subproblem,
                     buses_with_loads,
                     initialize=0.0,
                     domain=pe.NonNegativeReals)

    #libbus.declare_var_pl(model.subproblem, bus_attrs['names'], initialize=bus_p_loads)
    #model.subproblem.pl.fix()
    subproblem.pl = bus_p_loads

    ### declare the fixed shunts at the buses
    _, bus_gs_fixed_shunts = tx_utils.dict_of_bus_fixed_shunts(buses, shunts)

    ### declare the polar voltages
    va_bounds = {k: (-pi, pi) for k in bus_attrs['va']}
    va_init = {k: bus_attrs['va'][k] * (pi / 180) for k in bus_attrs['va']}
    libbus.declare_var_va(subproblem,
                          bus_attrs['names'],
                          initialize=bus_attrs['va'],
                          bounds=va_bounds)

    ### fix the reference bus
    ref_bus = md.data['system']['reference_bus']
    ref_angle = md.data['system']['reference_bus_angle']
    subproblem.va[ref_bus].fix(radians(ref_angle))

    ### declare the generator real power
    pg_init = {
        k: (gen_attrs['p_min'][k] + gen_attrs['p_max'][k]) / 2.0
        for k in gen_attrs['pg']
    }
    libgen.declare_var_pg(subproblem, gen_attrs['names'], initialize=pg_init)

    ### declare the current flows in the branches
    vr_init = {
        k: bus_attrs['vm'][k] * pe.cos(bus_attrs['va'][k])
        for k in bus_attrs['vm']
    }
    vj_init = {
        k: bus_attrs['vm'][k] * pe.sin(bus_attrs['va'][k])
        for k in bus_attrs['vm']
    }
    pf_init = dict()
    for branch_name, branch in branches.items():
        from_bus = branch['from_bus']
        to_bus = branch['to_bus']
        y_matrix = tx_calc.calculate_y_matrix_from_branch(branch)
        ifr_init = tx_calc.calculate_ifr(vr_init[from_bus], vj_init[from_bus],
                                         vr_init[to_bus], vj_init[to_bus],
                                         y_matrix)
        ifj_init = tx_calc.calculate_ifj(vr_init[from_bus], vj_init[from_bus],
                                         vr_init[to_bus], vj_init[to_bus],
                                         y_matrix)
        pf_init[branch_name] = tx_calc.calculate_p(ifr_init, ifj_init,
                                                   vr_init[from_bus],
                                                   vj_init[from_bus])

    libbranch.declare_var_pf(model=subproblem,
                             index_set=branch_attrs['names'],
                             initialize=pf_init)

    # need to include variable references on subproblem to variables, which exist on the master block
    #bi.components.varref(subproblem, origin = model)
    subproblem.add_component("u", Reference(model.u))
    subproblem.add_component("v", Reference(model.v))
    subproblem.add_component("w", Reference(model.w))
    if include_bigm:
        # create big-M
        _create_bigm(subproblem, md)
        ### declare the branch power flow disjuncts
        subcons.declare_eq_branch_power_btheta_approx_bigM(
            model=subproblem,
            index_set=branch_attrs['names'],
            branches=branches)

        ### declare the real power flow limits
        p_max = {k: branches[k]['rating_long_term'] for k in branches.keys()}
        subcons.declare_ineq_p_branch_thermal_lbub_switch(
            model=subproblem,
            index_set=branch_attrs['names'],
            p_thermal_limits=p_max)

    else:
        ### declare the branch power flow with indicator variable in the bilinear term
        subcons.declare_eq_branch_power_btheta_approx_nonlin(
            model=subproblem,
            index_set=branch_attrs['names'],
            branches=branches)

        ### declare the real power flow limits
        p_max = {k: branches[k]['rating_long_term'] for k in branches.keys()}
        libbranch.declare_ineq_p_branch_thermal_lbub(
            model=subproblem,
            index_set=branch_attrs['names'],
            branches=branches,
            p_thermal_limits=p_max,
            approximation_type=ApproximationType.BTHETA)

    ### declare the load shed
    subcons.declare_ineq_load_shed(model=subproblem,
                                   index_set=buses_with_loads)

    ### declare the generator compromised
    subcons.declare_ineq_gen(model=subproblem,
                             index_set=gen_attrs['names'],
                             gens=gens)

    ### declare the p balance
    rhs_kwargs = {'include_feasibility_slack_neg': 'load_shed'}
    libbus.declare_eq_p_balance_dc_approx(
        model=subproblem,
        index_set=bus_attrs['names'],
        bus_p_loads=bus_p_loads,
        gens_by_bus=gens_by_bus,
        bus_gs_fixed_shunts=bus_gs_fixed_shunts,
        inlet_branches_by_bus=inlet_branches_by_bus,
        outlet_branches_by_bus=outlet_branches_by_bus,
        approximation_type=ApproximationType.BTHETA,
        **rhs_kwargs)

    ### declare angle difference limits on interconnected buses
    if include_angle_diff_limits:
        libbranch.declare_ineq_angle_diff_branch_lbub(
            model=subproblem,
            index_set=branch_attrs['names'],
            branches=branches,
            coordinate_type=CoordinateType.POLAR)

    ### lower-level objective for interdiction problem (opposite to upper-level objective)
    subproblem.obj = pe.Objective(expr=sum(subproblem.load_shed[l]
                                           for l in buses_with_loads),
                                  sense=pe.minimize)

    return model, md
Example #7
0
def solve_lpac(model_data,
               solver,
               ac_solver=None,
               timelimit=None,
               solver_tee=True,
               symbolic_solver_labels=False,
               options=None,
               ac_options=None,
               lpac_model_generator=create_cold_start_lpac_model,
               return_model=False,
               return_results=False,
               kwargs={},
               kwargs_for_lpac={}):
    '''
    Create and solve a new lpac model

    Parameters
    ----------
    model_data : egret.data.ModelData
        An egret ModelData object with the appropriate data loaded.
    solver : str or pyomo.opt.base.solvers.OptSolver
        Either a string specifying a pyomo solver name, or an instantiated pyomo solver
    ac_solver : str or pyomo.opt.base.solvers.OptSolver (optional)
    	Either a string specifying a pyomo solver name, or an instantiated pyomo solver.
    	Default is None for the cold start lpac model. 
    timelimit : float (optional)
        Time limit for dcopf run. Default of None results in no time
        limit being set.
    solver_tee : bool (optional)
        Display solver log. Default is True.
    symbolic_solver_labels : bool (optional)
        Use symbolic solver labels. Useful for debugging; default is False.
    options : dict (optional)
        Other options to pass into the (LPAC) solver. Default is dict().
    ac_options : dict (optional)
    	Other options to pass into the ACOPF solver. Default is dict().
    lpac_model_generator : function (optional)
        Function for generating the lpac model. Default is
        the cold start lpac model
    return_model : bool (optional)
        If True, returns the pyomo model object
    return_results : bool (optional)
        If True, returns the pyomo results object
    kwargs : dictionary (optional)
        Additional arguments for building model. 
    kwargs_for_lpac : dictionary (optional)
    	Additional arguments for building lpac model (not used in ACOPF model)
    '''

    import pyomo.environ as pe
    import pyomo.opt as po
    from pyomo.environ import value
    from egret.common.solver_interface import _solve_model
    from egret.model_library.transmission.tx_utils import \
      scale_ModelData_to_pu, unscale_ModelData_to_pu

    if lpac_model_generator == create_hot_start_lpac_model or lpac_model_generator == create_warm_start_lpac_model:
        if ac_solver != None:
            ac_md, ac_m, ac_results = solve_acopf(
                model_data,
                ac_solver,
                options=ac_options,
                acopf_model_generator=create_psv_acopf_model,
                return_model=True,
                return_results=True,
                **kwargs)
        else:
            ac_md, ac_m, ac_results = solve_acopf(
                model_data,
                solver,
                options=options,
                acopf_model_generator=create_psv_acopf_model,
                return_model=True,
                return_results=True,
                **kwargs)
        voltages = dict({})
        for bus in ac_md.elements(element_type="bus"):
            voltages[bus[0]] = bus[1]['vm']
        #print(voltages)
        m, md = lpac_model_generator(model_data, voltages, **kwargs,
                                     **kwargs_for_lpac)
    else:
        m, md = lpac_model_generator(model_data, **kwargs, **kwargs_for_lpac)


    m, results, solver = _solve_model(m, solver, timelimit=timelimit, solver_tee=solver_tee, \
             symbolic_solver_labels = symbolic_solver_labels, solver_options=options, return_solver=True)

    # save results data to ModelData object

    gens = dict(md.elements(element_type='generator'))
    buses = dict(md.elements(element_type='bus'))
    branches = dict(md.elements(element_type='branch'))

    md.data['system']['total_cost'] = value(m.obj)

    for g, g_dict in gens.items():
        g_dict['pg'] = value(m.pg[g])
        g_dict['qg'] = value(m.qg[g])

    for b, b_dict in buses.items():
        #b_dict['lmp'] = value(m.dual[m.eq_p_balance[b]])
        #b_dict['qlmp'] = value(m.dual[m.eq_q_balance[b]])
        b_dict['pl'] = value(m.pl[b])
        #if hasattr(m, 'vj'):
        #b_dict['vm'] = tx_calc.calculate_vm_from_vj_vr(value(m.vj[b]), value(m.vr[b]))
        #b_dict['va'] = tx_calc.calculate_va_from_vj_vr(value(m.vj[b]), value(m.vr[b]))
        #else:
        #b_dict['vm'] = value(m.vm[b])
        #b_dict['va'] = value(m.va[b])

    for k, k_dict in branches.items():
        if hasattr(m, 'pf'):
            k_dict['pf'] = value(m.pf[k])
            k_dict['pt'] = value(m.pt[k])
            k_dict['qf'] = value(m.qf[k])
            k_dict['qt'] = value(m.qt[k])
        if hasattr(m, 'irf'):
            b = k_dict['from_bus']
            k_dict['pf'] = value(
                tx_calc.calculate_p(value(m.ifr[k]), value(m.ifj[k]),
                                    value(m.vr[b]), value(m.vj[b])))
            k_dict['qf'] = value(
                tx_calc.calculate_q(value(m.ifr[k]), value(m.ifj[k]),
                                    value(m.vr[b]), value(m.vj[b])))
            b = k_dict['to_bus']
            k_dict['pt'] = value(
                tx_calc.calculate_p(value(m.itr[k]), value(m.itj[k]),
                                    value(m.vr[b]), value(m.vj[b])))
            k_dict['qt'] = value(
                tx_calc.calculate_q(value(m.itr[k]), value(m.itj[k]),
                                    value(m.vr[b]), value(m.vj[b])))

    unscale_ModelData_to_pu(md, inplace=True)

    #print(buses)
    #print(gens)
    # print(branches)

    if return_model and return_results:
        return md, m, results
    elif return_model:
        return md, m
    elif return_results:
        return md, results
    return md
Example #8
0
def _create_base_acpf_model(model_data):
    md = model_data.clone_in_service()
    tx_utils.scale_ModelData_to_pu(md, inplace = True)

    gens = dict(md.elements(element_type='generator'))
    buses = dict(md.elements(element_type='bus'))
    branches = dict(md.elements(element_type='branch'))
    loads = dict(md.elements(element_type='load'))
    shunts = dict(md.elements(element_type='shunt'))

    gen_attrs = md.attributes(element_type='generator')
    bus_attrs = md.attributes(element_type='bus')
    branch_attrs = md.attributes(element_type='branch')
    inlet_branches_by_bus, outlet_branches_by_bus = \
        tx_utils.inlet_outlet_branches_by_bus(branches, buses)
    gens_by_bus = tx_utils.gens_by_bus(buses, gens)

    bus_pairs = zip_items(branch_attrs['from_bus'], branch_attrs['to_bus'])
    unique_bus_pairs = list(OrderedDict((val, None) for idx, val in bus_pairs.items()))

    model = pe.ConcreteModel()

    ### declare (and fix) the loads at the buses
    bus_p_loads, bus_q_loads = tx_utils.dict_of_bus_loads(buses, loads)

    libbus.declare_var_pl(model, bus_attrs['names'], initialize=bus_p_loads)
    libbus.declare_var_ql(model, bus_attrs['names'], initialize=bus_q_loads)
    model.pl.fix()
    model.ql.fix()

    ### declare the fixed shunts at the buses
    bus_bs_fixed_shunts, bus_gs_fixed_shunts = tx_utils.dict_of_bus_fixed_shunts(buses, shunts)

    libbus.declare_var_vmsq(model=model,
                            index_set=bus_attrs['names'],
                            initialize={k: v**2 for k, v in bus_attrs['vm'].items()}
                            )
    libbranch.declare_var_c(model=model, index_set=unique_bus_pairs)
    libbranch.declare_var_s(model=model, index_set=unique_bus_pairs)

    ### declare the generator real and reactive power
    #pg_init = {k: (gen_attrs['p_min'][k] + gen_attrs['p_max'][k]) / 2.0 for k in gen_attrs['pg']}
    libgen.declare_var_pg(model, gen_attrs['names'], initialize=gen_attrs['pg'])

    #qg_init = {k: (gen_attrs['q_min'][k] + gen_attrs['q_max'][k]) / 2.0 for k in gen_attrs['qg']}
    libgen.declare_var_qg(model, gen_attrs['names'], initialize=gen_attrs['qg'])

    ### declare the current flows in the branches
    vr_init = {k: bus_attrs['vm'][k] * pe.cos(radians(bus_attrs['va'][k])) for k in bus_attrs['vm']}
    vj_init = {k: bus_attrs['vm'][k] * pe.sin(radians(bus_attrs['va'][k])) for k in bus_attrs['vm']}
    pf_init = dict()
    pt_init = dict()
    qf_init = dict()
    qt_init = dict()
    for branch_name, branch in branches.items():
        from_bus = branch['from_bus']
        to_bus = branch['to_bus']
        y_matrix = tx_calc.calculate_y_matrix_from_branch(branch)
        ifr_init = tx_calc.calculate_ifr(vr_init[from_bus], vj_init[from_bus], vr_init[to_bus],
                                         vj_init[to_bus], y_matrix)
        ifj_init = tx_calc.calculate_ifj(vr_init[from_bus], vj_init[from_bus], vr_init[to_bus],
                                         vj_init[to_bus], y_matrix)
        itr_init = tx_calc.calculate_itr(vr_init[from_bus], vj_init[from_bus], vr_init[to_bus],
                                         vj_init[to_bus], y_matrix)
        itj_init = tx_calc.calculate_itj(vr_init[from_bus], vj_init[from_bus], vr_init[to_bus],
                                         vj_init[to_bus], y_matrix)
        pf_init[branch_name] = tx_calc.calculate_p(ifr_init, ifj_init, vr_init[from_bus], vj_init[from_bus])
        pt_init[branch_name] = tx_calc.calculate_p(itr_init, itj_init, vr_init[to_bus], vj_init[to_bus])
        qf_init[branch_name] = tx_calc.calculate_q(ifr_init, ifj_init, vr_init[from_bus], vj_init[from_bus])
        qt_init[branch_name] = tx_calc.calculate_q(itr_init, itj_init, vr_init[to_bus], vj_init[to_bus])

    libbranch.declare_var_pf(model=model,
                             index_set=branch_attrs['names'],
                             initialize=pf_init
                             )
    libbranch.declare_var_pt(model=model,
                             index_set=branch_attrs['names'],
                             initialize=pt_init
                             )
    libbranch.declare_var_qf(model=model,
                             index_set=branch_attrs['names'],
                             initialize=qf_init
                             )
    libbranch.declare_var_qt(model=model,
                             index_set=branch_attrs['names'],
                             initialize=qt_init
                             )

    ### declare the branch power flow constraints
    libbranch.declare_eq_branch_power(model=model,
                                      index_set=branch_attrs['names'],
                                      branches=branches
                                      )

    ### declare the pq balances
    libbus.declare_eq_p_balance(model=model,
                                index_set=bus_attrs['names'],
                                bus_p_loads=bus_p_loads,
                                gens_by_bus=gens_by_bus,
                                bus_gs_fixed_shunts=bus_gs_fixed_shunts,
                                inlet_branches_by_bus=inlet_branches_by_bus,
                                outlet_branches_by_bus=outlet_branches_by_bus
                                )

    libbus.declare_eq_q_balance(model=model,
                                index_set=bus_attrs['names'],
                                bus_q_loads=bus_q_loads,
                                gens_by_bus=gens_by_bus,
                                bus_bs_fixed_shunts=bus_bs_fixed_shunts,
                                inlet_branches_by_bus=inlet_branches_by_bus,
                                outlet_branches_by_bus=outlet_branches_by_bus
                                )

    # if there are multiple generators at the same bus, we will
    # have unwanted degrees of freedom in qg
    # therefore, we add a constraint making them equal
    # if the reference bus has multiple generators, we will also
    # have unwanted degrees of freedom in pg
    #ref_bus = md.data['system']['reference_bus']
    qg_equality_tuples = list()
    #pg_equality_tuples = list()
    for b, genlist in gens_by_bus.items():
        if len(genlist) > 1:
            # we have more than one generator at this bus
            for i in range(1,len(genlist)):
                qg_equality_tuples.append((genlist[0], genlist[i]))
    #        if b == ref_bus:
    #            pg_equality_tuples.append((genlist[0], genlist[i]))

    def _qg_equalities(m,i,j):
        return m.qg[i] == m.qg[j]
    model.qg_equalities = pe.Constraint(qg_equality_tuples, rule=_qg_equalities)

    #def _pg_equalities(m,i,j):
    #    return m.pg[i] == m.pg[j]
    #model.pg_equalities = pe.Constraint(pg_equality_tuples, rule=_pg_equalities)

    model.obj = pe.Objective(expr=0.0)
    return model, md
Example #9
0
def create_cold_start_lpac_model(model_data,
                                 cosine_segment_count=20,
                                 lower_bound=-pi / 3,
                                 upper_bound=pi / 3,
                                 include_feasibility_slack=False,
                                 mode="uniform"):
    """
	The cold start LPAC model assumes that no target voltages are available and that all voltages are initially approximated as 1 pu. 
	"""
    ###Grid data
    md = model_data.clone_in_service()
    tx_utils.scale_ModelData_to_pu(md, inplace=True)

    gens = dict(md.elements(element_type='generator'))
    buses = dict(md.elements(element_type='bus'))
    branches = dict(md.elements(element_type='branch'))
    loads = dict(md.elements(element_type='load'))
    shunts = dict(md.elements(element_type='shunt'))

    gen_attrs = md.attributes(element_type='generator')
    bus_attrs = md.attributes(element_type='bus')
    branch_attrs = md.attributes(element_type='branch')

    inlet_branches_by_bus, outlet_branches_by_bus = \
           tx_utils.inlet_outlet_branches_by_bus(branches, buses)

    gens_by_bus = tx_utils.gens_by_bus(buses, gens)

    model = pe.ConcreteModel()

    ### declare the polar voltages
    libbus.declare_var_va(model,
                          bus_attrs['names'],
                          initialize=bus_attrs['va'])

    libbus.declare_var_vmsq(
        model=model,
        index_set=bus_attrs['names'],
        initialize={k: v**2
                    for k, v in bus_attrs['vm'].items()},
        bounds=zip_items({k: v**2
                          for k, v in bus_attrs['v_min'].items()},
                         {k: v**2
                          for k, v in bus_attrs['v_max'].items()}))

    ### declare the voltage change variables
    decl.declare_var('phi', model, bus_attrs['names'])

    ### declare the cosine approximation variables
    cos_hat_bounds = {k: (0, 1) for k in branch_attrs['names']}
    decl.declare_var('cos_hat',
                     model,
                     branch_attrs['names'],
                     bounds=cos_hat_bounds)

    ### fix the reference bus
    ref_bus = md.data['system']['reference_bus']
    #ref_angle = md.data['system']['reference_bus_angle']
    model.va[ref_bus].fix(radians(0.0))

    ### declare (and fix) the loads at the buses
    bus_p_loads, bus_q_loads = tx_utils.dict_of_bus_loads(buses, loads)

    libbus.declare_var_pl(model, bus_attrs['names'], initialize=bus_p_loads)
    libbus.declare_var_ql(model, bus_attrs['names'], initialize=bus_q_loads)
    model.pl.fix()
    model.ql.fix()

    ### declare the fixed shunts at the buses
    bus_bs_fixed_shunts, bus_gs_fixed_shunts = tx_utils.dict_of_bus_fixed_shunts(
        buses, shunts)

    ### include the feasibility slack for the bus balances
    p_rhs_kwargs = {}
    q_rhs_kwargs = {}
    if include_feasibility_slack:
        p_rhs_kwargs, q_rhs_kwargs, penalty_expr = _include_feasibility_slack(
            model, bus_attrs, gen_attrs, bus_p_loads, bus_q_loads)

### declare the generator real and reactive power
    pg_init = {
        k: (gen_attrs['p_min'][k] + gen_attrs['p_max'][k]) / 2.0
        for k in gen_attrs['pg']
    }
    libgen.declare_var_pg(model,
                          gen_attrs['names'],
                          initialize=pg_init,
                          bounds=zip_items(gen_attrs['p_min'],
                                           gen_attrs['p_max']))

    qg_init = {
        k: (gen_attrs['q_min'][k] + gen_attrs['q_max'][k]) / 2.0
        for k in gen_attrs['qg']
    }
    libgen.declare_var_qg(model,
                          gen_attrs['names'],
                          initialize=qg_init,
                          bounds=zip_items(gen_attrs['q_min'],
                                           gen_attrs['q_max']))

    ### declare the current flows in the branches
    vr_init = {
        k: bus_attrs['vm'][k] * pe.cos(bus_attrs['va'][k])
        for k in bus_attrs['vm']
    }
    vj_init = {
        k: bus_attrs['vm'][k] * pe.sin(bus_attrs['va'][k])
        for k in bus_attrs['vm']
    }
    s_max = {k: branches[k]['rating_long_term'] for k in branches.keys()}
    s_lbub = dict()
    for k in branches.keys():
        if s_max[k] is None:
            s_lbub[k] = (None, None)
        else:
            s_lbub[k] = (-s_max[k], s_max[k])
    pf_bounds = s_lbub
    pt_bounds = s_lbub
    qf_bounds = s_lbub
    qt_bounds = s_lbub
    pf_init = dict()
    pt_init = dict()
    qf_init = dict()
    qt_init = dict()
    for branch_name, branch in branches.items():
        from_bus = branch['from_bus']
        to_bus = branch['to_bus']
        y_matrix = tx_calc.calculate_y_matrix_from_branch(branch)
        ifr_init = tx_calc.calculate_ifr(vr_init[from_bus], vj_init[from_bus],
                                         vr_init[to_bus], vj_init[to_bus],
                                         y_matrix)
        ifj_init = tx_calc.calculate_ifj(vr_init[from_bus], vj_init[from_bus],
                                         vr_init[to_bus], vj_init[to_bus],
                                         y_matrix)
        itr_init = tx_calc.calculate_itr(vr_init[from_bus], vj_init[from_bus],
                                         vr_init[to_bus], vj_init[to_bus],
                                         y_matrix)
        itj_init = tx_calc.calculate_itj(vr_init[from_bus], vj_init[from_bus],
                                         vr_init[to_bus], vj_init[to_bus],
                                         y_matrix)
        pf_init[branch_name] = tx_calc.calculate_p(ifr_init, ifj_init,
                                                   vr_init[from_bus],
                                                   vj_init[from_bus])
        pt_init[branch_name] = tx_calc.calculate_p(itr_init, itj_init,
                                                   vr_init[to_bus],
                                                   vj_init[to_bus])
        qf_init[branch_name] = tx_calc.calculate_q(ifr_init, ifj_init,
                                                   vr_init[from_bus],
                                                   vj_init[from_bus])
        qt_init[branch_name] = tx_calc.calculate_q(itr_init, itj_init,
                                                   vr_init[to_bus],
                                                   vj_init[to_bus])

    libbranch.declare_var_pf(model=model,
                             index_set=branch_attrs['names'],
                             initialize=pf_init,
                             bounds=pf_bounds)
    libbranch.declare_var_pt(model=model,
                             index_set=branch_attrs['names'],
                             initialize=pt_init,
                             bounds=pt_bounds)
    libbranch.declare_var_qf(model=model,
                             index_set=branch_attrs['names'],
                             initialize=qf_init,
                             bounds=qf_bounds)
    libbranch.declare_var_qt(model=model,
                             index_set=branch_attrs['names'],
                             initialize=qt_init,
                             bounds=qt_bounds)

    ################################
    #Constraints
    ################################

    ### Balance equations at a bus (based on Kirchhoff Current Law)

    #Should be able to just use DC OPF approximation of B-theta type?

    ### declare the p balance
    libbus.declare_eq_p_balance(model=model,
                                index_set=bus_attrs['names'],
                                bus_p_loads=bus_p_loads,
                                gens_by_bus=gens_by_bus,
                                bus_gs_fixed_shunts=bus_gs_fixed_shunts,
                                inlet_branches_by_bus=inlet_branches_by_bus,
                                outlet_branches_by_bus=outlet_branches_by_bus,
                                approximation_type=ApproximationType.BTHETA,
                                **p_rhs_kwargs)

    #Need one also for q balance

    libbus.declare_eq_q_balance(model=model,
                                index_set=bus_attrs['names'],
                                bus_q_loads=bus_q_loads,
                                gens_by_bus=gens_by_bus,
                                bus_bs_fixed_shunts=bus_bs_fixed_shunts,
                                inlet_branches_by_bus=inlet_branches_by_bus,
                                outlet_branches_by_bus=outlet_branches_by_bus,
                                **q_rhs_kwargs)

    ### Constraints for power in a branch

    branch_con_set = decl.declare_set('_con_eq_p_q_lpac_branch_power', model,
                                      branch_attrs['names'])

    model.eq_pf_branch_t = pe.Constraint(branch_con_set)
    model.eq_pt_branch_t = pe.Constraint(branch_con_set)
    model.eq_qf_branch_t = pe.Constraint(branch_con_set)
    model.eq_qt_branch_t = pe.Constraint(branch_con_set)

    for branch_name in branch_con_set:
        branch = branches[branch_name]

        from_bus = branch['from_bus']
        to_bus = branch['to_bus']

        g = tx_calc.calculate_conductance(branch)
        b = tx_calc.calculate_susceptance(branch)

        model.eq_pf_branch_t[branch_name] = \
               model.pf[branch_name] == \
               g - g * model.cos_hat[branch_name] - b * (model.va[from_bus] - model.va[to_bus])

        model.eq_pt_branch_t[branch_name] = \
               model.pt[branch_name] == \
               g - g * model.cos_hat[branch_name] - b * (model.va[to_bus] - model.va[from_bus])

        model.eq_qf_branch_t[branch_name] = \
               model.qf[branch_name] == \
               -b - g*(model.va[from_bus] - model.va[to_bus]) + b*model.cos_hat[branch_name] - b*(model.phi[from_bus] - model.phi[to_bus])

        model.eq_qt_branch_t[branch_name] = \
               model.qt[branch_name] == \
               -b - g*(model.va[to_bus] - model.va[from_bus]) +b*model.cos_hat[branch_name] - b*(model.phi[to_bus] - model.phi[from_bus])

### Piecewise linear cosine constraints

    model.N = pe.Set(initialize=list(range(cosine_segment_count + 1)))

    declare_pwl_cosine_bounds(model=model,
                              index_set=branch_attrs['names'],
                              branches=branches,
                              lower_bound=lower_bound,
                              upper_bound=upper_bound,
                              cosine_segment_count=cosine_segment_count,
                              mode=mode)

    ### Objective is to maximize cosine hat variables

    # obj_expr = sum(model.cos_hat[branch_name] for branch_name in branch_attrs['names'])

    # if include_feasibility_slack:
    # 	obj_expr += penalty_expr

    # model.obj = pe.Objective(expr=obj_expr)

    ###Objective to match with acopf.py

    ### declare the generator cost objective
    libgen.declare_expression_pgqg_operating_cost(model=model,
                                                  index_set=gen_attrs['names'],
                                                  p_costs=gen_attrs['p_cost'],
                                                  q_costs=gen_attrs.get(
                                                      'q_cost', None))

    obj_expr = sum(model.pg_operating_cost[gen_name]
                   for gen_name in model.pg_operating_cost)
    if include_feasibility_slack:
        obj_expr += penalty_expr
    if hasattr(model, 'qg_operating_cost'):
        obj_expr += sum(model.qg_operating_cost[gen_name]
                        for gen_name in model.qg_operating_cost)

    model.obj = pe.Objective(expr=obj_expr)

    return model, md
Example #10
0
def create_btheta_dcopf_model(model_data):
    md = tx_utils.scale_ModelData_to_pu(model_data)

    gens = dict(md.elements(element_type='generator'))
    buses = dict(md.elements(element_type='bus'))
    branches = dict(md.elements(element_type='branch'))
    loads = dict(md.elements(element_type='load'))
    shunts = dict(md.elements(element_type='shunt'))

    gen_attrs = md.attributes(element_type='generator')
    bus_attrs = md.attributes(element_type='bus')
    branch_attrs = md.attributes(element_type='branch')
    load_attrs = md.attributes(element_type='load')
    shunt_attrs = md.attributes(element_type='shunt')

    inlet_branches_by_bus, outlet_branches_by_bus = \
        tx_utils.inlet_outlet_branches_by_bus(branches, buses)
    gens_by_bus = tx_utils.gens_in_service_by_bus(buses, gens)

    model = pe.ConcreteModel()

    ### declare (and fix) the loads at the buses
    bus_p_loads, _ = tx_utils.dict_of_bus_loads(buses, loads)

    libbus.declare_var_pl(model, bus_attrs['names'], initialize=bus_p_loads)
    model.pl.fix()

    ### declare the fixed shunts at the buses
    _, bus_gs_fixed_shunts = tx_utils.dict_of_bus_fixed_shunts(buses, shunts)

    ### declare the polar voltages
    va_bounds = {k: (-pi, pi) for k in bus_attrs['va']}
    libbus.declare_var_va(model,
                          bus_attrs['names'],
                          initialize=bus_attrs['va'],
                          bounds=va_bounds)

    ### fix the reference bus
    ref_bus = md.data['system']['reference_bus']
    model.va[ref_bus].fix(0.0)

    ref_angle = md.data['system']['reference_bus_angle']
    if ref_angle != 0.0:
        raise ValueError('The BTHETA DCOPF formulation currently only supports'
                         ' a reference bus angle of 0 degrees, but an angle'
                         ' of {} degrees was found.'.format(ref_angle))

    ### declare the generator real power
    pg_init = {
        k: (gen_attrs['p_min'][k] + gen_attrs['p_max'][k]) / 2.0
        for k in gen_attrs['pg']
    }
    libgen.declare_var_pg(model,
                          gen_attrs['names'],
                          initialize=pg_init,
                          bounds=zip_items(gen_attrs['p_min'],
                                           gen_attrs['p_max']))

    ### declare the current flows in the branches
    vr_init = {
        k: bus_attrs['vm'][k] * pe.cos(bus_attrs['va'][k])
        for k in bus_attrs['vm']
    }
    vj_init = {
        k: bus_attrs['vm'][k] * pe.sin(bus_attrs['va'][k])
        for k in bus_attrs['vm']
    }
    p_max = {k: branches[k]['rating_long_term'] for k in branches.keys()}
    p_lbub = {k: (-p_max[k], p_max[k]) for k in branches.keys()}
    pf_bounds = p_lbub
    pf_init = dict()
    for branch_name, branch in branches.items():
        from_bus = branch['from_bus']
        to_bus = branch['to_bus']
        y_matrix = tx_calc.calculate_y_matrix_from_branch(branch)
        ifr_init = tx_calc.calculate_ifr(vr_init[from_bus], vj_init[from_bus],
                                         vr_init[to_bus], vj_init[to_bus],
                                         y_matrix)
        ifj_init = tx_calc.calculate_ifj(vr_init[from_bus], vj_init[from_bus],
                                         vr_init[to_bus], vj_init[to_bus],
                                         y_matrix)
        pf_init[branch_name] = tx_calc.calculate_p(ifr_init, ifj_init,
                                                   vr_init[from_bus],
                                                   vj_init[from_bus])

    libbranch.declare_var_pf(model=model,
                             index_set=branch_attrs['names'],
                             initialize=pf_init,
                             bounds=pf_bounds)

    ### declare the branch power flow approximation constraints
    libbranch.declare_eq_branch_power_dc_approx(
        model=model,
        index_set=branch_attrs['names'],
        branches=branches,
        approximation_type=ApproximationType.BTHETA)

    ### declare the p balance
    libbus.declare_eq_p_balance_dc_approx(
        model=model,
        index_set=bus_attrs['names'],
        bus_p_loads=bus_p_loads,
        gens_by_bus=gens_by_bus,
        bus_gs_fixed_shunts=bus_gs_fixed_shunts,
        inlet_branches_by_bus=inlet_branches_by_bus,
        outlet_branches_by_bus=outlet_branches_by_bus,
        approximation_type=ApproximationType.BTHETA)

    ### declare the real power flow limits
    libbranch.declare_ineq_p_branch_thermal_lbub(
        model=model,
        index_set=branch_attrs['names'],
        branches=branches,
        p_thermal_limits=p_max,
        approximation_type=ApproximationType.BTHETA)

    ### declare angle difference limits on interconnected buses
    libbranch.declare_ineq_angle_diff_branch_lbub(
        model=model,
        index_set=branch_attrs['names'],
        branches=branches,
        coordinate_type=CoordinateType.POLAR)

    ### declare the generator cost objective
    libgen.declare_expression_pgqg_operating_cost(model=model,
                                                  index_set=gen_attrs['names'],
                                                  p_costs=gen_attrs['p_cost'])

    obj_expr = sum(model.pg_operating_cost[gen_name]
                   for gen_name in model.pg_operating_cost)

    model.obj = pe.Objective(expr=obj_expr)

    return model
Example #11
0
def _create_base_power_ac_model(model_data, include_feasibility_slack=False, pw_cost_model='delta'):
    md = model_data.clone_in_service()
    tx_utils.scale_ModelData_to_pu(md, inplace=True)

    gens = dict(md.elements(element_type='generator'))
    buses = dict(md.elements(element_type='bus'))
    branches = dict(md.elements(element_type='branch'))
    loads = dict(md.elements(element_type='load'))
    shunts = dict(md.elements(element_type='shunt'))

    gen_attrs = md.attributes(element_type='generator')
    bus_attrs = md.attributes(element_type='bus')
    branch_attrs = md.attributes(element_type='branch')

    inlet_branches_by_bus, outlet_branches_by_bus = \
        tx_utils.inlet_outlet_branches_by_bus(branches, buses)
    gens_by_bus = tx_utils.gens_by_bus(buses, gens)

    bus_pairs = zip_items(branch_attrs['from_bus'], branch_attrs['to_bus'])
    unique_bus_pairs = list(OrderedDict((val, None) for idx, val in bus_pairs.items()))

    model = pe.ConcreteModel()

    ### declare (and fix) the loads at the buses
    bus_p_loads, bus_q_loads = tx_utils.dict_of_bus_loads(buses, loads)

    libbus.declare_var_pl(model, bus_attrs['names'], initialize=bus_p_loads)
    libbus.declare_var_ql(model, bus_attrs['names'], initialize=bus_q_loads)
    model.pl.fix()
    model.ql.fix()

    ### declare the fixed shunts at the buses
    bus_bs_fixed_shunts, bus_gs_fixed_shunts = tx_utils.dict_of_bus_fixed_shunts(buses, shunts)

    libbus.declare_var_vmsq(model=model,
                            index_set=bus_attrs['names'],
                            initialize={k: v**2 for k, v in bus_attrs['vm'].items()},
                            bounds=zip_items({k: v**2 for k, v in bus_attrs['v_min'].items()},
                                             {k: v**2 for k, v in bus_attrs['v_max'].items()}))
    libbranch.declare_var_c(model=model, index_set=unique_bus_pairs, initialize=1)
    libbranch.declare_var_s(model=model, index_set=unique_bus_pairs, initialize=0)

    ### include the feasibility slack for the bus balances
    p_rhs_kwargs = {}
    q_rhs_kwargs = {}
    if include_feasibility_slack:
        p_marginal_slack_penalty, q_marginal_slack_penalty = _validate_and_extract_slack_penalties(md)
        p_rhs_kwargs, q_rhs_kwargs, penalty_expr = _include_feasibility_slack(model, bus_attrs['names'],
                                                                              bus_p_loads, bus_q_loads,
                                                                              gens_by_bus, gen_attrs,
                                                                              p_marginal_slack_penalty,
                                                                              q_marginal_slack_penalty)

    ### declare the generator real and reactive power
    pg_init = {k: (gen_attrs['p_min'][k] + gen_attrs['p_max'][k]) / 2.0 for k in gen_attrs['pg']}
    libgen.declare_var_pg(model, gen_attrs['names'], initialize=pg_init,
                          bounds=zip_items(gen_attrs['p_min'], gen_attrs['p_max'])
                          )

    qg_init = {k: (gen_attrs['q_min'][k] + gen_attrs['q_max'][k]) / 2.0 for k in gen_attrs['qg']}
    libgen.declare_var_qg(model, gen_attrs['names'], initialize=qg_init,
                          bounds=zip_items(gen_attrs['q_min'], gen_attrs['q_max'])
                          )

    ### declare the current flows in the branches
    vr_init = {k: bus_attrs['vm'][k] * pe.cos(radians(bus_attrs['va'][k])) for k in bus_attrs['vm']}
    vj_init = {k: bus_attrs['vm'][k] * pe.sin(radians(bus_attrs['va'][k])) for k in bus_attrs['vm']}
    s_max = {k: branches[k]['rating_long_term'] for k in branches.keys()}
    s_lbub = dict()
    for k in branches.keys():
        if s_max[k] is None:
            s_lbub[k] = (None, None)
        else:
            s_lbub[k] = (-s_max[k],s_max[k])
    pf_bounds = s_lbub
    pt_bounds = s_lbub
    qf_bounds = s_lbub
    qt_bounds = s_lbub
    pf_init = dict()
    pt_init = dict()
    qf_init = dict()
    qt_init = dict()
    for branch_name, branch in branches.items():
        from_bus = branch['from_bus']
        to_bus = branch['to_bus']
        y_matrix = tx_calc.calculate_y_matrix_from_branch(branch)
        ifr_init = tx_calc.calculate_ifr(vr_init[from_bus], vj_init[from_bus], vr_init[to_bus],
                                         vj_init[to_bus], y_matrix)
        ifj_init = tx_calc.calculate_ifj(vr_init[from_bus], vj_init[from_bus], vr_init[to_bus],
                                         vj_init[to_bus], y_matrix)
        itr_init = tx_calc.calculate_itr(vr_init[from_bus], vj_init[from_bus], vr_init[to_bus],
                                         vj_init[to_bus], y_matrix)
        itj_init = tx_calc.calculate_itj(vr_init[from_bus], vj_init[from_bus], vr_init[to_bus],
                                         vj_init[to_bus], y_matrix)
        pf_init[branch_name] = tx_calc.calculate_p(ifr_init, ifj_init, vr_init[from_bus], vj_init[from_bus])
        pt_init[branch_name] = tx_calc.calculate_p(itr_init, itj_init, vr_init[to_bus], vj_init[to_bus])
        qf_init[branch_name] = tx_calc.calculate_q(ifr_init, ifj_init, vr_init[from_bus], vj_init[from_bus])
        qt_init[branch_name] = tx_calc.calculate_q(itr_init, itj_init, vr_init[to_bus], vj_init[to_bus])

    libbranch.declare_var_pf(model=model,
                             index_set=branch_attrs['names'],
                             initialize=pf_init,
                             bounds=pf_bounds
                             )
    libbranch.declare_var_pt(model=model,
                             index_set=branch_attrs['names'],
                             initialize=pt_init,
                             bounds=pt_bounds
                             )
    libbranch.declare_var_qf(model=model,
                             index_set=branch_attrs['names'],
                             initialize=qf_init,
                             bounds=qf_bounds
                             )
    libbranch.declare_var_qt(model=model,
                             index_set=branch_attrs['names'],
                             initialize=qt_init,
                             bounds=qt_bounds
                             )

    ### declare the branch power flow constraints
    libbranch.declare_eq_branch_power(model=model,
                                      index_set=branch_attrs['names'],
                                      branches=branches
                                      )

    ### declare the pq balances
    libbus.declare_eq_p_balance(model=model,
                                index_set=bus_attrs['names'],
                                bus_p_loads=bus_p_loads,
                                gens_by_bus=gens_by_bus,
                                bus_gs_fixed_shunts=bus_gs_fixed_shunts,
                                inlet_branches_by_bus=inlet_branches_by_bus,
                                outlet_branches_by_bus=outlet_branches_by_bus,
                                **p_rhs_kwargs
                                )

    libbus.declare_eq_q_balance(model=model,
                                index_set=bus_attrs['names'],
                                bus_q_loads=bus_q_loads,
                                gens_by_bus=gens_by_bus,
                                bus_bs_fixed_shunts=bus_bs_fixed_shunts,
                                inlet_branches_by_bus=inlet_branches_by_bus,
                                outlet_branches_by_bus=outlet_branches_by_bus,
                                **q_rhs_kwargs
                                )

    ### declare the thermal limits
    libbranch.declare_ineq_s_branch_thermal_limit(model=model,
                                                  index_set=branch_attrs['names'],
                                                  branches=branches,
                                                  s_thermal_limits=s_max,
                                                  flow_type=FlowType.POWER
                                                  )

    # declare angle difference limits on interconnected buses
    libbranch.declare_ineq_angle_diff_branch_lbub_c_s(model=model,
                                                      index_set=branch_attrs['names'],
                                                      branches=branches
                                                      )

    # declare the generator cost objective
    p_costs = gen_attrs['p_cost']
    pw_pg_cost_gens = list(libgen.pw_gen_generator(gen_attrs['names'], costs=p_costs))
    if len(pw_pg_cost_gens) > 0:
        if pw_cost_model == 'delta':
            libgen.declare_var_delta_pg(model=model, index_set=pw_pg_cost_gens, p_costs=p_costs)
            libgen.declare_pg_delta_pg_con(model=model, index_set=pw_pg_cost_gens, p_costs=p_costs)
        else:
            libgen.declare_var_pg_cost(model=model, index_set=pw_pg_cost_gens, p_costs=p_costs)
            libgen.declare_piecewise_pg_cost_cons(model=model, index_set=pw_pg_cost_gens, p_costs=p_costs)
    libgen.declare_expression_pg_operating_cost(model=model, index_set=gen_attrs['names'], p_costs=p_costs, pw_formulation=pw_cost_model)
    obj_expr = sum(model.pg_operating_cost[gen_name] for gen_name in model.pg_operating_cost)
    q_costs = gen_attrs.get('q_cost', None)
    if q_costs is not None:
        pw_qg_cost_gens = list(libgen.pw_gen_generator(gen_attrs['names'], costs=q_costs))
        if len(pw_qg_cost_gens) > 0:
            if pw_cost_model == 'delta':
                libgen.declare_var_delta_qg(model=model, index_set=pw_qg_cost_gens, q_costs=q_costs)
                libgen.declare_qg_delta_qg_con(model=model, index_set=pw_qg_cost_gens, q_costs=q_costs)
            else:
                libgen.declare_var_qg_cost(model=model, index_set=pw_qg_cost_gens, q_costs=q_costs)
                libgen.declare_piecewise_qg_cost_cons(model=model, index_set=pw_qg_cost_gens, q_costs=q_costs)
        libgen.declare_expression_qg_operating_cost(model=model, index_set=gen_attrs['names'], q_costs=q_costs, pw_formulation=pw_cost_model)
        obj_expr += sum(model.qg_operating_cost[gen_name] for gen_name in model.qg_operating_cost)

    if include_feasibility_slack:
        obj_expr += penalty_expr

    model.obj = pe.Objective(expr=obj_expr)

    return model, md
Example #12
0
def create_socp_acopf_model(model_data, include_feasibility_slack=False):
    md = model_data.clone_in_service()
    tx_utils.scale_ModelData_to_pu(md, inplace = True)

    gens = dict(md.elements(element_type='generator'))
    buses = dict(md.elements(element_type='bus'))
    branches = dict(md.elements(element_type='branch'))
    loads = dict(md.elements(element_type='load'))
    shunts = dict(md.elements(element_type='shunt'))

    gen_attrs = md.attributes(element_type='generator')
    bus_attrs = md.attributes(element_type='bus')
    branch_attrs = md.attributes(element_type='branch')
    load_attrs = md.attributes(element_type='load')
    shunt_attrs = md.attributes(element_type='shunt')

    inlet_branches_by_bus, outlet_branches_by_bus = \
        tx_utils.inlet_outlet_branches_by_bus(branches, buses)
    gens_by_bus = tx_utils.gens_by_bus(buses, gens)

    model = pe.ConcreteModel()

    ### declare (and fix) the loads at the buses
    bus_p_loads, bus_q_loads = tx_utils.dict_of_bus_loads(buses, loads)

    libbus.declare_var_pl(model, bus_attrs['names'], initialize=bus_p_loads)
    libbus.declare_var_ql(model, bus_attrs['names'], initialize=bus_q_loads)
    model.pl.fix()
    model.ql.fix()

    ### declare the fixed shunts at the buses
    bus_bs_fixed_shunts, bus_gs_fixed_shunts = tx_utils.dict_of_bus_fixed_shunts(buses, shunts)


    ### declare the rectangular voltages
    neg_v_max = map_items(op.neg, bus_attrs['v_max'])
    vr_init = {k: bus_attrs['vm'][k] * pe.cos(bus_attrs['va'][k]) for k in bus_attrs['vm']}
    # libbus.declare_var_vr(model, bus_attrs['names'], initialize=vr_init,
    #                       bounds=zip_items(neg_v_max, bus_attrs['v_max'])
    #                       )

    vj_init = {k: bus_attrs['vm'][k] * pe.sin(bus_attrs['va'][k]) for k in bus_attrs['vm']}
    # libbus.declare_var_vj(model, bus_attrs['names'], initialize=vj_init,
    #                       bounds=zip_items(neg_v_max, bus_attrs['v_max'])
    #                       )


    # w variable for socp
    vj2_init = {k: (bus_attrs['vm'][k] * pe.sin(bus_attrs['va'][k]))**2 for k in bus_attrs['vm']}
    vr2_init = {k: (bus_attrs['vm'][k] * pe.cos(bus_attrs['va'][k]))**2 for k in bus_attrs['vm']}
    w_init = {k: vr2_init[k]+vj2_init[k] for k in vj2_init}
    wub = {k:bus_attrs['v_max'][k]**2 for k in bus_attrs['v_max']}
    wlb = {k:bus_attrs['v_min'][k]**2 for k in bus_attrs['v_min']}
    ## v_min**2 <= w <= v_max**2
    libbus.declare_var_w(model, bus_attrs['names'], initialize = w_init, 
                        bounds =zip_items(wlb,wub))



    ### include the feasibility slack for the bus balances
    p_rhs_kwargs = {}
    q_rhs_kwargs = {}
    if include_feasibility_slack:
        p_rhs_kwargs, q_rhs_kwargs, penalty_expr = _include_feasibility_slack(model, bus_attrs, gen_attrs, bus_p_loads, bus_q_loads)

    ### fix the reference bus
    # ref_bus = md.data['system']['reference_bus']
    # ref_angle = md.data['system']['reference_bus_angle']
    # if ref_angle != 0.0:
    #     libbus.declare_eq_ref_bus_nonzero(model, ref_angle, ref_bus)
    # else:
    #     model.vj[ref_bus].fix(0.0)
    #     model.vr[ref_bus].setlb(0.0)

    ### declare the generator real and reactive power
    pg_init = {k: (gen_attrs['p_min'][k] + gen_attrs['p_max'][k]) / 2.0 for k in gen_attrs['pg']}
    libgen.declare_var_pg(model, gen_attrs['names'], initialize=pg_init,
                          bounds=zip_items(gen_attrs['p_min'], gen_attrs['p_max'])
                          )

    qg_init = {k: (gen_attrs['q_min'][k] + gen_attrs['q_max'][k]) / 2.0 for k in gen_attrs['qg']}
    libgen.declare_var_qg(model, gen_attrs['names'], initialize=qg_init,
                          bounds=zip_items(gen_attrs['q_min'], gen_attrs['q_max'])
                          )

    ### declare the current flows in the branches
    s_max = {k: branches[k]['rating_long_term'] for k in branches.keys()}
    s_lbub = dict()
    for k in branches.keys():
        if s_max[k] is None:
            s_lbub[k] = (None, None)
        else:
            s_lbub[k] = (-s_max[k],s_max[k])
    pf_bounds = s_lbub
    pt_bounds = s_lbub
    qf_bounds = s_lbub
    qt_bounds = s_lbub
    pf_init = dict()
    pt_init = dict()
    qf_init = dict()
    qt_init = dict()
    cbk_init = dict()
    sbk_init = dict()
    cbk_bounds = dict()
    sbk_bounds = dict()
    for branch_name, branch in branches.items():
        from_bus = branch['from_bus']
        to_bus = branch['to_bus']
        ba_max = branch['angle_diff_max']
        ba_min = branch['angle_diff_min']
        y_matrix = tx_calc.calculate_y_matrix_from_branch(branch)
        ifr_init = tx_calc.calculate_ifr(vr_init[from_bus], vj_init[from_bus], vr_init[to_bus],
                                         vj_init[to_bus], y_matrix)
        ifj_init = tx_calc.calculate_ifj(vr_init[from_bus], vj_init[from_bus], vr_init[to_bus],
                                         vj_init[to_bus], y_matrix)
        itr_init = tx_calc.calculate_itr(vr_init[from_bus], vj_init[from_bus], vr_init[to_bus],
                                         vj_init[to_bus], y_matrix)
        itj_init = tx_calc.calculate_itj(vr_init[from_bus], vj_init[from_bus], vr_init[to_bus],
                                         vj_init[to_bus], y_matrix)
        pf_init[branch_name] = tx_calc.calculate_p(ifr_init, ifj_init, vr_init[from_bus], vj_init[from_bus])
        pt_init[branch_name] = tx_calc.calculate_p(itr_init, itj_init, vr_init[to_bus], vj_init[to_bus])
        qf_init[branch_name] = tx_calc.calculate_q(ifr_init, ifj_init, vr_init[from_bus], vj_init[from_bus])
        qt_init[branch_name] = tx_calc.calculate_q(itr_init, itj_init, vr_init[to_bus], vj_init[to_bus])

        #SOCP related variable bounds and init
        cbk_init[from_bus,to_bus] = vr_init[from_bus]*vr_init[to_bus] + vj_init[from_bus]*vj_init[to_bus]
        sbk_init[from_bus,to_bus] = vr_init[from_bus]*vj_init[to_bus] - vr_init[to_bus]*vj_init[from_bus]

        if ba_max is None and ba_min is None:
          cbk_bounds[from_bus,to_bus] = ( bus_attrs['v_min'][from_bus]*bus_attrs['v_min'][to_bus]*min(pe.cos(-math.pi/2),pe.cos(math.pi/2)),
                                      bus_attrs['v_max'][from_bus]*bus_attrs['v_max'][to_bus]*1.0)
          sbk_bounds[from_bus,to_bus] = ( bus_attrs['v_max'][from_bus]*bus_attrs['v_max'][to_bus]*pe.sin(-math.pi/2),
                                      bus_attrs['v_max'][from_bus]*bus_attrs['v_max'][to_bus]*pe.sin(math.pi/2))
        if ba_max > 0 and ba_min < 0:
          cbk_bounds[from_bus,to_bus] = (bus_attrs['v_min'][from_bus]*bus_attrs['v_min'][to_bus]*min(pe.cos(ba_max * math.pi/180),pe.cos(ba_min * math.pi/180)),
                                      bus_attrs['v_max'][from_bus]*bus_attrs['v_max'][to_bus]*1.0)
          sbk_bounds[from_bus,to_bus] = ( bus_attrs['v_max'][from_bus]*bus_attrs['v_max'][to_bus]*pe.sin(ba_min * math.pi/180),
                                      bus_attrs['v_max'][from_bus]*bus_attrs['v_max'][to_bus]*pe.sin(math.pi/2))
        if ba_max <= 0:
          cbk_bounds[from_bus,to_bus] = (bus_attrs['v_min'][from_bus]*bus_attrs['v_min'][to_bus]*pe.cos(ba_min * math.pi/180),
                                      bus_attrs['v_max'][from_bus]*bus_attrs['v_max'][to_bus]*pe.cos(ba_max * math.pi/180))
          sbk_bounds[from_bus,to_bus] = ( bus_attrs['v_max'][from_bus]*bus_attrs['v_max'][to_bus]*pe.sin(ba_min * math.pi/180),
                                      bus_attrs['v_max'][from_bus]*bus_attrs['v_max'][to_bus]*pe.sin(math.pi/2))
        if ba_min >= 0:
          cbk_bounds[from_bus,to_bus] = (bus_attrs['v_min'][from_bus]*bus_attrs['v_min'][to_bus]*pe.cos(ba_max * math.pi/180),
                                      bus_attrs['v_max'][from_bus]*bus_attrs['v_max'][to_bus]*pe.cos(ba_min * math.pi/180))
          sbk_bounds[from_bus,to_bus] = ( bus_attrs['v_max'][from_bus]*bus_attrs['v_max'][to_bus]*pe.sin(ba_min * math.pi/180),
                                      bus_attrs['v_max'][from_bus]*bus_attrs['v_max'][to_bus]*pe.sin(math.pi/2))

    
    #print(bus_attrs)
    #print(branch_attrs)

    libbranch.declare_var_pf(model=model,
                             index_set=branch_attrs['names'],
                             initialize=pf_init,
                             bounds=pf_bounds
                             )
    libbranch.declare_var_pt(model=model,
                             index_set=branch_attrs['names'],
                             initialize=pt_init,
                             bounds=pt_bounds
                             )
    libbranch.declare_var_qf(model=model,
                             index_set=branch_attrs['names'],
                             initialize=qf_init,
                             bounds=qf_bounds
                             )
    libbranch.declare_var_qt(model=model,
                             index_set=branch_attrs['names'],
                             initialize=qt_init,
                             bounds=qt_bounds
                             )


    bus_pairs = zip_items(branch_attrs['from_bus'],branch_attrs['to_bus'])
    unique_bus_pairs = list(set([val for idx,val in bus_pairs.items()]))

    libbranch.declare_var_c(model = model,
                             index_set = unique_bus_pairs,
                             initialize = cbk_init,
                             bounds = cbk_bounds
                             )

    libbranch.declare_var_s(model = model,
                             index_set = unique_bus_pairs,
                             initialize = sbk_init,
                             bounds = sbk_bounds
                             )

    ### declare the branch power flow constraints
    libbranch.declare_eq_branch_power_socp(model=model,
                                      index_set=branch_attrs['names'],
                                      branches=branches,
                                      branch_attrs=branch_attrs,
                                      coordinate_type=CoordinateType.RECTANGULAR
                                      )

    ### declare the pq balances
    libbus.declare_eq_p_balance_socp(model=model,
                                index_set=bus_attrs['names'],
                                bus_p_loads=bus_p_loads,
                                gens_by_bus=gens_by_bus,
                                bus_gs_fixed_shunts=bus_gs_fixed_shunts,
                                inlet_branches_by_bus=inlet_branches_by_bus,
                                outlet_branches_by_bus=outlet_branches_by_bus,
                                coordinate_type=CoordinateType.RECTANGULAR,
                                **p_rhs_kwargs
                                )

    libbus.declare_eq_q_balance_socp(model=model,
                                index_set=bus_attrs['names'],
                                bus_q_loads=bus_q_loads,
                                gens_by_bus=gens_by_bus,
                                bus_bs_fixed_shunts=bus_bs_fixed_shunts,
                                inlet_branches_by_bus=inlet_branches_by_bus,
                                outlet_branches_by_bus=outlet_branches_by_bus,
                                coordinate_type=CoordinateType.RECTANGULAR,
                                **q_rhs_kwargs
                                )

    ### declare the thermal limits
    libbranch.declare_ineq_s_branch_thermal_limit(model=model,
                                                  index_set=branch_attrs['names'],
                                                  branches=branches,
                                                  s_thermal_limits=s_max,
                                                  flow_type=FlowType.POWER
                                                  )

    ### declare the voltage min and max inequalities
    # libbus.declare_ineq_vm_bus_lbub(model=model,
    #                                 index_set=bus_attrs['names'],
    #                                 buses=buses,
    #                                 coordinate_type=CoordinateType.RECTANGULAR
    #                                 )

    ### declare angle difference limits on interconnected buses
    # libbranch.declare_ineq_angle_diff_branch_lbub(model=model,
    #                                               index_set=branch_attrs['names'],
    #                                               branches=branches,
    #                                               coordinate_type=CoordinateType.RECTANGULAR
    #                                               )

    libbranch.declare_socp_scw(model = model, index_set = branch_attrs['names'],
                                 branches = branches, 
                                 branch_attrs = branch_attrs)

    ### declare the generator cost objective
    libgen.declare_expression_pgqg_operating_cost(model=model,
                                                  index_set=gen_attrs['names'],
                                                  p_costs=gen_attrs['p_cost'],
                                                  q_costs=gen_attrs.get('q_cost', None)
                                                  )

    obj_expr = sum(model.pg_operating_cost[gen_name] for gen_name in model.pg_operating_cost)
    if include_feasibility_slack:
        obj_expr += penalty_expr
    if hasattr(model, 'qg_operating_cost'):
        obj_expr += sum(model.qg_operating_cost[gen_name] for gen_name in model.qg_operating_cost)

    model.obj = pe.Objective(expr=obj_expr)

    return model, md
Example #13
0
def create_rsv_acopf_model(model_data):
    md = tx_utils.scale_ModelData_to_pu(model_data)

    gens = dict(md.elements(element_type='generator'))
    buses = dict(md.elements(element_type='bus'))
    branches = dict(md.elements(element_type='branch'))
    loads = dict(md.elements(element_type='load'))
    shunts = dict(md.elements(element_type='shunt'))

    gen_attrs = md.attributes(element_type='generator')
    bus_attrs = md.attributes(element_type='bus')
    branch_attrs = md.attributes(element_type='branch')
    load_attrs = md.attributes(element_type='load')
    shunt_attrs = md.attributes(element_type='shunt')

    inlet_branches_by_bus, outlet_branches_by_bus = \
        tx_utils.inlet_outlet_branches_by_bus(branches, buses)
    gens_by_bus = tx_utils.gens_in_service_by_bus(buses, gens)

    model = pe.ConcreteModel()

    ### declare (and fix) the loads at the buses
    bus_p_loads, bus_q_loads = tx_utils.dict_of_bus_loads(buses, loads)

    libbus.declare_var_pl(model, bus_attrs['names'], initialize=bus_p_loads)
    libbus.declare_var_ql(model, bus_attrs['names'], initialize=bus_q_loads)
    model.pl.fix()
    model.ql.fix()

    ### declare the fixed shunts at the buses
    bus_bs_fixed_shunts, bus_gs_fixed_shunts = tx_utils.dict_of_bus_fixed_shunts(
        buses, shunts)

    ### declare the rectangular voltages
    neg_v_max = map_items(op.neg, bus_attrs['v_max'])
    vr_init = {
        k: bus_attrs['vm'][k] * pe.cos(bus_attrs['va'][k])
        for k in bus_attrs['vm']
    }
    libbus.declare_var_vr(model,
                          bus_attrs['names'],
                          initialize=vr_init,
                          bounds=zip_items(neg_v_max, bus_attrs['v_max']))

    vj_init = {
        k: bus_attrs['vm'][k] * pe.sin(bus_attrs['va'][k])
        for k in bus_attrs['vm']
    }
    libbus.declare_var_vj(model,
                          bus_attrs['names'],
                          initialize=vj_init,
                          bounds=zip_items(neg_v_max, bus_attrs['v_max']))

    ### fix the reference bus
    ref_bus = md.data['system']['reference_bus']
    model.vj[ref_bus].fix(0.0)
    model.vr[ref_bus].setlb(0.0)

    ref_angle = md.data['system']['reference_bus_angle']
    if ref_angle != 0.0:
        raise ValueError('The RSV ACOPF formulation currently only supports'
                         ' a reference bus angle of 0 degrees, but an angle'
                         ' of {} degrees was found.'.format(ref_angle))

    ### declare the generator real and reactive power
    pg_init = {
        k: (gen_attrs['p_min'][k] + gen_attrs['p_max'][k]) / 2.0
        for k in gen_attrs['pg']
    }
    libgen.declare_var_pg(model,
                          gen_attrs['names'],
                          initialize=pg_init,
                          bounds=zip_items(gen_attrs['p_min'],
                                           gen_attrs['p_max']))

    qg_init = {
        k: (gen_attrs['q_min'][k] + gen_attrs['q_max'][k]) / 2.0
        for k in gen_attrs['qg']
    }
    libgen.declare_var_qg(model,
                          gen_attrs['names'],
                          initialize=qg_init,
                          bounds=zip_items(gen_attrs['q_min'],
                                           gen_attrs['q_max']))

    ### declare the current flows in the branches
    s_max = {k: branches[k]['rating_long_term'] for k in branches.keys()}
    s_lbub = {k: (-s_max[k], s_max[k]) for k in branches.keys()}
    pf_bounds = s_lbub
    pt_bounds = s_lbub
    qf_bounds = s_lbub
    qt_bounds = s_lbub
    pf_init = dict()
    pt_init = dict()
    qf_init = dict()
    qt_init = dict()
    for branch_name, branch in branches.items():
        from_bus = branch['from_bus']
        to_bus = branch['to_bus']
        y_matrix = tx_calc.calculate_y_matrix_from_branch(branch)
        ifr_init = tx_calc.calculate_ifr(vr_init[from_bus], vj_init[from_bus],
                                         vr_init[to_bus], vj_init[to_bus],
                                         y_matrix)
        ifj_init = tx_calc.calculate_ifj(vr_init[from_bus], vj_init[from_bus],
                                         vr_init[to_bus], vj_init[to_bus],
                                         y_matrix)
        itr_init = tx_calc.calculate_itr(vr_init[from_bus], vj_init[from_bus],
                                         vr_init[to_bus], vj_init[to_bus],
                                         y_matrix)
        itj_init = tx_calc.calculate_itj(vr_init[from_bus], vj_init[from_bus],
                                         vr_init[to_bus], vj_init[to_bus],
                                         y_matrix)
        pf_init[branch_name] = tx_calc.calculate_p(ifr_init, ifj_init,
                                                   vr_init[from_bus],
                                                   vj_init[from_bus])
        pt_init[branch_name] = tx_calc.calculate_p(itr_init, itj_init,
                                                   vr_init[to_bus],
                                                   vj_init[to_bus])
        qf_init[branch_name] = tx_calc.calculate_q(ifr_init, ifj_init,
                                                   vr_init[from_bus],
                                                   vj_init[from_bus])
        qt_init[branch_name] = tx_calc.calculate_q(itr_init, itj_init,
                                                   vr_init[to_bus],
                                                   vj_init[to_bus])

    libbranch.declare_var_pf(model=model,
                             index_set=branch_attrs['names'],
                             initialize=pf_init,
                             bounds=pf_bounds)
    libbranch.declare_var_pt(model=model,
                             index_set=branch_attrs['names'],
                             initialize=pt_init,
                             bounds=pt_bounds)
    libbranch.declare_var_qf(model=model,
                             index_set=branch_attrs['names'],
                             initialize=qf_init,
                             bounds=qf_bounds)
    libbranch.declare_var_qt(model=model,
                             index_set=branch_attrs['names'],
                             initialize=qt_init,
                             bounds=qt_bounds)

    ### declare the branch power flow constraints
    libbranch.declare_eq_branch_power(
        model=model,
        index_set=branch_attrs['names'],
        branches=branches,
        branch_attrs=branch_attrs,
        coordinate_type=CoordinateType.RECTANGULAR)

    ### declare the pq balances
    libbus.declare_eq_p_balance(model=model,
                                index_set=bus_attrs['names'],
                                bus_p_loads=bus_p_loads,
                                gens_by_bus=gens_by_bus,
                                bus_gs_fixed_shunts=bus_gs_fixed_shunts,
                                inlet_branches_by_bus=inlet_branches_by_bus,
                                outlet_branches_by_bus=outlet_branches_by_bus,
                                coordinate_type=CoordinateType.RECTANGULAR)

    libbus.declare_eq_q_balance(model=model,
                                index_set=bus_attrs['names'],
                                bus_q_loads=bus_q_loads,
                                gens_by_bus=gens_by_bus,
                                bus_bs_fixed_shunts=bus_bs_fixed_shunts,
                                inlet_branches_by_bus=inlet_branches_by_bus,
                                outlet_branches_by_bus=outlet_branches_by_bus,
                                coordinate_type=CoordinateType.RECTANGULAR)

    ### declare the thermal limits
    libbranch.declare_ineq_s_branch_thermal_limit(
        model=model,
        index_set=branch_attrs['names'],
        branches=branches,
        s_thermal_limits=s_max,
        flow_type=FlowType.POWER)

    ### declare the voltage min and max inequalities
    libbus.declare_ineq_vm_bus_lbub(model=model,
                                    index_set=bus_attrs['names'],
                                    buses=buses,
                                    coordinate_type=CoordinateType.RECTANGULAR)

    ### declare angle difference limits on interconnected buses
    libbranch.declare_ineq_angle_diff_branch_lbub(
        model=model,
        index_set=branch_attrs['names'],
        branches=branches,
        coordinate_type=CoordinateType.RECTANGULAR)

    ### declare the generator cost objective
    libgen.declare_expression_pgqg_operating_cost(model=model,
                                                  index_set=gen_attrs['names'],
                                                  p_costs=gen_attrs['p_cost'],
                                                  q_costs=gen_attrs.get(
                                                      'q_cost', None))

    obj_expr = sum(model.pg_operating_cost[gen_name]
                   for gen_name in model.pg_operating_cost)
    if hasattr(model, 'qg_operating_cost'):
        obj_expr += sum(model.qg_operating_cost[gen_name]
                        for gen_name in model.qg_operating_cost)

    model.obj = pe.Objective(expr=obj_expr)

    return model
Example #14
0
def create_btheta_dcopf_model(model_data, include_angle_diff_limits=False, include_feasibility_slack=False, pw_cost_model='delta'):
    md = model_data.clone_in_service()
    tx_utils.scale_ModelData_to_pu(md, inplace = True)

    gens = dict(md.elements(element_type='generator'))
    buses = dict(md.elements(element_type='bus'))
    branches = dict(md.elements(element_type='branch'))
    loads = dict(md.elements(element_type='load'))
    shunts = dict(md.elements(element_type='shunt'))

    dc_branches = dict(md.elements(element_type='dc_branch'))

    gen_attrs = md.attributes(element_type='generator')
    bus_attrs = md.attributes(element_type='bus')
    branch_attrs = md.attributes(element_type='branch')

    inlet_branches_by_bus, outlet_branches_by_bus = \
        tx_utils.inlet_outlet_branches_by_bus(branches, buses)
    gens_by_bus = tx_utils.gens_by_bus(buses, gens)

    model = pe.ConcreteModel()

    ### declare (and fix) the loads at the buses
    bus_p_loads, _ = tx_utils.dict_of_bus_loads(buses, loads)

    libbus.declare_var_pl(model, bus_attrs['names'], initialize=bus_p_loads)
    model.pl.fix()

    ### declare the fixed shunts at the buses
    _, bus_gs_fixed_shunts = tx_utils.dict_of_bus_fixed_shunts(buses, shunts)

    ### declare the polar voltages
    va_bounds = {k: (-pi, pi) for k in bus_attrs['va']}
    libbus.declare_var_va(model, bus_attrs['names'],
                          initialize=tx_utils.radians_from_degrees_dict(bus_attrs['va']),
                          bounds=va_bounds
                          )

    ### include the feasibility slack for the bus balances
    p_rhs_kwargs = {}
    penalty_expr = None
    if include_feasibility_slack:
        p_marginal_slack_penalty = _validate_and_extract_slack_penalty(md)        
        p_rhs_kwargs, penalty_expr = _include_feasibility_slack(model, bus_attrs['names'], bus_p_loads,
                                                                gens_by_bus, gen_attrs, p_marginal_slack_penalty)

    ### fix the reference bus
    ref_bus = md.data['system']['reference_bus']
    ref_angle = md.data['system']['reference_bus_angle']
    model.va[ref_bus].fix(radians(ref_angle))

    ### declare the generator real power
    pg_init = {k: (gen_attrs['p_min'][k] + gen_attrs['p_max'][k]) / 2.0 for k in gen_attrs['pg']}
    libgen.declare_var_pg(model, gen_attrs['names'], initialize=pg_init,
                          bounds=zip_items(gen_attrs['p_min'], gen_attrs['p_max'])
                          )

    ### declare the current flows in the branches
    vr_init = {k: bus_attrs['vm'][k] * pe.cos(radians(bus_attrs['va'][k])) for k in bus_attrs['vm']}
    vj_init = {k: bus_attrs['vm'][k] * pe.sin(radians(bus_attrs['va'][k])) for k in bus_attrs['vm']}
    p_max = {k: branches[k]['rating_long_term'] for k in branches.keys()}
    p_lbub = dict()
    for k in branches.keys():
        k_pmax = p_max[k]
        if k_pmax is None:
            p_lbub[k] = (None, None)
        else:
            p_lbub[k] = (-k_pmax,k_pmax)
    pf_bounds = p_lbub
    pf_init = dict()
    for branch_name, branch in branches.items():
        from_bus = branch['from_bus']
        to_bus = branch['to_bus']
        y_matrix = tx_calc.calculate_y_matrix_from_branch(branch)
        ifr_init = tx_calc.calculate_ifr(vr_init[from_bus], vj_init[from_bus], vr_init[to_bus],
                                         vj_init[to_bus], y_matrix)
        ifj_init = tx_calc.calculate_ifj(vr_init[from_bus], vj_init[from_bus], vr_init[to_bus],
                                         vj_init[to_bus], y_matrix)
        pf_init[branch_name] = tx_calc.calculate_p(ifr_init, ifj_init, vr_init[from_bus], vj_init[from_bus])

    libbranch.declare_var_pf(model=model,
                             index_set=branch_attrs['names'],
                             initialize=pf_init,
                             bounds=pf_bounds
                             )

    if dc_branches:
        dcpf_bounds = dict()
        for k, k_dict in dc_branches.items():
            kp_max = k_dict['rating_long_term']
            if kp_max is None:
                dcpf_bounds[k] = (None, None)
            else:
                dcpf_bounds[k] = (-kp_max, kp_max)
        libbranch.declare_var_dcpf(model=model,
                                   index_set=dc_branches.keys(),
                                   initialize=0.,
                                   bounds=dcpf_bounds,
                                  )
        dc_inlet_branches_by_bus, dc_outlet_branches_by_bus = \
                tx_utils.inlet_outlet_branches_by_bus(dc_branches, buses)
    else:
        dc_inlet_branches_by_bus = None
        dc_outlet_branches_by_bus = None


    ### declare the branch power flow approximation constraints
    libbranch.declare_eq_branch_power_btheta_approx(model=model,
                                                    index_set=branch_attrs['names'],
                                                    branches=branches
                                                    )

    ### declare the p balance
    libbus.declare_eq_p_balance_dc_approx(model=model,
                                          index_set=bus_attrs['names'],
                                          bus_p_loads=bus_p_loads,
                                          gens_by_bus=gens_by_bus,
                                          bus_gs_fixed_shunts=bus_gs_fixed_shunts,
                                          inlet_branches_by_bus=inlet_branches_by_bus,
                                          outlet_branches_by_bus=outlet_branches_by_bus,
                                          approximation_type=ApproximationType.BTHETA,
                                          dc_inlet_branches_by_bus=dc_inlet_branches_by_bus,
                                          dc_outlet_branches_by_bus=dc_outlet_branches_by_bus,
                                          **p_rhs_kwargs
                                          )

    ### declare the real power flow limits
    libbranch.declare_ineq_p_branch_thermal_lbub(model=model,
                                                 index_set=branch_attrs['names'],
                                                 branches=branches,
                                                 p_thermal_limits=p_max,
                                                 approximation_type=ApproximationType.BTHETA
                                                 )

    ### declare angle difference limits on interconnected buses
    if include_angle_diff_limits:
        libbranch.declare_ineq_angle_diff_branch_lbub(model=model,
                                                      index_set=branch_attrs['names'],
                                                      branches=branches,
                                                      coordinate_type=CoordinateType.POLAR
                                                      )

    # declare the generator cost objective
    p_costs = gen_attrs['p_cost']
    pw_pg_cost_gens = list(libgen.pw_gen_generator(gen_attrs['names'], costs=p_costs))
    if len(pw_pg_cost_gens) > 0:
        if pw_cost_model == 'delta':
            libgen.declare_var_delta_pg(model=model, index_set=pw_pg_cost_gens, p_costs=p_costs)
            libgen.declare_pg_delta_pg_con(model=model, index_set=pw_pg_cost_gens, p_costs=p_costs)
        else:
            libgen.declare_var_pg_cost(model=model, index_set=pw_pg_cost_gens, p_costs=p_costs)
            libgen.declare_piecewise_pg_cost_cons(model=model, index_set=pw_pg_cost_gens, p_costs=p_costs)
    libgen.declare_expression_pg_operating_cost(model=model, index_set=gen_attrs['names'], p_costs=p_costs, pw_formulation=pw_cost_model)
    obj_expr = sum(model.pg_operating_cost[gen_name] for gen_name in model.pg_operating_cost)

    if include_feasibility_slack:
        obj_expr += penalty_expr

    model.obj = pe.Objective(expr=obj_expr)

    return model, md
Example #15
0
def _create_base_relaxation(model_data):
    md = model_data.clone_in_service()
    tx_utils.scale_ModelData_to_pu(md, inplace=True)

    gens = dict(md.elements(element_type='generator'))
    buses = dict(md.elements(element_type='bus'))
    branches = dict(md.elements(element_type='branch'))
    loads = dict(md.elements(element_type='load'))
    shunts = dict(md.elements(element_type='shunt'))

    gen_attrs = md.attributes(element_type='generator')
    bus_attrs = md.attributes(element_type='bus')
    branch_attrs = md.attributes(element_type='branch')

    inlet_branches_by_bus, outlet_branches_by_bus = \
        tx_utils.inlet_outlet_branches_by_bus(branches, buses)
    gens_by_bus = tx_utils.gens_by_bus(buses, gens)

    bus_pairs = zip_items(branch_attrs['from_bus'], branch_attrs['to_bus'])
    unique_bus_pairs = list(
        OrderedDict((val, None) for idx, val in bus_pairs.items()))

    model = pe.ConcreteModel()

    ### declare (and fix) the loads at the buses
    bus_p_loads, bus_q_loads = tx_utils.dict_of_bus_loads(buses, loads)

    libbus.declare_var_pl(model, bus_attrs['names'], initialize=bus_p_loads)
    libbus.declare_var_ql(model, bus_attrs['names'], initialize=bus_q_loads)
    model.pl.fix()
    model.ql.fix()

    ### declare the fixed shunts at the buses
    bus_bs_fixed_shunts, bus_gs_fixed_shunts = tx_utils.dict_of_bus_fixed_shunts(
        buses, shunts)

    libbus.declare_var_vmsq(
        model=model,
        index_set=bus_attrs['names'],
        initialize={k: v**2
                    for k, v in bus_attrs['vm'].items()},
        bounds=zip_items({k: v**2
                          for k, v in bus_attrs['v_min'].items()},
                         {k: v**2
                          for k, v in bus_attrs['v_max'].items()}))
    libbranch.declare_var_c(model=model, index_set=unique_bus_pairs)
    libbranch.declare_var_s(model=model, index_set=unique_bus_pairs)

    ### declare the generator real and reactive power
    pg_init = {
        k: (gen_attrs['p_min'][k] + gen_attrs['p_max'][k]) / 2.0
        for k in gen_attrs['pg']
    }
    libgen.declare_var_pg(model,
                          gen_attrs['names'],
                          initialize=pg_init,
                          bounds=zip_items(gen_attrs['p_min'],
                                           gen_attrs['p_max']))

    qg_init = {
        k: (gen_attrs['q_min'][k] + gen_attrs['q_max'][k]) / 2.0
        for k in gen_attrs['qg']
    }
    libgen.declare_var_qg(model,
                          gen_attrs['names'],
                          initialize=qg_init,
                          bounds=zip_items(gen_attrs['q_min'],
                                           gen_attrs['q_max']))

    ### declare the current flows in the branches
    vr_init = {
        k: bus_attrs['vm'][k] * pe.cos(bus_attrs['va'][k])
        for k in bus_attrs['vm']
    }
    vj_init = {
        k: bus_attrs['vm'][k] * pe.sin(bus_attrs['va'][k])
        for k in bus_attrs['vm']
    }
    s_max = {k: branches[k]['rating_long_term'] for k in branches.keys()}
    s_lbub = dict()
    for k in branches.keys():
        if s_max[k] is None:
            s_lbub[k] = (None, None)
        else:
            s_lbub[k] = (-s_max[k], s_max[k])
    pf_bounds = s_lbub
    pt_bounds = s_lbub
    qf_bounds = s_lbub
    qt_bounds = s_lbub
    pf_init = dict()
    pt_init = dict()
    qf_init = dict()
    qt_init = dict()
    for branch_name, branch in branches.items():
        from_bus = branch['from_bus']
        to_bus = branch['to_bus']
        y_matrix = tx_calc.calculate_y_matrix_from_branch(branch)
        ifr_init = tx_calc.calculate_ifr(vr_init[from_bus], vj_init[from_bus],
                                         vr_init[to_bus], vj_init[to_bus],
                                         y_matrix)
        ifj_init = tx_calc.calculate_ifj(vr_init[from_bus], vj_init[from_bus],
                                         vr_init[to_bus], vj_init[to_bus],
                                         y_matrix)
        itr_init = tx_calc.calculate_itr(vr_init[from_bus], vj_init[from_bus],
                                         vr_init[to_bus], vj_init[to_bus],
                                         y_matrix)
        itj_init = tx_calc.calculate_itj(vr_init[from_bus], vj_init[from_bus],
                                         vr_init[to_bus], vj_init[to_bus],
                                         y_matrix)
        pf_init[branch_name] = tx_calc.calculate_p(ifr_init, ifj_init,
                                                   vr_init[from_bus],
                                                   vj_init[from_bus])
        pt_init[branch_name] = tx_calc.calculate_p(itr_init, itj_init,
                                                   vr_init[to_bus],
                                                   vj_init[to_bus])
        qf_init[branch_name] = tx_calc.calculate_q(ifr_init, ifj_init,
                                                   vr_init[from_bus],
                                                   vj_init[from_bus])
        qt_init[branch_name] = tx_calc.calculate_q(itr_init, itj_init,
                                                   vr_init[to_bus],
                                                   vj_init[to_bus])

    libbranch.declare_var_pf(model=model,
                             index_set=branch_attrs['names'],
                             initialize=pf_init,
                             bounds=pf_bounds)
    libbranch.declare_var_pt(model=model,
                             index_set=branch_attrs['names'],
                             initialize=pt_init,
                             bounds=pt_bounds)
    libbranch.declare_var_qf(model=model,
                             index_set=branch_attrs['names'],
                             initialize=qf_init,
                             bounds=qf_bounds)
    libbranch.declare_var_qt(model=model,
                             index_set=branch_attrs['names'],
                             initialize=qt_init,
                             bounds=qt_bounds)

    ### declare the branch power flow constraints
    libbranch.declare_eq_branch_power(model=model,
                                      index_set=branch_attrs['names'],
                                      branches=branches)

    ### declare the pq balances
    libbus.declare_eq_p_balance(model=model,
                                index_set=bus_attrs['names'],
                                bus_p_loads=bus_p_loads,
                                gens_by_bus=gens_by_bus,
                                bus_gs_fixed_shunts=bus_gs_fixed_shunts,
                                inlet_branches_by_bus=inlet_branches_by_bus,
                                outlet_branches_by_bus=outlet_branches_by_bus)

    libbus.declare_eq_q_balance(model=model,
                                index_set=bus_attrs['names'],
                                bus_q_loads=bus_q_loads,
                                gens_by_bus=gens_by_bus,
                                bus_bs_fixed_shunts=bus_bs_fixed_shunts,
                                inlet_branches_by_bus=inlet_branches_by_bus,
                                outlet_branches_by_bus=outlet_branches_by_bus)

    ### declare the thermal limits
    libbranch.declare_ineq_s_branch_thermal_limit(
        model=model,
        index_set=branch_attrs['names'],
        branches=branches,
        s_thermal_limits=s_max,
        flow_type=FlowType.POWER)

    ### declare the generator cost objective
    libgen.declare_expression_pgqg_operating_cost(model=model,
                                                  index_set=gen_attrs['names'],
                                                  p_costs=gen_attrs['p_cost'],
                                                  q_costs=gen_attrs.get(
                                                      'q_cost', None))

    obj_expr = sum(model.pg_operating_cost[gen_name]
                   for gen_name in model.pg_operating_cost)
    if hasattr(model, 'qg_operating_cost'):
        obj_expr += sum(model.qg_operating_cost[gen_name]
                        for gen_name in model.qg_operating_cost)

    model.obj = pe.Objective(expr=obj_expr)

    return model, md
Example #16
0
def create_hot_start_lpac_model(model_data,
                                voltages,
                                lower_bound=-pi / 3,
                                upper_bound=pi / 3,
                                cosine_segment_count=20,
                                include_feasibility_slack=False,
                                mode="uniform"):
    """
	The hot start LPAC model assumes that voltages are known, e.g. from an AC base point solution.
	"""
    ###Grid data
    md = model_data.clone_in_service()
    tx_utils.scale_ModelData_to_pu(md, inplace=True)

    gens = dict(md.elements(element_type='generator'))
    buses = dict(md.elements(element_type='bus'))
    branches = dict(md.elements(element_type='branch'))
    loads = dict(md.elements(element_type='load'))
    shunts = dict(md.elements(element_type='shunt'))

    gen_attrs = md.attributes(element_type='generator')
    bus_attrs = md.attributes(element_type='bus')
    branch_attrs = md.attributes(element_type='branch')

    inlet_branches_by_bus, outlet_branches_by_bus = \
           tx_utils.inlet_outlet_branches_by_bus(branches, buses)

    gens_by_bus = tx_utils.gens_by_bus(buses, gens)

    model = pe.ConcreteModel()

    ###declare (and fix) the voltage magnitudes and squares of voltage magnitudes

    bus_voltage_magnitudes = voltages  #Assumes voltages is given as a dictionary
    libbus.declare_var_vm(model,
                          bus_attrs['names'],
                          initialize=bus_voltage_magnitudes)
    model.vm.fix()

    libbus.declare_var_vmsq(
        model=model,
        index_set=bus_attrs['names'],
        initialize={k: v**2
                    for k, v in bus_attrs['vm'].items()},
        bounds=zip_items({k: v**2
                          for k, v in bus_attrs['v_min'].items()},
                         {k: v**2
                          for k, v in bus_attrs['v_max'].items()}))

    ### declare the polar voltages

    libbus.declare_var_va(model,
                          bus_attrs['names'],
                          initialize=bus_attrs['va'])

    ### declare the cosine approximation variables
    cos_hat_bounds = {k: (0, 1) for k in branch_attrs['names']}
    decl.declare_var('cos_hat',
                     model,
                     branch_attrs['names'],
                     bounds=cos_hat_bounds)

    ### fix the reference bus
    ref_bus = md.data['system']['reference_bus']
    #ref_angle = md.data['system']['reference_bus_angle']
    model.va[ref_bus].fix(radians(0.0))

    ### declare the fixed shunts at the buses
    bus_bs_fixed_shunts, bus_gs_fixed_shunts = tx_utils.dict_of_bus_fixed_shunts(
        buses, shunts)

    ### declare (and fix) the loads at the buses
    bus_p_loads, bus_q_loads = tx_utils.dict_of_bus_loads(buses, loads)

    libbus.declare_var_pl(model, bus_attrs['names'], initialize=bus_p_loads)
    libbus.declare_var_ql(model, bus_attrs['names'], initialize=bus_q_loads)
    model.pl.fix()
    model.ql.fix()

    ### include the feasibility slack for the bus balances
    p_rhs_kwargs = {}
    q_rhs_kwargs = {}
    if include_feasibility_slack:
        p_rhs_kwargs, q_rhs_kwargs, penalty_expr = _include_feasibility_slack(
            model, bus_attrs, gen_attrs, bus_p_loads, bus_q_loads)

### declare the generator real and reactive power
    pg_init = {
        k: (gen_attrs['p_min'][k] + gen_attrs['p_max'][k]) / 2.0
        for k in gen_attrs['pg']
    }
    libgen.declare_var_pg(model,
                          gen_attrs['names'],
                          initialize=pg_init,
                          bounds=zip_items(gen_attrs['p_min'],
                                           gen_attrs['p_max']))

    qg_init = {
        k: (gen_attrs['q_min'][k] + gen_attrs['q_max'][k]) / 2.0
        for k in gen_attrs['qg']
    }
    libgen.declare_var_qg(model,
                          gen_attrs['names'],
                          initialize=qg_init,
                          bounds=zip_items(gen_attrs['q_min'],
                                           gen_attrs['q_max']))

    ### declare the current flows in the branches
    vr_init = {
        k: bus_attrs['vm'][k] * pe.cos(bus_attrs['va'][k])
        for k in bus_attrs['vm']
    }
    vj_init = {
        k: bus_attrs['vm'][k] * pe.sin(bus_attrs['va'][k])
        for k in bus_attrs['vm']
    }
    s_max = {k: branches[k]['rating_long_term'] for k in branches.keys()}
    s_lbub = dict()
    for k in branches.keys():
        if s_max[k] is None:
            s_lbub[k] = (None, None)
        else:
            s_lbub[k] = (-s_max[k], s_max[k])
    pf_bounds = s_lbub
    pt_bounds = s_lbub
    qf_bounds = s_lbub
    qt_bounds = s_lbub
    pf_init = dict()
    pt_init = dict()
    qf_init = dict()
    qt_init = dict()
    for branch_name, branch in branches.items():
        from_bus = branch['from_bus']
        to_bus = branch['to_bus']
        y_matrix = tx_calc.calculate_y_matrix_from_branch(branch)
        ifr_init = tx_calc.calculate_ifr(vr_init[from_bus], vj_init[from_bus],
                                         vr_init[to_bus], vj_init[to_bus],
                                         y_matrix)
        ifj_init = tx_calc.calculate_ifj(vr_init[from_bus], vj_init[from_bus],
                                         vr_init[to_bus], vj_init[to_bus],
                                         y_matrix)
        itr_init = tx_calc.calculate_itr(vr_init[from_bus], vj_init[from_bus],
                                         vr_init[to_bus], vj_init[to_bus],
                                         y_matrix)
        itj_init = tx_calc.calculate_itj(vr_init[from_bus], vj_init[from_bus],
                                         vr_init[to_bus], vj_init[to_bus],
                                         y_matrix)
        pf_init[branch_name] = tx_calc.calculate_p(ifr_init, ifj_init,
                                                   vr_init[from_bus],
                                                   vj_init[from_bus])
        pt_init[branch_name] = tx_calc.calculate_p(itr_init, itj_init,
                                                   vr_init[to_bus],
                                                   vj_init[to_bus])
        qf_init[branch_name] = tx_calc.calculate_q(ifr_init, ifj_init,
                                                   vr_init[from_bus],
                                                   vj_init[from_bus])
        qt_init[branch_name] = tx_calc.calculate_q(itr_init, itj_init,
                                                   vr_init[to_bus],
                                                   vj_init[to_bus])

    libbranch.declare_var_pf(model=model,
                             index_set=branch_attrs['names'],
                             initialize=pf_init,
                             bounds=pf_bounds)
    libbranch.declare_var_pt(model=model,
                             index_set=branch_attrs['names'],
                             initialize=pt_init,
                             bounds=pt_bounds)
    libbranch.declare_var_qf(model=model,
                             index_set=branch_attrs['names'],
                             initialize=qf_init,
                             bounds=qf_bounds)
    libbranch.declare_var_qt(model=model,
                             index_set=branch_attrs['names'],
                             initialize=qt_init,
                             bounds=qt_bounds)

    ####################
    #Constraints
    ####################

    ###Balance equations in a bus

    #p balance

    libbus.declare_eq_p_balance(model=model,
                                index_set=bus_attrs['names'],
                                bus_p_loads=bus_p_loads,
                                gens_by_bus=gens_by_bus,
                                bus_gs_fixed_shunts=bus_gs_fixed_shunts,
                                inlet_branches_by_bus=inlet_branches_by_bus,
                                outlet_branches_by_bus=outlet_branches_by_bus,
                                **p_rhs_kwargs)

    #q balance

    libbus.declare_eq_q_balance(model=model,
                                index_set=bus_attrs['names'],
                                bus_q_loads=bus_q_loads,
                                gens_by_bus=gens_by_bus,
                                bus_bs_fixed_shunts=bus_bs_fixed_shunts,
                                inlet_branches_by_bus=inlet_branches_by_bus,
                                outlet_branches_by_bus=outlet_branches_by_bus,
                                **q_rhs_kwargs)

    ### Power in a branch

    branch_con_set = decl.declare_set('_con_eq_p_q_lpac_branch_power', model,
                                      branch_attrs['names'])

    model.eq_pf_branch_t = pe.Constraint(branch_con_set)
    model.eq_pt_branch_t = pe.Constraint(branch_con_set)
    model.eq_qf_branch_t = pe.Constraint(branch_con_set)
    model.eq_qt_branch_t = pe.Constraint(branch_con_set)

    for branch_name in branch_con_set:
        branch = branches[branch_name]

        from_bus = branch['from_bus']
        to_bus = branch['to_bus']

        g = tx_calc.calculate_conductance(branch)
        b = tx_calc.calculate_susceptance(branch)

        model.eq_pf_branch_t[branch_name] = \
         model.pf[branch_name] == \
         g*model.vmsq[from_bus] - model.vm[from_bus]*model.vm[to_bus]*(g * model.cos_hat[branch_name] + b * (model.va[from_bus] - model.va[to_bus]))

        model.eq_pt_branch_t[branch_name] = \
         model.pt[branch_name] == \
         g*model.vmsq[to_bus] - model.vm[from_bus]*model.vm[to_bus]*(g * model.cos_hat[branch_name] + b * (model.va[to_bus] - model.va[from_bus]))

        model.eq_qf_branch_t[branch_name] = \
         model.qf[branch_name] == \
         -b*model.vmsq[from_bus] - model.vm[from_bus]*model.vm[to_bus]*(g*(model.va[from_bus] - model.va[to_bus]) - b*model.cos_hat[branch_name])

        model.eq_qt_branch_t[branch_name] = \
         model.qt[branch_name] == \
         -b*model.vmsq[to_bus] - model.vm[from_bus]*model.vm[to_bus]*(g*(model.va[to_bus] - model.va[from_bus]) - b*model.cos_hat[branch_name])

### Piecewise linear cosine constraints

    model.N = pe.Set(initialize=list(range(cosine_segment_count + 1)))

    declare_pwl_cosine_bounds(model=model,
                              index_set=branch_attrs['names'],
                              branches=branches,
                              lower_bound=lower_bound,
                              upper_bound=upper_bound,
                              cosine_segment_count=cosine_segment_count,
                              mode=mode)

    ### Objective is to maximize cosine hat variables

    obj_expr = sum(model.cos_hat[branch_name]
                   for branch_name in branch_attrs['names'])

    if include_feasibility_slack:
        obj_expr += penalty_expr

    model.obj = pe.Objective(expr=obj_expr)

    return model, md
Example #17
0
def create_btheta_losses_dcopf_model(model_data, relaxation_type=RelaxationType.SOC, include_angle_diff_limits=False, include_feasibility_slack=False):
    md = model_data.clone_in_service()
    tx_utils.scale_ModelData_to_pu(md, inplace = True)

    gens = dict(md.elements(element_type='generator'))
    buses = dict(md.elements(element_type='bus'))
    branches = dict(md.elements(element_type='branch'))
    loads = dict(md.elements(element_type='load'))
    shunts = dict(md.elements(element_type='shunt'))

    gen_attrs = md.attributes(element_type='generator')
    bus_attrs = md.attributes(element_type='bus')
    branch_attrs = md.attributes(element_type='branch')
    load_attrs = md.attributes(element_type='load')
    shunt_attrs = md.attributes(element_type='shunt')

    inlet_branches_by_bus, outlet_branches_by_bus = \
        tx_utils.inlet_outlet_branches_by_bus(branches, buses)
    gens_by_bus = tx_utils.gens_by_bus(buses, gens)

    model = pe.ConcreteModel()

    ### declare (and fix) the loads at the buses
    bus_p_loads, _ = tx_utils.dict_of_bus_loads(buses, loads)

    libbus.declare_var_pl(model, bus_attrs['names'], initialize=bus_p_loads)
    model.pl.fix()

    ### declare the fixed shunts at the buses
    _, bus_gs_fixed_shunts = tx_utils.dict_of_bus_fixed_shunts(buses, shunts)

    ### declare the polar voltages
    va_bounds = {k: (-pi, pi) for k in bus_attrs['va']}
    libbus.declare_var_va(model, bus_attrs['names'], initialize=bus_attrs['va'],
                          bounds=va_bounds
                          )

    dva_initialize = {k: 0.0 for k in branch_attrs['names']}
    libbranch.declare_var_dva(model, branch_attrs['names'],
                              initialize=dva_initialize
                              )

    ### include the feasibility slack for the bus balances
    p_rhs_kwargs = {}
    penalty_expr = None
    if include_feasibility_slack:
        p_rhs_kwargs, penalty_expr = _include_feasibility_slack(model, bus_attrs, gen_attrs, bus_p_loads)

    ### fix the reference bus
    ref_bus = md.data['system']['reference_bus']
    ref_angle = md.data['system']['reference_bus_angle']
    model.va[ref_bus].fix(radians(ref_angle))

    ### declare the generator real power
    pg_init = {k: (gen_attrs['p_min'][k] + gen_attrs['p_max'][k]) / 2.0 for k in gen_attrs['pg']}
    libgen.declare_var_pg(model, gen_attrs['names'], initialize=pg_init,
                          bounds=zip_items(gen_attrs['p_min'], gen_attrs['p_max'])
                          )

    ### declare the current flows in the branches
    vr_init = {k: bus_attrs['vm'][k] * pe.cos(bus_attrs['va'][k]) for k in bus_attrs['vm']}
    vj_init = {k: bus_attrs['vm'][k] * pe.sin(bus_attrs['va'][k]) for k in bus_attrs['vm']}
    p_max = {k: branches[k]['rating_long_term'] for k in branches.keys()}
    pf_bounds = {k: (-p_max[k],p_max[k]) for k in branches.keys()}
    pf_init = dict()
    for branch_name, branch in branches.items():
        from_bus = branch['from_bus']
        to_bus = branch['to_bus']
        y_matrix = tx_calc.calculate_y_matrix_from_branch(branch)
        ifr_init = tx_calc.calculate_ifr(vr_init[from_bus], vj_init[from_bus], vr_init[to_bus],
                                         vj_init[to_bus], y_matrix)
        ifj_init = tx_calc.calculate_ifj(vr_init[from_bus], vj_init[from_bus], vr_init[to_bus],
                                         vj_init[to_bus], y_matrix)
        pf_init[branch_name] = tx_calc.calculate_p(ifr_init, ifj_init, vr_init[from_bus], vj_init[from_bus])
    pfl_bounds = {k: (0,p_max[k]**2) for k in branches.keys()}
    pfl_init = {k: 0 for k in branches.keys()}

    libbranch.declare_var_pf(model=model,
                             index_set=branch_attrs['names'],
                             initialize=pf_init,
                             bounds=pf_bounds
                             )

    libbranch.declare_var_pfl(model=model,
                              index_set=branch_attrs['names'],
                              initialize=pfl_init,
                              bounds=pfl_bounds
                             )

    ### declare the angle difference constraint
    libbranch.declare_eq_branch_dva(model=model,
                                    index_set=branch_attrs['names'],
                                    branches=branches
                                    )

    ### declare the branch power flow approximation constraints
    libbranch.declare_eq_branch_power_btheta_approx(model=model,
                                                    index_set=branch_attrs['names'],
                                                    branches=branches,
                                                    approximation_type=ApproximationType.BTHETA_LOSSES
                                                    )

    ### declare the branch power loss approximation constraints
    libbranch.declare_eq_branch_loss_btheta_approx(model=model,
                                                    index_set=branch_attrs['names'],
                                                    branches=branches,
                                                    relaxation_type=relaxation_type
                                                    )

    ### declare the p balance
    libbus.declare_eq_p_balance_dc_approx(model=model,
                                          index_set=bus_attrs['names'],
                                          bus_p_loads=bus_p_loads,
                                          gens_by_bus=gens_by_bus,
                                          bus_gs_fixed_shunts=bus_gs_fixed_shunts,
                                          inlet_branches_by_bus=inlet_branches_by_bus,
                                          outlet_branches_by_bus=outlet_branches_by_bus,
                                          approximation_type=ApproximationType.BTHETA_LOSSES,
                                          **p_rhs_kwargs
                                          )

    ### declare the real power flow limits
    libbranch.declare_ineq_p_branch_thermal_lbub(model=model,
                                                 index_set=branch_attrs['names'],
                                                 branches=branches,
                                                 p_thermal_limits=p_max,
                                                 approximation_type=ApproximationType.BTHETA
                                                 )

    ### declare angle difference limits on interconnected buses
    if include_angle_diff_limits:
        libbranch.declare_ineq_angle_diff_branch_lbub(model=model,
                                                      index_set=branch_attrs['names'],
                                                      branches=branches,
                                                      coordinate_type=CoordinateType.POLAR
                                                      )

    ### declare the generator cost objective
    libgen.declare_expression_pgqg_operating_cost(model=model,
                                                  index_set=gen_attrs['names'],
                                                  p_costs=gen_attrs['p_cost']
                                                  )

    obj_expr = sum(model.pg_operating_cost[gen_name] for gen_name in model.pg_operating_cost)
    if include_feasibility_slack:
        obj_expr += penalty_expr

    model.obj = pe.Objective(expr=obj_expr)

    return model, md
Example #18
0
def _create_base_ac_with_pwl_approx_model(model_data, branch_dict, Q, include_feasibility_slack=False):
    md = model_data.clone_in_service()
    tx_utils.scale_ModelData_to_pu(md, inplace = True)

    gens = dict(md.elements(element_type='generator'))
    buses = dict(md.elements(element_type='bus'))
    branches = dict(md.elements(element_type='branch'))
    loads = dict(md.elements(element_type='load'))
    shunts = dict(md.elements(element_type='shunt'))

    gen_attrs = md.attributes(element_type='generator')
    bus_attrs = md.attributes(element_type='bus')
    branch_attrs = md.attributes(element_type='branch')

    inlet_branches_by_bus, outlet_branches_by_bus = \
        tx_utils.inlet_outlet_branches_by_bus(branches, buses)
    gens_by_bus = tx_utils.gens_by_bus(buses, gens)

    bus_pairs = zip_items(branch_attrs['from_bus'], branch_attrs['to_bus'])
    unique_bus_pairs = list(OrderedDict((val, None) for idx, val in bus_pairs.items()))

    model = pe.ConcreteModel()

    ### declare (and fix) the loads at the buses
    bus_p_loads, bus_q_loads = tx_utils.dict_of_bus_loads(buses, loads)

    libbus.declare_var_pl(model, bus_attrs['names'], initialize=bus_p_loads)
    libbus.declare_var_ql(model, bus_attrs['names'], initialize=bus_q_loads)
    model.pl.fix()
    model.ql.fix()

    ### declare the fixed shunts at the buses
    bus_bs_fixed_shunts, bus_gs_fixed_shunts = tx_utils.dict_of_bus_fixed_shunts(buses, shunts)

    libbus.declare_var_vm(model=model, index_set=bus_attrs['names'], initialize=bus_attrs['vm'], bounds=zip_items(bus_attrs['v_min'], bus_attrs['v_max']))

    libbus.declare_var_vmsq(model=model,
                            index_set=bus_attrs['names'],
                            initialize={k: v**2 for k, v in bus_attrs['vm'].items()},
                            bounds=zip_items({k: v**2 for k, v in bus_attrs['v_min'].items()},
                                             {k: v**2 for k, v in bus_attrs['v_max'].items()}))
    # libbranch.declare_var_c(model=model, index_set=unique_bus_pairs)
    # libbranch.declare_var_s(model=model, index_set=unique_bus_pairs)

    ### declare the polar voltages
    va_bounds = {k: (-math.pi, math.pi) for k in bus_attrs['va']}
    libbus.declare_var_va(model, bus_attrs['names'], initialize=bus_attrs['va'],
                          bounds=va_bounds
                          )

    ###declare the phase angle differences in each branch
    libbranch.declare_var_dva(model, index_set=unique_bus_pairs)

    libbranch.declare_eq_delta_va(model, index_set=unique_bus_pairs)

    ### include the feasibility slack for the bus balances
    p_rhs_kwargs = {}
    q_rhs_kwargs = {}
    if include_feasibility_slack:
        p_rhs_kwargs, q_rhs_kwargs, penalty_expr = _include_feasibility_slack(model, bus_attrs, gen_attrs, bus_p_loads, bus_q_loads)

    ### declare the generator real and reactive power
    pg_init = {k: (gen_attrs['p_min'][k] + gen_attrs['p_max'][k]) / 2.0 for k in gen_attrs['pg']}
    libgen.declare_var_pg(model, gen_attrs['names'], initialize=pg_init,
                          bounds=zip_items(gen_attrs['p_min'], gen_attrs['p_max'])
                          )

    qg_init = {k: (gen_attrs['q_min'][k] + gen_attrs['q_max'][k]) / 2.0 for k in gen_attrs['qg']}
    libgen.declare_var_qg(model, gen_attrs['names'], initialize=qg_init,
                          bounds=zip_items(gen_attrs['q_min'], gen_attrs['q_max'])
                          )

    ### declare the current flows in the branches
    vr_init = {k: bus_attrs['vm'][k] * pe.cos(bus_attrs['va'][k]) for k in bus_attrs['vm']}
    vj_init = {k: bus_attrs['vm'][k] * pe.sin(bus_attrs['va'][k]) for k in bus_attrs['vm']}
    s_max = {k: branches[k]['rating_long_term'] for k in branches.keys()}
    s_lbub = dict()
    for k in branches.keys():
        if s_max[k] is None:
            s_lbub[k] = (None, None)
        else:
            s_lbub[k] = (-s_max[k],s_max[k])
    pf_bounds = s_lbub
    pt_bounds = s_lbub
    qf_bounds = s_lbub
    qt_bounds = s_lbub
    pf_init = dict()
    pt_init = dict()
    qf_init = dict()
    qt_init = dict()
    for branch_name, branch in branches.items():
        from_bus = branch['from_bus']
        to_bus = branch['to_bus']
        y_matrix = tx_calc.calculate_y_matrix_from_branch(branch)
        ifr_init = tx_calc.calculate_ifr(vr_init[from_bus], vj_init[from_bus], vr_init[to_bus],
                                         vj_init[to_bus], y_matrix)
        ifj_init = tx_calc.calculate_ifj(vr_init[from_bus], vj_init[from_bus], vr_init[to_bus],
                                         vj_init[to_bus], y_matrix)
        itr_init = tx_calc.calculate_itr(vr_init[from_bus], vj_init[from_bus], vr_init[to_bus],
                                         vj_init[to_bus], y_matrix)
        itj_init = tx_calc.calculate_itj(vr_init[from_bus], vj_init[from_bus], vr_init[to_bus],
                                         vj_init[to_bus], y_matrix)
        pf_init[branch_name] = tx_calc.calculate_p(ifr_init, ifj_init, vr_init[from_bus], vj_init[from_bus])
        pt_init[branch_name] = tx_calc.calculate_p(itr_init, itj_init, vr_init[to_bus], vj_init[to_bus])
        qf_init[branch_name] = tx_calc.calculate_q(ifr_init, ifj_init, vr_init[from_bus], vj_init[from_bus])
        qt_init[branch_name] = tx_calc.calculate_q(itr_init, itj_init, vr_init[to_bus], vj_init[to_bus])

    libbranch.declare_var_pf(model=model,
                             index_set=branch_attrs['names'],
                             initialize=pf_init,
                             bounds=pf_bounds
                             )
    libbranch.declare_var_pt(model=model,
                             index_set=branch_attrs['names'],
                             initialize=pt_init,
                             bounds=pt_bounds
                             )
    libbranch.declare_var_qf(model=model,
                             index_set=branch_attrs['names'],
                             initialize=qf_init,
                             bounds=qf_bounds
                             )
    libbranch.declare_var_qt(model=model,
                             index_set=branch_attrs['names'],
                             initialize=qt_init,
                             bounds=qt_bounds
                             )

    ### declare the branch power flow constraints



    ### declare a binary on/off variable for deenergizing a given branch

    decl.declare_var('u', model=model, index_set=branch_attrs['names'], within=pe.Binary)

    model.u.fix(1)

    branch_name_set = decl.declare_set('branch_name', model=model, index_set=branch_attrs['names'])

    model.box_index_set = pe.RangeSet(Q)

    model.power_type_set = pe.Set(initialize=[0,1])
    #Note: 0 is for power_type == "Active"; 1 is for power_type=="Reactive"

    #For active power energization/deenergization
    model.u_branch = pe.Var(branch_name_set, model.box_index_set, model.power_type_set, within=pe.Binary)

    #For selecting the appropriate interval of the PWL approximation
    model.dva_branch = pe.Var(branch_name_set, model.box_index_set, model.power_type_set)

    #(5) - Constraints for the on/off variable u

    def u_sum_rule(model, branch_name, j):
    	return model.u[branch_name] == sum(model.u_branch[branch_name, i, j] for i in model.box_index_set)

    model.u_sum_Constr = pe.Constraint(branch_name_set, model.power_type_set, rule=u_sum_rule)


    #(6) - Constraints that sum of dva variables should be equal to total dva

    #Upper bound constraints

    def delta_branch_ub_rule(model, branch_name, j):
    	branch = branches[branch_name]

    	from_bus = branch['from_bus']
    	to_bus = branch['to_bus']

    	return -model.dva[(from_bus, to_bus)] + sum(model.dva_branch[branch_name, i, j] for i in model.box_index_set) <= math.pi*(1-model.u[branch_name])

    model.delta_branch_ub_Constr = pe.Constraint(branch_name_set, model.power_type_set, rule=delta_branch_ub_rule)

    #Lower bound constraints

    def delta_branch_lb_rule(model, branch_name, j):
    	branch = branches[branch_name]

    	from_bus = branch['from_bus']
    	to_bus = branch['to_bus']

    	return -model.dva[(from_bus, to_bus)] + sum(model.dva_branch[branch_name, i, j] for i in model.box_index_set) >= -math.pi*(1-model.u[branch_name])

    model.delta_branch_lb_Constr = pe.Constraint(branch_name_set, model.power_type_set, rule=delta_branch_lb_rule)

    #(7) - Constraints that force dva variable to be in only one interval

    #Upper bound

    def delta_branch_box_ub_rule(model, branch_name, i, j):
    	if j==0:
    		delta_ub = branch_dict["Active_from_bus"][branch_name]['boxes']['coords'][i-1][7][2]
    	else:
    		delta_ub = branch_dict["Reactive_from_bus"][branch_name]['boxes']['coords'][i-1][7][2]
    	return model.dva_branch[branch_name, i, j] <= delta_ub*model.u_branch[branch_name, i, j]

    model.delta_branch_box_ub_Constr = pe.Constraint(branch_name_set, model.box_index_set, model.power_type_set, rule=delta_branch_box_ub_rule)

    def delta_branch_box_lb_rule(model, branch_name, i, j):
    	if j==0:
    		delta_lb = branch_dict["Active_from_bus"][branch_name]['boxes']['coords'][i-1][0][2]
    	else:
    		delta_lb = branch_dict["Reactive_from_bus"][branch_name]['boxes']['coords'][i-1][0][2]
    	return model.dva_branch[branch_name, i, j] >= delta_lb*model.u_branch[branch_name, i, j]

    model.delta_branch_box_lb_Constr = pe.Constraint(branch_name_set, model.box_index_set, model.power_type_set, rule=delta_branch_box_lb_rule)

    #(8) - Approximating power flow equation by PWL approximation



    #Active_from_bus
    def pwl_active_from_ub_rule(model, branch_name, i):
    	branch = branches[branch_name]

    	from_bus = branch['from_bus']
    	to_bus = branch['to_bus']

    	g = tx_calc.calculate_conductance(branch)
    	b = tx_calc.calculate_susceptance(branch)
    	coeffs = branch_dict["Active_from_bus"][branch_name]['boxes']['coefficients'][i-1]
    	#M = 10*(g+b) + 4*(coeffs[0]+coeffs[1]+coeffs[2]+coeffs[3])
    	M = 2*s_max[branch_name] + 10*(np.abs(coeffs[0])+np.abs(coeffs[1])+np.abs(coeffs[2])+np.abs(coeffs[3]))
    	return -model.pf[branch_name] + coeffs[0]*model.vm[from_bus] + coeffs[1]*model.vm[to_bus] + coeffs[2]*model.dva_branch[branch_name, i, 0] + coeffs[3] <= M*(1-model.u_branch[branch_name, i, 0])

    model.pwl_active_from_ub_Constr = pe.Constraint(branch_name_set, model.box_index_set, rule=pwl_active_from_ub_rule)

    def pwl_active_from_lb_rule(model, branch_name, i):
    	branch = branches[branch_name]

    	from_bus = branch['from_bus']
    	to_bus = branch['to_bus']

    	g = tx_calc.calculate_conductance(branch)
    	b = tx_calc.calculate_susceptance(branch)

    	coeffs = branch_dict["Active_from_bus"][branch_name]['boxes']['coefficients'][i-1]
    	#M = -(10*(g+b) + 4*(coeffs[0]+coeffs[1]+coeffs[2]+coeffs[3]))
    	M = -2*s_max[branch_name] - 10*(np.abs(coeffs[0])+np.abs(coeffs[1])+np.abs(coeffs[2])+np.abs(coeffs[3]))
    	return -model.pf[branch_name] + coeffs[0]*model.vm[from_bus] + coeffs[1]*model.vm[to_bus] + coeffs[2]*model.dva_branch[branch_name, i, 0] + coeffs[3] >= M*(1-model.u_branch[branch_name, i, 0])

    model.pwl_active_from_lb_Constr = pe.Constraint(branch_name_set, model.box_index_set, rule=pwl_active_from_lb_rule)

    #Active_to_bus
    def pwl_active_to_ub_rule(model, branch_name, i):
    	branch = branches[branch_name]

    	from_bus = branch['from_bus']
    	to_bus = branch['to_bus']

    	g = tx_calc.calculate_conductance(branch)
    	b = tx_calc.calculate_susceptance(branch)

    	coeffs = branch_dict["Active_to_bus"][branch_name]['boxes']['coefficients'][i-1]
    	#M = 10*(g+b) + 4*(coeffs[0]+coeffs[1]+coeffs[2]+coeffs[3])
    	M = 2*s_max[branch_name] + 10*(np.abs(coeffs[0])+np.abs(coeffs[1])+np.abs(coeffs[2])+np.abs(coeffs[3]))
    	return -model.pt[branch_name] + coeffs[0]*model.vm[from_bus] + coeffs[1]*model.vm[to_bus] + coeffs[2]*model.dva_branch[branch_name, i, 0] + coeffs[3] <= M*(1-model.u_branch[branch_name, i, 0])

    model.pwl_active_to_ub_Constr = pe.Constraint(branch_name_set, model.box_index_set, rule=pwl_active_to_ub_rule)

    def pwl_active_to_lb_rule(model, branch_name, i):
    	branch = branches[branch_name]

    	from_bus = branch['from_bus']
    	to_bus = branch['to_bus']

    	g = tx_calc.calculate_conductance(branch)
    	b = tx_calc.calculate_susceptance(branch)

    	coeffs = branch_dict["Active_to_bus"][branch_name]['boxes']['coefficients'][i-1]
    	#M = -(10*(g+b) + 4*(coeffs[0]+coeffs[1]+coeffs[2]+coeffs[3]))
    	M = -2*s_max[branch_name] - 10*(np.abs(coeffs[0])+np.abs(coeffs[1])+np.abs(coeffs[2])+np.abs(coeffs[3]))
    	return -model.pt[branch_name] + coeffs[0]*model.vm[from_bus] + coeffs[1]*model.vm[to_bus] + coeffs[2]*model.dva_branch[branch_name, i, 0] + coeffs[3] >= M*(1-model.u_branch[branch_name, i, 0])

    model.pwl_active_to_lb_Constr = pe.Constraint(branch_name_set, model.box_index_set, rule=pwl_active_to_lb_rule)

    #Reactive_from_bus

    def pwl_reactive_from_ub_rule(model, branch_name, i):
    	branch = branches[branch_name]

    	from_bus = branch['from_bus']
    	to_bus = branch['to_bus']

    	g = tx_calc.calculate_conductance(branch)
    	b = tx_calc.calculate_susceptance(branch)

    	coeffs = branch_dict["Reactive_from_bus"][branch_name]['boxes']['coefficients'][i-1]
    	#M = 10*(g+b) + 4*(coeffs[0]+coeffs[1]+coeffs[2]+coeffs[3])
    	M = 2*s_max[branch_name] + 10*(np.abs(coeffs[0])+np.abs(coeffs[1])+np.abs(coeffs[2])+np.abs(coeffs[3]))
    	return -model.qf[branch_name] + coeffs[0]*model.vm[from_bus] + coeffs[1]*model.vm[to_bus] + coeffs[2]*model.dva_branch[branch_name, i, 1] + coeffs[3] <= M*(1-model.u_branch[branch_name, i, 1])

    model.pwl_reactive_from_ub_Constr = pe.Constraint(branch_name_set, model.box_index_set, rule=pwl_reactive_from_ub_rule)

    def pwl_reactive_from_lb_rule(model, branch_name, i):
    	branch = branches[branch_name]

    	from_bus = branch['from_bus']
    	to_bus = branch['to_bus']

    	g = tx_calc.calculate_conductance(branch)
    	b = tx_calc.calculate_susceptance(branch)

    	coeffs = branch_dict["Reactive_from_bus"][branch_name]['boxes']['coefficients'][i-1]
    	#M = -(10*(g+b) + 4*(coeffs[0]+coeffs[1]+coeffs[2]+coeffs[3]))
    	M = -2*s_max[branch_name] - 10*(np.abs(coeffs[0])+np.abs(coeffs[1])+np.abs(coeffs[2])+np.abs(coeffs[3]))
    	return -model.qf[branch_name] + coeffs[0]*model.vm[from_bus] + coeffs[1]*model.vm[to_bus] + coeffs[2]*model.dva_branch[branch_name, i, 1] + coeffs[3] >= M*(1-model.u_branch[branch_name, i, 1])

    model.pwl_reactive_from_lb_Constr = pe.Constraint(branch_name_set, model.box_index_set, rule=pwl_reactive_from_lb_rule)

    #Reactive_to_bus

    def pwl_reactive_to_ub_rule(model, branch_name, i):
    	branch = branches[branch_name]

    	from_bus = branch['from_bus']
    	to_bus = branch['to_bus']

    	g = tx_calc.calculate_conductance(branch)
    	b = tx_calc.calculate_susceptance(branch)

    	coeffs = branch_dict["Reactive_to_bus"][branch_name]['boxes']['coefficients'][i-1]
    	#M = 10*(g+b) + 4*(coeffs[0]+coeffs[1]+coeffs[2]+coeffs[3])
    	M = 2*s_max[branch_name] + 10*(np.abs(coeffs[0])+np.abs(coeffs[1])+np.abs(coeffs[2])+np.abs(coeffs[3]))
    	return -model.qt[branch_name] + coeffs[0]*model.vm[from_bus] + coeffs[1]*model.vm[to_bus] + coeffs[2]*model.dva_branch[branch_name, i, 1] + coeffs[3] <= M*(1-model.u_branch[branch_name, i, 1])

    model.pwl_reactive_to_ub_Constr = pe.Constraint(branch_name_set, model.box_index_set, rule=pwl_reactive_to_ub_rule)

    def pwl_reactive_to_lb_rule(model, branch_name, i):
    	branch = branches[branch_name]

    	from_bus = branch['from_bus']
    	to_bus = branch['to_bus']

    	g = tx_calc.calculate_conductance(branch)
    	b = tx_calc.calculate_susceptance(branch)

    	coeffs = branch_dict["Reactive_to_bus"][branch_name]['boxes']['coefficients'][i-1]
    	#M = -(10*(g+b) + 4*(coeffs[0]+coeffs[1]+coeffs[2]+coeffs[3]))
    	M = -2*s_max[branch_name] - 10*(np.abs(coeffs[0])+np.abs(coeffs[1])+np.abs(coeffs[2])+np.abs(coeffs[3]))
    	return -model.qt[branch_name] + coeffs[0]*model.vm[from_bus] + coeffs[1]*model.vm[to_bus] + coeffs[2]*model.dva_branch[branch_name, i, 1] + coeffs[3] >= M*(1-model.u_branch[branch_name, i, 1])

    model.pwl_reactive_to_lb_Constr = pe.Constraint(branch_name_set, model.box_index_set, rule=pwl_reactive_to_lb_rule)

    
    ### declare the pq balances
    libbus.declare_eq_p_balance(model=model,
                                index_set=bus_attrs['names'],
                                bus_p_loads=bus_p_loads,
                                gens_by_bus=gens_by_bus,
                                bus_gs_fixed_shunts=bus_gs_fixed_shunts,
                                inlet_branches_by_bus=inlet_branches_by_bus,
                                outlet_branches_by_bus=outlet_branches_by_bus,
                                **p_rhs_kwargs
                                )

    libbus.declare_eq_q_balance(model=model,
                                index_set=bus_attrs['names'],
                                bus_q_loads=bus_q_loads,
                                gens_by_bus=gens_by_bus,
                                bus_bs_fixed_shunts=bus_bs_fixed_shunts,
                                inlet_branches_by_bus=inlet_branches_by_bus,
                                outlet_branches_by_bus=outlet_branches_by_bus,
                                **q_rhs_kwargs
                                )

    ### declare the thermal limits
    libbranch.declare_ineq_s_branch_thermal_limit(model=model,
                                                  index_set=branch_attrs['names'],
                                                  branches=branches,
                                                  s_thermal_limits=s_max,
                                                  flow_type=FlowType.POWER
                                                  )

    # declare angle difference limits on interconnected buses
    # libbranch.declare_ineq_angle_diff_branch_lbub_c_s(model=model,
    #                                                   index_set=branch_attrs['names'],
    #                                                   branches=branches
    #                                                   )

    ### declare the generator cost objective
    libgen.declare_expression_pgqg_operating_cost(model=model,
                                                  index_set=gen_attrs['names'],
                                                  p_costs=gen_attrs['p_cost'],
                                                  q_costs=gen_attrs.get('q_cost', None)
                                                  )

    obj_expr = sum(model.pg_operating_cost[gen_name] for gen_name in model.pg_operating_cost)
    if include_feasibility_slack:
        obj_expr += penalty_expr
    if hasattr(model, 'qg_operating_cost'):
        obj_expr += sum(model.qg_operating_cost[gen_name] for gen_name in model.qg_operating_cost)

    model.obj = pe.Objective(expr=obj_expr)

    return model, md