Example #1
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 #2
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 #3
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 #4
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 #5
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 #6
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