Exemple #1
0
    def admmopf_hessfcn(self, x=None, lmbda=None):
        if x is None:
            x = self.pb['x0']
        if lmbda is None:  # multiplier for power flow constraints
            lmbda = {'eqnonlin': 3000 * ones(2 * len(self.idx['rbus']['int']))}
            # lmbda = {'eqnonlin': 3000 * ones(2 * self.region['nb'])}
        nx = len(x)
        nb = self.region['nb']
        ng = self.region['ng']
        rho = self.var['rho']
        Ybus = self.region['Ybus']
        iv = self.idx['var']
        iVa = iv['iVa']
        iVm = iv['iVm']
        # reconstruct V
        Va, Vm = x[iVa], x[iVm]
        V = Vm * exp(1j * Va)
        # ---- evaluate Hessian of f ----------
        Adiff = self.mtx['Adiff']
        Asum = self.mtx['Asum']
        d2f_dVm2 = d2f_dVa2 = Adiff.T.dot(Adiff) * rho + Asum.T.dot(Asum) * rho
        data = self.region['gencost'][:, COST] * 2
        i = arange(0, ng)
        d2f_dPgQg2 = sparse((data, (i, i)), (2 * ng, 2 * ng))
        blankv = sparse((nb, nb))
        d2f_dV2 = vstack(
            [hstack([d2f_dVa2, blankv]),
             hstack([blankv, d2f_dVm2])], 'csr')
        blankvp = sparse((2 * nb, 2 * ng))
        d2f = vstack(
            [hstack([d2f_dV2, blankvp]),
             hstack([blankvp.T, d2f_dPgQg2])], 'csr')

        # ---- evaluate Hessian of power flow constraints ------
        nlam = len(lmbda["eqnonlin"]) // 2
        lamP = zeros(nb)  #for non-included pf balances use 0 as multiplier
        lamQ = zeros(nb)
        lamP[self.idx['rbus']['int']] = lmbda["eqnonlin"][:nlam]
        lamQ[self.idx['rbus']['int']] = lmbda["eqnonlin"][nlam:nlam + nlam]
        # lamP = lmbda["eqnonlin"][:nlam]
        # lamQ = lmbda["eqnonlin"][nlam:nlam + nlam]
        Gpaa, Gpav, Gpva, Gpvv = d2Sbus_dV2(Ybus, V, lamP)
        Gqaa, Gqav, Gqva, Gqvv = d2Sbus_dV2(Ybus, V, lamQ)

        d2G = vstack([
            hstack([
                vstack([hstack([Gpaa, Gpav]),
                        hstack([Gpva, Gpvv])]).real +
                vstack([hstack([Gqaa, Gqav]),
                        hstack([Gqva, Gqvv])]).imag,
                sparse((2 * nb, 2 * ng))
            ]),
            hstack([sparse((2 * ng, 2 * nb)),
                    sparse((2 * ng, 2 * ng))])
        ], 'csr')

        return d2f + d2G
Exemple #2
0
def opf_hessfcn(x, lmbda, om, Ybus, Yf, Yt, ppopt, il=None, cost_mult=1.0):
    """Evaluates Hessian of Lagrangian for AC OPF.

    Hessian evaluation function for AC optimal power flow, suitable
    for use with L{pips}.

    Examples::
        Lxx = opf_hessfcn(x, lmbda, om, Ybus, Yf, Yt, ppopt)
        Lxx = opf_hessfcn(x, lmbda, om, Ybus, Yf, Yt, ppopt, il)
        Lxx = opf_hessfcn(x, lmbda, om, Ybus, Yf, Yt, ppopt, il, cost_mult)

    @param x: optimization vector
    @param lmbda: C{eqnonlin} - Lagrange multipliers on power balance
    equations. C{ineqnonlin} - Kuhn-Tucker multipliers on constrained
    branch flows.
    @param om: OPF model object
    @param Ybus: bus admittance matrix
    @param Yf: admittance matrix for "from" end of constrained branches
    @param Yt: admittance matrix for "to" end of constrained branches
    @param ppopt: PYPOWER options vector
    @param il: (optional) vector of branch indices corresponding to
    branches with flow limits (all others are assumed to be unconstrained).
    The default is C{range(nl)} (all branches). C{Yf} and C{Yt} contain
    only the rows corresponding to C{il}.
    @param cost_mult: (optional) Scale factor to be applied to the cost
    (default = 1).

    @return: Hessian of the Lagrangian.

    @see: L{opf_costfcn}, L{opf_consfcn}

    @author: Ray Zimmerman (PSERC Cornell)
    @author: Carlos E. Murillo-Sanchez (PSERC Cornell & Universidad
    Autonoma de Manizales)
    """
    ##----- initialize -----
    ## unpack data
    ppc = om.get_ppc()
    baseMVA, bus, gen, branch, gencost = \
        ppc["baseMVA"], ppc["bus"], ppc["gen"], ppc["branch"], ppc["gencost"]
    cp = om.get_cost_params()
    N, Cw, H, dd, rh, kk, mm = \
        cp["N"], cp["Cw"], cp["H"], cp["dd"], cp["rh"], cp["kk"], cp["mm"]
    vv, _, _, _ = om.get_idx()

    ## unpack needed parameters
    nb = bus.shape[0]  ## number of buses
    nl = branch.shape[0]  ## number of branches
    ng = gen.shape[0]  ## number of dispatchable injections
    nxyz = len(x)  ## total number of control vars of all types

    ## set default constrained lines
    if il is None:
        il = arange(nl)  ## all lines have limits by default
    nl2 = len(il)  ## number of constrained lines

    ## grab Pg & Qg
    Pg = x[vv["i1"]["Pg"]:vv["iN"]["Pg"]]  ## active generation in p.u.
    Qg = x[vv["i1"]["Qg"]:vv["iN"]["Qg"]]  ## reactive generation in p.u.

    ## put Pg & Qg back in gen
    gen[:, PG] = Pg * baseMVA  ## active generation in MW
    gen[:, QG] = Qg * baseMVA  ## reactive generation in MVAr

    ## reconstruct V
    Va = x[vv["i1"]["Va"]:vv["iN"]["Va"]]
    Vm = x[vv["i1"]["Vm"]:vv["iN"]["Vm"]]
    V = Vm * exp(1j * Va)
    nxtra = nxyz - 2 * nb
    pcost = gencost[arange(ng), :]
    if gencost.shape[0] > ng:
        qcost = gencost[arange(ng, 2 * ng), :]
    else:
        qcost = array([])

    ## ----- evaluate d2f -----
    d2f_dPg2 = zeros(ng)  #sparse((ng, 1))               ## w.r.t. p.u. Pg
    d2f_dQg2 = zeros(ng)  #sparse((ng, 1))               ## w.r.t. p.u. Qg
    ipolp = find(pcost[:, MODEL] == POLYNOMIAL)
    d2f_dPg2[ipolp] = \
            baseMVA**2 * polycost(pcost[ipolp, :], Pg[ipolp] * baseMVA, 2)
    if any(qcost):  ## Qg is not free
        ipolq = find(qcost[:, MODEL] == POLYNOMIAL)
        d2f_dQg2[ipolq] = \
                baseMVA**2 * polycost(qcost[ipolq, :], Qg[ipolq] * baseMVA, 2)
    i = r_[arange(vv["i1"]["Pg"], vv["iN"]["Pg"]),
           arange(vv["i1"]["Qg"], vv["iN"]["Qg"])]
    #    d2f = sparse((vstack([d2f_dPg2, d2f_dQg2]).toarray().flatten(),
    #                  (i, i)), shape=(nxyz, nxyz))
    d2f = sparse((r_[d2f_dPg2, d2f_dQg2], (i, i)), (nxyz, nxyz))

    ## generalized cost
    if issparse(N) and N.nnz > 0:
        nw = N.shape[0]
        r = N * x - rh  ## Nx - rhat
        iLT = find(r < -kk)  ## below dead zone
        iEQ = find((r == 0) & (kk == 0))  ## dead zone doesn't exist
        iGT = find(r > kk)  ## above dead zone
        iND = r_[iLT, iEQ, iGT]  ## rows that are Not in the Dead region
        iL = find(dd == 1)  ## rows using linear function
        iQ = find(dd == 2)  ## rows using quadratic function
        LL = sparse((ones(len(iL)), (iL, iL)), (nw, nw))
        QQ = sparse((ones(len(iQ)), (iQ, iQ)), (nw, nw))
        kbar = sparse((r_[ones(len(iLT)),
                          zeros(len(iEQ)), -ones(len(iGT))], (iND, iND)),
                      (nw, nw)) * kk
        rr = r + kbar  ## apply non-dead zone shift
        M = sparse((mm[iND], (iND, iND)), (nw, nw))  ## dead zone or scale
        diagrr = sparse((rr, (arange(nw), arange(nw))), (nw, nw))

        ## linear rows multiplied by rr(i), quadratic rows by rr(i)^2
        w = M * (LL + QQ * diagrr) * rr
        HwC = H * w + Cw
        AA = N.T * M * (LL + 2 * QQ * diagrr)

        d2f = d2f + AA * H * AA.T + 2 * N.T * M * QQ * \
                sparse((HwC, (arange(nw), arange(nw))), (nw, nw)) * N
    d2f = d2f * cost_mult

    ##----- evaluate Hessian of power balance constraints -----
    nlam = len(lmbda["eqnonlin"]) / 2
    lamP = lmbda["eqnonlin"][:nlam]
    lamQ = lmbda["eqnonlin"][nlam:nlam + nlam]
    Gpaa, Gpav, Gpva, Gpvv = d2Sbus_dV2(Ybus, V, lamP)
    Gqaa, Gqav, Gqva, Gqvv = d2Sbus_dV2(Ybus, V, lamQ)

    d2G = vstack([
        hstack([
            vstack([hstack([Gpaa, Gpav]),
                    hstack([Gpva, Gpvv])]).real +
            vstack([hstack([Gqaa, Gqav]),
                    hstack([Gqva, Gqvv])]).imag,
            sparse((2 * nb, nxtra))
        ]),
        hstack([sparse(
            (nxtra, 2 * nb)), sparse((nxtra, nxtra))])
    ], "csr")

    ##----- evaluate Hessian of flow constraints -----
    nmu = len(lmbda["ineqnonlin"]) / 2
    muF = lmbda["ineqnonlin"][:nmu]
    muT = lmbda["ineqnonlin"][nmu:nmu + nmu]
    if ppopt['OPF_FLOW_LIM'] == 2:  ## current
        dIf_dVa, dIf_dVm, dIt_dVa, dIt_dVm, If, It = dIbr_dV(branch, Yf, Yt, V)
        Hfaa, Hfav, Hfva, Hfvv = d2AIbr_dV2(dIf_dVa, dIf_dVm, If, Yf, V, muF)
        Htaa, Htav, Htva, Htvv = d2AIbr_dV2(dIt_dVa, dIt_dVm, It, Yt, V, muT)
    else:
        f = branch[il, F_BUS].astype(int)  ## list of "from" buses
        t = branch[il, T_BUS].astype(int)  ## list of "to" buses
        ## connection matrix for line & from buses
        Cf = sparse((ones(nl2), (arange(nl2), f)), (nl2, nb))
        ## connection matrix for line & to buses
        Ct = sparse((ones(nl2), (arange(nl2), t)), (nl2, nb))
        dSf_dVa, dSf_dVm, dSt_dVa, dSt_dVm, Sf, St = \
                dSbr_dV(branch[il,:], Yf, Yt, V)
        if ppopt['OPF_FLOW_LIM'] == 1:  ## real power
            Hfaa, Hfav, Hfva, Hfvv = d2ASbr_dV2(dSf_dVa.real, dSf_dVm.real,
                                                Sf.real, Cf, Yf, V, muF)
            Htaa, Htav, Htva, Htvv = d2ASbr_dV2(dSt_dVa.real, dSt_dVm.real,
                                                St.real, Ct, Yt, V, muT)
        else:  ## apparent power
            Hfaa, Hfav, Hfva, Hfvv = \
                    d2ASbr_dV2(dSf_dVa, dSf_dVm, Sf, Cf, Yf, V, muF)
            Htaa, Htav, Htva, Htvv = \
                    d2ASbr_dV2(dSt_dVa, dSt_dVm, St, Ct, Yt, V, muT)

    d2H = vstack([
        hstack([
            vstack([hstack([Hfaa, Hfav]),
                    hstack([Hfva, Hfvv])]) +
            vstack([hstack([Htaa, Htav]),
                    hstack([Htva, Htvv])]),
            sparse((2 * nb, nxtra))
        ]),
        hstack([sparse(
            (nxtra, 2 * nb)), sparse((nxtra, nxtra))])
    ], "csr")

    ##-----  do numerical check using (central) finite differences  -----
    if 0:
        nx = len(x)
        step = 1e-5
        num_d2f = sparse((nx, nx))
        num_d2G = sparse((nx, nx))
        num_d2H = sparse((nx, nx))
        for i in range(nx):
            xp = x
            xm = x
            xp[i] = x[i] + step / 2
            xm[i] = x[i] - step / 2
            # evaluate cost & gradients
            _, dfp = opf_costfcn(xp, om)
            _, dfm = opf_costfcn(xm, om)
            # evaluate constraints & gradients
            _, _, dHp, dGp = opf_consfcn(xp, om, Ybus, Yf, Yt, ppopt, il)
            _, _, dHm, dGm = opf_consfcn(xm, om, Ybus, Yf, Yt, ppopt, il)
            num_d2f[:, i] = cost_mult * (dfp - dfm) / step
            num_d2G[:, i] = (dGp - dGm) * lmbda["eqnonlin"] / step
            num_d2H[:, i] = (dHp - dHm) * lmbda["ineqnonlin"] / step
        d2f_err = max(max(abs(d2f - num_d2f)))
        d2G_err = max(max(abs(d2G - num_d2G)))
        d2H_err = max(max(abs(d2H - num_d2H)))
        if d2f_err > 1e-6:
            print('Max difference in d2f: %g' % d2f_err)
        if d2G_err > 1e-5:
            print('Max difference in d2G: %g' % d2G_err)
        if d2H_err > 1e-6:
            print('Max difference in d2H: %g' % d2H_err)

    return d2f + d2G + d2H
Exemple #3
0
def t_hessian(quiet=False):
    """Numerical tests of 2nd derivative code.

    @author: Ray Zimmerman (PSERC Cornell)
    """
    t_begin(44, quiet)

    ## run powerflow to get solved case
    ppopt = ppoption(VERBOSE=0, OUT_ALL=0)
    results, _ = runpf(case30(), ppopt)
    baseMVA, bus, gen, branch = \
        results['baseMVA'], results['bus'], results['gen'], results['branch']

    ## switch to internal bus numbering and build admittance matrices
    _, bus, gen, branch = ext2int1(bus, gen, branch)
    Ybus, Yf, Yt = makeYbus(baseMVA, bus, branch)
    Vm = bus[:, VM]
    Va = bus[:, VA] * (pi / 180)
    V = Vm * exp(1j * Va)
    f = branch[:, F_BUS]       ## list of "from" buses
    t = branch[:, T_BUS]       ## list of "to" buses
    nl = len(f)
    nb = len(V)
    Cf = sparse((ones(nl), (range(nl), f)), (nl, nb))  ## connection matrix for line & from buses
    Ct = sparse((ones(nl), (range(nl), t)), (nl, nb))  ## connection matrix for line & to buses
    pert = 1e-8

    ##-----  check d2Sbus_dV2 code  -----
    t = ' - d2Sbus_dV2 (complex power injections)'
    lam = 10 * random.rand(nb)
    num_Haa = zeros((nb, nb), complex)
    num_Hav = zeros((nb, nb), complex)
    num_Hva = zeros((nb, nb), complex)
    num_Hvv = zeros((nb, nb), complex)
    dSbus_dVm, dSbus_dVa = dSbus_dV(Ybus, V)
    Haa, Hav, Hva, Hvv = d2Sbus_dV2(Ybus, V, lam)
    for i in range(nb):
        Vap = V.copy()
        Vap[i] = Vm[i] * exp(1j * (Va[i] + pert))
        dSbus_dVm_ap, dSbus_dVa_ap = dSbus_dV(Ybus, Vap)
        num_Haa[:, i] = (dSbus_dVa_ap - dSbus_dVa).T * lam / pert
        num_Hva[:, i] = (dSbus_dVm_ap - dSbus_dVm).T * lam / pert

        Vmp = V.copy()
        Vmp[i] = (Vm[i] + pert) * exp(1j * Va[i])
        dSbus_dVm_mp, dSbus_dVa_mp = dSbus_dV(Ybus, Vmp)
        num_Hav[:, i] = (dSbus_dVa_mp - dSbus_dVa).T * lam / pert
        num_Hvv[:, i] = (dSbus_dVm_mp - dSbus_dVm).T * lam / pert

    t_is(Haa.todense(), num_Haa, 4, ['Haa', t])
    t_is(Hav.todense(), num_Hav, 4, ['Hav', t])
    t_is(Hva.todense(), num_Hva, 4, ['Hva', t])
    t_is(Hvv.todense(), num_Hvv, 4, ['Hvv', t])

    ##-----  check d2Sbr_dV2 code  -----
    t = ' - d2Sbr_dV2 (complex power flows)'
    lam = 10 * random.rand(nl)
    # lam = [1 zeros(nl-1, 1)]
    num_Gfaa = zeros((nb, nb), complex)
    num_Gfav = zeros((nb, nb), complex)
    num_Gfva = zeros((nb, nb), complex)
    num_Gfvv = zeros((nb, nb), complex)
    num_Gtaa = zeros((nb, nb), complex)
    num_Gtav = zeros((nb, nb), complex)
    num_Gtva = zeros((nb, nb), complex)
    num_Gtvv = zeros((nb, nb), complex)
    dSf_dVa, dSf_dVm, dSt_dVa, dSt_dVm, _, _ = dSbr_dV(branch, Yf, Yt, V)
    Gfaa, Gfav, Gfva, Gfvv = d2Sbr_dV2(Cf, Yf, V, lam)
    Gtaa, Gtav, Gtva, Gtvv = d2Sbr_dV2(Ct, Yt, V, lam)
    for i in range(nb):
        Vap = V.copy()
        Vap[i] = Vm[i] * exp(1j * (Va[i] + pert))
        dSf_dVa_ap, dSf_dVm_ap, dSt_dVa_ap, dSt_dVm_ap, Sf_ap, St_ap = \
            dSbr_dV(branch, Yf, Yt, Vap)
        num_Gfaa[:, i] = (dSf_dVa_ap - dSf_dVa).T * lam / pert
        num_Gfva[:, i] = (dSf_dVm_ap - dSf_dVm).T * lam / pert
        num_Gtaa[:, i] = (dSt_dVa_ap - dSt_dVa).T * lam / pert
        num_Gtva[:, i] = (dSt_dVm_ap - dSt_dVm).T * lam / pert

        Vmp = V.copy()
        Vmp[i] = (Vm[i] + pert) * exp(1j * Va[i])
        dSf_dVa_mp, dSf_dVm_mp, dSt_dVa_mp, dSt_dVm_mp, Sf_mp, St_mp = \
            dSbr_dV(branch, Yf, Yt, Vmp)
        num_Gfav[:, i] = (dSf_dVa_mp - dSf_dVa).T * lam / pert
        num_Gfvv[:, i] = (dSf_dVm_mp - dSf_dVm).T * lam / pert
        num_Gtav[:, i] = (dSt_dVa_mp - dSt_dVa).T * lam / pert
        num_Gtvv[:, i] = (dSt_dVm_mp - dSt_dVm).T * lam / pert

    t_is(Gfaa.todense(), num_Gfaa, 4, ['Gfaa', t])
    t_is(Gfav.todense(), num_Gfav, 4, ['Gfav', t])
    t_is(Gfva.todense(), num_Gfva, 4, ['Gfva', t])
    t_is(Gfvv.todense(), num_Gfvv, 4, ['Gfvv', t])

    t_is(Gtaa.todense(), num_Gtaa, 4, ['Gtaa', t])
    t_is(Gtav.todense(), num_Gtav, 4, ['Gtav', t])
    t_is(Gtva.todense(), num_Gtva, 4, ['Gtva', t])
    t_is(Gtvv.todense(), num_Gtvv, 4, ['Gtvv', t])

    ##-----  check d2Ibr_dV2 code  -----
    t = ' - d2Ibr_dV2 (complex currents)'
    lam = 10 * random.rand(nl)
    # lam = [1, zeros(nl-1)]
    num_Gfaa = zeros((nb, nb), complex)
    num_Gfav = zeros((nb, nb), complex)
    num_Gfva = zeros((nb, nb), complex)
    num_Gfvv = zeros((nb, nb), complex)
    num_Gtaa = zeros((nb, nb), complex)
    num_Gtav = zeros((nb, nb), complex)
    num_Gtva = zeros((nb, nb), complex)
    num_Gtvv = zeros((nb, nb), complex)
    dIf_dVa, dIf_dVm, dIt_dVa, dIt_dVm, _, _ = dIbr_dV(branch, Yf, Yt, V)
    Gfaa, Gfav, Gfva, Gfvv = d2Ibr_dV2(Yf, V, lam)

    Gtaa, Gtav, Gtva, Gtvv = d2Ibr_dV2(Yt, V, lam)
    for i in range(nb):
        Vap = V.copy()
        Vap[i] = Vm[i] * exp(1j * (Va[i] + pert))
        dIf_dVa_ap, dIf_dVm_ap, dIt_dVa_ap, dIt_dVm_ap, If_ap, It_ap = \
            dIbr_dV(branch, Yf, Yt, Vap)
        num_Gfaa[:, i] = (dIf_dVa_ap - dIf_dVa).T * lam / pert
        num_Gfva[:, i] = (dIf_dVm_ap - dIf_dVm).T * lam / pert
        num_Gtaa[:, i] = (dIt_dVa_ap - dIt_dVa).T * lam / pert
        num_Gtva[:, i] = (dIt_dVm_ap - dIt_dVm).T * lam / pert

        Vmp = V.copy()
        Vmp[i] = (Vm[i] + pert) * exp(1j * Va[i])
        dIf_dVa_mp, dIf_dVm_mp, dIt_dVa_mp, dIt_dVm_mp, If_mp, It_mp = \
            dIbr_dV(branch, Yf, Yt, Vmp)
        num_Gfav[:, i] = (dIf_dVa_mp - dIf_dVa).T * lam / pert
        num_Gfvv[:, i] = (dIf_dVm_mp - dIf_dVm).T * lam / pert
        num_Gtav[:, i] = (dIt_dVa_mp - dIt_dVa).T * lam / pert
        num_Gtvv[:, i] = (dIt_dVm_mp - dIt_dVm).T * lam / pert

    t_is(Gfaa.todense(), num_Gfaa, 4, ['Gfaa', t])
    t_is(Gfav.todense(), num_Gfav, 4, ['Gfav', t])
    t_is(Gfva.todense(), num_Gfva, 4, ['Gfva', t])
    t_is(Gfvv.todense(), num_Gfvv, 4, ['Gfvv', t])

    t_is(Gtaa.todense(), num_Gtaa, 4, ['Gtaa', t])
    t_is(Gtav.todense(), num_Gtav, 4, ['Gtav', t])
    t_is(Gtva.todense(), num_Gtva, 4, ['Gtva', t])
    t_is(Gtvv.todense(), num_Gtvv, 4, ['Gtvv', t])

    ##-----  check d2ASbr_dV2 code  -----
    t = ' - d2ASbr_dV2 (squared apparent power flows)'
    lam = 10 * random.rand(nl)
    # lam = [1 zeros(nl-1, 1)]
    num_Gfaa = zeros((nb, nb), complex)
    num_Gfav = zeros((nb, nb), complex)
    num_Gfva = zeros((nb, nb), complex)
    num_Gfvv = zeros((nb, nb), complex)
    num_Gtaa = zeros((nb, nb), complex)
    num_Gtav = zeros((nb, nb), complex)
    num_Gtva = zeros((nb, nb), complex)
    num_Gtvv = zeros((nb, nb), complex)
    dSf_dVa, dSf_dVm, dSt_dVa, dSt_dVm, Sf, St = dSbr_dV(branch, Yf, Yt, V)
    dAf_dVa, dAf_dVm, dAt_dVa, dAt_dVm = \
                            dAbr_dV(dSf_dVa, dSf_dVm, dSt_dVa, dSt_dVm, Sf, St)
    Gfaa, Gfav, Gfva, Gfvv = d2ASbr_dV2(dSf_dVa, dSf_dVm, Sf, Cf, Yf, V, lam)
    Gtaa, Gtav, Gtva, Gtvv = d2ASbr_dV2(dSt_dVa, dSt_dVm, St, Ct, Yt, V, lam)
    for i in range(nb):
        Vap = V.copy()
        Vap[i] = Vm[i] * exp(1j * (Va[i] + pert))
        dSf_dVa_ap, dSf_dVm_ap, dSt_dVa_ap, dSt_dVm_ap, Sf_ap, St_ap = \
            dSbr_dV(branch, Yf, Yt, Vap)
        dAf_dVa_ap, dAf_dVm_ap, dAt_dVa_ap, dAt_dVm_ap = \
            dAbr_dV(dSf_dVa_ap, dSf_dVm_ap, dSt_dVa_ap, dSt_dVm_ap, Sf_ap, St_ap)
        num_Gfaa[:, i] = (dAf_dVa_ap - dAf_dVa).T * lam / pert
        num_Gfva[:, i] = (dAf_dVm_ap - dAf_dVm).T * lam / pert
        num_Gtaa[:, i] = (dAt_dVa_ap - dAt_dVa).T * lam / pert
        num_Gtva[:, i] = (dAt_dVm_ap - dAt_dVm).T * lam / pert

        Vmp = V.copy()
        Vmp[i] = (Vm[i] + pert) * exp(1j * Va[i])
        dSf_dVa_mp, dSf_dVm_mp, dSt_dVa_mp, dSt_dVm_mp, Sf_mp, St_mp = \
            dSbr_dV(branch, Yf, Yt, Vmp)
        dAf_dVa_mp, dAf_dVm_mp, dAt_dVa_mp, dAt_dVm_mp = \
            dAbr_dV(dSf_dVa_mp, dSf_dVm_mp, dSt_dVa_mp, dSt_dVm_mp, Sf_mp, St_mp)
        num_Gfav[:, i] = (dAf_dVa_mp - dAf_dVa).T * lam / pert
        num_Gfvv[:, i] = (dAf_dVm_mp - dAf_dVm).T * lam / pert
        num_Gtav[:, i] = (dAt_dVa_mp - dAt_dVa).T * lam / pert
        num_Gtvv[:, i] = (dAt_dVm_mp - dAt_dVm).T * lam / pert

    t_is(Gfaa.todense(), num_Gfaa, 2, ['Gfaa', t])
    t_is(Gfav.todense(), num_Gfav, 2, ['Gfav', t])
    t_is(Gfva.todense(), num_Gfva, 2, ['Gfva', t])
    t_is(Gfvv.todense(), num_Gfvv, 2, ['Gfvv', t])

    t_is(Gtaa.todense(), num_Gtaa, 2, ['Gtaa', t])
    t_is(Gtav.todense(), num_Gtav, 2, ['Gtav', t])
    t_is(Gtva.todense(), num_Gtva, 2, ['Gtva', t])
    t_is(Gtvv.todense(), num_Gtvv, 2, ['Gtvv', t])

    ##-----  check d2ASbr_dV2 code  -----
    t = ' - d2ASbr_dV2 (squared real power flows)'
    lam = 10 * random.rand(nl)
    # lam = [1 zeros(nl-1, 1)]
    num_Gfaa = zeros((nb, nb), complex)
    num_Gfav = zeros((nb, nb), complex)
    num_Gfva = zeros((nb, nb), complex)
    num_Gfvv = zeros((nb, nb), complex)
    num_Gtaa = zeros((nb, nb), complex)
    num_Gtav = zeros((nb, nb), complex)
    num_Gtva = zeros((nb, nb), complex)
    num_Gtvv = zeros((nb, nb), complex)
    dSf_dVa, dSf_dVm, dSt_dVa, dSt_dVm, Sf, St = dSbr_dV(branch, Yf, Yt, V)
    dAf_dVa, dAf_dVm, dAt_dVa, dAt_dVm = \
           dAbr_dV(dSf_dVa.real, dSf_dVm.real, dSt_dVa.real, dSt_dVm.real, Sf.real, St.real)
    Gfaa, Gfav, Gfva, Gfvv = d2ASbr_dV2(dSf_dVa.real, dSf_dVm.real, Sf.real, Cf, Yf, V, lam)
    Gtaa, Gtav, Gtva, Gtvv = d2ASbr_dV2(dSt_dVa.real, dSt_dVm.real, St.real, Ct, Yt, V, lam)
    for i in range(nb):
        Vap = V.copy()
        Vap[i] = Vm[i] * exp(1j * (Va[i] + pert))
        dSf_dVa_ap, dSf_dVm_ap, dSt_dVa_ap, dSt_dVm_ap, Sf_ap, St_ap = \
            dSbr_dV(branch, Yf, Yt, Vap)
        dAf_dVa_ap, dAf_dVm_ap, dAt_dVa_ap, dAt_dVm_ap = \
            dAbr_dV(dSf_dVa_ap.real, dSf_dVm_ap.real, dSt_dVa_ap.real, dSt_dVm_ap.real, Sf_ap.real, St_ap.real)
        num_Gfaa[:, i] = (dAf_dVa_ap - dAf_dVa).T * lam / pert
        num_Gfva[:, i] = (dAf_dVm_ap - dAf_dVm).T * lam / pert
        num_Gtaa[:, i] = (dAt_dVa_ap - dAt_dVa).T * lam / pert
        num_Gtva[:, i] = (dAt_dVm_ap - dAt_dVm).T * lam / pert

        Vmp = V.copy()
        Vmp[i] = (Vm[i] + pert) * exp(1j * Va[i])
        dSf_dVa_mp, dSf_dVm_mp, dSt_dVa_mp, dSt_dVm_mp, Sf_mp, St_mp = \
            dSbr_dV(branch, Yf, Yt, Vmp)
        dAf_dVa_mp, dAf_dVm_mp, dAt_dVa_mp, dAt_dVm_mp = \
            dAbr_dV(dSf_dVa_mp.real, dSf_dVm_mp.real, dSt_dVa_mp.real, dSt_dVm_mp.real, Sf_mp.real, St_mp.real)
        num_Gfav[:, i] = (dAf_dVa_mp - dAf_dVa).T * lam / pert
        num_Gfvv[:, i] = (dAf_dVm_mp - dAf_dVm).T * lam / pert
        num_Gtav[:, i] = (dAt_dVa_mp - dAt_dVa).T * lam / pert
        num_Gtvv[:, i] = (dAt_dVm_mp - dAt_dVm).T * lam / pert

    t_is(Gfaa.todense(), num_Gfaa, 2, ['Gfaa', t])
    t_is(Gfav.todense(), num_Gfav, 2, ['Gfav', t])
    t_is(Gfva.todense(), num_Gfva, 2, ['Gfva', t])
    t_is(Gfvv.todense(), num_Gfvv, 2, ['Gfvv', t])

    t_is(Gtaa.todense(), num_Gtaa, 2, ['Gtaa', t])
    t_is(Gtav.todense(), num_Gtav, 2, ['Gtav', t])
    t_is(Gtva.todense(), num_Gtva, 2, ['Gtva', t])
    t_is(Gtvv.todense(), num_Gtvv, 2, ['Gtvv', t])

    ##-----  check d2AIbr_dV2 code  -----
    t = ' - d2AIbr_dV2 (squared current magnitudes)'
    lam = 10 * random.rand(nl)
    # lam = [1 zeros(nl-1, 1)]
    num_Gfaa = zeros((nb, nb), complex)
    num_Gfav = zeros((nb, nb), complex)
    num_Gfva = zeros((nb, nb), complex)
    num_Gfvv = zeros((nb, nb), complex)
    num_Gtaa = zeros((nb, nb), complex)
    num_Gtav = zeros((nb, nb), complex)
    num_Gtva = zeros((nb, nb), complex)
    num_Gtvv = zeros((nb, nb), complex)
    dIf_dVa, dIf_dVm, dIt_dVa, dIt_dVm, If, It = dIbr_dV(branch, Yf, Yt, V)
    dAf_dVa, dAf_dVm, dAt_dVa, dAt_dVm = \
                            dAbr_dV(dIf_dVa, dIf_dVm, dIt_dVa, dIt_dVm, If, It)
    Gfaa, Gfav, Gfva, Gfvv = d2AIbr_dV2(dIf_dVa, dIf_dVm, If, Yf, V, lam)
    Gtaa, Gtav, Gtva, Gtvv = d2AIbr_dV2(dIt_dVa, dIt_dVm, It, Yt, V, lam)
    for i in range(nb):
        Vap = V.copy()
        Vap[i] = Vm[i] * exp(1j * (Va[i] + pert))
        dIf_dVa_ap, dIf_dVm_ap, dIt_dVa_ap, dIt_dVm_ap, If_ap, It_ap = \
            dIbr_dV(branch, Yf, Yt, Vap)
        dAf_dVa_ap, dAf_dVm_ap, dAt_dVa_ap, dAt_dVm_ap = \
            dAbr_dV(dIf_dVa_ap, dIf_dVm_ap, dIt_dVa_ap, dIt_dVm_ap, If_ap, It_ap)
        num_Gfaa[:, i] = (dAf_dVa_ap - dAf_dVa).T * lam / pert
        num_Gfva[:, i] = (dAf_dVm_ap - dAf_dVm).T * lam / pert
        num_Gtaa[:, i] = (dAt_dVa_ap - dAt_dVa).T * lam / pert
        num_Gtva[:, i] = (dAt_dVm_ap - dAt_dVm).T * lam / pert

        Vmp = V.copy()
        Vmp[i] = (Vm[i] + pert) * exp(1j * Va[i])
        dIf_dVa_mp, dIf_dVm_mp, dIt_dVa_mp, dIt_dVm_mp, If_mp, It_mp = \
            dIbr_dV(branch, Yf, Yt, Vmp)
        dAf_dVa_mp, dAf_dVm_mp, dAt_dVa_mp, dAt_dVm_mp = \
            dAbr_dV(dIf_dVa_mp, dIf_dVm_mp, dIt_dVa_mp, dIt_dVm_mp, If_mp, It_mp)
        num_Gfav[:, i] = (dAf_dVa_mp - dAf_dVa).T * lam / pert
        num_Gfvv[:, i] = (dAf_dVm_mp - dAf_dVm).T * lam / pert
        num_Gtav[:, i] = (dAt_dVa_mp - dAt_dVa).T * lam / pert
        num_Gtvv[:, i] = (dAt_dVm_mp - dAt_dVm).T * lam / pert

    t_is(Gfaa.todense(), num_Gfaa, 3, ['Gfaa', t])
    t_is(Gfav.todense(), num_Gfav, 3, ['Gfav', t])
    t_is(Gfva.todense(), num_Gfva, 3, ['Gfva', t])
    t_is(Gfvv.todense(), num_Gfvv, 2, ['Gfvv', t])

    t_is(Gtaa.todense(), num_Gtaa, 3, ['Gtaa', t])
    t_is(Gtav.todense(), num_Gtav, 3, ['Gtav', t])
    t_is(Gtva.todense(), num_Gtva, 3, ['Gtva', t])
    t_is(Gtvv.todense(), num_Gtvv, 2, ['Gtvv', t])

    t_end()
Exemple #4
0
def opf_hessfcn(x, lmbda, om, Ybus, Yf, Yt, ppopt, il=None, cost_mult=1.0):
    """Evaluates Hessian of Lagrangian for AC OPF.

    Hessian evaluation function for AC optimal power flow, suitable
    for use with L{pips}.

    Examples::
        Lxx = opf_hessfcn(x, lmbda, om, Ybus, Yf, Yt, ppopt)
        Lxx = opf_hessfcn(x, lmbda, om, Ybus, Yf, Yt, ppopt, il)
        Lxx = opf_hessfcn(x, lmbda, om, Ybus, Yf, Yt, ppopt, il, cost_mult)

    @param x: optimization vector
    @param lmbda: C{eqnonlin} - Lagrange multipliers on power balance
    equations. C{ineqnonlin} - Kuhn-Tucker multipliers on constrained
    branch flows.
    @param om: OPF model object
    @param Ybus: bus admittance matrix
    @param Yf: admittance matrix for "from" end of constrained branches
    @param Yt: admittance matrix for "to" end of constrained branches
    @param ppopt: PYPOWER options vector
    @param il: (optional) vector of branch indices corresponding to
    branches with flow limits (all others are assumed to be unconstrained).
    The default is C{range(nl)} (all branches). C{Yf} and C{Yt} contain
    only the rows corresponding to C{il}.
    @param cost_mult: (optional) Scale factor to be applied to the cost
    (default = 1).

    @return: Hessian of the Lagrangian.

    @see: L{opf_costfcn}, L{opf_consfcn}

    @author: Ray Zimmerman (PSERC Cornell)
    @author: Carlos E. Murillo-Sanchez (PSERC Cornell & Universidad
    Autonoma de Manizales)
    """
    ##----- initialize -----
    ## unpack data
    ppc = om.get_ppc()
    baseMVA, bus, gen, branch, gencost = \
        ppc["baseMVA"], ppc["bus"], ppc["gen"], ppc["branch"], ppc["gencost"]
    cp = om.get_cost_params()
    N, Cw, H, dd, rh, kk, mm = \
        cp["N"], cp["Cw"], cp["H"], cp["dd"], cp["rh"], cp["kk"], cp["mm"]
    vv, _, _, _ = om.get_idx()

    ## unpack needed parameters
    nb = bus.shape[0]          ## number of buses
    nl = branch.shape[0]       ## number of branches
    ng = gen.shape[0]          ## number of dispatchable injections
    nxyz = len(x)              ## total number of control vars of all types

    ## set default constrained lines
    if il is None:
        il = arange(nl)            ## all lines have limits by default
    nl2 = len(il)           ## number of constrained lines

    ## grab Pg & Qg
    Pg = x[vv["i1"]["Pg"]:vv["iN"]["Pg"]]  ## active generation in p.u.
    Qg = x[vv["i1"]["Qg"]:vv["iN"]["Qg"]]  ## reactive generation in p.u.

    ## put Pg & Qg back in gen
    gen[:, PG] = Pg * baseMVA  ## active generation in MW
    gen[:, QG] = Qg * baseMVA  ## reactive generation in MVAr

    ## reconstruct V
    Va = x[vv["i1"]["Va"]:vv["iN"]["Va"]]
    Vm = x[vv["i1"]["Vm"]:vv["iN"]["Vm"]]
    V = Vm * exp(1j * Va)
    nxtra = nxyz - 2 * nb
    pcost = gencost[arange(ng), :]
    if gencost.shape[0] > ng:
        qcost = gencost[arange(ng, 2 * ng), :]
    else:
        qcost = array([])

    ## ----- evaluate d2f -----
    d2f_dPg2 = zeros(ng)#sparse((ng, 1))               ## w.r.t. p.u. Pg
    d2f_dQg2 = zeros(ng)#sparse((ng, 1))               ## w.r.t. p.u. Qg
    ipolp = find(pcost[:, MODEL] == POLYNOMIAL)
    d2f_dPg2[ipolp] = \
            baseMVA**2 * polycost(pcost[ipolp, :], Pg[ipolp] * baseMVA, 2)
    if any(qcost):          ## Qg is not free
        ipolq = find(qcost[:, MODEL] == POLYNOMIAL)
        d2f_dQg2[ipolq] = \
                baseMVA**2 * polycost(qcost[ipolq, :], Qg[ipolq] * baseMVA, 2)
    i = r_[arange(vv["i1"]["Pg"], vv["iN"]["Pg"]),
           arange(vv["i1"]["Qg"], vv["iN"]["Qg"])]
#    d2f = sparse((vstack([d2f_dPg2, d2f_dQg2]).toarray().flatten(),
#                  (i, i)), shape=(nxyz, nxyz))
    d2f = sparse((r_[d2f_dPg2, d2f_dQg2], (i, i)), (nxyz, nxyz))

    ## generalized cost
    if issparse(N) and N.nnz > 0:
        nw = N.shape[0]
        r = N * x - rh                    ## Nx - rhat
        iLT = find(r < -kk)               ## below dead zone
        iEQ = find((r == 0) & (kk == 0))  ## dead zone doesn't exist
        iGT = find(r > kk)                ## above dead zone
        iND = r_[iLT, iEQ, iGT]           ## rows that are Not in the Dead region
        iL = find(dd == 1)                ## rows using linear function
        iQ = find(dd == 2)                ## rows using quadratic function
        LL = sparse((ones(len(iL)), (iL, iL)), (nw, nw))
        QQ = sparse((ones(len(iQ)), (iQ, iQ)), (nw, nw))
        kbar = sparse((r_[ones(len(iLT)), zeros(len(iEQ)), -ones(len(iGT))],
                       (iND, iND)), (nw, nw)) * kk
        rr = r + kbar                  ## apply non-dead zone shift
        M = sparse((mm[iND], (iND, iND)), (nw, nw))  ## dead zone or scale
        diagrr = sparse((rr, (arange(nw), arange(nw))), (nw, nw))

        ## linear rows multiplied by rr(i), quadratic rows by rr(i)^2
        w = M * (LL + QQ * diagrr) * rr
        HwC = H * w + Cw
        AA = N.T * M * (LL + 2 * QQ * diagrr)

        d2f = d2f + AA * H * AA.T + 2 * N.T * M * QQ * \
                sparse((HwC, (arange(nw), arange(nw))), (nw, nw)) * N
    d2f = d2f * cost_mult

    ##----- evaluate Hessian of power balance constraints -----
    nlam = len(lmbda["eqnonlin"]) / 2
    lamP = lmbda["eqnonlin"][:nlam]
    lamQ = lmbda["eqnonlin"][nlam:nlam + nlam]
    Gpaa, Gpav, Gpva, Gpvv = d2Sbus_dV2(Ybus, V, lamP)
    Gqaa, Gqav, Gqva, Gqvv = d2Sbus_dV2(Ybus, V, lamQ)

    d2G = vstack([
            hstack([
                vstack([hstack([Gpaa, Gpav]),
                        hstack([Gpva, Gpvv])]).real +
                vstack([hstack([Gqaa, Gqav]),
                        hstack([Gqva, Gqvv])]).imag,
                sparse((2 * nb, nxtra))]),
            hstack([
                sparse((nxtra, 2 * nb)),
                sparse((nxtra, nxtra))
            ])
        ], "csr")

    ##----- evaluate Hessian of flow constraints -----
    nmu = len(lmbda["ineqnonlin"]) / 2
    muF = lmbda["ineqnonlin"][:nmu]
    muT = lmbda["ineqnonlin"][nmu:nmu + nmu]
    if ppopt['OPF_FLOW_LIM'] == 2:       ## current
        dIf_dVa, dIf_dVm, dIt_dVa, dIt_dVm, If, It = dIbr_dV(Yf, Yt, V)
        Hfaa, Hfav, Hfva, Hfvv = d2AIbr_dV2(dIf_dVa, dIf_dVm, If, Yf, V, muF)
        Htaa, Htav, Htva, Htvv = d2AIbr_dV2(dIt_dVa, dIt_dVm, It, Yt, V, muT)
    else:
        f = branch[il, F_BUS].astype(int)    ## list of "from" buses
        t = branch[il, T_BUS].astype(int)    ## list of "to" buses
        ## connection matrix for line & from buses
        Cf = sparse((ones(nl2), (arange(nl2), f)), (nl2, nb))
        ## connection matrix for line & to buses
        Ct = sparse((ones(nl2), (arange(nl2), t)), (nl2, nb))
        dSf_dVa, dSf_dVm, dSt_dVa, dSt_dVm, Sf, St = \
                dSbr_dV(branch[il,:], Yf, Yt, V)
        if ppopt['OPF_FLOW_LIM'] == 1:     ## real power
            Hfaa, Hfav, Hfva, Hfvv = d2ASbr_dV2(dSf_dVa.real, dSf_dVm.real,
                                                Sf.real, Cf, Yf, V, muF)
            Htaa, Htav, Htva, Htvv = d2ASbr_dV2(dSt_dVa.real, dSt_dVm.real,
                                                St.real, Ct, Yt, V, muT)
        else:                  ## apparent power
            Hfaa, Hfav, Hfva, Hfvv = \
                    d2ASbr_dV2(dSf_dVa, dSf_dVm, Sf, Cf, Yf, V, muF)
            Htaa, Htav, Htva, Htvv = \
                    d2ASbr_dV2(dSt_dVa, dSt_dVm, St, Ct, Yt, V, muT)

    d2H = vstack([
            hstack([
                vstack([hstack([Hfaa, Hfav]),
                        hstack([Hfva, Hfvv])]) +
                vstack([hstack([Htaa, Htav]),
                        hstack([Htva, Htvv])]),
                sparse((2 * nb, nxtra))
            ]),
            hstack([
                sparse((nxtra, 2 * nb)),
                sparse((nxtra, nxtra))
            ])
        ], "csr")

    ##-----  do numerical check using (central) finite differences  -----
    if 0:
        nx = len(x)
        step = 1e-5
        num_d2f = sparse((nx, nx))
        num_d2G = sparse((nx, nx))
        num_d2H = sparse((nx, nx))
        for i in range(nx):
            xp = x
            xm = x
            xp[i] = x[i] + step / 2
            xm[i] = x[i] - step / 2
            # evaluate cost & gradients
            _, dfp = opf_costfcn(xp, om)
            _, dfm = opf_costfcn(xm, om)
            # evaluate constraints & gradients
            _, _, dHp, dGp = opf_consfcn(xp, om, Ybus, Yf, Yt, ppopt, il)
            _, _, dHm, dGm = opf_consfcn(xm, om, Ybus, Yf, Yt, ppopt, il)
            num_d2f[:, i] = cost_mult * (dfp - dfm) / step
            num_d2G[:, i] = (dGp - dGm) * lmbda["eqnonlin"]   / step
            num_d2H[:, i] = (dHp - dHm) * lmbda["ineqnonlin"] / step
        d2f_err = max(max(abs(d2f - num_d2f)))
        d2G_err = max(max(abs(d2G - num_d2G)))
        d2H_err = max(max(abs(d2H - num_d2H)))
        if d2f_err > 1e-6:
            print('Max difference in d2f: %g' % d2f_err)
        if d2G_err > 1e-5:
            print('Max difference in d2G: %g' % d2G_err)
        if d2H_err > 1e-6:
            print('Max difference in d2H: %g' % d2H_err)

    return d2f + d2G + d2H
    def admmopf_hessfcn(self, x=None, lmbda=None, cost_mult=1.0):
        if x is None:
            x = self.pb['x0']
        if lmbda is None:  # multiplier for power flow constraints
            lmbda = {'eqnonlin': 3000 * ones(2 * len(self.idx['rbus']['int']))}
            # lmbda = {'eqnonlin': 3000 * ones(2 * self.region['nb'])}
        nx = len(x)
        nb = self.region['nb']
        nl = self.region['nl']
        ng = self.region['ng']
        rho = self.var['rho']
        Ybus = self.region['Ybus']
        iv = self.idx['var']

        branch = self.region['branch']
        baseMVA = self.region['baseMVA']
        bus = self.region['bus']

        iVa = iv['iVa']
        iVm = iv['iVm']
        # reconstruct V
        Va, Vm = x[iVa], x[iVm]
        V = Vm * exp(1j * Va)
        # ---- evaluate Hessian of f ----------
        Adiff = self.mtx['Adiff']
        Asum = self.mtx['Asum']
        d2f_dVm2 = d2f_dVa2 = Adiff.T.dot(Adiff) * rho + Asum.T.dot(Asum) * rho
        data = self.region['gencost'][:, COST] * 2
        i = arange(0, ng)
        d2f_dPgQg2 = sparse((data, (i, i)), (2 * ng, 2 * ng))
        blankv = sparse((nb, nb))
        d2f_dV2 = vstack(
            [hstack([d2f_dVa2, blankv]),
             hstack([blankv, d2f_dVm2])], 'csr')
        blankvp = sparse((2 * nb, 2 * ng))
        d2f = vstack(
            [hstack([d2f_dV2, blankvp]),
             hstack([blankvp.T, d2f_dPgQg2])], 'csr')

        # ---- evaluate Hessian of power flow constraints ------
        nlam = len(lmbda["eqnonlin"]) // 2
        lamP = zeros(nb)  #for non-included pf balances use 0 as multiplier
        lamQ = zeros(nb)
        lamP[self.idx['rbus']['int']] = lmbda["eqnonlin"][:nlam]
        lamQ[self.idx['rbus']['int']] = lmbda["eqnonlin"][nlam:nlam + nlam]
        # lamP = lmbda["eqnonlin"][:nlam]
        # lamQ = lmbda["eqnonlin"][nlam:nlam + nlam]
        Gpaa, Gpav, Gpva, Gpvv = d2Sbus_dV2(Ybus, V, lamP)
        Gqaa, Gqav, Gqva, Gqvv = d2Sbus_dV2(Ybus, V, lamQ)

        d2G = vstack([
            hstack([
                vstack([hstack([Gpaa, Gpav]),
                        hstack([Gpva, Gpvv])]).real +
                vstack([hstack([Gqaa, Gqav]),
                        hstack([Gqva, Gqvv])]).imag,
                sparse((2 * nb, 2 * ng))
            ]),
            hstack([sparse((2 * ng, 2 * nb)),
                    sparse((2 * ng, 2 * ng))])
        ], 'csr')

        ##----- evaluate Hessian of flow constraints -----
        """
		il = find((branch[:, RATE_A] != 0) & (branch[:, RATE_A] < 1e10))
		nl2 = len(il) 
		
		
		Ybus2, Yf2, Yt2 = makeYbus(baseMVA, bus, branch)
		Yf = Yf2[il,:]
		Yt = Yt2[il,:]
		
		
		
		if il is None:
			il = arange(nl)            ## all lines have limits by default
		nl2 = len(il) ## number of constrained lines
		
		
		nmu = int(len(lmbda["ineqnonlin"]) / 2)
		muF = lmbda["ineqnonlin"][:nmu]
		muT = lmbda["ineqnonlin"][nmu:nmu + nmu]



		f = branch[il, F_BUS].astype(int)    ## list of "from" buses
		t = branch[il, T_BUS].astype(int)    ## list of "to" buses
		## connection matrix for line & from buses
		Cf = sparse((ones(nl2), (arange(nl2), f)), (nl2, nb))
		## connection matrix for line & to buses
		Ct = sparse((ones(nl2), (arange(nl2), t)), (nl2, nb))
		dSf_dVa, dSf_dVm, dSt_dVa, dSt_dVm, Sf, St = \
                dSbr_dV(branch[il,:], Yf, Yt, V)

		Hfaa, Hfav, Hfva, Hfvv = d2ASbr_dV2(dSf_dVa.real, dSf_dVm.real,
                                                Sf.real, Cf, Yf, V, muF)
		Htaa, Htav, Htva, Htvv = d2ASbr_dV2(dSt_dVa.real, dSt_dVm.real,
                                                St.real, Ct, Yt, V, muT)
		nxtra = nx - 2 * nb
		d2H = vstack([
            hstack([
                vstack([hstack([Hfaa, Hfav]),
                        hstack([Hfva, Hfvv])]) +
                vstack([hstack([Htaa, Htav]),
                        hstack([Htva, Htvv])]),
                sparse((2 * nb, nxtra))
            ]),
            hstack([
                sparse((nxtra, 2 * nb)),
                sparse((nxtra, nxtra))
            ])
        ], "csr")
		
		
		"""

        return d2f + d2G  #+d2H