pfsoln

PFSOLN  Updates bus, gen, branch data structures to match power flow soln.
   [BUS, GEN, BRANCH] = PFSOLN(BASEMVA, BUS0, GEN0, BRANCH0, ...
                                   YBUS, YF, YT, V, REF, PV, PQ)

0001 function [bus, gen, branch] = pfsoln(baseMVA, bus0, gen0, branch0, Ybus, Yf, Yt, V, ref, pv, pq)
0002 %PFSOLN  Updates bus, gen, branch data structures to match power flow soln.
0003 %   [BUS, GEN, BRANCH] = PFSOLN(BASEMVA, BUS0, GEN0, BRANCH0, ...
0004 %                                   YBUS, YF, YT, V, REF, PV, PQ)
0005 
0006 %   MATPOWER
0007 %   Copyright (c) 1996-2015 by Power System Engineering Research Center (PSERC)
0008 %   by Ray Zimmerman, PSERC Cornell
0009 %
0010 %   $Id: pfsoln.m 2644 2015-03-11 19:34:22Z ray $
0011 %
0012 %   This file is part of MATPOWER.
0013 %   Covered by the 3-clause BSD License (see LICENSE file for details).
0014 %   See http://www.pserc.cornell.edu/matpower/ for more info.
0015 
0016 %% define named indices into bus, gen, branch matrices
0017 [PQ, PV, REF, NONE, BUS_I, BUS_TYPE, PD, QD, GS, BS, BUS_AREA, VM, ...
0018     VA, BASE_KV, ZONE, VMAX, VMIN, LAM_P, LAM_Q, MU_VMAX, MU_VMIN] = idx_bus;
0019 [GEN_BUS, PG, QG, QMAX, QMIN, VG, MBASE, GEN_STATUS, PMAX, PMIN, ...
0020     MU_PMAX, MU_PMIN, MU_QMAX, MU_QMIN, PC1, PC2, QC1MIN, QC1MAX, ...
0021     QC2MIN, QC2MAX, RAMP_AGC, RAMP_10, RAMP_30, RAMP_Q, APF] = idx_gen;
0022 [F_BUS, T_BUS, BR_R, BR_X, BR_B, RATE_A, RATE_B, RATE_C, ...
0023     TAP, SHIFT, BR_STATUS, PF, QF, PT, QT, MU_SF, MU_ST, ...
0024     ANGMIN, ANGMAX, MU_ANGMIN, MU_ANGMAX] = idx_brch;
0025 
0026 %% initialize return values
0027 bus     = bus0;
0028 gen     = gen0;
0029 branch  = branch0;
0030 
0031 %%----- update bus voltages -----
0032 bus(:, VM) = abs(V);
0033 bus(:, VA) = angle(V) * 180 / pi;
0034 
0035 %%----- update Qg for gens at PV/slack buses and Pg for slack bus(es) -----
0036 %% generator info
0037 on = find(gen(:, GEN_STATUS) > 0 & ...  %% which generators are on?
0038         bus(gen(:, GEN_BUS), BUS_TYPE) ~= PQ);  %% ... and not at PQ buses
0039 off = find(gen(:, GEN_STATUS) <= 0);    %% which generators are off?
0040 gbus = gen(on, GEN_BUS);                %% what buses are they at?
0041 
0042 %% compute total injected bus powers
0043 Sbus = V(gbus) .* conj(Ybus(gbus, :) * V);
0044 
0045 %% update Qg for generators at PV/slack buses
0046 gen(off, QG) = zeros(length(off), 1);   %% zero out off-line Qg
0047 %% don't touch the ones at PQ buses
0048 gen(on, QG) = imag(Sbus) * baseMVA + bus(gbus, QD); %% inj Q + local Qd
0049 %% ... at this point any buses with more than one generator will have
0050 %% the total Q dispatch for the bus assigned to each generator. This
0051 %% must be split between them. We do it first equally, then in proportion
0052 %% to the reactive range of the generator.
0053 
0054 if length(on) > 1
0055     %% build connection matrix, element i, j is 1 if gen on(i) at bus j is ON
0056     nb = size(bus, 1);
0057     ngon = size(on, 1);
0058     Cg = sparse((1:ngon)', gbus, ones(ngon, 1), ngon, nb);
0059 
0060     %% divide Qg by number of generators at the bus to distribute equally
0061     ngg = Cg * sum(Cg)';    %% ngon x 1, number of gens at this gen's bus
0062     gen(on, QG) = gen(on, QG) ./ ngg;
0063 
0064     %% divide proportionally
0065     Cmin = sparse((1:ngon)', gbus, gen(on, QMIN), ngon, nb);
0066     Cmax = sparse((1:ngon)', gbus, gen(on, QMAX), ngon, nb);
0067     Qg_tot = Cg' * gen(on, QG);     %% nb x 1 vector of total Qg at each bus
0068     Qg_min = sum(Cmin)';            %% nb x 1 vector of min total Qg at each bus
0069     Qg_max = sum(Cmax)';            %% nb x 1 vector of max total Qg at each bus
0070     ig = find(Cg * Qg_min == Cg * Qg_max);  %% gens at buses with Qg range = 0
0071     Qg_save = gen(on(ig), QG);
0072     gen(on, QG) = gen(on, QMIN) + ...
0073         (Cg * ((Qg_tot - Qg_min)./(Qg_max - Qg_min + eps))) .* ...
0074             (gen(on, QMAX) - gen(on, QMIN));    %%    ^ avoid div by 0
0075     gen(on(ig), QG) = Qg_save;
0076 end                                             %% (terms are mult by 0 anyway)
0077 
0078 %% update Pg for slack gen(s)
0079 for k = 1:length(ref)
0080     refgen = find(gbus == ref(k));              %% which is(are) the reference gen(s)?
0081     gen(on(refgen(1)), PG) = real(Sbus(refgen(1))) * baseMVA ...
0082                             + bus(ref(k), PD);  %% inj P + local Pd
0083     if length(refgen) > 1       %% more than one generator at this ref bus
0084         %% subtract off what is generated by other gens at this bus
0085         gen(on(refgen(1)), PG) = gen(on(refgen(1)), PG) ...
0086                                 - sum(gen(on(refgen(2:length(refgen))), PG));
0087     end
0088 end
0089 
0090 %%----- update/compute branch power flows -----
0091 out = find(branch(:, BR_STATUS) == 0);      %% out-of-service branches
0092 br = find(branch(:, BR_STATUS));            %% in-service branches
0093 Sf = V(branch(br, F_BUS)) .* conj(Yf(br, :) * V) * baseMVA; %% complex power at "from" bus
0094 St = V(branch(br, T_BUS)) .* conj(Yt(br, :) * V) * baseMVA; %% complex power injected at "to" bus
0095 branch(br, [PF, QF, PT, QT]) = [real(Sf) imag(Sf) real(St) imag(St)];
0096 branch(out, [PF, QF, PT, QT]) = zeros(length(out), 4);