Home > matpower4.0 > pfsoln.m

pfsoln

PURPOSE ^

PFSOLN Updates bus, gen, branch data structures to match power flow soln.

SYNOPSIS ^

function [bus, gen, branch] = pfsoln(baseMVA, bus0, gen0, branch0, Ybus, Yf, Yt, V, ref, pv, pq)

DESCRIPTION ^

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)

CROSS-REFERENCE INFORMATION ^

This function calls: This function is called by:

SOURCE CODE ^

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 %   $Id: pfsoln.m,v 1.19 2010/04/26 19:45:25 ray Exp $
0008 %   by Ray Zimmerman, PSERC Cornell
0009 %   Copyright (c) 1996-2010 by Power System Engineering Research Center (PSERC)
0010 %
0011 %   This file is part of MATPOWER.
0012 %   See http://www.pserc.cornell.edu/matpower/ for more info.
0013 %
0014 %   MATPOWER is free software: you can redistribute it and/or modify
0015 %   it under the terms of the GNU General Public License as published
0016 %   by the Free Software Foundation, either version 3 of the License,
0017 %   or (at your option) any later version.
0018 %
0019 %   MATPOWER is distributed in the hope that it will be useful,
0020 %   but WITHOUT ANY WARRANTY; without even the implied warranty of
0021 %   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
0022 %   GNU General Public License for more details.
0023 %
0024 %   You should have received a copy of the GNU General Public License
0025 %   along with MATPOWER. If not, see <http://www.gnu.org/licenses/>.
0026 %
0027 %   Additional permission under GNU GPL version 3 section 7
0028 %
0029 %   If you modify MATPOWER, or any covered work, to interface with
0030 %   other modules (such as MATLAB code and MEX-files) available in a
0031 %   MATLAB(R) or comparable environment containing parts covered
0032 %   under other licensing terms, the licensors of MATPOWER grant
0033 %   you additional permission to convey the resulting work.
0034 
0035 %% define named indices into bus, gen, branch matrices
0036 [PQ, PV, REF, NONE, BUS_I, BUS_TYPE, PD, QD, GS, BS, BUS_AREA, VM, ...
0037     VA, BASE_KV, ZONE, VMAX, VMIN, LAM_P, LAM_Q, MU_VMAX, MU_VMIN] = idx_bus;
0038 [GEN_BUS, PG, QG, QMAX, QMIN, VG, MBASE, GEN_STATUS, PMAX, PMIN, ...
0039     MU_PMAX, MU_PMIN, MU_QMAX, MU_QMIN, PC1, PC2, QC1MIN, QC1MAX, ...
0040     QC2MIN, QC2MAX, RAMP_AGC, RAMP_10, RAMP_30, RAMP_Q, APF] = idx_gen;
0041 [F_BUS, T_BUS, BR_R, BR_X, BR_B, RATE_A, RATE_B, RATE_C, ...
0042     TAP, SHIFT, BR_STATUS, PF, QF, PT, QT, MU_SF, MU_ST, ...
0043     ANGMIN, ANGMAX, MU_ANGMIN, MU_ANGMAX] = idx_brch;
0044 
0045 %% initialize return values
0046 bus     = bus0;
0047 gen     = gen0;
0048 branch  = branch0;
0049 
0050 %%----- update bus voltages -----
0051 bus(:, VM) = abs(V);
0052 bus(:, VA) = angle(V) * 180 / pi;
0053 
0054 %%----- update Qg for all gens and Pg for swing bus -----
0055 %% generator info
0056 on = find(gen(:, GEN_STATUS) > 0);      %% which generators are on?
0057 gbus = gen(on, GEN_BUS);                %% what buses are they at?
0058 refgen = find(gbus == ref);             %% which is(are) the reference gen(s)?
0059 
0060 %% compute total injected bus powers
0061 Sg = V(gbus) .* conj(Ybus(gbus, :) * V);
0062 
0063 %% update Qg for all generators
0064 gen(:, QG) = zeros(size(gen, 1), 1);                %% zero out all Qg
0065 gen(on, QG) = imag(Sg) * baseMVA + bus(gbus, QD);   %% inj Q + local Qd
0066 %% ... at this point any buses with more than one generator will have
0067 %% the total Q dispatch for the bus assigned to each generator. This
0068 %% must be split between them. We do it first equally, then in proportion
0069 %% to the reactive range of the generator.
0070 
0071 if length(on) > 1
0072     %% build connection matrix, element i, j is 1 if gen on(i) at bus j is ON
0073     nb = size(bus, 1);
0074     ngon = size(on, 1);
0075     Cg = sparse((1:ngon)', gbus, ones(ngon, 1), ngon, nb);
0076 
0077     %% divide Qg by number of generators at the bus to distribute equally
0078     ngg = Cg * sum(Cg)';    %% ngon x 1, number of gens at this gen's bus
0079     gen(on, QG) = gen(on, QG) ./ ngg;
0080     
0081     
0082     %% divide proportionally
0083     Cmin = sparse((1:ngon)', gbus, gen(on, QMIN), ngon, nb);
0084     Cmax = sparse((1:ngon)', gbus, gen(on, QMAX), ngon, nb);
0085     Qg_tot = Cg' * gen(on, QG);     %% nb x 1 vector of total Qg at each bus
0086     Qg_min = sum(Cmin)';            %% nb x 1 vector of min total Qg at each bus
0087     Qg_max = sum(Cmax)';            %% nb x 1 vector of max total Qg at each bus
0088     ig = find(Cg * Qg_min == Cg * Qg_max);  %% gens at buses with Qg range = 0
0089     Qg_save = gen(on(ig), QG);
0090     gen(on, QG) = gen(on, QMIN) + ...
0091         (Cg * ((Qg_tot - Qg_min)./(Qg_max - Qg_min + eps))) .* ...
0092             (gen(on, QMAX) - gen(on, QMIN));    %%    ^ avoid div by 0
0093     gen(on(ig), QG) = Qg_save;
0094 end                                             %% (terms are mult by 0 anyway)
0095 
0096 %% update Pg for swing bus
0097 gen(on(refgen(1)), PG) = real(Sg(refgen(1))) * baseMVA + bus(ref, PD);  %% inj P + local Pd
0098 if length(refgen) > 1       %% more than one generator at the ref bus
0099     %% subtract off what is generated by other gens at this bus
0100     gen(on(refgen(1)), PG) = gen(on(refgen(1)), PG) - sum(gen(on(refgen(2:length(refgen))), PG));
0101 end
0102 
0103 %%----- update/compute branch power flows -----
0104 out = find(branch(:, BR_STATUS) == 0);      %% out-of-service branches
0105 br = find(branch(:, BR_STATUS));            %% in-service branches
0106 Sf = V(branch(br, F_BUS)) .* conj(Yf(br, :) * V) * baseMVA; %% complex power at "from" bus
0107 St = V(branch(br, T_BUS)) .* conj(Yt(br, :) * V) * baseMVA; %% complex power injected at "to" bus
0108 branch(br, [PF, QF, PT, QT]) = [real(Sf) imag(Sf) real(St) imag(St)];
0109 branch(out, [PF, QF, PT, QT]) = zeros(length(out), 4);

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