fm_lf.m

电力系统的psat

function fm_lf(flag)
% FM_LF compute power flow equations and Jacobian for
%       transmission lines.
%
% FM_LF(FLAG)
%      FLAG = 1: power flow equations
%      FLAG = 2: power flow Jacobian matrix
%
%see also FM_Y and DAE, Bus and Line structures
%
%Author:    Federico Milano
%Date:      11-Nov-2002
%Version:   1.0.0
%
%E-mail:    [e-mail]
%Web-site:  http://thunderbox.uwaterloo.ca/~fmilano
%
% Copyright (C) 2002-2005 Federico Milano
%
% This toolbox is free software; you can redistribute it and/or modify
% it under the terms of the GNU General Public License as published by
% the Free Software Foundation; either version 2.0 of the License, or
% (at your option) any later version.
%
% This toolbox is distributed in the hope that it will be useful, but
% WITHOUT ANY WARRANTY; without even the implied warranty of
% MERCHANDABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
% General Public License for more details.
%
% You should have received a copy of the GNU General Public License
% along with this toolbox; if not, write to the Free Software
% Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307,
% USA.

global Bus Line DAE jay Settings

switch flag
 case 1
  
  DAE.V = max(DAE.V,1e-6);
  Vc = DAE.V.*exp(jay*DAE.a);
  S = Vc.*conj(Line.Y*Vc);
  DAE.gp = real(S);
  DAE.gq = imag(S);
  DAE.glfp = DAE.gp;
  DAE.glfq = DAE.gq;
  
 case 2

  n = 1:Bus.n;
  U = exp(jay*DAE.a);
  V = DAE.V.*U;
  I = Line.Y*V;

  if Settings.octave

    diagVc = diag(V);
    diagVn = diag(U);
    diagIc = diag(I);

    dS = diagVc*conj(Line.Y*diagVn)+conj(diagIc)*diagVn;
    DAE.J12 = real(dS);
    DAE.J22 = imag(dS)+1e-6*eye(Bus.n);

    dS = jay*diagVc*conj(diagIc-Line.Y*diagVc);
    DAE.J11 = real(dS)+1e-6*eye(Bus.n);
    DAE.J21 = imag(dS);

  else

    diagVc = sparse(n,n,V,Bus.n,Bus.n);
    diagVn = sparse(n,n,U,Bus.n,Bus.n);
    diagIc = sparse(n,n,I,Bus.n,Bus.n);

    dS = diagVc * conj(Line.Y * diagVn) + conj(diagIc) * diagVn;
    DAE.J12 = real(dS);
    DAE.J22 = imag(dS) + 1e-6*speye(Bus.n);

    dS = jay * diagVc * conj(diagIc - Line.Y * diagVc);
    DAE.J11 = real(dS) + 1e-6*speye(Bus.n);
    DAE.J21 = imag(dS);

  end
  
end