fm_connectivity.m

基于PSAT 软件的多目标最优潮流计算用于中小型电力系统的分析和管理

function fm_connectivity(actual_time,flag)
% FM_CONNECTIVITY determines in how many islands the system is
%                 fractioned after braker interventions
%
% FM_CONNECTIVTY(T)
%       T actual simulation time
%
%Author:    Federico Milano
%Date:      03-Nov-2005
%Version:   1.0.0
%
% This function has been fully rewritten based on the original
% version by Laurent Lenoir, June 2005.
%
%E-mail:    [e-mail]
%Web-site:  http://thunderbox.uwaterloo.ca/~fmilano
%
% Copyright (C) 2002-2006 Federico Milano

global Line Bus Syn SW PV
persistent old_time

switch flag

 case 'init'

  old_time = -999;

 case 'islands'

  %global PQ Mn Pl Fl Exload Thload Jimma Mixed

  global Ltc Phs Hvdc Lines
  
  % accounting for PV and load buses
  %busPQV = zeros(Bus.n,1);
  %if PV.n,     busPQV(PV.bus) = 1;     end
  %if PQ.n,     busPQV(PQ.bus) = 1;     end
  %if Mn.n,     busPQV(Mn.bus) = 1;     end
  %if Pl.n,     busPQV(Pl.bus) = 1;     end
  %if Fl.n,     busPQV(Fl.bus) = 1;     end
  %if Exload.n, busPQV(Exload.bus) = 1; end
  %if Thload.n, busPQV(Thload.bus) = 1; end
  %if Jimma.n,  busPQV(Jimma.bus) = 1;  end
  %if Mixed.n,  busPQV(Mixed.bus) = 1;  end

  % looking for islanded buses
  traceY = abs(sum(Line.Y).'-diag(Line.Y));
  
  if Lines.n
    traceY(Lines.bus1) = 1;
    traceY(Lines.bus2) = 1;
  end
  if Hvdc.n
    traceY(Hvdc.bus1) = 1;
    traceY(Hvdc.bus2) = 1;
  end
  if Ltc.n
    traceY(Ltc.bus1) = 1;
    traceY(Ltc.bus2) = 1;
  end
  if Phs.n
    traceY(Phs.bus1) = 1;
    traceY(Phs.bus2) = 1;
  end
  
  % defining critical islanded buses
  Bus.island = find(traceY < 1e-4); % & busPQV);
  if ~isempty(Bus.island)
    fm_disp(strcat(' * * Bus #',num2str(Bus.island), ' is islanded.'))
  end

 case 'areas'

  % do not repeat computations if the simulation is stucking
  if old_time ~= actual_time
    old_time = actual_time;
  else
    return
  end

  % connectivity matrix
  connect_mat = sparse(Line.from,Line.to,1,Bus.n,Bus.n);
  connect_mat = connect_mat + sparse(Line.from,Line.from,1,Bus.n,Bus.n);
  connect_mat = connect_mat + sparse(Line.to,Line.to,1,Bus.n,Bus.n);
  connect_mat = connect_mat + sparse(Line.to,Line.from,1,Bus.n,Bus.n);

  % check for open lines
  open_lines = find(Line.con(:,9) > 1e5);

  if ~isempty(open_lines)

    % modify connectivity matrix if there are open lines
    hhh = Line.from(open_lines);
    kkk = Line.to(open_lines);
    connect_mat = connect_mat - sparse(hhh,kkk,1,Bus.n,Bus.n);
    connect_mat = connect_mat - sparse(kkk,hhh,1,Bus.n,Bus.n);

    % find network islands using QR factorization
    [Q,R] = qr(connect_mat);
    idx = find(abs(sum(R,2)-diag(R)) < 1e-5);
    % find generators for each island
    nisland = length(idx);
    if nisland > 1
      disp(['There are ' num2str(nisland) ' islanded networks'])
      gen_bus = [Syn.bus;SW.bus;PV.bus];
      for i = 1:nisland
        buses = find(Q(:,idx(i)));
        ngen = 0;
        nbuses = length(buses);
        for j = 1:nbuses
          ngen = ngen + length(find(gen_bus == buses(j)));
        end
        disp([' * * Sub_network has ', num2str(nbuses), ...
              ' bus(es) and ', num2str(ngen), ' generator(s)'])
      end
    end

  end

 otherwise

  % unknown option

end