Dear sir and matpower committee
It is very strange for me that when the load of some PQ buses in IEEE 39
bus test system are reduced and then cpf is performed then the load margin
of the system is becoming lower . It should be noted that i use the
following code to estimate the load margin of the system using maximum
lambda.:
clc
clear all
a=0;
for ii=1:20
mpcb = loadcase(case39); % load base case
for v=[1 3 4 7];
mpcb.bus(v,3)=mpcb.bus(v,3)-a*mpcb.bus(v,3);
end
mpopt = mpoption('verbose',0,'out.all',0); %default
result=runopf(mpcb,mpopt);%bayad print ro disable koni
mpcb.gen(:,2)=result.gen(:,2);
load=sum(mpcb.bus(:,3))
generation=sum(mpcb.gen(:,2))
mpopt = mpoption('out.all',0,'verbose',0);
mpopt = mpoption(mpopt,'cpf.stop_at','NOSE','cpf.step', 0.2);
mpopt = mpoption(mpopt,'cpf.plot.level',0,'cpf.plot.bus',8);
mpct = mpcb; % set up target case with
mpct.gen(:,[2 3]) = mpcb.gen(:,[2 3]) * 3.5; % increased generation
mpct.bus(:,[3 4]) = mpcb.bus(:,[3 4]) * 3.5; % and increased load
results = runcpf(mpcb, mpct, mpopt);
landa(ii)=results.cpf.max_lam;%
Pf= mpcb.bus(:,3) +landa(ii)*(mpct.bus(:,3)-mpcb.bus(:,3));
Pinitial(ii)=sum(mpcb.bus(:,3));
Pfinal(ii)=sum(Pf);
loadmargin(ii)=Pfinal(ii)-Pinitial(ii);
a=a+0.1;
end
bar(loadmargin)
Is there any wrong calculation of final or initial load with maximum
lambda? as you see, the load margin is final load minus the initial load:
Pf= mpcb.bus(:,3) +landa(ii)*(mpct.bus(:,3)-mpcb.bus(:,3));
Pinitial(ii)=sum(mpcb.bus(:,3));
Pfinal(ii)=sum(Pf);
loadmargin(ii)=Pfinal(ii)-Pinitial(ii);
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*Best RegardsMajid MehdizadehPh.D Student of electrical engineering, Power
Department,Ferdowsi University of MashhadSubstation and Transmission Line
Expert, Engineering office,Khorasan Regional Electric
Co.http://mehdizadeh.majid.student.um.ac.ir
<http://mehdizadeh.majid.student.um.ac.ir> *
