Sorry for the delay in replying. Just to clarify, the continuation power does not stop ‘exactly’ at the nose point, but pretty close it. The condition for detecting nose point in runcpf is "lam < lamprv" (line 303 in runcpf), i.e., lambda at the current continuation step is less than lambda at previous step. So, runcpf actually gives a close estimate of the nose point which can be improved by reducing the continuation step size, mpoption(‘cpf.step’,<stepsize>). However, I do not think you can calculate an exact zero determinant in MATLAB for the power flow partly because of the way MATLAB calculates the determinant (pivoted LU factorization) and the ill-conditioning of the Jacobian near the nose point.
Shri From: nilesh patel <[email protected]<mailto:[email protected]>> Reply-To: MATPOWER discussion forum <[email protected]<mailto:[email protected]>> Date: Tuesday, August 18, 2015 at 12:29 PM To: matpower-l <[email protected]<mailto:[email protected]>>, MATPOWER-L <[email protected]<mailto:[email protected]>> Subject: Jacobian at nose point Sir, At nose point in P-V curve using cpf, Jacobian matrix becomes singular. i.e. determinant of Jacobian to be zero. I am getting very high negative value of determinant of jacobian at nose point. I have used following code: define_constants; mpopt = mpoption('out.all',0,'verbose',2,'out.bus',1); mpopt = mpoption(mpopt,'cpf.stop_at','nose','cpf.step',0.03); mpopt = mpoption(mpopt,'cpf.plot.bus',7,'cpf.plot.level',2); mpcb = loadcase('case39'); % load base case mpct = mpcb; % set up target case with mpct.gen(:,[PG QG]) = mpcb.gen(:,[PG QG])*1.35 mpct.bus(:,[PD QD]) = mpcb.bus(:,[PD QD])*1.35 results = runcpf(mpcb, mpct, mpopt); J=makeJac(results) %%% determinant of J det(J) ans = -1.0471e+126 Could you please suggest me what necessary steps I should follow to get determinant zero? Thanking you. Nilesh Patel [https://sigads.rediff.com/RealMedia/ads/adstream_nx.ads/www.rediffmail.com/signatureline.htm@Middle]<https://sigads.rediff.com/RealMedia/ads/click_nx.ads/www.rediffmail.com/signatureline.htm@Middle?> Get your own FREE website, FREE domain & FREE mobile app with Company email. Know More ><http://track.rediff.com/click?url=___http://businessemail.rediff.com?sc_cid=sign-1-10-13___&cmp=host&lnk=sign-1-10-13&nsrv1=host>
