Hi Shri, Thank you so much for your kind advice. I changed the code as your suggestion, the CPF converged for my base case. And it would be fine for me which CPF won't stop exactly at lam=0.
Then I tried with the 14-bus system from case14.m, the CPF did not converge at the last step. If you can fix it, please inform me. It would be highly appreciated. Best Regards, Natakorn Thasnas Ph.D Student Khonkaen University, Thailand 2015-02-13 2:43 GMT+07:00 Abhyankar, Shrirang G. <[email protected]>: > First, > >> mpct.bus(:,[PD QG]) = mpcb.bus(:,[PD QG])*2.5; is incorrect if you > trying to scale both the real and the reactive power load. > It should be mpct.bus(:,[PD QD]) = mpcb.bus(:,[PD QD])*2.5; > > Even after making this change, the CPF does not converge at the last > step. This is because it overshoots (crosses lam = 0) in the previous step > and cannot recover after that due to a negative step. I can also see that > there is a big difference between the predicted and correction solutions at > the last step. It will take a bit of investigation to fix this properly. In > the meantime, as a quick fix, you can change line 292 in runcpf() > > if abs(lam) < 1e-8 > > > to > > > if lam < 1e-8 > > > The only caveat is that now cpf won't stop exactly at lam = 0, but it > will overshoot (which I presume may be fine with you?) > > > Shri > > > > > From: Natakorn Thasnas <[email protected]> > Reply-To: MATPOWER discussion forum <[email protected]> > Date: Fri, 13 Feb 2015 01:05:23 +0700 > > To: MATPOWER discussion forum <[email protected]> > Subject: Re: PV Curve > > Please see the base case file in attachment > > Natakorn > > 2015-02-13 0:57 GMT+07:00 Abhyankar, Shrirang G. <[email protected]>: > >> Can you please send your base case file. >> >> Shri >> >> From: Natakorn Thasnas <[email protected]> >> Reply-To: MATPOWER discussion forum <[email protected]> >> Date: Fri, 13 Feb 2015 00:21:15 +0700 >> To: MATPOWER discussion forum <[email protected]> >> Subject: Re: PV Curve >> >> Hi Shri >> >> I tried using a smaller continuation step size as your suggestion (step >> size=0.05). And I tried decreasing step size to 0.002, >> I still got the same result, the PV curve is not full nose curve. >> >> Best Regards, >> >> Natakorn Thasnas >> Ph.D Student >> Khonkaen University, Thailand >> >> 2015-02-12 20:41 GMT+07:00 Abhyankar, Shrirang G. <[email protected]>: >> >>> Try using a smaller continuation step size. >>> mpopt = mpoption(mpopt, 'cpf.stop_at', 'full', 'cpf.step', 0.05); >>> >>> Shri >>> >>> > On Feb 12, 2015, at 4:03 AM, "Natakorn Thasnas" < >>> [email protected]> wrote: >>> > >>> > Hi All >>> > >>> > I am trying to run a continuation power flow with the following code >>> > >>> > define_constants; >>> > mpopt = mpoption('out.all', 0, 'verbose', 2); >>> > mpopt = mpoption(mpopt, 'cpf.stop_at', 'full', 'cpf.step', 0.2); >>> > mpopt = mpoption(mpopt, 'cpf.plot.level', 2 ,'cpf.plot.bus', 14); >>> > mpcb = loadcase('case14result'); % load base case >>> > mpct = mpcb; % set up target case with >>> > mpct.gen(:, [PG QG]) = mpcb.gen(:, [PG QG])*2.5; >>> > mpct.bus(:,[PD QG]) = mpcb.bus(:,[PD QG])*2.5; >>> > results = runcpf(mpcb, mpct, mpopt); >>> > >>> > After running it, I got the warning message "corrector did not >>> converge in 1000 iterations" and the PV curve is not full nose curve as >>> showing in attached file (c14.jpg) >>> > >>> > <c14.jpg> >>> > >>> > Then I increased "max_it" ​from 1000 to 10000. I got the warning >>> messages as following >>> > >>> > Warning: Matrix is close to singular or badly scaled. >>> > Results may be inaccurate. RCOND = 1.944067e-018. >>> > > In cpf_corrector at 143 >>> > In runcpf at 268 >>> > In cpfrun at 55 >>> > step 48 : lambda = -7.770, corrector did not converge in 10000 >>> iterations >>> > >>> > >>> > Could you please suggest me how to fix it to get "the full nose curve"? >>> > >>> > Thank you in advance. >>> > >>> > Best Regards, >>> > >>> > Natakorn Thasnas >>> > Ph.D Student >>> > Khonkaen University, Thailand >>> >>> >> >
