You do not *need* to multiply the generation, but if you don’t then all of the additional generation, as you increase load, will come from the slack generator. Scaling the other generators is simply a more uniform way to handle the additional load.
Lambda is the continuation parameter and is proportional to the power. Lambda = 0 means you are at the base loading level and Lambda = 1 means you are at the target loading level. See equations (5.3) and (5.4) in the User’s Manual <http://www.pserc.cornell.edu/matpower/manual.pdf> for the details. Ray > On Jan 17, 2015, at 10:24 PM, arun s nair <arunsnair...@gmail.com> wrote: > > Hi > > Thanks a lot of the input Shri, I am able to run the code now and now able to > get the nose power and voltage values. > > I used the below code. > > define_constants; > mpopt = mpoption('out.all',0,'verbose',2,'out.bus',1); > mpopt = mpoption(mpopt,'cpf.stop_at','nose','cpf.step',0.2); > mpopt = mpoption(mpopt,'cpf.plot.bus',4,'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])*2 > mpct.bus(:,[PD QG]) = mpcb.bus(:,[PD QG])*2 > results = runcpf(mpcb, mpct, mpopt); > realpower = results.bus(4,3) > vm = results.bus(4,8) > > I have a small doubt, In the example for plotting the PV curve, they are both > multiplying the load and generation by a factor. For plotting the curve do we > need to multiply the gen bus also? > > One more doubt, in the curve its V vs Lamda, is the lamda factor same as > power? > > Sorry if these are silly doubts, I am new to Matpower and the power area. > > Thanking in advance. > > Nair > > > > > On Fri, Jan 16, 2015 at 12:30 PM, Abhyankar, Shrirang G. <abhy...@mcs.anl.gov > <mailto:abhy...@mcs.anl.gov>> wrote: > runcpf returns a MATPOWER case struct that has the loading/genration and the > voltages at its last continuation step. By using the option > 'cpf_stop_at_nose', the continuation power flow will stop when it is near the > nose point. You can then extract the voltages and power from the MATPOWER > case struct. > > For example, > > define_constants; > mpopt = mpoption('out.all',0,'verbose',2); > mpopt = mpoption('cpf.stop_at','nose','cpf.step',0.2); > mpopt = mpoption(mpopt,'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])*2.5 > mpct.bus(:,[PD QG]) = mpcb.bus(:,[PD QG])*2.5 > results = runcpf(mpcb, mpct, mpopt); > > Vm = results.bus(:,8); % Voltage magnitude at the nose point for all the > buses. > > Other values can be extracted from the case struct by accessing the > appropriate fields and their corresponding columns. The data format for the > case struct is defined in caseformat.m. > > Shri > > > > From: arun s nair <arunsnair...@gmail.com <mailto:arunsnair...@gmail.com>> > Reply-To: MATPOWER discussion forum <matpowe...@list.cornell.edu > <mailto:matpowe...@list.cornell.edu>> > Date: Fri, 16 Jan 2015 12:06:50 -0700 > To: MATPOWER discussion forum <matpowe...@list.cornell.edu > <mailto:matpowe...@list.cornell.edu>> > Subject: Re: Matpower- Continuation Power Flow > > Hi > > Thank you Abhyanker for your input, the example in the manual worked. > > I am really new to Matpower and I am learning it from scratch. My intention > is to get the critical value of power and voltage values(Nose point of the PV > curve) of a particular bus, Can anyone please tell me is it possible to get > the values using Matpower using continuation power flow ? > > I am trying to modify the example code from the manual (I am working on IEEE > 39 bus system) > > define_constants; > mpopt = mpoption('out.all',0,'verbose',2); > mpopt = mpoption('cpf.stop_at','nose','cpf.step',0.2); > mpopt = mpoption(mpopt,'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])*2.5 > mpct.bus(:,[PD QG]) = mpcb.bus(:,[PD QG])*2.5 > results = runcpf(mpcb, mpct, mpopt); > results.cpf > > > Thanking in advance > > Regards > > Nair > > > On Thu, Jan 15, 2015 at 3:25 PM, Abhyankar, Shrirang G. <abhy...@mcs.anl.gov > <mailto:abhy...@mcs.anl.gov>> wrote: > Arun, > You have the same generation/load for both the base (mpcb) and target > (mpct) cases. What are you seeing is that runcpf is solving the base case > over and over again since there is zero power transfer. Use different > generation/load for mpcb and mpct and run the continuation power flow again. > See the MATPOWER User's Manual > <http://www.pserc.cornell.edu//matpower/manual.pdf> for a CPF example on a > test 9-bus case. > > Shri > > From: arun s nair <arunsnair...@gmail.com <mailto:arunsnair...@gmail.com>> > Reply-To: MATPOWER discussion forum <matpowe...@list.cornell.edu > <mailto:matpowe...@list.cornell.edu>> > Date: Thu, 15 Jan 2015 13:02:57 -0700 > To: <MATPOWER-L@cornell.edu <mailto:MATPOWER-L@cornell.edu>> > Subject: Matpower- Continuation Power Flow > > Hi All > > I am trying to use matpower to evaluate IEEE 39 bus system and I tried to run > an example code for runcpf (Continuation Power Flow) > > define_constants; > mpopt = mpoption('out.all',0,'verbose',2); > mpopt = mpoption('cpf.stop_at','nose','cpf.step',0.2); > mpopt = mpoption(mpopt,'cpf.plot.level',2); > mpcb = loadcase(t_case9_pfv2); % load base case > mpct = mpcb; % set up target case with > mpct.gen(:, [PG QG]) = mpcb.gen(:, [PG QG]) > mpct.bus(2,[PD]) = mpcb.bus(2, [PD]) > results = runcpf(mpcb, mpct, mpopt); > results.cpf > > The program is keep on running and is not converging. Can anybody please help > on this. > > If anyone can send me a running example for runcpf of matpower , it will be > of great help and if anybody has worked on IEEE 39 bus using runcpf, please > let me know > > > Thanking you all in advance. > > Regards > > Arun Nair > > > >
