If you run a continuation power flow in MATPOWER, runcpf(), with the option 'cpf_stop_at' set to NOSE then the CPF will terminate on reaching the nose point. runcpf() returns a mpc case struct that has details on the generation and loading at the critical point and the lambda (continuation parameter) and the predicted and corrected solutions at each continuation step. Please go through Chapter 5 in the MATPOWER manual<http://www.pserc.cornell.edu/matpower/manual.pdf> for a discussion of the formulation, implementation, and the available options for MATPOWER's CPF.
Shri From: Natakorn Thasnas <[email protected]<mailto:[email protected]>> Reply-To: MATPOWER discussion forum <[email protected]<mailto:[email protected]>> Date: Mon, 9 Feb 2015 15:55:31 +0700 To: MATPOWER discussion forum <[email protected]<mailto:[email protected]>> Subject: Re: Power Voltage curve using matpower Dear Ray, Regarding your previous email. Could you please explain more detail with example calculation how to get the values of critical power? Because I am new for continuation power flow. Best Regards, Natakorn Thasnas 2015-02-04 4:33 GMT+07:00 Ray Zimmerman <[email protected]<mailto:[email protected]>>: Hi Arun, Since MATPOWER’s continuation power flow transfer is set up in a very general fashion as the difference between a base and target case, which may involve changes at multiple buses, there isn’t a single “power” number associated with each step. However, you can recover any power of interest from the results.cpf.lam_p and/or results.cpf.lam_c values and transfer (target - base) vector from equation (5.3) in the manual. The lambda values are used to interpolate between the base injections (lambda = 0) and the target injections (lambda = 1). -- Ray Zimmerman Senior Research Associate B30 Warren Hall, Cornell University, Ithaca, NY 14853 USA phone: (607) 255-9645 On Feb 3, 2015, at 12:47 PM, arun s nair <[email protected]<mailto:[email protected]>> wrote: Hi All I am trying to use matpower to evaluate IEEE 39 bus system. I am able to plot the PV curve of load buses and was also able to get the critical power and voltage values. I would like to know if its possible to get the power values at each iterations along with the voltage values ? I am using runcpf, and used the below code. 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',3,'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(3,PD) = mpcb.bus(3,PD)*2.5; results = runcpf(mpcb, mpct, mpopt); CriticalPower = results.bus(3,3) CriticalVoltage = results.bus(3,8) Thanking in advance With Regards. Arun Nair
