The power flow problem solved by MATPOWER finds the reactive power dispatches of the generators which result in the specified generator voltage setpoints. The OPF problem, optimizes the bus voltages, by varying the generator real and reactive injections, in order to find the feasible operating point with lowest total cost.
For the power flow, the ENFORCE_Q_LIMS option can be set to tell the algorithm to modify the generator voltage setpoints as needed in order to keep the reactive power injections of the generators within their limits. -- Ray Zimmerman Senior Research Associate 419A Warren Hall, Cornell University, Ithaca, NY 14853 phone: (607) 255-9645 On Feb 1, 2012, at 9:04 AM, Boris Penaloza wrote: > Hi dr Zimmerman, > > I just sent you an email with a inquiry and an observation.. please forget > the observation as I found my error.. your algorithm is ok.. but I still have > the doubt about the voltage regulation throught reactive power consumption... > > many thanks On Feb 1, 2012, at 8:42 AM, Boris Penaloza wrote: > Hi dr Zimmerman, > > I have one question and one observation > > Question ---> As generators can consume and inject reactive power, does > matpower control de voltage in the nodes via reactive power consumption? In > order to reduce the voltage at the injection node. > > > Observation --> If I am not wrong you calculate the Line Series Losses using > this equation Loss = (Vf - Vt)^2 / (R +jX) > > I think Ploss SERIES depends more strongly on the line current I^2 than on > the voltage variation at the nodes. > > My understanding is that Ploss SHUNT depends more strongly on the voltage > than on the current. > > I found this equation for Ploss series > > Ploss,series = [P/V]^2*Rline + [Q/V]^2*Rline > > So that the voltage does not influence the losses but the injection of P and > Q. > > Am I wrong about this?? I would appreciate your comments.. > > >>> Ray Zimmerman <[email protected]> 1/31/2012 4:31 >>> > I'm not certain exactly what characteristic of the problem results in this > issue, but I have seen it often. The primal/dual interior point algorithm > solves an A x = b linear system of equations to compute the update step, and > in some cases the corresponding A matrix becomes singular or nearly singular. > It may be that the problem is too flat or something, I'm not sure. If it > solves successfully anyway, just printing these warnings, it's fine, but > sometimes the optimization will fail completely. In that case, my only > solution is to switch to a different solver. > > There are probably improvements that can be made to the MIPS algorithm to > make it more robust under these circumstances. Any suggestions are > appreciated. > > -- > Ray Zimmerman > Senior Research Associate > 419A Warren Hall, Cornell University, Ithaca, NY 14853 > phone: (607) 255-9645 > > > > > On Jan 31, 2012, at 4:23 AM, Boris Penaloza wrote: > >> Warning: Matrix is singular to working precision. >> > In mips at 422 >> In mipsopf_solver at 145 >> In opf_execute at 106 >> In opf at 225 >> In runopf at 96 >> In pqinput at 53 >> >> I am getting this message error as I try to run a simulation. Does anybody >> know what it means?? >> >> thanks... >
