1. If you set OPF_ALG = 520, MATPOWER will use fmincon (which now uses an interior point method by default). 2. MATPOWER's default solver is an interior point solver (see Section 5.5 in the User's Manual). 3. Depending on the cost function, the DC OPF can be a QP or an LP, and yes, the optimum should be a global optimum.
-- Ray Zimmerman Senior Research Associate B30 Warren Hall, Cornell University, Ithaca, NY 14853 phone: (607) 255-9645 On Jul 23, 2013, at 1:28 PM, spyros gian <sp.g...@hotmail.com> wrote: > fmincon finds local optima. > However, I have the impression that interior point methods find global > optima. > I am not sure though. > 1.Does matpower use fmincon in its source code to do a non-linear ACOPF? > 2.Does matpower use interior point method for the non-linear ACOPF ? > 3. Since DC-OPF is linear , is the optimum found a global optimum ? > > Thank you > > CC: matpower-l@cornell.edu > From: abhy...@mcs.anl.gov > Subject: Re: OPF on matpower > Date: Tue, 23 Jul 2013 10:05:21 -0700 > To: matpowe...@list.cornell.edu > > > > On Jul 23, 2013, at 9:42 AM, spyros gian <sp.g...@hotmail.com> wrote: > > Dear Dr Zimmerman, > > Running an OPF in matpower means that > > 1. Bus types play no role (eg slack, PV, PQ etc) > Yes. > 2. All values for Real Power generation and reactive power generation are > unknown > Yes. > 3. All values for bus_voltages and voltage phase angles in buses, are unknown > as well > The voltage angle of the reference bus is fixed and set to 0. > 4. As a result, all values for real and reactive power flows are unknown. > Yes. > 5. Losses are unknown. > Yes. > > What is known : > 1. The resistance, reactance, admittance per unit / per conductor > 2. Values for Real and Reactive demand at each bus > 3. Limits on voltage magnitude , limits on real and reactive power generation > 4. MVA limits on each line > 5. Fuel cost for each generator. > Yes for all > > So my question is > a. Are the above correct for matpower ? > b. Since matpower uses a non-linear optimisation, is the result a local > minimum or a global minimum? > (for the case of a cost-minimization OPF) ? i.e. the values for voltages, > reactive powers etc, are > globally optimum or perhaps other optimum values for all the unknown > quantities exist ? > I believe most of the optimization tools, such as fmincon in Matlab, find a > local minimum. > > Shri > > Thank you, > Spyros Gian > >
