I guess the answer is "maybe", as it depends on the reactive power needs of both lines and loads. The best way to know is to start solving just regular powerflows before you attepmpt OPF. Make all solar panel generators run as PV-type (use VG=1 for all of them), and without enforcing Q limits (use powerflow option pf.enforce_q_lims=0). Look at the Q values resulting from the solutions you obtain, and you will get a feeling as to how much reactive power they will need to inject/absorb. That will help you to bracket the [QMIN, QMAX] values that you need for feasibility. Also the values of the power factors that you would need to use when type-switching them to PQ mode.
I would also make sure that you obtain good powerflows with all solar panels running as PQ, before attempting OPF, just in case. -- Jose L. Marin Grupo AIA 2016-05-16 19:26 GMT+02:00 Zé Miguel <zem20...@hotmail.com>: > Hi Jose, thank you for your help. > > So, the only change that I need to implement in my .m file is the QMAX of > each PV generator, according to the specified power factor. Right ? > > Cheers, > José Miguel > > ------------------------------ > From: mari...@aia.es > Date: Fri, 13 May 2016 17:39:08 +0200 > Subject: Re: Convergence problems in a Microgrid > To: matpowe...@list.cornell.edu > > > > You won't even have a mathematically solvable powerflow unless you allow > at least one generator to inject/absorb reactive power (since you do have > loads with a reactive component). PV generation actually can do this, > through their inverters. The following article may help: > http://solarprofessional.com/articles/design-installation/reactive-power-control-in-utility-scale-pv?v=disable_pagination > Reactive capabilities of about -0.90 to +0.90 power factor are cited in > there. > > -- > Jose L. Marin > Grupo AIA > > > > 2016-05-13 17:19 GMT+02:00 Zé Miguel <zem20...@hotmail.com>: > > Hello, > > Thank you for your help Ray. What do you suggest to solve this issue, > since my test-microgrid only have PV generation ? > > Cheers, > Zé Miguel > > ------------------------------ > From: r...@cornell.edu > Subject: Re: Convergence problems in a Microgrid > Date: Thu, 12 May 2016 13:17:13 -0400 > To: matpowe...@list.cornell.edu > > It appears that you have no reactive generation capacity to meet any > reactive demand. > > Ray > > > >> case_info('rede_teste') > Checking connectivity ... single fully connected network > Elapsed time is 0.007586 seconds. > > ================================================================================ > Full > System > Number of: ---------- > buses 33 > loads 28 > on 28 > off - > fixed 28 > dispatchable - > on - > off - > generators 15 > on 15 > off - > shunt elements - > branches 32 > on 32 > off - > ties (off) - > > Load > active (MW) > dispatched 0.2 > fixed 0.2 > dispatchable - > nominal 0.2 > on 0.2 > off - > fixed 0.2 > dispatchable - > on - > off - > reactive (MVAr) > dispatched 0.1 > fixed 0.1 > dispatchable - > nominal 0.1 > on 0.1 > off - > fixed 0.1 > dispatchable - > on - > off - > > Generation > active (MW) > dispatched - > max capacity 0.1 > on 0.1 > off - > min capacity - > on - > off - > reactive (MVAr) > dispatched - > max capacity - > on - > off - > min capacity - > on - > off - > > Shunt Injections > active (MW) - > reactive (MVAr) - > > Branch Losses > active (MW) - > reactive (MVAr) - > > DC line > export (MW) > dispatch - > max capacity - > on - > off - > min capacity - > on - > off - > > Reference Buses > num of ref buses 1 > ref bus numbers 1 > >> > > > On May 12, 2016, at 7:51 AM, Zé Miguel <zem20...@hotmail.com> wrote: > > Dear all, > > I'm trying to simulate the operation of a microgrid functioning in > islanded mode composed by 15 photovoltaic (PV) micro-generation units, > therefore I classified all the buses with generation as PQ, since solar > panels only produce active power. I set that, to all the generators: > > PG = PMAX = PMIN > QG = QMAX = QMIN = 0 > > To evaluate the load curtailment I modelized all the loads as dispatchable > loads. > > My slack bus has a baterry, which I modelized from the addition of two > dummy generators: one that modelizes the behaviour of the battery when it's > charging (LOAD) and another representative of the behaviour of the baterry > when it's discharging (GENERATOR). > > The problem is that after running the OPF I noticed that normally it > doesn't converge; and when it does the values of the PG produced by the > dispatchable loads are practically zero (so, I have a total load > curtailment), even when I have solar power available. > > Other issue is that the baterry isn't working (the powers of the two dummy > generators are equal, with opposite signs), though it was enough energy to > cover part of the loads. > > Anyone have an idea of the cause of this behaviour ? > > PS - I've attached my microgrid test network. > > Cheers, > Zé Miguel > > > <rede_teste.m> > > > >
