Carlos, Thank you once more for your help. My objective is to solve an optimum
power flow and I want to obtain an optimal voltage profile and minimise
dissipation losses. I have modelled the Photovoltaic generators to inject
active(Pmax=0.032MV) & reactive power and tested the network for convergency
using pf before proceeding to the opf model. The network converged when I
modelled the buses containing the photovoltaic generators as either slack bus
or PQ bus but does not converge when I model the buses as PV. Would the
situation change if I test the model using opf? I have one traditional
generator modelled as a HV infinite source.
> Date: Sat, 1 Sep 2012 22:32:51 -0400
> From: [email protected]
> To: [email protected]
> Subject: Re: Photovoltaic Generators modelling
>
> Richard:
>
> Are you sure that you want to specify the power injections of the
> photovoltaic generators as zero in a power flow?
>
> The trapezoidal model for (P,Q) feasibility is intended for use in an
> optimal power flow setting, not a power flow setting. If you have all
> generators with Pg = 0 then you may not have enough generation to meet
> the demand. Do you have additional, traditional generators?
>
> In a power flow, the reactive dispatches are found such that the voltage
> at the bus is at the specified Vg. In an optimal power flow, the
> reactive dispatches are modulated to obtain an optimal voltage profile.
>
> Which is it that you want to achieve? Do you want to solve a power flow
> or an optimal power flow?
>
> Richard Ngonga wrote:
> > Hi ,
> >
> > I have modelled 20 photovoltaic generators in a 100 bus radial
> > distribution network with the parameters shown below(in the generator
> > field). The problem I am having is that when I model the nodes with
> > the Photovoltaic generators as PV buses the AC Newton Raphson loadflow
> > does not coverge, but when I model the same nodes as swing
> > buses(option 3) the network converges. My aim is to model
> > the photovoltaic generators as var controllers, is there a way this
> > can be done in Matpower?
> >
> > Pg=0
> > Qg=0
> > Pmin = 0
> > Pmax = 0
> > Qmax = 0.01563
> > Qmin = -0.01563
> > mBase=100
> > Pc1 = 0
> > Qc1min = 0
> > Qc1max = 0
> > Pc2 = 0.032
> > Qc2min = -0.01563
> > Qc2max = 0.01563
> >
> > Richard Ngonga
> >
> >
> > > Date: Thu, 30 Aug 2012 21:36:52 -0400
> > > Subject: Re: Photovoltaic Generators modelling
> > > From: [email protected]
> > > To: [email protected]
> > >
> > > Assuming that you want to specify a reactive dispatch capability
> > > within the .9 power factor cone that we talked about earlier, and
> > > assuming Pmin = 0 and Pmax = 1MW, then at Pmax the reactive dispatch
> > > could be in [-0.4843, 0.4843] MVAr. Then, the following parameters
> > > define that cone for Matpower:
> > >
> > > Pmin = 0
> > > Pmax = 0
> > > Qmax = 0.4843
> > > Qmin = -0.4843
> > > Pc1 = 0
> > > Qc1min = 0
> > > Qc1max = 0
> > > Pc2 = 1
> > > Qc2min = -0.4843
> > > Qc2max = 0.4843
> > >
> > >
> > >
> > >
> > > On Thu, Aug 30, 2012 at 4:56 PM, Richard Ngonga
> > <[email protected]> wrote:
> > > >
> > > > Hi Carlos,
> > > >
> > > > Do I have to model photovoltaic generators in matpower like diesel
> > > > generators? My aim is to model photovoltaic inverters as dispatchable
> > > > reactive power sources using Matpower's trapezidal modeling of the
> > (P,Q)
> > > > feasible region. What is the best way to model them in matpower?
> > > >
> > > > Regards
> > > >
> > > > Richard
> > > >
> > > >> Date: Mon, 20 Aug 2012 12:23:10 -0400
> > > >> From: [email protected]
> > > >> To: [email protected]
> > > >> Subject: Re: PV Generators and Transformer modelling
> > > >>
> > > >> So, if the reactive dispatch of your generators is constrained to be
> > > >> within a 0.95 power factor, then you can use MATPOWER's trapezoidal
> > > >> modeling of the (P,Q) feasible region. as opposed to simple bound
> > > >> constraints on P and Q
> > > >> for a generator. In your case, if Pmin reaches down to 0, then
> > you have
> > > >> more of a cone instead of a trapezoid.
> > > >> This is best explained using a picture; see manual for details.
> > > >>
> > > >> carlos.
> > > >>
> > > >> Richard Ngonga wrote:
> > > >> > Thanks for that, I mean photo voltaic. I am modelling PV generators
> > > >> > that are able to dispatch reactive power(i.e operating at -0.95 to
> > > >> > 0.95 power factor).
> > > >> >
> > > >> >
> > > >> > > Date: Mon, 20 Aug 2012 01:34:09 -0400
> > > >> > > From: [email protected]
> > > >> > > To: [email protected]
> > > >> > > Subject: Re: PV Generators and Transformer modelling
> > > >> > >
> > > >> > > Um, an unfortunate crisscross with acronyms... by PV
> > generators do you
> > > >> > > mean power-voltage as in classical power flow problem
> > parlance or do
> > > >> > you
> > > >> > > rather mean "photo voltaic"?
> > > >> > >
> > > >> > > Richard Ngonga wrote:
> > > >> > > >
> > > >> > > > Hi there,
> > > >> > > >
> > > >> > > > I am working on a thesis on reactive power control on a
> > distributed
> > > >> > > > network with transformers and PV generators. Can I model
> > the PVs as
> > > >> > > > generators on a PV bus or should I model them as capacitors
> > on a PQ
> > > >> > > > bus? I'm also having problems modelling transformers from a
> > 20KV
> > > >> > > > network to a 0.4KV network; when I use the transformer
> > ration 50 I
> > > >> > get
> > > >> > > > very large power flows and losses. The transformer data is: Sn
> > > >> > 400KVA,
> > > >> > > > Usc=10%, Uprm/Usec=20/0.4(KV) and Usec set=1.05.
> > > >> > > >
> > > >> > > > Regards
> > > >> > >
> > > >> > >
> > > >>
> > > >>
> > >
>
>
