The LMPs for a DC OPF problem do incorporate any generator limits as well as generation cost. Consider the case with no congestion, where the LMPs are uniform at all nodes. For nodes with generators that are dispatched between their lower and upper limits, the LMP equals their marginal cost of generation. For a node with a generator at a binding upper (lower) limit, the LMP will equal the marginal cost of generation plus (minus) the shadow price on the binding upper (lower) generation constraint.
Ray > On Nov 19, 2015, at 8:27 AM, Victor Hugo Hinojosa M. <[email protected]> > wrote: > > Dear Jovan and Sarmad, > I agree with your comments about LMP. In this analysis I’m not considered the > congestion. If the generation inequality constraints aren’t active, Matpower > prints this information correctly, and It’s possible to realize different > prices when the lines is congested. Sarmad, I’ve verified your idea. Despite > the fact that the shadow price for the minimum or maximum is active, the LMP > shown are the same for all buses. > My question is about why LMP doesn’t include the Lagrange multipliers related > to generation inequality constraints. I did a model using the dual problem > for the DCOPF, and I realized that dual constraints are the prices for each > buses. It’s very clear in those constraints that those “prices” take into > account the marginal cost, the congestion cost through the partial > transmission distribution factors (PTDF) and the generation constraints. > In the technical literature for the DCOPF (losses are neglected), the LPM are > modeled considering energy cost and congestion cost. However, in the book > “Spot pricing of electricity” from F. Schweppe et all, authors include these > shadow prices in order to compute the spot prices. > I’d like to know your feedback about these comments. > Regards, > Vh > > De: [email protected] > [mailto:[email protected]] En nombre de Jovan Ilic > Enviado el: jueves, 19 de noviembre de 2015 1:13 > Para: MATPOWER discussion forum > Asunto: Re: Question about LMP > > > Dear Victor, > > If there is no congestion in the network, there is the same LMP at all the > nodes. > The LMP consists of loss, congestion, and energy costs. DCOPF has no > losses, and if there is no congestion only the energy cost is accounted for. > You can think of it as if since there is no congestion or loss cost the > energy can > be distributed to all nodes at the same price. > > Regards, > Jovan Ilic > > On Wed, Nov 18, 2015 at 4:37 PM, Victor Hugo Hinojosa M. > <[email protected] <mailto:[email protected]>> wrote: > Dear Prof. Zimmerman, > > I have a question about Local Marginal Prices (LMP) that are shown in > Matpower. > > The definition of the LMP is the marginal cost of supplying, at least cost, > the next increment of electric demand at a specific location (node) on the > electric power network, taking into account both supply (generation/import) > bids and demand (load/export) offers and the physical aspects of the > transmission system including transmission and other operational > constraints. > > When it is performed a DCOPF, Matpower shows LMP for each bus considering > the marginal cost (energy cost) and the congestion cost so that I'd like to > know why the generation constraints (maximum and minimum power) aren't > considered in the LMP. > > Thank you so much for your ideas and comments. > > Regards, > > Vh > > >
