I'm afraid I don't have any papers that discuss it, but I remember running into an example several years ago where the OPF was giving a few nodal prices that were significantly higher than the highest generator cost. When I investigated to try to understand the issue and uncover the possible "bug", using sensitivity analysis, I discovered that the high nodal price was correct. It was due to a large shift from inexpensive to expensive generation that was required by a marginal increment in load at the bus in question.
-- Ray Zimmerman Senior Research Associate 419A Warren Hall, Cornell University, Ithaca, NY 14853 phone: (607) 255-9645 On Nov 29, 2012, at 5:43 PM, Geev Mokryani <[email protected]> wrote: > Dear Prof. Zimmerman, > > Thank you so much for your reply and very useful comments. > > I need some papers or documents to verify this issue that you discussed. I > will be appreciated if you address or send me a paper or a report about this. > > Best regards, > > Geev > > > On Thu, Nov 29, 2012 at 5:52 PM, Ray Zimmerman <[email protected]> wrote: > If the dispatchable load price is at $200, then if congestion causes one of > these loads to become marginal (not fully dispatched), the price at that bus > will be $200. Due to losses, prices at nearby buses could be slightly higher. > > I should also mention that, with inelastic demand, it is possible for nodal > prices to go well above the highest generator offer in a highly constrained > system. The intuition is that an extra increment of load at that bus may > require a much larger shift of generation from cheap to expensive sources. > > -- > Ray Zimmerman > Senior Research Associate > 419A Warren Hall, Cornell University, Ithaca, NY 14853 > phone: (607) 255-9645 > > > > > On Nov 29, 2012, at 11:26 AM, Geev Mokryani <[email protected]> wrote: > >> Dear Prof. Zimmerman, >> >> >> My main problem is this: I have generators offers price of 80 USD/MWh and >> bids of dispatchable loads price of 200 USD/MWh and in the network I have >> congestion. When I do runmarket in MATPOWER at some buses it gives me the >> LMP around 200 USD/MWh. Could you please let me know how it occures and why? >> Usually it has to give us the LMP in the range between 200 and 80 USD/MWh. >> >> If you need I can send the network and m.file. >> >> Looking forward to hearing from you. >> >> >> Best regards, >> >> Geev > >
