Hmmm ... it sounds like you have already tried something very close to what I was going to suggest. If you solve the case without line constraints, then use the resulting dispatch to define the size of block one for a set of offers, where block one has a zero price and block two has some uniform non-zero price.
This should minimize the quantity of redispatch needed to meet the line constraints. If some gens are dispatched at zero, then it must mean that using them at all would force a larger redispatch of other units. Hope this helps, -- Ray Zimmerman Senior Research Associate 211 Warren Hall, Cornell University, Ithaca, NY 14853 phone: (607) 255-9645 On May 12, 2011, at 3:38 PM, Malcolm Barnacle wrote: > Hi fellow Matpower users, > > I am trying to run a DC OPF on a network consisting of 184 generators and > 1204 branches. The network is heavily strained and there are, currently, 35 > thermal overloads present. I have an expected generation output for each > generator type in column 2 of the gen matrix. I want to find out how the > generation output, in column 2, varies, due to the restrictions imposed by > the thermal line ratings, without the added influence of cost. In other > words, for the generator's that are required to reduce their outputs due to > thermal line ratings, I want to see what generation output they are still > able to provide under this heavily constrained network. > > When I run a DC OPF, giving an identical polynomial cost model for each > generator (to eliminate preference), the gen matrix output does not provide > me with the solution I require. Instead it reduce's alot of generators > directly down to zero output, and increases others to their maximum. I was > hoping, instead, for the DC OPF to reduce the generation output of some > generators, that are restricted by the network, as far as is needed and > increase the generation output of other generators that are not restricted, > to compensate. > > I am only interested, at this stage, in finding out about the generators that > are required to reduce their output, and to what extent they have to do this. > Does anyone have any suggestions on how I can do this? > > I have tried to use offer prices (consisting of the same offer price for the > first capacity block and varying offer prices for the second block) for each > generator and use the off2case function, followed by the uopf function, but > this still results in some generation outputs being reduced all the way down > to zero, even though the network would allow for atleast some generation > output. > > Thank you all for your attention. I would greatly appreciate some help on > this matter. > > Regards > Malcolm Barnacle > > --------------------------------- > Malcolm Barnacle, MEng MIET > PhD Research Student > > Institute for Energy and Environment > Department of Electronic and Electrical Engineering > University of Strathclyde > Royal College Building > 204 George Street > Glasgow G1 1XW > > Email: [email protected] > Tel: +44 (0)141 548 4839 > > The University of Strathclyde is a charitable body, registered in Scotland, > number SC015263
