By default the cost of reactive power provided by generators is zero in MATPOWER. However, this does not mean that the nodal price of reactive power is necessarily zero. Nodal prices are sensitivities of overall objective function value to an incremental change in load at the bus. Because of the fact that an incremental change in reactive load at a bus may require a redispatch, with some associated cost impact, of active power, the reactive power nodal price can be non-zero even if all reactive power generation is free. This will happen at buses where the corresponding generator is at a reactive limit, or if there is no generator at the bus.
The computation of the prices themselves are handled by the individual solvers. Each solver computes the dual variables in according to its own algorithm. -- Ray Zimmerman Senior Research Associate 419A Warren Hall, Cornell University, Ithaca, NY 14853 phone: (607) 255-9645 On Mar 11, 2013, at 2:51 AM, muisyo irene <[email protected]> wrote: > Hi, > > > > I am a student in Jomo Kenyatta University of Agriculture and Technology > (JKUAT), in Kenya – Africa. > > > > I am doing my research on nodal pricing (using MATPOWER) and I’m writing to > get more information on how nodal prices are obtained, especially for > reactive power.I have run the AC OPF, got the results but I want to > understand how they are arrived at. For example in case6ww, the quadratic > cost of P is given, hence Lambda can be obtained, but the cost of Q is not > given. I looked at grad_copf and fun_copf but it’s still not clear to me. > > > > Kindly assist. > > -- > Regards, > Irene Muisyo > +254 721 332 377
