That's almost what I had in mind. However, I think you want to use a uniform cost of deviation of Pg from the original dispatch Pg0. Let's call the original marginal cost C and the cost of deviation from that D. So for Pg < Pg0 you want to use C-D and for Pg > Pg0 you want to use C+D.
When you use zero and the original cost in place of C-D and C+D, you are essentially assigning different costs of deviation to different units. -- Ray Zimmerman Senior Research Associate 211 Warren Hall, Cornell University, Ithaca, NY 14853 phone: (607) 255-9645 On Jul 5, 2011, at 4:40 PM, przemyslaw_lipiecki wrote: > Thank You for your explanation. > For example: > First I’ve run standard OPF on case13 but without any branch constraints ( > Rate A in branch data is 9999 ) and generator cost data looks as shown below: > > gencost = [ > 2 0.00 0.00 3 0.000000 90.000000 0.000000; > 2 0.00 0.00 3 0.000000 70.000000 0.000000; > 2 0.00 0.00 3 0.000000 60.000000 0.000000; > 2 0.00 0.00 3 0.000000 80.000000 0.000000; > 2 0.00 0.00 3 0.000000 50.000000 0.000000; > ]; > > As a result P1 = 30MW ; P2 = 60MW ; P3 = 60MW ; P6 = 45.74MW and P7 = 60MW > > Next I’ve set constraints on branches and created new gencost matrix using > piecewise linear cost. > Because all generators are limited Pmin = 30MW ; Pmax = 60MW I haven’t > changed cost for P1 (becuse P1 = Pmin ) but for generators P2, P3, P7 I’ve > changed cost to 0 (because P2 = P3 = P7 = Pmax). For P6 from 0 – 45.74MW cost > is 0 and from 45.74 – 60MW cost is 80. > With this settings I’ve run OPF. > > As a result P1 = 30MW ; P2 = 57.25MW ; P3 = 60MW ; P6 = 52.69MW and P7 = > 56.71MW > And these values are minimum control change, am I correct ? > > Beat Regaeds > Przemek Lipiecki > > > Dnia 5 lipca 2011 19:28 Ray Zimmerman <[email protected]> napisał(a): > >> MATPOWER only solves OPF problems with continuous variables. I believe that >> minimum control changes is implicitly a discrete variable problem. A >> possibly related continuous variable problem would be to minimize the change >> in dispatch from a given dispatch point. This can be accomplished by >> shifting the portion of the each cost curve to the right of the dispatch >> point up by some amount (an incremental cost) and the portion to the left >> down by some amount (a decremental cost). >> >> > >
