I was not able to use your data without manual editing, due to the way the text wrapped, but you can try relaxing the Qmin constraint a bit and see how the solution changes to understand the tradeoffs the optimization is making in order to accommodate the Q injection.
-- Ray Zimmerman Senior Research Associate B30 Warren Hall, Cornell University, Ithaca, NY 14853 phone: (607) 255-9645 On Jun 19, 2013, at 6:27 AM, Jiashen Teh <jiashen.te...@manchester.ac.uk> wrote: > Dear Dr Ray, > > I am trying to find out what will happen if I have excessive reactive power > supply on a 3 bus network. > > I did that by forcing synchronous generator to have max and min VAR supply of > 100 MVAR. > > When I do that, I expect bus voltages to increase (done by relaxing bus > voltage limits). However, from MATPOWER simulation shows me that bus voltages > drop instead. > > Could you please explain why this is happening? I attached here are my > network data. Thanks in advance. > > %% bus data > % bus_i > type Pd Qd Gs > Bs area > Vm Va > baseKV zone > Vmax Vmin > mpc.bus = [ > 1 2 0 0 0 0 1 1 0 230 > 1 5 0 > 2 2 0 0 0 0 1 1 > 0 230 1 5 0 > 3 3 0 0 0 0 1 1 > 0 230 1 5 0 > ]; > %% generator data > % bus Pg Qg Qmax > Qmin Vg mBase > status Pmax > Pmin > mpc.gen = [ > 1 0 0 100 0 1.00 100 1 > 400 0 > 2 0 0 50 0 1.00 100 1 > 200 0 > 2 0 0 50 0 1.00 100 1 > 200 0 > 3 0 0 100 100 1.00 100 1 0 > 0 % SG > 2 0 0 0 -20 1.00 100 1 > 0 -100 % Dispatchable load > 3 0 0 0 -33 1.00 100 1 > 0 -165 % Dispatchable load > ]; > %% branch data > % fbus > tbus r x b rateA rateB rateC > ratio angle > status angmin > angmax > mpc.branch = [ > 1 3 0.0342 0.180 0.0106*2 150 85 85 > 0 0 1 -360 360 > 1 2 0.0912 0.480 0.0282*2 100 85 85 > 0 0 1 -360 360 > 2 3 0.1140 0.600 0.0352*2 200 71 71 > 0 0 1 -360 360 > 1 3 0.0342 0.180 0.0106*2 150 85 85 > 0 0 1 -360 360 > 1 2 0.0912 0.480 0.0282*2 100 85 85 > 0 0 1 -360 360 > 2 3 0.1140 0.600 0.0352*2 200 71 71 > 0 0 1 -360 360 > ]; > %% generator cost data > % model Startup Cost Shutdown Cost Coefficient number Coefficient > mpc.gencost = [ > 2 10 0 3 10 100 > 1000 > 2 10 0 3 2.5 5 > 10 > 2 10 0 3 2.5 5 > 10 > 2 10 0 3 0 0 > 0 % SG > 2 10 0 2 5000 > 2500 0 % Dispatchable load > 2 10 0 2 5000 > 2500 0 % Dispatchable load > ]; > > Yours sincerely, > > Jiashen Teh > PhD Student > Electrical Energy & Power Systems Group, School of Electrical & Electronic > Engineering > Ferranti Building (B18), The University of Manchester, M13 9PL, United Kingdom > Tel: +44 (0) 161 306 2263; Mobile: +44 (0) 792 322 4864
