Re: Non-trapezoidal capability curve

Mon, 26 Jan 2015 09:09:06 -0800

Hi Irina,

Thanks for the additional information. You uncovered a bug in the hasPQcap() function that affected generator capability curves which have increasing Q capacity as P increases. I’ve attached the fixed version and a test file which should fail on the old version and pass on the fixed version.

I also wanted to thank you publicly for your persistence in looking into and reporting what appeared to be suspicious results. In research, it is always dangerous to ignore an unexpected result you can’t explain. You never know the impact until you understand the reason.

Thanks,

-- 
Ray Zimmerman
Senior Research Associate
B30 Warren Hall, Cornell University, Ithaca, NY 14853  USA
phone: (607) 255-9645


Attachment: t_hasPQcap.m
Description: Binary data

Attachment: hasPQcap.m
Description: Binary data



On Jan 23, 2015, at 10:07 AM, Ray Zimmerman <[email protected]> wrote:

Hi Irina,

I believe this should work. I can’t think of anything that should prevent it from working. Let’s see if we can sort this out off-list.

Can you point me to the index of a specific generator whose constraint is violated in the solution?

    Ray



On Jan 23, 2015, at 4:57 AM, Irina Boiarchuk <[email protected]> wrote:

Dear Matpower community,

I have a question regarding capability curves of generators. It was mentioned here and in the Manual that capability curve has a trapezoidal shape. In my case I'd like to modify the curve to be triangular. Therefore, the six points I've specified in mpc.gen are:

mpc.gen(:,11) = 0;                                 % pc1
mpc.gen(:,12) = mpc.gen(:,9)*cos(0.85);  % pc2

mpc.gen(:,13) = 0;   % min q at pc1
mpc.gen(:,14) = 0;   % max q at pc1

mpc.gen(:,15) = mpc.gen(:,5);       % min q at pc2
mpc.gen(:,16) = mpc.gen(:,4);       % max q at pc2

But when I check results of OPF I see that reactive power output of some generators is outside of these limits of capability curves. 

Could you tell me if such 'triangular' formulation of capability curve is handled correctly by OPF? Or only trapezoidal shapes are allowed?
Unfortunately, I cannot understand why OPF converges with such constraints violation....

My system has additional gen buses which play a role of unlimited compensators, so in case of violation of generator's capability curve limits, reactive power should be supplied from compensators (I suppose). Costs of reactive power for generators and compensators are equal.
The mpc file is attached.

I'm looking forward to your reply and would appreciate any help!

Best regards,
Irina Boiarchuk
<mpc123.mat>


Reply via email to