Hi,
I am currently working with a model of a 1000+ bus transmission network.
I wanted to implement the dropping efficiency factor of power plants when working under off-nominal conditions. Therefore i tried altering the cost function, but with that my opf doesn't converge anymore, which I can't explain.
Here's what I did:
I assigned each power plant a quadratic polynomial cost function (ax² + bx +c).
a = - 1 * (costs at nominal power output) / (nominal power output)²;
b = 2 * (costs at nominal power output) / (nominal power output);
c = 0.
So basically a function with its apex above the nominal power output, sloping down to 0 towards the origin.
Does someone have an idea, why the opf stopped converging? Or what i could do differently?
I also unsuccesfully tried using the solver IPOpt.
And I tried using a piecewise linear cost function instead looking approximately the same as the quadratic function. With this function the opf did converge but not to a feasible solution. At least for this case I think it doesn't work because the shape of the function is not "convex" as described in the manual.
I would be grateful for any help, regards
Julian B.
