Dear Dr Zimmerman,I am using an 11kV distribution system, which is consisted of
two radial circuits connected by a normally open point. The network has one
grid infeed (Vg=1) whereas all the other nodes where occupied only by loads
(with Vm<1). Now I increase the loading of the circuits and have added
distributed generators in all the load buses, which will only operate in case
there is a line fault in the system(otherwise there is no need for them to
operate because the grid infeed can give really high power, comparing to the
load and the lines rating is also really big) . For the voltage problems, I
have added reactive power in each node. The thing that confuses me is , that
when there is a line fault (the worst case scenario line loss), there is always
energy not supplied , although a path from the main supply exists and also the
rating of the lines allows that power to pass through the line. This happens
mainly for the most distant nodes. In that case, all the available distributed
generators generate at their Pmax , but the grid infeed value is really small.
Why the opf prefers to use the really expensive generators of the distant
nodes (used for the energy not supplied) instead of absorbing that power from
the free of cost grid infeed? I can guess that is a reactive problem or a
voltage problem but I cannot find a suitable solution. Any help would be of
high importance,King Regards,Angelina
