Optimal reactive power dispatch in a large power system with AC-DC and FACTS controllers

With the increased loading of existing power system, the problem of voltage stability and voltage collapse has become a major concern in power system planning and operation. The dependence of the system voltage profile on reactive power distribution forms the basis for reactive power optimisation. The technique attempts to utilises fully the reactive power sources in the system to improve the voltage profile and also to meet the reactive power requirements at the AC-DC terminals to facilitate the smooth operation of DC links. The method involves successive solution of steady-state power flows and optimisation of reactive power control variables with unified power flow controllers using linear programming technique. The proposed method has been tested on a real life equivalent 96-bus AC and a two terminal DC system.