Risk analysis of power systems for both real and reactive power

With the high penetration of renewable energy sources, the reliability of power systems becomes more vulnerable than ever because of the greater uncertainty and intermittence in power generation. Reactive power plays an important role in the power system reliability, because it is closely related to the system voltage stability and voltage collapse. However, reactive power-related reliability issues are seldom emphasized in conventional power reliability evaluations. This article investigates power system reliability of real and reactive power. Real and reactive power shortages and the associated voltage violations due to system failures are considered on reliability evaluation of power systems. A three-stage load-shedding technique for post contingencies is implemented to determine the contributions of real and reactive power on the system reliability and to find an optimal way to release network violation. The results provide the detailed information on power system planning and operation for system planners and operators from real and reactive power aspects.