EVALUATION OF EFFECT OF REACTIVE POWER CONTROL STRATEGY BASED ON VOLTAGE TERMINAL OF GENERATORS ON LIMIT INDUCED BIFURCATION AND DYNAMIC VOLTAGE STABILITY MARGIN Print

Reactive power limit of power system generators has a significant effect on the static voltage stability margin such as maximum load ability point and dynamic voltage stability margin such as HB, LIB and SNB. However, as the load increases, reactive power demand increases as well and thus reactive power limit of generators or other voltage-regulating devices such as Static Var Compensators (SVCs) may reach. Therefore, the voltage stability margin is decreased and or voltage collapse is occurred. Hence, different techniques such as reactive power re-dispatch or change of terminal voltage of generators, use of reactive power compensation devices and optimization method to determine optimum sizing and setting of this device is proposed for improving and increasing reactive power capacity. In this paper, based on a combined method include of time domain simulation, modal analysis and bifurcation theory effect of the regulation of terminal voltage of critical generators on the reactive power limit of generators and dynamic voltage stability status of power system based on the HB and LIB is evaluated. The obtained results give good information for network operators to optimize planning and operating of the power system. The proposed dynamic method is examined on the New England 39-bus, IEEE 68-bus test systems.