A new coordinated voltage/reactive power control scheme for interconnected power systems

As interconnected power networks becoming increasingly meshed, the non-ignorable effects of interaction could cause some adverse consequences, such as reactive power unreasonable distribution, control oscillation or even instability, if regional automatic voltage control(AVC) systems operate uncoordinatedly. A new coordination variable named Voltage/Var Area Control Error(VACE) is proposed based on sensitivity analysis and linearization. The new coordination variable can distinguish whether a disturbance occurs inside or outside the region and indicate the magnitude and direction of inter-regional interactions. Based on this coordination variable, a new coordinated control scheme is proposed. The responsibility of AVC system in each region is explicitly defined. If each control region keeps the VACE values close to zeros, the negative effect between different AVC systems can be reduced. The simulation results of the New England System show that with VACE under consideration, control oscillation is effectively attenuated and higher reactive power reserve is achieved.