Coordinated Reactive Power Optimal Control Considering the Voltage Security of Wind Farm

Abstract

With the increasing penetration of wind farms (WFs) in power systems, they are demanded to support reactive power to guarantee the economical operation of power grids. Limited by the operational security of WFs, their reactive power output may not meet the system requirements. This paper introduces a bi-layer coordinated reactive power optimal control method to ensure the WFs' reactive power support to the system while guaranteeing the operational security and economy of them. The system layer focuses on reducing network loss through coordinating the reactive power outputs of WFs, transformers and other sources. The WF layer tries to meet the reactive power demands set by the system layer while ensuring the voltage security in WF with the minimum network loss. Information of the reactive power demand and the WFs' maximum reactive power supply within their voltage security limitation is exchanged between the two layers and the iteration will converge until all WFs meet the system's reactive power demands. The validity of the strategy is validated in the modified IEEE 14-bus system and an actual regional power system of China.