Coordinated voltage and island Self-healing control of the BESS group

Abstract

In order to solve the problem of voltage fluctuation caused by distributed generation connected to feeder and the failure of reclosing caused by disordered operation after isolated island, a comprehensive control method including coordinated voltage controller and frequency deviation controller is proposed in this paper, which is applied to distributed energy storage group.When the feeder is connected normally, the frequency deviation controller is invalid, and the coordinated voltage controller based on the improved droop control strategy improves the voltage of each node of the feeder.The improved droop control strategy adjusts the voltage control behavior of BESS through the slope to ensure that multiple BESS jointly undertake the voltage control task, and effectively suppress the voltage fluctuation of feeders. In order to simplify the calculation method of each slope of BESS group, a simple calculation method of BESS slope considering line impedance and capacity is proposed;When the feeder is isolated due to fault, the frequency deviation controller based on double hysteresis loop activates the frequency control loop to control the frequency and voltage of the island together with the coordinated voltage controller, so as to realize the self-healing of the island, and then realize the grid re-connection of the island through reclosing.In addition, a real-time closed-loop simulation platform Composed of RTDS and line protection device is built.The voltage control effect is verified by simulating the power fluctuation of feeders, and the effect of islanding self-healing is verified by simulating the whole process from feeder fault, fault isolation, island self-healing to grid-re-connection.Index Terms: BESS group; Improved droop control; Slope setting; Coordinated voltage control; Frequency deviation control; Island self-healing.