不对称短路故障下电池储能影响交流系统短路电流机理及算法

电池储能系统(BESS)在国内外电力系统中已得到快速发展和广泛应用,但对BESS影响短路电流机理认识尚不深入,且现有短路电流计算标准均未涉及交流系统发生不对称短路故障时考虑BESS影响的短路电流计算方法.基于BESS电磁暂态模型,分析不对称短路故障下BESS电压源换流器(VSC)外环控制器控制方式、VSC外环控制器限幅...

Mechanism and algorithm of short circuit current in AC system affected by BESS under asymmetric short circuit faults

BESS(Battery Energy Storage System) has been rapidly developed and widely used in domestic and foreign power grids. However, there is no in-depth study on the mechanism of short circuit current affected by BESS, and the existing short circuit current calculation standards do not involve calculation method of short circuit current in AC system considering the influence of BESS under asymmetric short circuit faults. Based on the electromagnetic transient model of BESS, the influence mechanism on the output current of BESS under asymmetric short circuit faults is analyzed, such as control mode of outer loop controller of VSC(Voltage Source Converter) of BESS, limiting strategy of outer loop controller of VSC, rated capacity and transmission power of BESS before fault occurs, LVRT(Low-Voltage Ride-Through) strategy of BESS and over-discharge protection strategy of battery. On this basis, the mechanism of short circuit current affected by BESS under asymmetric short circuit faults and different limiting strategies is studied. The study results show that with the increasing reactive power output current of BESS, the phase difference between the short circuit current component provided by BESS and the short circuit current component provided by AC system is smaller, moreover the influence of short circuit current contributed by BESS is stronger. Finally, the iteration algorithm of short circuit current in AC system affected by BESS under asymmetric short circuit faults is proposed. Compared with several common algorithms, the effectiveness and superiority of the proposed algorithm are verified. The research results can provide reference for accurate evaluation of short circuit current level in AC system and reasonable setting of control and protection parameters of BESS.