基于复合故障补偿因子的微电网反时限电流保护方法

为了解决逆变型分布式能源(Distributed Generator, DG)对微电网保护速动性和协调性的影响，提出了一种基于复合故障补偿因子和天牛须搜索(Beetle Antenna Search, BAS)算法的改进反时限微电网电流保护方法。首先，通过分析故障时保护安装处的电压分布特性，并结合测量阻抗特征构建复合故障补偿因子，以解决反时限过电流保护由于短路电流变化引起的动作延时问题，提高保护速动性。同时，为了解决DG接入、微电网运行方式改变等因素引起的微电网保护协调问题，利用BAS算法对改进反时限电流保护的参数进行优化，以保证相邻保护的协调配合。最后，在DIgSILENT/PF软件中建立微电网仿真模型，以验证改进方法的有效性。仿真结果表明，与传统反时限过电流保护相比，改进保护方法在速动性方面明显提升，且在微电网不同运行模式、故障条件下均满足协调性要求。

Inverse-time current protection method of a microgrid based on a composite fault compensation factor

In order to solve the problem of the influence of an inverter interfaced Distributed Generation (DG) on the speed and coordination of microgrid protection, an improved inverse-time microgrid current protection method based on composite fault compensation factor and a Beetle Antenna Search (BAS) algorithm is proposed. First, by analyzing the voltage distribution characteristics of the protection installation at the time of the fault and combining the characteristics of the measured impedance, a composite fault compensation factor is constructed. This solves the problem of long time delay caused by the short-circuit current changes in inverse-time overcurrent protection and improves the speed of protection. In addition, in order to solve the problem of microgrid protection coordination caused by factors such as DG access and changes in the operation mode of microgrids, the BAS algorithm is used to optimize the parameters of improved inverse-time overcurrent protection to ensure the coordination and cooperation of adjacent protections. Finally, a microgrid simulation model is built in DIgSILENT/PF software to verify the effectiveness of the improved method. The simulation results show that compared with the traditional inverse-time overcurrent protection, the improved protection method significantly improves the speed performance and meets the coordination requirements under different operating modes and fault conditions of the microgrid. This work is supported by National Natural Science Foundation of China (No. 51807114).