分布式电源对配电网三段式电流保护的影响

分布式电源的并网,改变了配电网原有的单电源辐射型网络结构,从而影响到原有继电保护的灵敏性、选择性、可靠性.以分布式电源通过10 kV线路并入配电网的模型为例,针对分布式电源的接入位置和容量等因素,推导了含分布式电源配电网的短路电流计算公式,根据并网前后短路电流的大小变化及方向改变,分析了在线路不同位置发生短路故障时分布式电源对配电网三段式电流保护的影响,并通过实例进行MATLAB仿真,验证了分析过程的正确性.

Effects of Distributed Generator on Three-section Current Protection of Distribution Network

With the interconnection of distributed generation （DG）, the original single-source radial-network structure has been changed, and thereby, the sensitivity, selectivity, reliability of the existing relay protection is affected. Based on the model in which a DG is connected to the 10 kV distribution network, considering the capacity and accessing position of DG, the fault current formula of distributed network with a DG is deduced. According to the variation in strength, flowing direction of fault current before and after the interconnection of DG, the effects of DG on three-section current protection of distribution network when the short circuit fault occurs in different positions of the circuit are analyzed. Simultaneously, by an actual example and MATLAB simulation, the correctness of the a- nalysis process is verified.