距离保护在含分布式电源配网中的应用

Study on Application of Distance Protection in Distribution System with Distributed Generation

由于传统电流保护在含分布式电源配网中的缺陷,为此本文考虑将距离保护应用到配电网中,通过仿真验证了距离保护可以弥补原电流保护的不足。但是距离保护应用到中低压配电网中,也会产生一些问题,尤其是过渡电阻对距离保护的影响。本文分析了分布式电源接入配电网后形成的双侧电源线路上发生短路故障时过渡电阻对距离保护的影响,利用序分量算法研究了一种不受过渡电阻影响,通过采集线路的电流电压相量值,就能够正确测量故障阻抗值的算法。并在Matlab平台上搭建了含风机的配电网模型,进行了仿真验证。仿真结果证明该算法能够正确测量故障阻抗值,准确识别保护区内的故障,且计算精度高,能很好地消除过渡电阻对距离保护的影响。

Distributed generation changes distribution network structure. Because of limitations of current protection in distribution system with distributed generation, the paper applies distance protection to distribution network. Re- sults of simulation verified distance protection making up the loss of current protection. But it can cause some prob- lems when distance protection applied to distribution system, especially the effect of transition resistance. The paper focuses on the effect of duplicate supply with transition resistance. In order to reduce the impact of transition resist- ance to distance protection, in this paper, sequence component algorithm can be achieved. The algorithm collects cur- rent and voltage values. It is not influenced by the transition resistance and can measure fault impedance. The model of distribution system with wind turbines is developed in the MATLAB environment. Results of simulation verified the algorithm can eliminate the impact of the transition resistance from the protection, accurately reflects the positive sequence resistance from the point of failure to protection device.