分布式电源对配电网继电保护的影响分析及对策

Analysis of the Effect and Countermeasures of Distributed Generation on Distribution Network Protection

分布式电源的短路电流特征可分三类,与传统的同步发电机不尽相同。通过分析同步发电机型、异步发电机型、逆变型分布式电源型的短路电流特征,发现同步发电机型的短路电流最具代表性,为此利用PSCAD仿真软件,构建等效的分布式电源接入配电网模型,分析对继电保护的影响。结合实际算例,分析分布式电源接入配电网后,对传统三段式电流保护造成保护灵敏度下降、保护出现误动、重合闸不成功等原因,提出将距离保护应用于分布式电源接入的配电网。计算结果表明,接入距离保护装置必要可行,可以有效地解决三段式保护灵敏度下降和误动等问题。

The short circuit current characteristic of the distributed generation can be divided into three catego ries, is different with the traditional synchronous generators. Through the analysis of short circuit current characteristics of synchronous generator, induction generator, inverter type distributed power type, found the short-circuit current of synchronous generator is the most representative, so using PSCAD simulation soft- ware, distributed generation connected to distribution network model to construct the equivalent, analysis the influence on relay protection. Combined with a practical example, the analysis of distribution system with distributed generators, resulting in decreased sensitivity, protection of protection maloperation, reclosing unsuccessful on the traditional three stage current protection of distribution network, the distance protection used in distributed power supply access. The calculation results show that, the access distance protective device is necessary and feasible, and can effectively solve the problem of falling three section type and sensitivity of protec tion maloperation.