苏州电网并网分布式电源防孤岛的继电保护控制策略研究

目前孤岛检测和防孤岛策略主要是基于并网分布式电源的特性而设计，而鲜有以孤岛发生时公用电网的电气特性为核心的继电保护防孤岛策略的研究。为了找到一种利用公用电网继电保护防孤岛的新方法，结合苏州电网，通过对孤岛形成机理的分析，找出了孤岛发生前后零序电压的变化规律。进而基于零序电压的变化规律设计了公用电网防孤岛的继电保护控制策略。数值仿真及苏州电网的防孤岛实例验证了该并网分布式电源防孤岛的继电保护控制策略的有效性。结果表明，该控制策略具有较高可靠性和实用前景。

Research on the relay protection control strategy for anti-islanding of distributed generator connected to the power grid of Suzhou

The present study on islanding and anti-islanding is mainly based on the characteristic of the distributed generator, however there is few research on anti-islanding by relay protection based on the electrical characteristics of the public power grid when islanding occurs. In order to find a new method which is using public power grid relay protection for anti-islanding, the analysis of the formation of islanding in Suzhou power grid is given, and the changing regulation of the zero-sequence voltage is then found. So the relay protection of public power grid for anti-islanding can be designed with zero-sequence voltage. The relay protection for anti-islanding of distributed generator is proved reasonable both by the simulation on PSCAD and the practical application of the strategy in power grid of Suzhou. The study proves that the relay protection strategy has high reliability and practical prospect.