含分布式电源的闭环配电网保护方案研究

Protection Schemes for Closed Loop Distribution System with Distributed Generation

分布式电源接入配电网改变了系统的潮流分布和短路电流。配电网闭环运行可以提高系统供电可靠性,更好地维持分布式电源稳定运行,更适应于含有分布式电源的配电网。但同时,系统短路电流增大,对保护的要求更高。为此,有针对性地探讨了几种对应的保护方案,在此基础上,提出一种改进型纵联过流保护方案。该方案只需对带有分布式电源母线两侧加装一个断路器,其他线路均采用原配电网的单侧断路器。该保护方案投资少,并可快速可靠地切除故障。

With the connected of distributed generation,the power flow and short circuit currents in distribution system are changed.Closed loop operation improving the continuity of power supply and the stability of distributed generation.Thus it＇s much suitable for distribution system with distributed generation.But it also increases the short circuit currents.So,it requires more completed protection scheme.This paper investigates some of the corresponding protection schemes.And also proposes a novel protection scheme called the improved pilot wire over-current protection.It only installs one more circuit breaker on the side of power bus with distributed generation,and holds the single side circuit breaker circuit breakers used in the traditional distribution system.This protection could cut the fault instantaneously and reliably,and reduce the investment.