分布式电源并网对配网继电保护的影响及应对方案

Influence of Distributed Generation Grid Connection on Distribution Network Relay Protection and Countermeasures

大量分布式电源并入配电网将对系统运方、潮流走向及短路特性等产生重大影响,并导致电流保护选择性、速动性等主要指征出现下滑甚至失效,需要统筹经济性、可靠性、安全性等原则提出综合性保护改进方案。首先对当下配电网广泛采用的反时限过电流保护的运行机制进行阐述。其次从定性和定量层面研究了分布式电源并网对电流保护的影响细项。再次基于以上分析提出依托电压因子修正的保护改进方案。最后借助仿真手段进行新型保护方案的有效性验证,结果表明所提方案对解决分布式电源大量并网所产生的不利影响有积极意义,可予以推广。

The integration of a large number of distributed generation into the distribution network will have a significant impact on the system operation,trend of power flow and short-circuit characteristics,and lead to the decline or even failure of the main indicators such as current protection selectivity and rapidity.It is necessary to put forward comprehensive protection improvement scheme based on the principles of economy,reliability and safety.Firstly,the operation mechanism of inverse time overcurrent protection widely used in distribution network is described.Secondly,the influence of DG grid connection on current protection is studied qualitatively and quantitatively.Thirdly,based on the above analysis,an improved protection scheme based on voltage factor correction is proposed.Finally,the effectiveness of the new protection scheme is verified by means of simulation.The results show that the proposed scheme has positive significance to solve the adverse impact of large number of grid connected distributed generation,and can be promoted.