调相机接入对发电机失磁保护的影响

Impact of synchronous condenser access on generator loss of excitation protection

近年来,随着电网"强直弱交"的问题日渐突出,同步调相机重新受到关注,300 Mvar大型同步调相机即将投入使用。但调相机引入的同时,也会给系统继电保护的正常运行造成一定影响。针对调相机接入对发电机失磁保护的影响进行了分析研究。运用PSCAD/EMTDC仿真软件搭建单机无穷大系统仿真模型,分别在发电机带不同负荷水平及不同失磁故障类型的条件下进行仿真。仿真结果表明,调相机的接入,会导致发电机失磁保护延时动作甚至拒动,威胁发电机的安全运行。

Recently, more attention is paid to Synchronous Condenser（SC） as the problem of ＂strong DC and weak AC＂ is becoming increasingly serious. 300 Mvar SC will be put into service soon, which may affect the normal operation of the system relay protection. This paper analyses the impact of the SC access on the operation of Loss of Excitation（LOE） relay. A single machine infinite bus system model with SC is established in PSCAD/EMTDC and the operation of LOE protection under different generator loadings and different LOE modes is simulated. The simulation results show that the installation of the SC has adverse impacts on the LOE relay in the form of delay time and/or under-reach phenomenon, which is bound to threaten the security of generators.