基于二次电流下降的电流互感器饱和判别方法

Detection Method for Current Transformer Saturation Based on the Dropping of the Secondary Current

基于电流互感器饱和后二次电流突然下降的特点,提出了一种新的电流互感器饱和判别方法——电流下降法。EMTP仿真结果表明,区外故障时该方法能可靠闭锁电流差动保护,区内故障时则能快速开放差动保护,且解决了电流互感器饱和情况下同名相转换性故障差动保护的开放问题。该方法性能优越,特征清晰,判据逻辑简单。

Based on the sudden decline of the secondary current after current transformer saturation, a new saturation criterion called current-dropping method is presented. It can be concluded from the simulation results on EMTP that the differential protection can be effectively blocked during the external fault, while they are quickly opened during the internal fault due to the current-dropping method. Meanwhile the problem of opening the differential protection during the transitional fault of the same phase with current transformer saturation is also solved. The proposed method is a promising current transformer saturation criterion with predominant performance, clear characteristics and simple logic.