摘要
Abstract
Aiming at the main transformer ratio differential protection device many times continuous actions happened outside the zone in Unit 1 and Unit 2 of Maliantai Power Plant,through theoretical analysis,draws the conclusion： after two times continuous faults impact happened outside the zone in Unit 1 and Unit 2 of Maliantai Power Plant,especially when the fault current appeared for the first time,the line opposite side breaker brings on the trip fault in Xulv No.1 bus bar of 330 kV Xujiazhang substation,the current transformer（CT） of main transformer has remanent magnetism,after the line protection reclose for 750 ms,the line opposite side breaker reclose for permanent fault,the fault current differs with remanent magnetism of the two kinds of CT in attenuation time,brings on the induced current of two kinds of CT disagree,and that the contents of harmonic wave in three-phase differential current are very low,leads to the main transformer ratio differential protection device action.Through the simulation test proves the conclusion,and puts forward the relevant solutions according to the practical situation.关键词
主变比率/差动保护/区外故障Key words
the main transformer ratio/differential protection/the fault outside the zone分类
信息技术与安全科学
