摘要
通过对一次牵引变压器的差动保护误动作情况进行分析,判断为保护装置内部电流互感器(TA)暂态饱和引起,对该类型TA的测试也证实推断的正确。减少和避免TA饱和对保护影响的方法有多种。外部故障时,对各分相采用差流变化量与制动电流变化量的异步出现特性可识别TA暂态饱和。基于该次牵引变压器差动保护外部TA接线的情况,异步法在该次故障识别中失效;采用三相制动电流变化量之和与差动电流变化量之和进行判别,可以判断外部故障的TA饱和,从而暂时闭锁保护,并通过仿真验证了该判据的合理性。
The analysis shows that the transient saturation of CT（Current Transformer）causes the misoperation of a traction transformer differential protection,which is verified by the CT test. There are different methods to reduce and avoid the influence of CT transient saturation. For external fauh,asynchronism method can recognize CT transient saturation according to the different occurrence times of differential current variation and restraint current variation. But it is failed in this case because of the external connection conditions of CT. It is proposed to use the sums of 3- phase differential current variations and restraint current variations to recognize CT transient saturation and then block the differential protection. This criterion is validated by simulation.
出处
《电力自动化设备》
EI
CSCD
北大核心
2007年第5期122-125,共4页
Electric Power Automation Equipment
关键词
差动保护
TA暂态饱和
异步法
differential protection
CT transient saturation
asynchronous method
