一起励磁变压器差动保护误动原因分析及启示

由于励磁变压器两侧电流含有丰富的谐波分量,正常运行时差动不平衡电流较大,对于是否配置励磁变压器差动保护存在一定的争议。分析了一起励磁变压器差动保护误动案例,指出高次谐波并不是引起本次误动的根本原因。励磁变压器差动保护具有成熟的运行经验,合理整定其定值,可提高励磁变压器内部故障检测的灵敏度。

Analysis on Mal-operation of Excitation Transformer Differential Protection

As the current contains many harmonic components at both sides of the transformer,in the normal operation,the unbalanced current generated in differential protection is greater,which cause certain dispute over whether the excitation transformers should be equipped with differential protection.This paper analyses an example of the mal-operation of excitation transformer differential protection,and finds that high-order harmonic is not the root cause of the mal-operation.Mature operating experience of differential protection of excitation transformer has been accumulated,through proper setting calculation and configuration,the sensitivity of the protection for detecting internal faults of excitation transformer can be improved.