变压器和应涌流对继电保护影响的分析

首先简要阐述了变压器和应涌流的产生机理,指出偏磁是和应涌流产生的根本原因。然后结合和应涌流的特点,在实际仿真的基础上,系统地分析了串联和并联2种情况下的和应涌流对变压器差动保护、变压器后备保护及其他相关保护的影响。分析表明:在串联和应涌流时,TA容易发生暂态饱和,在变压器差动保护中应增加TlA饱和检测环节;和应涌流使得零序电流衰减比较缓慢,容易引起变压器零序过流保护误动,建议增加二次谐波制动环节;另外,和应涌流对上一级后备保护如过流保护、零序过流保护也会产生影响,建议采取2、3次谐波综合制动涌流鉴别方案。

Influence of Sympathetic Interaction between Transformers on Relay Protection

The principle of sympathetic interaction is analyzed firstly, which indicates that the bias flux is the primary factor in the produce process of sympathetic inrush. Then based on the simulation and combined with the characteristics of sympathetic interaction, we make a systematic study on the infection to the differential protection, back-up protection and other relative protection in the parallel connection and the series connection. The analysis shows that the saturation of current transformer caused by sympathetic inrush would bring some difficult in identifying the inrush in series connection; Moreover, it has great effect on the zero-sequence over-current protection of transformer and the back-up protection of the element in high level, such as over-current protection. The unit to identify inrush base on the harmonic restraint should be added to the protection.