一种可靠的变压器差动保护综合实现方案

One Reliable Comprehensive Realization Scheme for Transformer Differential Protection

介绍了一种较为可靠的变压器差动保护综合实现方案。励磁涌流制动采用新型二次谐波制动法,较好地解决了变压器差动保护快速性与可靠性之间的矛盾;采用基于双制动曲线的抗电流互感器(current transformer,CT)饱和措施,区外故障CT饱和后,根据变压器各绕组谐波比确定CT饱和程度,适时采用不同的制动曲线;配置采样值差动保护并与常规差动保护协同合作,保障了保护动作的灵敏性和快速性,使得变压器差动保护整体性能更佳。实时数字仿真实验和动态模拟试验结果表明该方案整体性能优越,投入现场运行后效果良好。

This paper introduces one reliable comprehensive realization scheme for transformer differential protection which is to use a new second harmonic restraint to realize excitation surge restraint and primely solve contradiction between speed- ability and reliability of transformer differential protection. Meanwhile, it uses anti-current transformer saturated measures based on double restraint curve which means that when the external faulted CT is reaching to be saturated, it is feasible to determine saturation of CT according to harmonic ratio of each winding and use different restraint curves. In addition, on the basis of collaboration of sampled value differential protection and traditional differential protection, it is able to ensure sensitivity and speedability of protection action which may make the overall performance of transformer differential protec- tion better. Results of real-time digital simulation experiment and dynamic analog testing show that the overall performance of this scheme is advantageous which is provided with good effect after being put into field operation.