基于多判据的变压器差动保护方法

摘要

In order to make the transformer differential protection identify the transformer’s running state more accurately, a method combined multi criteria transformer differential protection is proposed. First the characteristics of inrush current is analyzed and the situations that traditional secondary harmonic restraint may malfunction or delay action even refuse to move is discussed. Therefore, adaptive secondary harmonic restraint principle based on fundamental amplitude variation characteristics is used. Meanwhile, the four-line-percentage restraint principle combined with overcurrent instantaneous trip protection principle and zero sequence current differential protection principle are used to compose a differential protection scheme which can quickly and accurately to identify the transformer running state. Matlab/Simulink modeling and simulation is adopted to verify that the performance of transformer differential protection scheme utilizing each criterion’s advantages is greatly improved.%为了使变压器差动保护能更准确地识别出变压器的运行状态，提出一种联合多判据的变压器差动保护方法。分析了励磁涌流的性质，并讨论了传统二次谐波制动原理可能误动作或延迟动作甚至拒动的情况。为此，采用一种基于基波幅值变化特征的自适应二次谐波制动原理。同时采用四折线比例制动原理并联合过电流速断保护原理和零序电流差动保护原理，组成了可以快速准确识别出变压器运行状态的差动保护方案。利用Matlab/Simulink建模仿真，验证了综合利用各判据优点的变压器差动保护方案，其性能有很大的提高。