变压器复杂电磁暂态下涌流特征及其对差动保护影响分析

Analysis on Characteristics of Inrush Current in Complex Electromagnetic Transient of Transformer and Its Influence on Differential Protection

摘要:

近年来变压器差动保护误动拒动现象时有发生,现场数据表明差动保护事故多发生于比典型空载合闸复杂的场景。针对以上问题,基于电磁暂态仿真计算,研究了电力变压器在剩磁、直流偏磁、CT饱和以及复杂谐波等工况下的励磁涌流特性,深入分析了复杂电磁暂态环境下主保护的动作性能,并针对变压器保护的拒动和误动问题,提出了切实可行的措施,以提高复杂电磁暂态工况下变压器主保护的性能,减少不正确动作的发生,保证电力系统的安全运行。

Abstract:

The maloperation and refuse operation of transformer differential protection often occur in recent years. The field data show that the fault of differential protection often occurs in the situation which is more complex than the typical no-load energizing of transformer. It is necessary to study the action of transformer differential protection in the complex electromagnetic transient environment. Aiming at those problems, the mechanism and characteristics of inrush current in the case of remanence, DC bias and CT saturation of transformer are studied, the causes of malo-peration and refuse operation of differential protection in the above cases are analyzed, the factors leading tomaloperation and refuse operation of transformer are summarized, and the corresponding measures to improve the correct operation rate of differential protection in complex electromagnetic transient are put forward in order to guarantee the safe operation of power system.