500kV变压器纵差保护试验方法

Test method of 500kV transformer differential protection

500kV变压器在低压侧配置总断路器的情况下,多采用纵差保护作为电量主保护。纵差保护动作时,故障相的准确判别对保护装置的正确动作和故障的分析及处理至关重要。本文以△→Y处理方式下的保护装置为例,研究高低压侧电流相位校正和幅值校正原理,以及常规接线调试方法下,模拟单相故障时的纵差保护动作情况。为准确模拟单相故障情况下,保护装置对故障相的准确判定,本文对接线方式进行改进处理。理论分析和试验结果表明,新接线方式下的保护调试可以正确模拟单相故障下的纵差保护动作情况,对研究单相故障时变压器的纵差保护动作特性有积极的指导意义。

Differential protection is one of the main protections of transformers when there exists breaker in low-voltage side.The identification of the fault phase is very important to analyze the grid failure.This paper focuses on the △→Y handling method to research the action results in normal simulation methods based on the phase correction and amplitude correction principle.The test method is improved to precisely simulate the identification of the fault phase.The test results show that the novel test method with the new wiring mode can correctly simulate the single-phase current differential protection of the transformer.It has a positive guiding significance for studying the protection action characteristics of transformers in single-phase faults.