换流变档位调节对差动保护的影响及解决方案

The Effect of Adjustment of Converter Transformer Taps upon Differential Protection and Its Solution

按照传统的换流变压器保护方案,在换流变压器档位发生变化时,换流变保护装置CPU会误计算出一定的差流,可能导致差动保护启动。分析了差流产生的原因,指出在直流输电工程应用中应如何减小换流变调档对差动保护的影响,提出了一种引入换流变分接头档位信号的差动保护方案。能避免换流变调档对差动保护的影响,且原理接线简单、可行性强。

According to the traditional protection scheme for the converter transformer, when the taps of the converter transformer are changed, the CPU of its prntection device will make a wrong calculation of a false differential current, which might start differential protection. This paper analyzes the cause of differential current and tells you how to reduce the effect of tap adjustment of the converter transformer upon differential protection in the DC power transmission. It introduces a scheme of differeutial protection using a signal of the taps of the converter transformer-a practical scheme with a simple principle and wiring which carl avoid the effect of tap ehange of the converter transformer upon differential protection.