保护用电流互感器5%误差测试数据的计算分析

Calculation Analysis of 5% Error Test Data for Protective Current Transformer

对某风电场的1组保护用电流互感器进行5%误差现场实测,测试负载电阻值、准确限值系数等数据,以《DL/T 866-2004电流互感器和电压互感器选择及计算导则》中3个不同验算标准为计算依据,即一般选择验算、按额定二次极限电动势验算、按实际准确限值系数验算,计算当主变压器高压侧发生短路故障时,电流互感器的二次测量值。测量结果为该组电流互感器符合5%误差要求,可保证保护装置采集到的二次电流值正确、有效,不会因电流采集值的误差过大而发生误动、拒动。

Make a 5%error filed test for a unit of protective current transformer in a wind farm.The test data included the load impedance and the accuracy limit coefficient,etc.Based on three different checking criteria in DL/T 886-2004 The guide for selection and calculation of current transtormers and voltage transtormers,including general choice checking,rated limiting secondary e.m.f.checking,and the accuracy limit coefficient checking,with which calculating the secondary measurement value as short-circuit fault occured on the main transformer high voltage side.The measurement result showed that the current transformer met the requirement of 5%error,which could guarantee the secondary current value correct and effective,and avoid the maloperation and refuse operation resulted from the overlarge current value.