城市地区主变直流偏磁研究与处理

主变直流偏磁会降低主变运行的稳定性及寿命。通过对一起实际案例分析研究,结合大量实际测量数据,明确了地铁杂散电流是城市电网主变压器直流偏磁的主要原因之一。研究采用一种新型电容隔直装置,并在实际投运过程中提出隔直装置标准接入和不停电接入两种方式,实际运行效果良好,可解决城市地区主变直流偏磁的问题。

Research and Treatment of Main Transformer DC Magnetic Bias in Urban Areas

The stability and life of the main transformer is reduced by its DC magnetic bias.Through an analysis of an actual case and under consideration of a large number of actual measurement data,it is proved that metro stray current is one of the main causes for the DC magnetic bias of the main transformer in urban power grid.A new type of capacitive DC blocking device is adopted in this study.In practical operation process,two access methods are presented for the device,namely standard? access and access without power cut.Practical operation achieves good result,thus solving the problem of main transformer DC bias in urban areas.