220 kV变压器剩磁检测及消磁技术分析

Analysis on Remanence Detection and Degaussing Technique for 220 kV Transformers

介绍了一种新型变压器剩磁检测及消磁仪,通过采用该仪器对多台220 kV变压器进行剩磁检测及消磁试验,发现主变电气试验后剩磁率远大于停电后初始剩磁率,通过将绕组短路接地可以逐渐降低铁心剩磁,但是所需时间较长,无法满足现场送电要求。通过采用变压器剩磁检测及消磁仪多次消磁,可使送电前变压器的实际剩磁率降至极低量值,送电时高压励磁电流也有明显降低。使用此仪器结合现有的选相合闸技术,可以有效降低主变空载合闸励磁涌流的发生率,提高主变送电成功率。

A new type of transformer remanence detection and degaussing instrument is introduced,which is applied to detect the remanence and conduct the degaussing tests for several 220 kV transformers,and it is found that the remanence rate after the electrical test of the main transformer is much greater than the initial remanence rate after power failure.The core remanence can be gradually reduced by short-circuiting of the winding to ground,but it takes a long time and can not meet the requirements of on-site power transmission.By using transformer remanence detection and degaussing instruments for multiple degaussing,the actual remanence rate of transformer before power transmission can be reduced to a very low value,and the high-voltage excitation current can also be significantly reduced during power transmission.Such an instrument,combined with the existing phase-based closing technique,is available to effectively reduce the incidence of inrush current during no-load closing of main transformer and improve the success rate of power transmission via main transformer.