变压器的差动保护中不平衡电流产生的主要原因有哪些？如何克服？
参考答案：
（1）原因：
1、变压器接线方式的影响，
2、电路互感器类型的影响，
3、电流互感器便闭的影响，
4、变压器励磁涌流的影响，在正常运行时，会有较小的电流流入继电器，当外部短路时，此电流会更大，该电流成为不平衡电流，该电流过大时，可能造成差动保护误动作。
（2）
1、采用相位补偿的方法；
2、提高保护装置的动作电流，引入同型系数；
3、采用BCH型差动继电器，通过调整差动继电器平衡线圈的匝数来补偿。
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