（1）电(dian)(dian)(dian)(dian)流(liu)二次回路是通过(guo)电(dian)(dian)(dian)(dian)缆连接的，当(dang)接地网(wang)上出现(xian)短(duan)路电(dian)(dian)(dian)(dian)流(liu)或雷击(ji)电(dian)(dian)(dian)(dian)流(liu)时，由于(yu)电(dian)(dian)(dian)(dian)缆屏蔽层(ceng)(ceng)两点的电(dian)(dian)(dian)(dian)位不同，使屏蔽层(ceng)(ceng)内流(liu)过(guo)电(dian)(dian)(dian)(dian)流(liu)，可能(neng)烧毁屏蔽层(ceng)(ceng)。当(dang)屏蔽层(ceng)(ceng)内流(liu)过(guo)电(dian)(dian)(dian)(dian)流(liu)时，对每个芯线将产生干扰信号。

（2）在(zai)(zai)电(dian)(dian)(dian)(dian)(dian)流(liu)(liu)(liu)(liu)二(er)次(ci)回路(lu)(lu)中(zhong)(zhong)，如果(guo)正(zheng)好在(zai)(zai)继(ji)(ji)电(dian)(dian)(dian)(dian)(dian)器电(dian)(dian)(dian)(dian)(dian)流(liu)(liu)(liu)(liu)线(xian)圈(quan)(quan)的(de)(de)(de)两侧都有(you)接(jie)地(di)点，一方面两点接(jie)地(di)点和地(di)所构(gou)成的(de)(de)(de)并联回路(lu)(lu)，会短(duan)路(lu)(lu)电(dian)(dian)(dian)(dian)(dian)流(liu)(liu)(liu)(liu)线(xian)圈(quan)(quan)，使(shi)通过(guo)电(dian)(dian)(dian)(dian)(dian)流(liu)(liu)(liu)(liu)线(xian)圈(quan)(quan)的(de)(de)(de)电(dian)(dian)(dian)(dian)(dian)流(liu)(liu)(liu)(liu)大为减少。此(ci)外，在(zai)(zai)发(fa)生(sheng)接(jie)地(di)故障(zhang)(zhang)时，两接(jie)地(di)点间将因地(di)网通过(guo)零序电(dian)(dian)(dian)(dian)(dian)流(liu)(liu)(liu)(liu)而产生(sheng)地(di)电(dian)(dian)(dian)(dian)(dian)位差，将在(zai)(zai)电(dian)(dian)(dian)(dian)(dian)流(liu)(liu)(liu)(liu)线(xian)圈(quan)(quan)中(zhong)(zhong)产生(sheng)极大的(de)(de)(de)额外电(dian)(dian)(dian)(dian)(dian)流(liu)(liu)(liu)(liu)。这两种原因，将使(shi)通过(guo)继(ji)(ji)电(dian)(dian)(dian)(dian)(dian)器电(dian)(dian)(dian)(dian)(dian)流(liu)(liu)(liu)(liu)线(xian)圈(quan)(quan)的(de)(de)(de)电(dian)(dian)(dian)(dian)(dian)流(liu)(liu)(liu)(liu)与(yu)电(dian)(dian)(dian)(dian)(dian)流(liu)(liu)(liu)(liu)互感(gan)器二(er)次(ci)通入的(de)(de)(de)故障(zhang)(zhang)电(dian)(dian)(dian)(dian)(dian)流(liu)(liu)(liu)(liu)有(you)极大差异，会引起(qi)保护的(de)(de)(de)不(bu)正(zheng)确动作，同时会引起(qi)计量(liang)的(de)(de)(de)不(bu)准确。