（1）电(dian)流二(er)次回路是经(jing)过电(dian)缆连接的，当接地网上呈现短(duan)路电(dian)流或雷击(ji)电(dian)流时，由于(yu)电(dian)缆屏(ping)蔽(bi)(bi)层两点的电(dian)位(wei)不同，使屏(ping)蔽(bi)(bi)层内(nei)流过电(dian)流，或许(xu)烧毁屏(ping)蔽(bi)(bi)层。当屏(ping)蔽(bi)(bi)层内(nei)流过电(dian)流时，对每个芯线将发生干扰(rao)信(xin)号。

（2）在(zai)电(dian)(dian)(dian)(dian)流(liu)二次回(hui)路中，如(ru)果正好在(zai)继电(dian)(dian)(dian)(dian)器(qi)电(dian)(dian)(dian)(dian)流(liu)线(xian)圈的(de)两边(bian)都有接(jie)地(di)(di)(di)址，一(yi)方面(mian)两点(dian)接(jie)地(di)(di)(di)址和地(di)(di)(di)所构成(cheng)的(de)并(bing)联回(hui)路，会短路电(dian)(dian)(dian)(dian)流(liu)线(xian)圈，使经(jing)过电(dian)(dian)(dian)(dian)流(liu)线(xian)圈的(de)电(dian)(dian)(dian)(dian)流(liu)大(da)为减少。此外，在(zai)发生(sheng)接(jie)地(di)(di)(di)毛(mao)病(bing)(bing)时，两接(jie)地(di)(di)(di)址间(jian)将(jiang)因地(di)(di)(di)网经(jing)过零序电(dian)(dian)(dian)(dian)流(liu)而发生(sheng)地(di)(di)(di)电(dian)(dian)(dian)(dian)位差(cha)，将(jiang)在(zai)电(dian)(dian)(dian)(dian)流(liu)线(xian)圈中发生(sheng)极大(da)的(de)额外电(dian)(dian)(dian)(dian)流(liu)。这两种原因，将(jiang)使经(jing)过继电(dian)(dian)(dian)(dian)器(qi)电(dian)(dian)(dian)(dian)流(liu)线(xian)圈的(de)电(dian)(dian)(dian)(dian)流(liu)与电(dian)(dian)(dian)(dian)流(liu)互感(gan)器(qi)二次通入的(de)毛(mao)病(bing)(bing)电(dian)(dian)(dian)(dian)流(liu)有极大(da)差(cha)异，会引起维(wei)护的(de)不(bu)正确动(dong)作，同时会引起计(ji)量的(de)不(bu)准确。