1应保证选用零序电流互感器>内径大于电缆终端头外径;

1 the zero sequence current transformer should be selected and the inner diameter of the current transformer is larger than the outer diameter of the cable terminal.

2施工中尽量不要拆动零序电流互感器'>电流互感器，如必须拆动，工作完结必须恢复原状;

2 construction and try not to open the zero sequence current transformer '> current transformer, such as to be dismantled, the completion of the job must be restored;

3接地线须采用铜绞线或镀锡铜编织线，接地线的截面不应小于25 mm2，接地端部要焊接接线端子，并正确处理接地线与零序电流互感器'>电流互感器的相对位置，接地线必须安装在接地铜排上;

The 3 grounding wire should be used in copper wire or tinned copper braided wire, grounding wire section should not be less than 25 mm2, the grounding end to welding terminals, and correctly handle the relative position of the grounding wire and the zero sequence current transformer '> current transformer, the grounding wire must be installed on the ground on the bar;

4 通电前要对零序保护系统进行整定，确保保护工作正常；

The zero sequence protection system should be set up before the 4 power transmission to ensure the normal protection work.

5不论零序电流互感器与电缆头接地线的相对位置如何，零序电流互感器与接地线的关系应掌握一个原则：电缆两端端部接地线与电缆金属护层、大地形成的闭合回路不得与零序电流互感器匝链。即当电缆接地点在零序电流互感器以下时，接地线应直接接地；接地点在零序电流互感器以上时，接地线应穿过零序电流互感器接地。同时，由电缆头至零序电流互感器的一段电缆金属护层和接地线应对地绝缘，对地绝缘电阻值应不低于50kΩ。以上做法是为了防止电缆接地时的零序电流在零序电流互感器前面泄漏，造成误判断；经电缆金属护层流动的杂散电流由接地线流入大地，也不与零序电流互感器匝链，杂散电流也不会影响正确判断。

5 no matter how the zero sequence current transformer and cable head ground relative position, the relationship between the zero sequence current transformer and a grounding wire should master a principle: closed loop cable ends end grounding wire and cable metal sheath, the earth may not be formed and the zero sequence current transformer turns. That is to say, when the cable location is below the zero sequence current transformer, the grounding wire should be directly grounded. When the grounding point is above zero sequence current transformer, the grounding wire shall go through the zero sequence current transformer grounding. At the same time, the insulation resistance of a cable metal shield and grounding wire from the cable head to the zero sequence current transformer should be less than 50K Omega. The above approach is to prevent the zero sequence current cable grounding leakage when in front of zero sequence current transformer, caused by error judgment; stray current cable metal sheath flow from the ground into the earth, nor with the zero sequence current transformer turns, stray current will not affect the correct judgment.