Fault phenomenon and treatment

A factory 6kV outdoor busbar in the operation of a phase of overheating phenomenon, with infrared thermometer measurement temperature up to 80 ℃, heating place for two busbar row, and then detect the temperature of the other two phases but only 30 ℃. An insulated heat shrinkable casing with a phase color indication is arranged on the Busbar.

After the blackout inspection, it was found that there was a 5mm long insulating heat shrinkable casing at the junction of the two busbar rows pressed under the splice. In this way, it is not possible to make the contact surface of the two female rows in good contact, and the rain will seep into the contact surface. The increase in contact resistance results in an increase in the temperature at the junction at the operation.

After removing the master row, it was found that the contact surface had been burned and the hemp point had been out. The excess insulating heat shrinkable casing is cut off, the contact surface is re-polished and smooth with a fine flat file, coated with conductive paste (power composite grease). After fastening, put into operation, no further detection of overheating phenomenon. In a steel plant newly installed 6kV distribution cabinet acceptance inspection, also found that the insulation heat shrinkage casing pressure under the contact surface of the problem, immediately so that the construction unit re-processing, eliminating the hidden danger of accidents.

Lessons learned

Insulation heat shrinkable casing is widely used in cable and mother row because of its high insulation strength, easy construction and simple process. If the installation of improper construction, it may cause the cable, the master row of the joint heat, serious will arc, resulting in arc short circuit and other accidents. Should arouse great attention, eliminate the hidden danger of accidents, ensure safe production.

母排套管使用不当引起的故障处理

故障现象及处理

某厂6kV室外母线排在运行中有一相出现过热现象，用红外线测温仪测量温度达80℃，发热处为两块母线排的搭接头，再检测另外两相的温度却只有30℃。母线排上套有带相色指示的绝缘热缩套管。

停电后检查，发现两块母线排的搭接头处有5mm长的绝缘热缩套管被压在搭接头下。这样，就无法使两块母排接触面接触良好，同时雨水也会渗进接触面。由于接触电阻增大，从而造成运行中搭接头处温度升高。

拆下母排后，发现接触面已烧蚀并出了麻点。将多余的绝缘热缩套管剪去，接触面用细平锉重新打磨光滑后，涂上导电膏(电力复合脂)。连接紧固后，投入运行，没有再发现过热现象。曾在某钢铁厂新安装的6kV配电柜验收检查中，也发现过绝缘热缩套管压在接触面下面的问题，立即令施工单位重新进行处理，消除了事故隐患。

经验教训

绝缘热缩套管由于绝缘强度高、易于施工、工艺简单，已普遍用于电缆、母排上。如果安装施工不当，就可能造成电缆、母排的接头发热，严重时会起弧，造成弧光短路等事故。应引起高度重视，消除事故隐患，确保安全生产。