国网公司电科院探讨中压开关最新进展态势

截至2005年底,在网12～750kV高压开关设备总量为295101台,其中40.5kV 48012台,12kV191852台,各占全网设备16%和65%。在网12kV以真空占绝对优势,而40.5kV真空、SF6、油分别占有27%、51%、22%,SF6占了半壁江山。而各电压等级全年事故率中12kV占45.2%,40.5kV占32.3%,可见中压等级无论在全网数量比例还是事故比重都占有较大比例。总事故率较高的是绝缘事故,占53.2%,障碍率最高的是漏气,占14.9%,其次是拒合、拒分,主要表现为机械障碍,而开断关合故障很少占3.2%,绝缘事故中主要形式有柜内放电,CT闪络和相间闪络三种,原因是断路器与开关柜不匹配,绝缘尺寸不够,隔板及绝缘件吸潮,老旧开关设备改造未进行加强绝缘措施等。总之中压开关事故率较高,应引起制造商和用户密切关注。

By end of 2005, the total number of 12 - 750kV high voltage switches in the power grid is 295101, of which, 48012 40.5kV switches and 191852 12kV switches respectively account for 16% and 65%. Among the 12 kV switches, high voltage vacuum switches are absolutely dominant; while for 40.5 kV switches, the vacuum switches, SF6 switches and high voltage oil switches respectively account for 27%. 51%. 22%. Of which, the SF6-switches account for more than half of them. While among the accidents, the 12 kV high voltage switch accidents account for 45.2%, the 40.5 kV high voltage switch accidents account for 32.3%, which means that the rates of the medium voltage switches are high either the quantity proportion or the accidents proportion in the power grid. Among these accidents, the rate of insulation accidents is very high, accounting for 53.2%; the most faults are air leakage, switch close rejection and break rejection, mainly mechanical faults, the switch close and break faults account for 3.2%. The insulation accidents mainly include the electric discharge in the cabinet, CT flashover and phase flashover. The major reasons are the mismatch between the breaker and switch cabinet, inadequate insulation, the humidity absorption of separators and insulation pieces and the insulation measures have not been taken when reconstructing the old switches. In conclusion, the accident rates of the medium voltage switches are very high, the manufacturers and users shall pay close attention to them.