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12～750 kV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12 kV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12 kV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.

State Power Grid Development Co., Ltd and Electric Power Research Institute, Inc discuss the latest development trend of medium voltage switch

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.