多雷地区110kV和220kV敞开式变电所的雷电侵入波保护

INCOMING LIGHTNING PROTECTION FOR 110kV AND 220kV OPEN-AIR SUBSTATIONS AT LIGHTNING INTENSIFIED AREA

随着电网的发展,进线断路器出现暂时分闸状态的概率随之增多。近年来南方多雷地区发生多起由雷电侵入波过电压引起的暂时分闸的SF6断路器或电流互感器内部绝缘击穿爆炸的事故。作者提出在多雷地区新设计的110kV 和220kV 敞开式变电所,无间隙金属氧化物避雷器(MOA)宜装设在每回进线的断路器线路侧。文章通过雷电侵入波过电压的计算分析,给出了MOA至变压器之间的最大保护距离,即取标准DL/T620-1997中规定的MOA装在母线上的数值。对已运行的变电所,确需考虑进线路断路器出现暂时性分闸状态又要加以保护时,可视安装位置的方便在进线断路器线路侧附近或进线终端塔上增设一组MOA,MOA至分闸断路器之间的最大保护距离按本文推荐的数据取值。MOA安装在进线终端塔上,杆塔接地装置的冲击接地电阻应小于7W。

Along with the enlargement of power network the temporary opening of circuit breakers is accordinglyincreased. In the lightning intensified area at South China, the accidents of the internal insulation breakdown and explosion of temporary opening SF6 circuit breakers or current transformers caused by lightning intruding waves occurred many times in recent years. Therefore, the authors put forward that in the newly designed 110kV and 220kV outdoor substations located in lightning intensified area the gap-less MOA should be installed by the line side of the circuit breaker of each incoming line. Through the calculation and analysis of the overvoltages caused by lightning intruding waves the maximum protection distance between the MOA and the transformer, i.e., the value specified in DL/T620-1997 when the MOA is installed on the busbar, is given. For the substations in operation, if thetemporary opening of the circuit breaker installed at theincoming line side should be considered and the breaker is to be protected, a group of MOA can be added near the line side of circuit breaker at incoming line or onto the dead-end tower according to the convenience of installation. The maximum protection distance between the MOA and the opening circuit breaker can be fetched in accordance with the value recommended in this paper. When the MOA is installed on the dead-end tower of incoming line, the grounding resistancevalue of the tower must be less than 7W.