避雷器接地电阻对10 kV配电线路终端设备雷击暂态特性影响分析

The Influence of Lightning Arrester Grounding Resistance on Transient Characteristics of 10 kV Distribution Line Terminal Equipment

雷电击中配电线路后,沿线路入侵的雷电浪涌十分容易造成配变低压侧设备的损坏,安装避雷器能够提高线路的耐雷水平,为了有效的提高避雷器的防雷效率,有必要分析其对线路终端设备雷击暂态特性的影响。利用EMTP软件搭建完整的安装柱上变压器的配电系统模型,分析避雷器接地电阻、安装避雷器的杆塔之间的间距及敷设避雷线三种因素对终端设备雷击暂态特性的综合影响。结果表明:终端设备过电压随避雷器接地电阻的增大而增大,接地电阻越大,增大幅度越小;敷设避雷线后,终端设备过电压有一定程度的降低;安装避雷器的杆塔之间的距离越小,终端设备过电压也越小。最后得出通过避雷线的安装以及减小安装避雷器的杆塔之间的距离,可以在不降低终端低压设备雷电防护水平的情况下适当的增加高电阻率地区避雷器的接地电阻,所得结果对于降低接地结构的成本以及对配电线路终端设备的雷电防护有一定的指导意义。

Lightning surge intruded into the distribution line may result in damage to equipmentin low voltage side of the distribution transformer.The installation of arresters can improve the lightning withstand level of the line.In order to improve the lightning protection efficiency of arresters,it is necessary to analyze its impact on lightning transient characteristics of line terminal equipment.In this paper,the EMTP is used to build a complete distribution system model with pole-mounted transformer.The comprehensive effects of the grounding resistance of arresters,interval between poles with arresters and laying lightning shield line on lightning transient characteristics of terminal equipment are analyzed.The results show that the overvoltage on terminal equipment increases with the increase of the grounding resistance of arresters,the larger the grounding resistance,the smaller the magnitude of the increase.After the lightning shield line is laid,the overvoltage of the terminal equipment is reduced to a certain extent;The shorter the interval between poles with arresters,the smaller the overvoltage of terminal equipment.Finally,through the installation of arresters and reducing the interval between poles with arresters,the lightning protection level of the low-voltage equipment can be maintained,but the grounding resistance of arresters in high resistivity areas can be properly improved.The results have certain guiding significance for reducing the cost of grounding structure and lightning protection of distribution line terminal equipment.