摘要
为了对埋地电缆进行有效雷电防护,必须合理分析电缆遭受直接雷击后暂态过电压。分析了埋地电缆遭受直接雷击的危害途径及危害机理,利用拉普拉斯变换计算埋地电缆雷击暂态过电压,分析芯线-缆皮间电位差随雷电流幅值、电缆埋深、雷击点距电缆水平距离的变化,讨论双层土壤结构下土壤电阻率对电缆雷击过电压的影响。分析结果表明:芯线-缆皮间暂态电位差随着雷电流幅值的增大近似呈线性增加;电缆埋深和雷击点距电缆水平距离的增大对芯线-缆皮间暂态电位差有着十分明显的衰减作用;双层土壤结构中下层土壤电阻率对电缆暂态电位影响非常大,当下层土壤电阻率远大于上层土壤时,电缆暂态电位较均匀土壤情况下增加显著。在埋地电缆敷设过程中可以尽量增大埋设深度,同时避开高土壤电阻率区域。
In order to protect underground cables from lightning effectively, it is essential to analyze transient overvohage due to lightning stroke. Lightning damage mechanism and damageable pattern to underground cables were presented. Transient overvoltage was assessed by means of Laplace transform. Effect of lightning current amplitude, burial depth of the underground cable and lightning strike distance from the buried cable on voltage difference between the core and isolation layer were analyzed. Influence of soil resistivity in double layer soil structure was also discussed. Results show that： voltage difference between the core and isolation layer increases with increasing of lightning current amplitude. The attenuation of increasing burial depth of the buried cable and lightning strike distance from the buried cable is obvious. Soil resistivity in double layer soil structure strongly influences transient overvoltage. It is necessary to increase burial depth of the underground cable and avoid high soil resistivity zone.
作者
沙立成
刘辉
李涛
SHA Licheng;LIU Hui;LI Tao(State Grid Beijing Electric Power Company, Beijing 100031, China)
出处
《电瓷避雷器》
CAS
北大核心
2018年第3期1-5,共5页
Insulators and Surge Arresters
基金
国家自然科学基金(编号:E070602)
关键词
埋地电缆
雷电
暂态过电压
土壤分层
buried cable
lightning
transient overvoltage
soil layered
