摘要
采用时域有限差分法(FDTD)论证了屏蔽线对直埋电缆预防直接雷击的保护作用。FDTD模型由一公里长的绝缘电缆以及屏蔽线构成,雷击地点设置在正上方。该模型仿真计算得到的结果与文献中的实验实测结果相吻合,由此可证实模型正确性。结果表明,屏蔽线能有效防止直埋电缆被直接雷击;雷击点附近电缆上电压与接地电阻呈现非线性正相关关系;土壤表面电离是决定屏蔽线上分流电流和绝缘电缆上电压大小的主要因素。另外,屏蔽线周围的土壤电离作用很小,屏蔽线的电阻率对电缆电压峰值影响不明显,但对波形持续时间有影响。
The author adopts finite-difference time-domain( FDTD) method to investigate the protection mechanism of a shield wire against direct lightning strike to a buried power cable. The proposed model takes soil ionization into account,and has been validated by comparing its results with rock-triggered experiment results. The results indicate that the shield wire can effectively prevent the buried cable from direct lightning strikes. Some conclusions can be drawn in this paper: the voltage across the cable increase with ground resistance but not linear;the current in shield wire and the voltage across the cable depend on the soil surface ionization. Moreover,the influence of the soil ionization around the shield wire can be neglected. The electric resistivity of the shield wire has no effect on the voltage but on the duration time.
作者
夏怀民
XIA Huaimin(State Grid Xiaogan Power Supply Company of Hubei Electric Power Company Limited,Xiaogan 432000,China)
出处
《电瓷避雷器》
CAS
北大核心
2020年第1期82-87,共6页
Insulators and Surge Arresters
关键词
电缆绝缘
电磁屏蔽
时域有限差分法
防雷保护
buried cable
direct lightning strike
shield wire
finite-difference time-domain method
