带电作业人员侵入110kV电缆终端塔间隙方式对套管及应力锥电场分布的影响研究

Influence of Live Worker′s Intrusion into Gap of 110 kV Cable Terminal Tower on the Distribution of Electric Field of Bushing and Stress Cone

电缆终端套管是电缆线路的薄弱环节,为了掌握带电作业人员不同侵入电缆终端塔间隙的方式对套管及其应力锥电场分布的影响,根据实际110 kV电缆终端搭建仿真模型,因电缆终端塔和应力锥的尺度差异大采用子模型法来优化计算模型,分析了电缆终端正常运行及带电作业人员处于地电位作业、中间电位作业以及等电位作业3种情况对电缆终端应力锥电场分布的影响。计算结果表明:子模型法在保证计算精度的条件下可以有效减少网格数量和缩短计算时间;应力锥在3种作业方式下的电场变化相对于正常运行时均在3.5%以内,应力锥电场在地电位接触作业时几乎无影响,而在等电位和中间电位时分别增大约2%和减小3.5%;作业人员体表电场在应力锥处地电位作业时最小,等电位作业时体表电场随着与高压引线距离增加而减小;中间电位作业时与电缆终端套管距离每增大1 m,体表电场下降约13%;整体来看等电位作业使高压引线电场小幅上升,地电位和中间电位作业使高压引线电场值下降,变化范围在20%左右。110 kV电缆终端带电作业建议采用地电位或中间电位作业,作业过程中手部不宜覆盖套管伞群。

The cable terminal is a weak link in high voltage cable lines, to acquire the influence of different ways of intrusion of live worker into the gap of cable terminal tower on the electric field distribution of bushing and stress cone, a simulation model was built based on the actual 110 kV cable terminal. Due to the large scale difference between cable terminal tower and cable stress cone, the submodel method was used to optimize the calculation model, and analyzed the influence of distribution of electric field of stress cone under normal operation and ground potential operation, intermediate potential operation and equipotential operation. The results show that the submodel method can effectively reduce the number of grids and short the calculation time under the condition of ensuring the calculation accuracy;Compared with normal operation, the electric field variation of the stress cone under the three working conditions is within 3.5%. Stress cone electric field has little effect on ground potential when contact working, but increases by about 2% and decreases by 3.5% at equal potential and intermediate potential, respectively. The surface electric field of worker is the smallest when ground potential working, while the surface electric field decreases with the increase of the distance from the high voltage lead. For each 1 m increase in the distance between worker and bushings, the electric field on the body surface decreases by about 13% during intermediate potential working;As a whole, equipotential operation makes the electric field of the high voltage lead increase slightly, while ground potential and intermediate potential operation make the electric field value of the high voltage lead decrease, and the range of change is about 20%. It is suggested to use ground potential or intermediate potential in live operation of 110 kV cable terminal, and hands should not cover sheds.