基于子模型技术的500kV复合杆塔横担电场分析及均压环结构参数优化

Electric Field Analysis of 500kV Composite Cross-Arm and Structure Parameters Optimization of Its Grading Rings Based on Submodeling Technology

猫头型复合杆塔首次应用于国内500 kV输电线路,其横担端部各支柱绝缘子、斜拉绝缘子布置紧凑,电场畸变严重,均场问题突出。以500 kV猫头型复合杆塔为研究对象,依据图纸进行了1[BFZ]:[BFY]1实体三维建模,通过数值计算研究分析了猫头型复合杆塔中相横担和边相横担的电场集中区域,对比分析了复合横担与现有线路绝缘子的电位分布,设计了各相横担的均压环配置方案,并应用子模型技术研究了各均压环不同结构参数变化对复合横担关键位置场强的影响规律,研究结果表明,初始方案下复合杆塔部分位置场强过高,不利于复合杆塔长期稳定运行,500 kV复合横担的电位分布要优于现有500 kV线路绝缘子,通过配置合理的均压屏蔽装置,复合杆塔各关键位置场强均已满足控制要求。

The cathead composite tower has been firstly used in domestic 500 kV circuit transmission line.Owing to its compact arrangement of post insulators and tension insulators at the end of cross-arm,the uneven electric field distribution is a prominent problem in practical operation that needs to be solved.A 500 kV cathead composite tower is chosen as the research object,and the 3D simulation model has been established with finite element software.The electric field concentration regions of middle phase and side phase are computed and then analyzed with finite element method(FEM).The potential distributions of composite cross-arm are compared and analyzed with normal 500 kV line insulators.The grading and shielding devices for this 500 kV cathead composite tower are designed.The influences of different structural parameters of each grading ring on the field strength at the key position of the composite cross-arm are studied with submodeling technology to save computing time.The results show that the key positions beard very high electric field intensities in initial scheme.It is not conductive to the long term stable operation of composite tower.The 500 kV composite cross-arm has better potential distribution than that of normal 500 kV line insulators.With the configuration of reasonable grading and shielding devices,the electric field distribution on key positions could meet with the critical value.