750kV四分裂耐张塔跳线和导线表面电场分布

Surface Electric Field Distribution of 4-Bundled Conductor and Jumper of Tension Tower for 750 kV Transmission Line

与6分裂导线相比,750 kV线路采用4分裂导线在工程初期投资降低,在经济性上具有一定优势,但导线周围电磁环境是否满足要求则需要进行深入研究。运用三维有限元软件,采用谐响应分析方法,考虑了杆塔、金具、绝缘子串等因素和相间影响,仿真计算了750 kV 4分裂耐张塔跳线、导线的表面电场分布,分析了跳线表面场强的影响因素;给出了表面场强较高的4分裂上相跳线的合理优化建议;并计算了750 kV 6分裂耐张塔跳线、导线的表面电场分布,对比分析了4分裂和6分裂的计算结果。结果表明:4分裂上相跳线表面最高场强高于外角侧与内角侧的原因是受相间影响;相近条件下,750 kV线路采用6分裂导线时的电磁环境要优于4分裂;4分裂上相跳线选用JL/G3A-900/40型扩径导线后其表面最高场强降至2600V/mm以下。所得研究成果可为后续工程导线型号的选取及跳线的安装布置所借鉴。

In the initial stage of 750 kV transmission project adoption of 4-bundled conductor makes investment reduced than the adoption of 6-bundled conductor, so it possesses a certain advantage in economy, however whether the electromagnetic environment around transmission line could meet the demand needs to be further studied. Applying three-dimensional finite element software and adopting harmonic response analysis, the simulation calculation of surface electric field distribution of 4-bundled conductor and jumper of tension tower for 750 kV transmission line is performed while the factors such as tower, fitting, insulator string and so on as well as the interaction among phases are taken into account, and the influencing factors of surface electric field strength of the jumper are analyzed; reasonable optimization suggestions for the 4-bundled conductor jumper of upper phase with higher surface electric field strength are given; the surface electric field distribution of 6-bundled conductor and jumper of tension tower for 750 kV transmission line is calculated and compared with that of 4-bundled conductor and jumper. Comparison results show that due to the influence of interaction among phases the maximum surface electric field strength of the jumper of the upper phase is higher than those of two other phases; under similar conditions the electromagnetic environment around the 750 kV transmission line adopting 6-bundled conductor is better than that adopting 4-bundled conductor; when the JL/G3A-900/40 type of expanded diameter conductor is applied to the jumper of the upper phase, the maximum surface electric field strength of the jumper is dropped to below 2 600 V/mm. Results of this research are available for reference to the selection of conductor type and arrangement and installation of jumpers for follow-up projects.