1000kV/500kV同杆混压四回输电线路电磁环境影响因素及优化措施分析

Electromagnetic Environment Influence Factors of Quadruple-circuit Transmission Line with 1 000 kV/500 kV Dual Voltage on the Same Tower and Optimization Measures Analysis

针对1 000 kV/500 kV同杆混压四回输电线路的电磁环境问题,采用有限元法分析了线路下工频电场的特征及主要影响因素,研究了电场环境的优化方案以及屏蔽线位置与屏蔽效果的关系;对于多目标区域的电场环境优化,可采用层次分析法确定每个区域在优化过程中所占权重,进而找到最优值的屏蔽线位置。结果表明:屏蔽线架设在电场强度峰值附近时屏蔽效果最好(算例中电场强度峰值下降率最高为26.7%);对于规划中的或者已经建成的输变电线路,若下方存在一些电磁环境指标超标区域或者对电磁环境要求很高的区域,选择合适的屏蔽线位置可以以较低成本实现目标点以及目标区域的最优屏蔽;一般在电场强度峰值和目标区域之间架设一根屏蔽线可以有效屏蔽目标区域电场强度,算例中区域电场强度平均值下降率最高为34%。

In order to solve the electromagnetic environment of quadruple-circuit transmission line with 1 000 kV/500 kV dual voltage on the same tower, we used the finite element method to analyze features and influential factors of power frequency electric fields under transmission line. Then we researched the optimized solutions of electric field environment and the relation between the position of shield wires and its shielding effect. For more than one target area, each region was weighted in the optimization process based on the analytic hierarchy process to find the optimal shield wires position. The results show that the shielding effect is better when shield wires are erected near the peak of the electric field, and the highest drop rate of peak electric field is 26.7% in the case. For the planned or built transmission lines, if there exists an excessive electromagnetic area or electromagnetic sensitive area, the optimal shielding of shield target point and target area can be realized with lower cost by choosing appropriate location of shield wires.When a shield wire is erected be- tween the electric field peakand the target area, it will be more effective for shielding effect of electric field in target area, and the highest drop rate of the average regional electric field is 34% in the case.