多路供电系统高压输电线考虑弧垂的场强计算模型

交流输电线路附近的空间场强是随时间变化的,在电磁环境保护和ADSS光缆架设中都需要计算出空间点在一个时间周期内的最大场强值,而对于实际输电线路还要充分考虑弧垂的影响。针对上述情况,采用等效电荷法,在考虑弧垂时分别基于频域和时域建立了多路供电系统高压输电线下的分段三维计算模型,并推导出了相应的最大场强计算公式。比较两种模型发现时域模型占用内存较少且延拓性较强,建议采用时域模型。最后用其公式编程对一条输电线路进行了计算比较,得出所推导的最大场强公式计算结果比以往场强计算结果更准确,弧垂对输电线路的最大场强有很大的影响,输电线路的场强计算应该采用三维模型。

Calculation of Electric Field Strength Under High Voltage Transmission Lines in a Multiple-Way Supply System Considering the Sag Effects

Electromagnetic environment protection and setting ADSS require the maximal electric field strength at a point in the space considered during a time period as the electric field around AC transmission lines is time varying.Since the sags of transmission lines have significant effects on the calculation of field strength,the sag effects should be taken into account.This paper establishes two subsection 3-D models for the calculation of electric field strength under high voltage transmission lines in a multiple-way supply system considering the sag effects in frequency-domain and time-domain using the equivalent electric charge method.It also derives the formulae of calculating the maximal electric field strength for both models.It has been observed that the time-domain model is preferable to the frequency-domain model because the former uses less computer memory and can be expanded easily compared with the latter.Furthermore,the time-domain model was applied to calculate the electric field strength under one actual transmission line.The results show that the calculated maximal field strength is more accurate than the ones obtained using the existing methods and the sags have a great effect on the maximal electric field strength,which means that the 3-D models are essential in the calculations.