有架空地线的10 kV线路导—地线间距取值建议

Suggestions for the Spacing Between Conductor and Ground Wire of 10 kV Line with Overhead Ground Wire

我国现行技术标准给出的有架空地线线路档距中央导—地线最小间距计算经验公式为S=0.012L+1,该公式生成过程并未考虑10 kV架空线路情况,不宜简单套用到10 kV线路上。笔者采用仿真模拟计算方法,建立了雷电直击10 kV线路架空地线档距中央瞬态过程计算模型,经大量雷电过电压计算比较研究,确定了仿真关键线路参数和取值。基于档距中央耐雷水平指标,计算获得了通用系列档距下的导—地线间距值,供工程设计人员参考。为简化工程操作,进一步提出了对技术标准经验公式的修正公式为S=0.034L+0.04。

The empirical formula for calculating the minimum distance between conductor and ground wire in the center of the span length of the line with overhead ground wire is S=0.012L+1, given by the current technical standards in China. The generation process of this formula did not consider the situation of 10 kV overhead lines and should not be simply applied to 10 kV line. A simulation calculation method is used to establish a transient process calculation model of lightning strikes on 10 kV overhead ground wire in the center of the span length. After a large number of lightning overvoltage calculations and comparisons, the simulation key line parameters and values are determined. Based on lightning resistance level index, the conductor-ground wire spacing values corresponding to general series of spans are obtained by calculations, which can be used as a reference for engineering designers. In order to simplify the engineering operation, the revised formula for the technical standard empirical formula is further proposed as S=0.034L+0.04.