电气化铁路接地困难区段避雷线架设方式研究

Study on Erection of Lightning Conductor in Difficult Sections of Electrified Railway

在接地困难的路基段接触网支柱大多采用自然接地,支柱接地电阻较大,雷击避雷线后容易遭受反击。分析间隔接地改造和部分绝缘改造对接触网雷电防护性能的影响,并利用PSCAD/EMTDC仿真分析两种接地改造方案的雷电防护性能,从而确定合理的避雷线接地改造方案。研究结果表明:采用间隔接地改造时,接地改造后支柱耐雷水平有较大提高,未改造支柱耐雷水平几乎不受影响,并且接地改造间距小于200 m时雷击跳闸率有较好改善,大于200 m以后雷击跳闸率基本没有改善;采用部分绝缘架设时,导线绝缘子由最初的反击过电压闪络演变成感应过电压闪络,无论避雷线绝缘肩架的绝缘等级高低,都无法提高接触网的耐雷水平和雷击跳闸率,因此不建议采用避雷线绝缘架设模式。

The pillar is commonly used in the natural grounding in difficult sections wheregrounding resistance is high and the conductor tends to suffer from the flashover of the back striking. This paper analyzes lightning protection performances of the interval earth reconstruction mode and partial insulation transformation method. PSCAD/EMTDC software is used to analyze the lightning protection performances of the two methods and determine the reasonable grounding reconstruction scheme. The results show that the lightning withstand level improves greatly after the transformation and the lightning withstand level without transformation is almost not affected when the interval earth reconstruction mode is used in the contact network. The lightning trip-out rate is also improved when the transformation distance is less than 200 m. The rate doesn＇t change much when the transformation distance is more than 200 m.When the partial insulation erection method is used in the contact network,the insulator of the conductor initially flashes because of the overvoltage of back striking and then turns to flash on account of the induced overvoltage. As the lightning withstand level and the trip-out rate of the catenary could hardly be improved regardless of the insulation level of the insulation shoulder of the lightning conductor,it is not recommended to use the insulation erection of the lighting conductor.