Study on Comprehensive Treatment Plan of Lightning Disturbance for the Operating Overhead Transmission Line
|Course||Proceedings of the|
|Keywords||overhead transmission line lightning Monte Carlo method GIS lightning protection measures|
Lightning is knowed as one of the top ten natural disasters. Lightning disturbance is the main reason of causing the transmission line faults. Lightning protection of overhead transmission lines is always the emphasis and difficulty to electric power departments. This paper explores the related law of lightning disturbance on overhead transmission line, and put forward a comprehensive treatment plan of lightning disturbance on overhead transmission line based on Geographic Information System (GIS).With the increase of voltage level of transmission lines, the proportion of outages because of shielding failure is higher. In order to exactly evaluate lightning withstanding level of transmission line, an algorithm of shielding failure trip-out rate (SFTOR) of overhead transmission line based on Monte Carlo method is presented in the second chapter.The influence of ground obliquity, protection angle, deepness of the gorge spanned by the transmission line and the synthesis of ground obliquity and protection angle on SFTOR of transmission lines is analyzed based on the algorithm.Results show that the algorithm has high precision, fast computing speed and strong analysis ability.Microtopography is an important and complicated factor of affecting lightning strike trip-out. The rule of how microtopography affects lightning strike to the transmission line is explored based on GIS and Excel. How to form the files of transmission lines and lightning strike information by using GIS is introduced firstly. Combined with the microtopography of GIS, lightning strike data collected from the electric power company is analyzed. The correlation rules between exposed surface and fault phases of 110kV,220kV and 500kV transmission lines caused by lightning strike are obtained in the third chapter. And some characteristics of influence on lightning selectivity by microtopography factors including peak, river, valley, mountain ridge, windward slope and so on are explored. The results show that this statistic analysis method is very intuitive and imaginal. And the results can provide references for the path design of transmission line and the selection of lightning protection measures.Correct judgment of shielding failure and back striking is the basic of how to get the comprehensive treatment plan of lightning disturbance for the overhead transmission line. Considering the microtopography or not, two methods of statistical analysis for the ratios of shielding failure and back striking about 110kV,220kV and 500kV transmission lines is proposed in the forth chapter. And the results of statistical analysis can provide references for putting forward the comprehensive treatment plan of lightning disturbance for the overhead transmission line.Through studing the lightning protection measures deeply, considering the prevention emphasis of shielding failure and back striking about 110kV,220kV and 500kV transmission lines, and combined with the factor of microtopography and the economy and reliability of lightning protection measures, the fifth chapter put forward the comprehensive treatment plan of lightning disturbance for the overhead transmission line base on GIS. And this chapter has analyzed some 110kV,220kV and 500kV transmission lines case. The results show that the comprehensie treatment plan is very intuitive and imaginal, and it can manage the lightning protection measures easily and provide references for the practical lightning protection project of overhead transmission lines.In the end, the paper summarizes the innovative points and puts forward the future prospects about lightning protection of overhead transmission lines.