Research On Counter-attack Failure And Lightning Protection Of 220kV Transmission Lines

Lightning disasters seriously affect people's normal lives,from damage to facilities to large-scale power outages.Therefore,lightning protection is still the key to the safe and stable operation of power systems.According to statistics,lightning strikes will not only cause single-phase flashovers on transmission line towers Network,and even caused a serious trip accident with two trips.The Suihua area of Heilongjiang is located in the northeast of the province.Thunderstorms are frequent,the terrain is complex,lightning accidents occur frequently,and the stability of the local power system is seriously threatened.In the past three years,there have been six lightning flashover accidents on Sank Ang Line A and Sank Ang Line B.Most of the accidents were caused by lightning tower pole counter-tripping,which caused bad safety and stable operation of the power system in Suihua District.influences.This paper analyzes the accidents and reappears of the faults on the six 220 k V transmission lines in the region,and evaluates the lightning resistance performance of the region's counterattacks,which seriously affects the transmission.It has a reference role in reducing the trip rate of the towers in this area and improving the safe and stable operation of the power system.This article mainly includes the calculation of the lightning induced voltage on the transmission line tower,detailed analysis of the main lightning parameters,introduction of the Bergeron algorithm and typical modules in the electromagnetic transient software EMTP.All of them provide theoretical support for the analysis and modeling of the 220 k V transmission line counterattack accident in Suihua area.The lightning simulation model for the lightning strike of 220 k V single-circuit and double-circuit transmission lines was established using EMTP electromagnetic transient software,and the theoretical reliability of the model was verified by data,which was used to calculate the lightning strike-proof level of transmission lines.Theinfluence of different factors on the lightning resistance of the 220 k V single and double-circuit transmission lines is analyzed,and it is shown that the phase of the power frequency voltage directly determines the order of the conductor flashover;the most critical factor that affects the lightning strike resistance of the tower is the size of the grounding resistance.According to the test data,it is concluded that the grounding resistance of the double-circuit transmission line on the same tower is preferably less than 10?;balanced high insulation also significantly improves the lightning resistance level of the tower's counterattack,and the use of unbalanced insulation can avoid the occurrence of double-circuit simultaneous tripping accidents.In this paper,according to the special terrain and landform of Suihua mountainous area,the complex line structure and other factors,the idea of differentiated lightning protection is adopted to reform the lightning protection measures of the line.A risk assessment was carried out on the entire 89-base tower,and a targeted protection plan was given.