Analysis on lightning flashover voltage characteristics of insulators on 110 kV lines
WANG Zhenyu
FU Gang
Abstract：[Objective]In the power system,transmission lines serving as a key component are often prone to failures caused by natural disasters such as lightning strikes due to their remote location and long distance.Lightning strokes on transmission lines in China account for about 50%of the total accidents,which can cause tower insulation flashover,abnormal voltage,and even power supply interruption.Additionally,they can also damage electronic equipment and cause significant economic losses.An analysis of flashover voltage characteristics of 110 kV line insulators was conducted to improve the design of transmission lines and enhance their lightning resistance,thus strengthening the resistance of transmission lines to lightning strikes.[Methods]Based on the electric field theory and the energy conservation principle,the energy conservation equation of electrons in the electric field was constructed.Combined with the motion equations of three types of particles(positive attribute particles,negative attribute particles,and neutral particles)and Poisson's equation,a mathematical model for lightning strokes on insulators was built.By adopting this model to calculate the lightning current overvoltage,the standard waveform of the current of the lightning impulse transmission line was obtained.At the same time,the relationship between the lightning resistance level of transmission lines and flashover voltage of insulator strings was analyzed.By analyzing the characteristics of lightning flashover voltage of insulators via overvoltage,the current value and lightning current overvoltage at the lightning strike point were obtained.Additionally,silicone rubber insulators for 110 kV lines were selected for experiments to simulate different parameters such as the call height,grounding resistance,lightning current waveform,and insulation distance,and analyze the influence of each parameter on the voltage waveform.[Results]The experimental results show that the voltage of the insulator gradually flattens after 12 μs when the insulator is subjected to different waveform lightning strikes.Specifically,the double exponential voltage peak is the largest,the oblique angle model has the best effect on voltage control,and the voltage waveform tends to be more stable under the insulation distance greater than 5 m.Compared with other methods,the voltage waveform analyzed by this method is closer to the actual situation,with an error of less than 1 kV and higher accuracy.[Conclusions]Under the tower height of 25 m,the insulator is the most sensitive to lightning impulse response,and the peak voltage increases with the rising grounding resistance.The oblique angle lightning current model has the best effect on voltage control,and the insulation distance greater than 5 m can improve the insulator's ability to resist lightning impulse.In this study,mathematical models were combined with electric field theory,the influence of various parameters on insulators was comprehensively considered,and a more comprehensive and accurate voltage waveform and mathematical equation for insulator strings was established.The results provide scientific basis for the design of transmission lines,and hold engineering and reference significance for improving the lightning resistance of transmission lines and ensuring the safe and stable operation of power systems.
Keywords：110 kV linetransmission lineinsulator voltagelightning strikeflashover voltagevoltage characteristic analysis
Publication Date：2026-01-25
Online Publishing Date：2026-03-17(First online date of this platform, not the publication date of the document)
Pages：9( 10-18 )