Research On Lightning Protection Performance And Lightning Outage Rate Of 110kV Transmission-Lines In Rugao Area

China is vast in territory and rich in resources, and rides through several climatic zones. The frequent lightning activity in our county can cause great loss, especially to the power system. The power system involves the production, transmission, distribution and consumption of electricity. The power transmission and distribution networks are the vital links between power stations and users and are of great importance. The reliability of the transmission system is the primary factor to consider and to maintain the normal operation of the system and avoid failures of the lines is the most important task to workers. In spite of the factors such as the weak structure of the grid, overhauling with plans and power rationing, the lightning outrage is another important one who has great influence on the reliability of the grid. In this paper, in view of the highly-occurred lightning weather, the lightning overage of the 110kV tower is under study in Rugao area in Jiangsu province. According to the practical statistics, the typical 110kV towers are analyzed in this paper. In order to analyze the wave propagation process in the tower precisely, in the light of the fact that the existing specifications to calculate the lightning outrage in the tower are not accurate enough, the detailed the multi-wave impedance model of the 110kV towers are built. The multi-wave impedance model is superior to other methods and parameters of the specified model are calculated in ATP-EMTP. Research on the modeling of 110kV tower and calculation of the lightning outrage rate in Rugao area in Jiangsu province are launched in this paper. Factors such as the tower height, grounding resistance, line span and line sag that have influence on the value of the lightning outrage rate are analyzed and evaluated. From the results we can see that the grounding resistance and the tower height are relatively important factors. From another angle, based on the studied results, many practical measurements can be used to enhance the lightning protection performance, such as by improving the insulator string’s U50% voltage level, by installing surge arresters, by reducing the grounding resistance, etc.