Study On Calculation Of Anti-Windage Yaw Flashover Performance For Ultra High Voltage Transmission Line

With the construction of China UHV (Ultra High Voltage) Power Grid, more and more±800 kV DC and 1,000 kV AC transmission lines or above will be constructed and used in the future. According to the State Power Grid planning research, China's main Power Grid will be constructed by UHV Grid at million V-level to satisfy the need of "Nationwide interconnection, West to East power transmission and North-south power exchange" in 2020. For the string is much longer (above 10 m), the performance requirement of anti-windage yaw of UHV transmission lines is higher. Jindongnan～Nanyang～Jingmen 1,000 kV UHV AC demonstration project will be involved in production this year, and this project is a new milestone to China UHV Power Grid construction. The performance of anti-windage yaw is one of the main factors which will ensure the safe and stable operation, so it is necessary to calculate the windage yaw under strong wind.This paper firstly analyses the meteorological condition and geographical environment of stress influence factors to transmission lines, and introduces 3 mature wire suspended equations at present. According to the analysis of using horizontal span and vertical span which replace the real length of lines about traditional computational method of load, the insufficiency is pointed out and a new method is given for calculating lines' length. Analytic method is adopted for avoiding the shortcoming of analysis qualitative of geometric method to calculate air space between conductors and tower after getting windage yaw angle. Windage yaw angles of suspension insulators and cage jumped lines to Jindongnan～Nanyang～Jingmen 1,000 kV UHV AC are calculated and analyzed in detail, and programs accomplished respectively to cup-towers, cat head towers, strain towers and special towers of windage yaw calculated module of prediction and evaluation system to UHV transmission lines can get date from database or by manual input when it does not include some transmission lines. Computation to tower N8 of Jindongnan～Nanyang～Jingmen 1,000 kV UHV AC is presented by the module and general analysis of various influencing factors to windage yaw angles is given in detail. The existing problems in static stress balancing algorithm adopted in windage yaw angle calculation are analyzed in detail, and a modified method for maximum windage yaw angle calculation is given. Finally, the detailed method on anti-windage yaw is summarized.