500 kV输电线路耐张线夹电接触计算及其发热研究

针对500 kV架空线路线夹运行温度过高引起线夹脱断,造成停电的事故,以NY型耐张线夹为研究对象,分析了耐张线夹接触电阻的计算方法,建立了耐张线夹电接触温升的有限元模型,以此研究了电接触最高温度与接触压力的关系,同时探明了电接触内部到外部的温度变化规律。研究表明：随着压力增大,最高温度呈现先迅速下降后下降变缓的趋势,额定压力下电流600 A引起的最高温度为31.42 ℃;随着压力增大,最高温度先后出现在铝板与螺栓的电接触、铝板间电接触和铝板与螺栓的电接触;线夹电接触内外存在温差,但内外温度变化具有一致性,外表面温度可间接表达线夹的运行温度。最后利用试验验证了电接触计算方法和仿真结果的正确性。

Research on Electric Contact Calculation and Heating of 500 kV Transmission Line Clamps

In order to solve the clamp breaking problems caused by high operating temperature of 500 kV transmission line clamps, the calculation method of clamp contact resistance is investigated based on the NY-type clamps, and a finite element model of clamp electric contact heating is established with ANSYS to study the relation between the maximum electric contact temperature and the contact pressure and the temperature variation from the internal to external of the clamp. From the studies, it is found that the maximum temperature tends to decrease rapidly first and slowly afterwards with the pressure increase, and the maximum temperature reaches 31.42 ℃ at I=600 A under rated pressure; With the pressure increase, the maximum temperature occurs successively on the electric contact between aluminum plate and bolt, and the electric contact between the aluminums, and the electric contact between aluminum plate and bolt; A temperature difference exist between the internal and external of clamps but their temperature varies consistently, so the external temperature of clamps can present indirectly the operating temperature of clamps. Finally, the calculation method and simulation results are verified by experiments.