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.