Research on Influencing Factors of Current-carrying Temperature Rise on Connector Terminal of Current Circuit in UHVDC Converter Station

Abstract

Relying on the high current temperature rise test, starting from three aspects of different materials, different structural strengths, and different contact conditions, the research on the current-carrying-temperature rise characteristics of the joint terminals of ±800kV UHVDC converter stations under different conditions is carried out. The results show that, for joint terminals of the same structure type and contact area, the difference in resistivity of joint terminals of different materials has a significant impact on the temperature rise level. When the material is the same, the temperature rise level can be reduced to a certain extent after the silver (tin) layer is added to the contact surface of the terminal. When the contact resistance of the joint terminal and the current density are the same, after increasing the contact area, the temperature rise and decrease level of the aluminum alloy plate lap type joint terminal is significantly better than other types of joint terminals. The contact resistance and temperature rise of the joint terminal decrease with the increase of the bolt tightening torque, and become stable when it reaches more than 80%. When the bolt tightening torque reaches more than 90%, the surface finish of the contact surface has no obvious effect on the contact resistance of the joint terminal. By controlling the material properties, structural strength, contact conditions, significantly reduces the temperature rise of the level of the joint terminal, effectively ensuring the safety ±800kV UHVDC converter station stable operation.