The overheating problems of terminal connectors severely threaten the operation of ultra-high voltage projects and cause enormous losses of economy

so a higher currentcarrying reliability of the connectors has an important engineering significance with the development of transmission capacity. In this paper

a bivariate mathematical model of contact resistance as functions of temperature and tightening torque was deduced based on the large current temperature rise tests. To perform such analysis

four typical terminal connectors

namely: overlapping terminal of aluminum plates

overlapping terminal of copper plates

overlapping terminal of plates with clad layer and overlapping terminal of copper rod with aluminum clamp

were chosen for the experiments. The changing rules of DC resistance with different tightening torques and different currents were studied. Then the empirical formula of contact resistance was deduced. Finally

temperature calculations of different terminal connectors were realized to verify the effectiveness of the bivariate mathematical model.