Experimental analysis on influence of temperature and bolted torque to DC contact resistance of terminal connector in UHV valve hall

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.