Stress analysis and temperature rise calculation of dry bushing spring contact finger structure under electric-thermal-force multi-field coupling

Spring contacts, as the electrically connected parts of dry bushing, are susceptible to thermal failure, which can seriously affect the reliability of equipment operation. In order to study the overheating failure mechanism of the spring contact, the spring contact for the electrical connection of 110kV dry bushing is selected as the research object, and a three-dimensional electric-thermal-force multi-physical field coupling simulation model of the spring contact is constructed. Firstly, based on the classical contact stress theory, the stress distribution under different compression is analyzed, and then, the equivalent force is calculated for the case of the minimum effective force. On the basis of this, the contact resistance value of the spring contact finger at each point is calculated for the case of minimum effective force, and then the temperature rise distribution of the spring contact finger under rated working conditions is studied. Finally, the model is verified by the true type test, and the simulation results coincide with the general characteristics of thermal failure of the bushing spring contact finger. The paper has important guiding significance for the thermal fault investigation and analysis of spring contact fingers of dry bushing contacts, and its structure optimization design.