Heat Dissipation Improvement of Medium-Voltage Switch-gear: Simulation Study and Experimental Validation

As protective equipment of the electrical power systems, switching device is of great importance in the transmission and distribution of the power systems. Switchgear is widely used in the medium power system. Long-term excessive temperature rise will lead to reduction of insulation property and mechanical property, which may finally lead to fatal accidents. To maintain safe and stable operation of switch-gear, long-term excessive temperature rise has to be avoided. The research on the distribution of temperature in the switch-gear is of great importance for the optimum design and improvement of service life of switch-gear. Based on electromagnetic-fluid-temperature coupling, multi-physics simulations are adopted to analyze the temperature rise distribution of switch-gear. In this paper, we conducted simulations and experiments to analyze the temperature rise of a medium-voltage switchgear whose rated current is 4000A. The 3D model of the switch-gear is established in UG with 1:1 ratio. To achieve high accuracy, contact resistance at the vacuum interrupters and the tulip contact is considered in the 3D model. The simulations are conducted with ANSYS Multiphysics and CFX coupling. In the ANSYS section, the heat generated by the alternating current is obtained and later transported to CFX as energy source. In the CFX section, thermal-fluid coupling simulation is conducted and the temperature rise distribution is obtained. Using this method, the temperature rise of the switch-gear is firstly simulated and analyzed, and simulation results also are compared with the experiment result. Comparison result verified the correctness of simulation result. Secondly, a heat dissipation improvement method is put forward to reduce the temperature rise of the medium-voltage switchgear. Simulation and experiment on the modified switchgear model is conducted. By simulation and experiment, it can be found that the method is effective in reduction of the temperature rise of the switch-gear.