Simulation Study of Temperature Rise Characteristics of Medium Voltage Switchgear Under Fault Conditions

The heating faults of the medium voltage switchgear account for a relatively high proportion, and it is difficult to meet the temperature-rise standard in the case of a fault. Therefore, it is of critical significance for the safe operation of power system to investigate the temperature-rise characteristics of a switchgear under the fault state. Firstly, we established the simulation model of electromagnetic-fluid-temperature coupling by using the finite element simulation software ANSYS apdl and CFX. Meanwhile,we analyzed the temperature rise distribution at 1.1 times the rated current and verified it through experiment. Secondly, the influences of the contact pressure in vacuum interrupter and plum contact on the temperature rise were simulated and analyzed, respectively. Finally, the influence of the simultaneous changes of the two contact pressures on the temperature rise was analyzed. Based on the simulation results, function fitting was performed to obtain the relationship between contact resistance and temperature rise. It is found that the increase in contact resistance caused by the decrease in contact pressure will lead to an increase in temperature rise. By observing its change trend, it can be found that the influence of contact resistance on temperature rise is linear. The contact resistances in the vacuum interrupter and plum contact have independent effects on the temperature rise. © 2022 Science Press. All rights reserved.