With the rapid development of switchgear

the heating problem caused by contact fault exists for a long time and significantly affects the working performance of switch cabinet. To explore the temperature rise characteristics of medium-voltage switchgear in case of three typical contact failures

including the lapping zone of the bus bar contact failure

tulip contacts contact failure and circuit breaker contact failure

a three-dimensional multi-physics coupling model of temperature field and flow field is established by the use of finite element analysis method for KYN28-12 medium-voltage switch cabinet

and the distribution characteristics of flow field and temperature field between normal and typical contact faults of switch cabinet are compared and analyzed. The results show that the overall temperature rise of the switchgear increases when the contact failure occurs

and the temperature rise at the fault point is the highest. Under the same resistance of contact fault

the temperature rise of circuit breaker contact fault is the highest

that of the lapping zone of the bus bar contact failure is the next

and that of the tulip contacts contact failure is the lowest. In the case of different contact faults

the characteristics of flow field changes greatly when contact failure exists on the lapping zone of bus bar

especially the flow field in the bus room no longer surrounds the bus bar but shows a trend of flowing towards the bus bar

while the distribution of flow field changes slightly in other cases. The temperature field and flow field show coupling characteristics under all of three contact faults. The research results lay the foundation for the improved design of the switchgear in terms of temperature rise and provide a theoretical basis for the selection of monitoring points for the online monitoring of the switchgear temperature.