With the gradual increase of unit capacity of the capacitor

the temperature of the internal fuse in the capacitor also rises gradually.In order to prevent the insulating oil from aging in the internal fuse under the action of high temperature

it is therefore necessary to calculate and check its temperature rise in the design.In this paper

the calculation method of internal fuse in high voltage film capacitors is studied.Considering the complex internal structure of capacitor

the temperature of internal fuse is simulated and analyzed in two steps.Firstly

on the basis of simplification and equivalence of the internal structure

a thermal field simulation model of capacitor without internal fuse is established.The thermal field of the element inside the capacitor is simulated and analyzed

then the thermal field of partial field of capacitor with internal fuse is set up by the use of calculation result as boundarycondition

finally the temperature rise result of the internal fuse is obtained.In this paper

the calculation is made by taking the high voltage parallel capacitor for UHV AC project as an example and the temperature of internal fuse at severe condition is checked.It is shown by the result that the maximum temperature of the thermal fuse is 74.056 ℃

which meets the requirements.The related research results can be used to instruct the structural design of internal fuse in high voltage film capacitor.