1.loss of insulation due to aging. This aging mode usually has electrical aging, mechanical aging, thermal aging and environmental factors.

2.how to prevent the insulation failure: it is understood that the main method to prevent the insulation failure is to increase the electrical insulation material resistivity and enhance the dielectric strength of the dielectric of two aspects. It includes prevention of solid dielectric, prevention of liquid dielectrics and prevention of gas dielectric.

3.insulation failure due to breakdown is specific to four categories, including liquid breakdown, surface breakdown, solid breakdown and gas breakdown.