222 / 2022-03-14 20:02:19

Research on Insulation Aging Law of Switchgear Operating for Different Years under Actual Conditions

Switchgear,Aging,Finite element simulation,Dielectric properties,Mechanical properties,Infrared spectral properties

Purpose/Aim

As the key equipment in the power system, the switchgear has an increasing proportion of over-aged equipment in the power system, which seriously threatens the safe and reliable operation of the power system. However, there is almost no effective method to evaluate the insulation aging state of these over-aged switchgears, because few researchers in the past carried out systematic research on the electrical and physical and chemical properties of insulation parts of switchgears that have been in operation for different years. Therefore, it is necessary to study the variation law of electrical insulation performance of key insulation parts of switchgears of different operating years.  

Experimental/Modeling methods

In this paper, the electric field distribution of 10 kV switchgear is obtained by finite element simulation with the software, COMSOL, and some weak points of the switchgear have been observed. Then, samples are taken from the key insulation parts of switchgears that have been in operation for different years. And the dielectric properties, the mechanical properties and the infrared spectral absorption properties of the samples are tested and compared. Finally, the changing rule of the ageing properties of the switchgears that have been in operation for different years under actual working conditions is obtained based on the testing results.

Results/discussion

The finite element simulation results show that the area of electric field distortion in the switchgear is mainly located at the gas-solid interface and solid-solid interface in the cabinet under actual working conditions. With the increase of the operating years of the switchgear, the electrical properties and mechanical properties of the insulating parts of the switchgear have changed, and the rules of variation are different.

Conclusions

The key to determine the overall life of the switchgear is not the insulating material itself, but the electric field distortion points at the gas-solid interface and the solid-solid interface in the cabinet.