Water Resources and Power

In order to solve the problem of 750 kV porcelain jacketed arrester uneven potential distribution that may easily lead to the aging failure, three-dimensional simulation model of the arrester was established based on the COMSOL finite element simulation software. The impact of uneven voltage capacitor, number of even voltage capacitor, different layout of capacitance, number of resistor and different layout of relative dielectric constant on the potential distribution of arrester was studied by setting continuous operation peak voltage(704.278 kV) in high voltage terminal of arrester and zero potential in low voltage terminal of arrester. When there is no capacitor inside the arrester and the number of resistor in each core unit are 46, the maximum electric field strength is 2.03 kV/mm, and the uniformity coefficient of the maximum potential distribution is 1.554, exceeding the threshold of 1.15. When the number of arrester unit core ~#1, ~#2, ~#3, ~#4 are 60, 54, 40, 30, its uniformity coefficient reduces by 1.348. When the arrester unit core ~#1 is paralleled with 3 columns capacitor(each column is composed of 41 1100 pF capacitors), arrester unit core ~#2 is paralleled with 3 columns capacitor(each column is composed of 41 700 pF capacitors), arrester unit core ~#3 is paralleled with 1 column capacitor(column is composed of 43 700 pF capacitors), the maximum internal electric field strength of arrester is 2.198 kV/mm, the uniformity coefficient of the maximum potential distribution is 1.146, and the bearing voltage of capacitor meets the requirement. When the relative permittivity of the arrester unit core ~#3 is set to 484 and the remaining resistors are still 440, the uniformity coefficient of the maximum potential distribution reduces to 1.105, accounts for 4.1%. At the same time, the relative permittivity of other arrester unit cores increase, but it still meets the requirement.