12 kV 开关柜介电梯度支撑绝缘子优化设计与制造应用

Dielectrically graded insulation（DGI）is an insulation material or structure with non-uniform dielectric parameter distribution，which can significantly suppress the local electric field concentration and improve the dielectric strength and operational reliability. At present，DGI research is mainly limited in the laboratorial stage，and the field application of DGI components is still difficult. In this paper，taking a post insulator of a 12 kV switchgear as an example，the topology optimization is used to construct the internal dielectric gradient structure，and the combined fabrication method（‘3D printing’plus‘vacuum casting’）is used to build the DGI support insulator. Finally，the performance test and field trial operation are carried out. Results show that comparing to homogeneous insulators，the electric field in and along the surface of graded insulators decreases by 50.6% and 56.1%，respectively，and the partial discharge inception voltage in air increases by 17.5%.The comprehensive performance meets the requirements of GB/T 11022—2020 and other relevant standards. Supported by the above research，the first trial operation of DGI support insulator has been carried out since November 2021，and the operation is in good condition so far.