Dielectrically coated electrode is an important way to improve lifting field of metal particles in DC GIL

and study on the lifting field calculation with dielectric coated electrodes can provide a theoretical support for the selection of coating in practical GIL.The effect of coating dielectric constant and the space charge in the electron avalanche head when the partial discharge occurs between particles and dielectric coated electrodes have not been considered in the Parekh calculation model about lifting field

and the calculation formula of electrostatic force is contrary to what it actually is

thus we improved the model.Results under different groups of SF

6

gas pressure

coating material and thickness were gained based on the optimization model to verify the accu

racy of optimization model.The electric field of partial discharge between particles and dielectric coated electrodes is decreased with considering the effect of coating dielectric constant

particle charge increases obviously when space charge is taken into account

improving the computing accuracy of lifting field;moreover

the new electric field force calculation formula can better explain the physical properties of coating’s effect on electric field force.It is concluded that the decreasing of particle charge and downward electric field force are causes for enhancement of lifting field.