Optimization of Small Layer with Conductivity on Cone Type GIS Spacer Surface for Relaxation of Electric Field

Summary

For compact design of HV-GIS, the maximum electric field stress should be relaxed as much as possible. Especially, in general, the electric field distribution around GIS solid spacer becomes critical for electrical insulation performance. For the electric field relaxation, various kinds of techniques have been reported. In this paper, we examine the applicability of the small layer with conductivity on the spacer surface for the electric field relaxation from the results of the finite element simulation. In the numerical simulation, we give the thin layer around the triple junction of GIS spacer. Then, we obtain the electric field distribution with or without the conductive layer on the spacer surface. As the design parameters of the conductive layer, we choose the conductivity of the layer under keeping the layer configurations. Firstly we obtain the fundamental characteristics of the relaxation of electric field by the introduction of conductive layer. Furthermore, in order to investigate the applicability of the conductive layer for various kinds of spacer, we change the contact angle of the spacer with the high voltage electrode to vary the degree of electric field concentration close to the triple junction. The relaxation effect of electric field by introducing the conductive layer is quantified. From the results, we clarified that the conductivity of layer for the optimum relaxation of electric field becomes higher when the electric field concentration becomes stronger. In other words, the relaxation effect increases when the optimum conductivity is chosen. Finally, from the results, we obtain the optimum conductivity for both AC and impulse voltage applications.

Additional informations

Authors

Gjonaj Erion, Psotta Torsten, Franck Christian