Electric Field Measurement in Gas-Solid Insulation System under Lightning Impulse

Abstract

The insertion of a dielectric barrier between the conductors in gas insulation can improve effectively the insulation performance in high voltage equipment such as MV gas insulated switchgear. The dielectric barrier increases the breakdown voltage because of two main reasons: increasing the shortest path, and allowing surface charge deposition to reduce the total electric field. The electric field measurement in such systems is a very important to understand the physical involved phenomena, however, it is so challenging. In this work, the electric field at the vicinity of the HV electrode is investigated experimentally and numerically in a needle-barrier-plane configuration under positive lightning impulse. The electric field is measured using a very compact and fully dielectric electrooptic probe. The results of the experimental measurements show a good agreement with the numerical simulations for both Ez and Er field components. The surface charge density having the same polarity as the applied voltage impacts mainly the vertical
component of the electric field, while the space charge density generated by the PD activity impacts mainly the radial component of the electric field.

Luan Caizergues, SuperGrid Institute ; Ayyoub Zouaghi, Ecole Centrale de Lyon ; Gwenael Gabori, Université Savoie Mont Blanc ; Caterina Toigo, SuperGrid Institute ; Lionel Duvillaret, Grenoble Ecole de Management

Presented at International Conference on Dielectrics (ICD) 2026