A half-wave voltage regulation method of electro-optic crystal based on center-symmetric electrodes and arbitrary direction electric field

TL;DR

This paper proposes a novel half-wave voltage regulation method for electro-optic crystals using center-symmetric electrodes and arbitrary electric fields, enhancing stability and reducing thermal birefringence in optical voltage sensors.

Contribution

It introduces a new electrode configuration and electric field control technique to directly improve the half-wave voltage of BGO crystals without additional gases or materials.

Findings

Maximum regulated half-wave voltage reaches 2.67 kV considering a 1° angle.

Experimental results show a 35.6% difference from simulation.

Achieves required measurement accuracy with less than 3.9' angle error.

Abstract

To solve the problems of instability and thermal stress birefringence of voltage divided medium in optical voltage sensor (OVS), a half-wave voltage regulation method based on a central symmetry electrode and an arbitrary directional electric field is proposed in this paper. The method uses a center-symmetric copper foil electrode or the ITO (Indium Tin Oxide) transparent electrode to apply voltage, which can arbitrarily adjust the direction of the average electric field in the crystal, so as to improve the half-wave voltage of the bismuth germanate (Bi4Ge3O12, or BGO) crystal directly without additional SF6 gas or quartz glass. The internal electric field of the BGO crystal is simulated by the finite element method, and the half-wave voltage is calculated by the coupling wave theory of electro-optic effect. The results show that the maximum regulated half-wave voltage, considering the 1{\deg} angle, can reach 2.67e3 kV. And this is consistent to the experimental results 1.72e3 kV with difference of 35.6%. For the measurement of 110kV line voltage, that is, 63.5kV phase voltage, to ensure a 0.2 accuracy class, the angle error of incident light, and the polarization direction and the electric field direction is required to be less than 3.9', which can be achieved by the existing technologies.