Linear birefringence-free optical voltage sensor based on dual-crystal structure

This paper proposes an optical voltage sensor (OVS) with a dual-crystal structure for eliminating the impacts of linear birefringence in sensing crystal, which is induced by thermal gradients and pressure on a crystal surface. First, the configuration and the principle of the linear birefringence-free OVS are introduced. Second, the effectiveness of the dual-crystal structure is analyzed by the theoretical method and eventually verified by experiments. Moreover, the impact of the half-wave plate employed in the dual-crystal structure is investigated. When applied AC voltages exceed 500 V, the OVS achieves accuracy within ±0.1% at indoor temperature and ±0.3% with temperature varying from 0°C to 60°C. On the other hand, the scale factor error of the OVS is within ±0.078% at indoor temperature and ±1.63% when temperature varies from 0°C to 60°C.