VOLTAGE sensors are widely exploited for the metering,protecting and relaying applications in electricpower transmission and distribution systems [1], [2]. In recent years, one tendency of electric power system development has been the usage of optical voltage sensors (OVSs), which have higher measurement precision, smaller size and weight, higher operation safety as compared with the conventional voltage sensors [3]–[5].Particularly,bymeansoftheBi4Ge3O12 (BGO)crystal as sensing unit, the OVSs based on Pockels effect have been widely investigated [6], [7].