Characterization of a bismuth germanate electric field sensor

Summary form only given. Optical sensors show considerable promise for measurements of voltage and current on high voltage transmission lines. Several commercial sensor systems have recently been reported for current and voltage measurements. The voltage sensor provides excellent performance by applying the line voltage directly across a bismuth germanate electro-optic crystal. However, due to the large electric fields that result, the sensor element must be insulated with pressurized SF/sub 6/ gas, which adds cost to both the manufactured structure and the routine maintenance mandated by any high voltage equipment insulated with a pressurized gas dielectric. A desirable alternative is the development of a voltage sensor that has low dielectric stresses throughout the sensor structure while retaining high measurement accuracy. A highly stable, optically isolated electric field sensor plays an important role in any new design. We describe the design and performance of an electric field sensor based on bismuth germanate (Bi/sub 4/Ge/sub 3/O/sub 12/ or BGO). This cubic electro-optic material has already been shown to have stable optical properties suitable for high accuracy sensor applications, and excellent dielectric properties.