High Voltage Monitoring with a Fiber-Optic Recirculation Measuring System

Optical technologies for measuring electrical quantities have unique properties and significant advantages in the high-voltage electric power industry; for example, the use of optical fibers ensures the high stability of measuring equipment to electromagnetic interference and galvanic isolation of high-voltage sensors; external electromagnetic fields do not influence the data transmitted from optical sensors via fiber-optic communication lines; problems associated with ground loops are avoided, and there are no side electromagnetic radiation or cross-coupling between the channels. The structure and operation principle of a quasi-distributed fiber-optic recirculation system for monitoring high voltages are presented. The sensitive element of the system is a combination of a piezoceramic tube with an optical fiber beam waveguide where the inverse transverse piezoelectric effect occurs. The electrical voltage measurement principle is based on recording the change in the recirculation frequency under the applied voltage influence. When the measuring sections are arranged in ascending order of the measured effective voltages relative to the receiving-transmitting unit, a relative resolution of 0.30–0.45% for the PZT-5H and 0.8–1.2% for the PZT-4 is achieved in the voltage range of 20–150 kV.