A novel transducer to replace current and voltage transformers in high-voltage measurements

A transducer which combines both current and voltage sensors in a single integrated unit is described. The principle of operation is based on Poynting's theorem which defines the rate of how of electromagnetic energy in terms of the electric and magnetic field intensities at a point in space. Current is measured by sensing the tangential component of the magnetic held, and voltage is measured by sensing the radial component of the electric field in a well-defined region around the high-voltage conductor. Signals from the two sensors are processed by simple electronic circuits to give an output suitable for direct connection to modern analog and digital meters, relays and computers for continuous on-line monitoring and protection. The new transducer overcomes the limitations of conventional current and voltage transformers. It is also ideally suitable for incorporation as a module in gas-insulated systems. Typical applications of the transducer in high-voltage power systems are also discussed