A Sensor Topology for Noncontact AC Voltage Measurement of Polyphase Cables

This article presents a sensor topology and signal processing technique for noncontact measurement of polyphase line-to-line voltage. Conductive plates around the exterior of a three-phase cable form a circuit that can be used to disaggregate the ac voltages in the cable. Fully differential transimpedance amplifiers detect capacitive currents that can be related mathematically to line-to-line voltages. Sensor calibration and line-to-line voltage reconstruction results are presented.