Voltage Measurement of Multi-Wire Cables With a Noncontact Electrode-Array Sensor

This article presents a noncontact voltage sensing method and hardware prototype for multi-wire cables. The system self-calibrates and never requires contact with energized system conductors. A flexible printed circuit board (PCB) wraps around the cable. An array of onboard sensing electrodes couples to the wires inside the cable. One transimpedance amplifier (TIA) channel connects to each sensing electrode and measures the currents through its associated coupling capacitances. A combination of signal injection and estimation techniques identifies coupling capacitance values for sensor calibration. Finally, digital signal processing algorithms use capacitance estimates to reconstruct voltage waveforms. This work demonstrates the performance of three proposed coupling capacitance estimation techniques. Voltage reconstruction tests verify the measurement methods, capacitance estimation techniques, and sensor hardware.