Research on Adaptive Calibration Technique for Noncontact Voltage Sensors Based on Parameter-Independence Architecture

The coupling capacitance parameter of capacitively coupled noncontact voltage sensors often encounters challenges due to variations in wire diameter and installation position. Additionally, the existing impedance transformation self-calibration method depends on factory-provided capacitance parameters, resulting in an uncertain transmission relationship. In response to these challenges, we propose an adaptive calibration technology that is based on a parameter-independent architecture. This method utilizes a multimodal sensing structure and impedance network to establish a calibration model that does not require the prediction of capacitance parameters. It enables online calibration of sensor gain. The structural parameters of the three-electrode circular probe are optimized by combining the parameter sensitivity curves, and the parameters of the dual-mode switching measurement circuit are designed. An experimental platform with insulated wires of different diameters (1–50 mm<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup>) is constructed to verify the validity of the method. The results show that the maximum error of voltage amplitude measurement of the sensor on multidiameter wires is 1.41% at 180–280 V, with a phase error of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$0.95^{\circ }~\pm ~0.16^{\circ }$ </tex-math></inline-formula>. This supports the 50th harmonic measurement, which has a maximum measurement error of 1.73% in the anti-jamming experiment. Notably, this approach eliminates the need to rely on capacitance parameters. The technology breaks through the parameter constraints through architectural innovation, providing technical support for the scale application of noncontact voltage sensors under complex working conditions.