Non-contact Immunity Voltage Sensor Based on Look-up Table Calibration

The non-contact voltage sensor offers advantages such as simple structure, easy installation, immunity to insulation effects on power lines, and high stability. However, in practical measurements, the accuracy of the sensor is affected by the instability of the coupling capacitance between the wire and the probe. Additionally, interference from inter-phase and ambient coupled electric fields is also a concern. Therefore, a measurement method of non-contact immunity voltage sensor based on look-up meter calibration is proposed, aiming to address the issues of the uncertain voltage division relationship and interference from inter-phase and ambient coupled electric fields in traditional capacitive coupling-based non-contact voltage measurement. The principle of electric field coupling measurement is introduced, followed by an analysis of the shielding structure and dielectric strength of FR4 material using COMSOL to optimize the model and parameter design of the sensor. Based on this, a sensor prototype with shielded interference and a remotely controlled lumped parameter capacitance unit is developed. Finally, tests are conducted on the prototype to evaluate its magnitude accuracy, phase accuracy, disturbance resistance, and line adaptability. The magnitude accuracy test shows a maximum relative error of-1.89%, the maximum phase error is 1.613°. The disturbance resistance test exhibits a maximum error offset of 0.58%, indicating the effective shielding capability of the designed probe. The line adaptability test demonstrates a maximum relative error of-1.85% when testing different wire specifications.