An External Interference-Resistant Noncontact Voltage Sensor With Negative Feedback Design

In this study, a negative feedback mechanism was implemented in a noncontact voltage sensor to enhance its resistance to external interference. The noncontact sensor relies on capacitance coupling in space between the sensor probe and the power line being measured. However, this configuration leaves the sensor vulnerable to interference caused by environmental changes. The negative feedback mechanism was found to significantly improve the anti-interference properties of the sensor. The sensor exhibited stable voltage sensitivity at 50 Hz, operating within a voltage range of 800 V, with a nonlinearity of less than 1% between 100 and 800 V. In addition, the −3-dB frequency bandwidth of the sensor spanned a range from 10 Hz to 10 kHz, representing a significant improvement over sensors without the feedback design. This compact noncontact voltage sensor, equipped with a feedback structure, holds great potential for applications within distributed sensor networks in smart grids.