Research on Non-Contact Voltage Measurement for Insulated Transmission Line

Advanced device sensing technology is a prerequisite for achieving intelligent state identification of power equipment. However, accurately sensing voltage signals remains a common challenge for almost all high-voltage equipment, and conventional voltage sensors are inadequate in meeting the existing non-contact voltage measurement requirements. This paper investigates the distribution of electric fields in insulated wires, explores the voltage-electric field relationship under regional boundary conditions, proposes a non-contact voltage measurement method based on electric field perception, and validates the principle through experimental methods. The results indicate that the insulation skin has little effect on the external electric field distribution intensity of transmission lines. By using non-contact voltage measurement methods coupled with electric fields, high-precision measurement of voltage within the range of 4 kV to 20 kV can be achieved, with measurement accuracy reaching level 0.2. Real-time monitoring of voltage waveforms, including power frequency AC, triangular wave, and pulse signal, can be achieved with a maximum phase error within 0.1°. Due to the sharp slope of the pulse edge, there may be slight burrs in peak voltage measurement; however, overall measurement error remains within 1%. This indicates that the method exhibits high measurement accuracy for voltage signals of varying waveforms, enabling real-time and precise voltage measurement feedback. As such, it holds significant potential in facilitating intelligent perception and fault self-healing within smart grid systems.