A Noninvasive and Self-Powered Current Measurement for Power Lines Based on Magnetic Field Intensity Inversion

High current measurement technology is of great significance for power systems, including protection and control, power metering, reliability diagnosis, performance evaluation of power equipment, and life prediction, etc. Traditional toroidal current transformers are bulky and exhibit poor anti-saturation performance. Although the measurement range can be expanded by compensating circuits and increasing the number of winding turns, the problem of magnetic core saturation remains unresolved. Motivated by this challenge, a high-precision current measurement method based on magnetic field intensity inversion using a free-standing magnetic field energy harvester (FSMFEH) is proposed, significantly enhancing the anti-saturation performance of the current measurement with magnetic cores. Also, the magnetic field energy can be harvested by the current measurement to provide power for the current signal acquisition circuits without battery. Meanwhile, an ultra-low power energy management and parameter configuration methods for self-powered current measurement (SPCM) are proposed. Consequently, under normal room temperature conditions, experimental results demonstrate that the SPCM can achieve current data acquisition without external power supply, with measurement accuracy within 1%.