Induction Fault Traveling Wave Measurement Technique Based on Tunnel Magnetoresistance

To improve the measurement accuracy of high-frequency traveling wave signals, eliminate the measurement errors of the existing measuring device caused by its complex distribution parameters, an induction fault traveling wave measurement method based on tunnel magnetoresistance (TMR) is proposed. A new type of induction current traveling wave sensor is designed and developed in this study. The influence of the sensor's spatial position in the magnetic field on measurement accuracy is analyzed. The high-frequency traveling wave signal is obtained by measuring the magnetic field generated by the wave in the conductor. A unique coefficient matrix based on the sensor installation position on the overhead line is established to correct the interference error of the sensor and to calculate the accurate primary system waveform to enable high-precision, wideband, and induction measurement of the traveling wave signals. Simulation and experimental tests demonstrate that the proposed method outperforms existing traveling wave measurement methods in terms of accuracy and reflects the primary system current traveling wave more accurately. The proposed sensor has the advantages of small size, excellent frequency characteristics, and live installation without power outage, making it suitable for widely applied in the distribution networks to measure low amplitude high-frequency current traveling wave signals.