Development of Non-contact Traveling Wave Sensor Based on Tunnel Magnetoresistance

Sensitivity of traveling wave detection plays a decisive role in the accuracy of traveling wave positioning. This paper firstly analyzes the tunnel magnetoresistance as a quantum effect, and illustrates the tunnel magnetoresistance effect based on Slonczewski theory. Mechanism of tunnel magnetoresistance measurement for traveling wave signal is analyzed. The amplification and filtering circuit is designed and the TMR2701 chip is designed. High-precision traveling wave sensor has been developed. Simulation and experiments show that the non-contact sensor can correctly transmit signals up to 50MHz, and the detection sensitivity reaches mA level. Based on theoretical calculation, the transition resistance of the distribution network can be detected up to 8kΩ, and ground fault location is better than the current fault location indicator of the distribution network.