On-Line Detection of Railway Power Frequency Current Based on Tunnel Magnetoresistance

In an electrified railway system, electrical energy is provided to the train through the traction network for its normal operation. Starting from the traction substation, the traction current flows through the catenary, the train, and finally returns to the traction substation via the steel rail. Due to the absence of the on-line detection technology for rail current, it has been a long time that the magnitude of the current flowing on the rail is unclear. Therefore, how to effectively detect rail current has become an industrial and academic focus recently. This article uses a new type of tunnel magnetoresistance (TMR) sensor, focusing on the rail power frequency current online detection technology based on the TMR gradient method. First, this article analyzes the current and the magnetic field distribution characteristics near the rail, then considers the actual installation situation on the spot, and selects the appropriate sensor installation location. Finally, through simulation and actual measurement, it is verified that the scheme has a flexible structure, easy installation, strong anti-interference ability, and good detection accuracy.