Position Deviation Analysis and Correction Method of Tunnelling Magnetoresistance Sensor used in Transformer Core Earthing Current Monitoring

Tunnelling magnetoresistance current sensing technology is an effective measuring method which can be used in weak current monitoring in power system. Aiming at transformer core earthing current monitoring, a non-contact current monitoring method based on a single monaxial tunneling magnetoresistance sensor is proposed, and the basic principle and structure of current sensor are introduced. The influence of position deviation between current sensor and earthing copper bar on magnetic field distribution is studied, and the influence of the designed magnetic gathering structure on the position deviation is analyzed. The simulation results show that the magnetic gathering structure designed can effectively reduce the measurement error caused by position deviations. This paper provides reference for subsequent design of transformer core earthing current monitoring system.