Addressing the issue of increased failure rates of reactors due to frequent switching operations, which impacts the stable operation of power systems, this paper investigates an effective monitoring method for inter-turn short circuit faults in dry-type air-core reactors. Using the finite element method and field-circuit coupling analysis, the magnetic field distribution of a BKDCKL-20000/35 outdoor dry-type air-core shunt reactor under normal and inter-turn short-circuit conditions was simulated and analyzed. The study reveals that the magnetic field of a dry-type air-core reactor exhibits a symmetric distribution during normal operation, whereas an inter-turn short circuit fault causes magnetic field distortion. Based on this finding, a method employing dual detection sensors to acquire magnetic field differential signals for condition monitoring is proposed. The theoretical feasibility of this approach was verified through finite element model simulations, and the influence of the magnetic field environment around the reactor on the monitoring effectiveness was investigated. The results demonstrate the practicality of using dual sensors to obtain magnetic field differential signals for assessing the operational status of dry-type air-core reactors. Reliability tests data indicate that this monitoring device can track the reactor's operational state in real time, provide early warning at the initial stage of inter-turn faults, and ensure the safe operation of the reactor.

dry-type air-core reactor,difference method,electromagnetic characteristics,interturn short circuit,monitoring method