A Wireless Differential Protection System for Air-Core Inductors

This paper describes a new wireless differential protection system for detection of turn-to-turn faults in air-core inductors. The proposed system is composed of a pair of floating magnetic field sensors placed at opposite ends of an air-core inductor, which wirelessly communicate their measurements to a remote receiver. The receiver compares the magnetic field measurements from the sensors and triggers an alarm or circuit interruption system if the mean-squared field difference exceeds a specified threshold. The main contributions of this paper are a description of a specific realization of this differential air-core inductor protection system with several novel features and experimental results that demonstrate the sensitivity and latency of the proposed protection system. Our results suggest that deployment of the proposed system in shunt-connected inductors could help to prevent catastrophic damage resulting from turn-to-turn faults by detecting and arresting these faults in their incipient stages.