Detection Method for Turn-to-Turn Short-Circuit of Air Core Reactor Based on Vibration Characteristics

Dry-type air-core reactors are subjected to the combined effects of electrical, thermal, mechanical and other stresses during operation, which can easily lead to packaging cracking, moisture damage, and inter turn-to-turn short-circuit causing fires. The vibration analysis method can reflect the changes in the stress and vibration of the encapsulation after a short circuit, and is suitable for detecting short-circuit faults in reactors. This article first constructs a three-dimensional finite element simulation model of the reactor to explore the modal characteristics of the reactor, and uses a two-dimensional model to investigate the changes in characteristic parameters after inter turn-to-turn short-circuit. Then, a fiber optic vibration measurement experimental platform for reactor is built to collect and analyze the distribution of vibration signals in normal and short-circuit states. The results indicate that the modal features of an encapsulation have axial symmetry, and vibration measurement points with obvious responses should be selected for arrangement. During normal operation, the magnetic field and force values of a longitudinal row of measuring points on the surface of the encapsulation are not significantly different. After the occurrence of a turn-to-turn short-circuit, the magnetic field and force value at the short circuit position increase significantly. The occurrence of turn-to turn short-circuit fault and the position of the short circuit turn can be determined by the significant enhancement of the vibration signal.