Study for spatial magnetic field distribution of inter-turn short-circuit fault degree in dry air-core reactors

Equipment can be burned with great losses when inter-turn short-circuit fault occurs in Dry-type Air-core Reactor (DAR). The finite element method and curve fitting method was used to put forward a method detect inter-turn short-circuit based on spatial magnetic field distribution of DAR. Firstly, the faults with different degree of inter-turn short circuit were set at different points in the fault simulation model. Secondly, the connection between inter-turn short-circuit fault and spatial magnetic field was obtained after the spatial magnetic field distribution along Axial Traverse in Center(ATC) and Lateral Traverse in Center(LTC) had been simulated and analyzed. Finally, the functions to detect the fault degree were established and verified with the variation of magnetic field at observation points and the fault degree as the fitting variables respectively. The results showed that the absolute errors between the results of functions and the actual value were little while the relative errors were within the error range allowed, which proved the availability of the functions simulated to detect fault.