In case of slight inter-turn short of dry type iron-core reactor

the circulating current of its short circuit turn can be up to ten or dozens of times

leading to insulation damage of windings.However

it’s such electrical feature variation as phase voltage and current etc is less and cannot be taken as reliable base for the inter-turn protection of reactor.In this paper

the spatial magnetic field distribution of the iron core reactor under different conditions is simulated and analyzed by the field path coupled finite element method.Under normal condition

the magnetic flux leakage induction strength is small and the spatial magnetic field shows longitudinal symmetrical distribution.In case of fault

the asymmetry of the spatial magnetic field increase with the increase of the short circuit turn number and the asymmetry difference of the spatial magnetic field in the fault at different axial and radial positions is bigger.Throughout the comprehensive analysis result

the asymmetry of the spatial magnetic files of reactor is taken as the criteria of inter-turn short circuit.