The electromagnetic parameters of the dry-type air-core reactor are calculated by the finite element method in this paper

which contain self inductance

mutual inductance

and eddy-current loss.The overall changing patterns of the dry-type air-core reactor’s inductance are analyzed under different frequency source with inter-turn insulation defects.An effective method of impulse-voltage test to detect the inter-turn insulation defects within reactor is proposed based on the experimental results.Moreover

the testing method is actually implemented on a set of device to detect the reactor’s insulation defects

which is also extensively discussed in the paper.Under conditions of good quality and short-circuit of inter-turn insulation in the reactor

the waveforms of its voltage and current are compared to examine the proposed method.The final result validates the effectiveness of the impulse-voltage test technique.