In this paper

the inductance of the air-core reactor is analyzed by using the magnetic vector potential method in the case of dry-type air-core reactor inter-turn insulation failure.In the process of analysis

taking into account the influence of the magnetic field caused by the current in the fault coil to the inductance of the dry-type aircore reactor

the exact analytical expression for the inductance calculation of the dry-type air-core reactor is obtained.On this basis

the electromagnetic simulation software MAGNET is used to simulate the magnetic field of the dry-type air-core reactor and the coil current of the fault.The inductance of the same fault state is measured at different frequencies.As demonstrated by the simulation and test results:the current of fault coil has great influence on the inductance of dry-type air-core reactor

the effect increases with the increase of frequency

finally tends to be stable

and it’s consistent with analytical expression for the inductance calculation of the dry-type air-core reactor.Therefore

the deduced analytical expression of the inductance calculation of dry-type air-core reactor under fault condition can be used in engineering practice.