For the analysis of frequent fault of dry-type air-core reactor in 500 k V substation

the structure and features of the reactor is studied. After the analysis of the multiple faults inside the power grid

it is found that the most direct fault reason is the inter-turn short circuit within one hours of the reactor operation. The reason of inter-turn short circuit is due to improper maintenance

operating overvoltage caused during normal switching period

imperfect manufacturing process and material etc. Insulation defects in inter-turn of coil

the surface of encapsulation insulation and excessive high partial temperature are the three weak points which easily leading to fault of the reactor. According to these fault characteristics

the effective protective measures to the fault of the reactor are proposed from the aspects of following the counter measures and strengthening daily patrol and maintenance etc.