Turn-to-turn fault analysis of dry-type air-core reactor based on finite element method

In this paper, a simulation model is constructed using finite element software to investigate the physical characteristics of inter-tum insulation faults in dry-type air-core shunt reactor windings, and to explore the appropriate sensitive state quantities for fault monitoring. Firstly, a coupled field-circuit model based on the actual reactor is constructed in the finite element simulation software, and its accuracy is verified. Subsequently, turn-to-tum insulation faults are applied at different levels and heights of the winding to study the variation rules of the current and space magnetic field distribution of the circuit with the fault location. The results of the study show that the short-circuit loop current increases nearly 100 times when a turn-to-turn short-circuit occurs in the reactor, and the maximum short-circuit loop current decreases as the short-circuit location gets closer to the top. The space magnetic field strength will also increase nearly ten times, and the closer to the outer envelope and the top of the envelope, the magnetic field strength will become larger.