Research on inter-turn short-circuit fault of power transformer by using third harmonic

The inter-turn short-circuit fault of a power transformer has a large current in the winding, which will cause serious heating and deformation of the winding and may threaten the safety of the power transformer. Under this background, this paper proposes a scheme based on open-delta voltage monitoring and identification of inter-turn short circuits in power transformers. First, the mathematical modeling and analysis of the principle of inter-turn short-circuit monitoring of power transformers are carried out, and the mathematical expression to characterize power transformers with different short-circuit turns are given. Second, the magnetic field distribution of the power transformer under different short-circuit conditions, the relationship between the eigenvalue and the number of short-circuit turns etc. are given. Finally, the experimental study verifies the correctness of the proposed scheme.