Transformer Inter-Turn Fault Identification Method Suitable for Small Hydropower Grid Connection

In recent years, distributed power grids dominated by small hydro-power have effectively alleviated the pressure on local power grids for power supply and distribution. Transformers play an irreplaceable role when small hydro-power is connected to the distribution network. Transformer inter-turn short circuit fault is one of the common faults in transformers, which poses a serious safety hazard for the integration of small hydro-power into the distribution network. This article proposes a method for identifying inter-turn faults in transformers suitable for small hydro-power grid connection. Firstly, based on the characteristics of the winding structure of the new energy grid connected transformer, the zero-sequence equivalent circuit is used to establish the zero-sequence node voltage equation; Secondly, the identification criteria for inter-turn faults are constructed based on the different characteristics of the zero-sequence equivalent circuit of transformers during inter-turn faults, normal operation, and external faults. Finally, through numerical simulations, it is demonstrated that the proposed criterion has high reliability and higher accuracy compared to traditional differential current algorithms.