Based on the dual equivalent model of a sin-gle-phase two-winding transformer and a single-phase three-winding autotransformer,a method for identifying inrush current in single-phase transformers is proposed.This meth...Based on the dual equivalent model of a sin-gle-phase two-winding transformer and a single-phase three-winding autotransformer,a method for identifying inrush current in single-phase transformers is proposed.This method distinguishes inrush current from internal fault current using the instantaneous equivalent induct-ance of the dual model.The setting principle of the method is determined by analyzing the air-core induct-ance and the equivalent model of the faulty transformer.PSCAD simulations and recorded transformer protection data demonstrate that the proposed method can accu-rately identify inrush current when the transformer core is deeply saturated,and can quickly discriminate between currents during a critical internal fault.Furthermore,the simulation results show that the proposed method is sen-sitive to minor turn-to-turn faults but is less sensitive to the equivalent impedance of an external source.展开更多
基金supported by the National Natural Sci-ence Foundation of China(No.U1866603)the Headquarters Technology Project of the State Grid Corporation of China(No.5100-202340030A-1-1-ZN).
文摘Based on the dual equivalent model of a sin-gle-phase two-winding transformer and a single-phase three-winding autotransformer,a method for identifying inrush current in single-phase transformers is proposed.This method distinguishes inrush current from internal fault current using the instantaneous equivalent induct-ance of the dual model.The setting principle of the method is determined by analyzing the air-core induct-ance and the equivalent model of the faulty transformer.PSCAD simulations and recorded transformer protection data demonstrate that the proposed method can accu-rately identify inrush current when the transformer core is deeply saturated,and can quickly discriminate between currents during a critical internal fault.Furthermore,the simulation results show that the proposed method is sen-sitive to minor turn-to-turn faults but is less sensitive to the equivalent impedance of an external source.
