Identification and Control of Distribution Transformer Inrush Current

When a distribution transformer is switched on without load, it will produce inrush current. If the value of inrush current is greater than the setting value of line protection, it will lead to the failure of circuit breaker closing. In order to deal with the inrush current accurately, this paper uses the improved Prony algorithm and Fourier algorithm to identify the inrush current with multi-characteristics, and tests it with the field data of Jiangxi inrush current. On this basis, for the lines with poor identification effect, the line impedance is controlled by controlling the closing resistance device when the transformer is closed without load, so as to suppress the inrush current. The simulation results show that the series resistance control can significantly reduce the magnitude of inrush current and increase the reliability of distribution network power supply.