In order to meet the actual situation and protection demands of the consumers’ branches in 10 kV distribution system.A special inrush controller of protection tripping was developed

the hardware diagram and software flow of designed 10 kV feeder inrush controller were given out.Considering the characteristic of full-wave and half-wave Fourier algorithm calculable result on difference current

according to the difference with inrush current and internal failure current

put forward a new method to identify inrush current based on the characteristic of differential current waveform.The theoretical analysis and simulation experiment show that the method can distinguish inrush current and internal failure current quickly.At the same time

it overcomes shortcoming on traditional brake principle and increases difference protection credibly and safety.An EMC measurement verified its merits of anti-interference.