A new two-sampling point method for AC short-circuit fault identification

Effective fault detection method is the premise of stable operation of circuit breaker, and it is also a necessary condition to ensure the safe operation of power system. The advantages and disadvantages of fault detection methods are rapidity, accuracy and stability. The traditional fault detection algorithm will be affected by grid harmonics and noise. The twopoint sampling method uses the signal change rate and the instantaneous value to fit the maximum signal, which also has the above problems. In this paper, a two-point sampling method for fitting the signal change rate is proposed. The instantaneous value and maximum value of the signal are sampled to avoid direct derivation of the signal, thereby reducing the error of the change rate, and then the short-circuit fault is judged by the fitting change rate. The simulation and experimental results show that the fitting signal change rate curve error is smaller, and it is more accurate in fault diagnosis.