A new method based on the discrete time energy separation algorithm for high and low impedance faults detection in distribution systems

•A new method based on the discrete energy separation algorithm presents to HIF and LIF detection in distribution system.•Simple implementation and low computational burden are main advantages of the method.•The method detects HIF and LIF from other disturbances with high detection accuracy and low detection time even in noisy condition.•The method has proper performance in detection of recorded real HIFs in distribution system.•CT saturation has no impact on the detection accuracy and time of the method in LIF detection. Due to the low fault current of high impedance fault (HIF), it is not recognized by overcurrent relays. Moreover, due to the similar characteristics of HIF and other disturbances like capacitor bank (CB) and non-linear load (NL) switching, detection of HIF is one of the main challenges in protection of distribution system. Furthermore, detection of low impedance fault (LIF) is important for protection system. In this paper, a new statistical method is proposed based on a discrete time separation algorithm of energy for detection of HIF and LIF from other disturbances to improve detection accuracy and time. The method consists of two main parts, the first one detects switching on/off the linear load, switching off the CB and switching off the NL from abnormal conditions, while the second part identifies the HIF and LIF from switching on the CB and switching on the NL. High detection speed, simple implementation, and low computational burden are advantages of the method. The method is tested on IEEE 13-node and IEEE 34-node distribution test systems, and a real feeder in Iran. Obtained results show that the high efficiency of the proposed method in detection of disturbances even in noisy conditions, with low detection time.