A Novel High-Impedance Fault Detection Technique in Smart Active Distribution Systems

Identification of high-impedance fault (HIF) is important in smart active distribution systems. The existing protection methods fail to detect HIF, as HIFs have peculiar fault current characteristics. However, if HIFs are left undetected, they result in severe fire hazards and arcing. The article proposes a novel fault detection indicator that utilizes the differential energy associated with the positive sequence current components during faults. IEEE-13 bus and IEEE-34 bus systems are used for simulation in real-time digital simulator. The results show that proposed technique accurately identifies HIFs and perfectly discriminates the transients due to HIFs, nonlinear loads, and voltage and reactive power compensation devices. Furthermore, it differentiates HIFs from other switching transients like capacitor or load switching events. Other factors, like transformer inrush currents, effect of noise and sampling rate are also considered to ensure the accuracy and reliability of the proposed method. Moreover, the practical feasibility of the proposed method is also experimentally validated.