Novel Fault Detection & Classification Index for Active Distribution Network Using Differential Components

Integrating distributed generation resources (DGRs) in the distribution system, forming microgrids or multi-microgrids (MMGs), has fulfilled the continuous rise in load demand over the past decade. However, the deeper infiltration of microgrids or MMGs in the distribution system provides an uninterruptable power supply and enhances the system's reliability. But their integration changes the system's fault current characteristics, radial nature, and fault current contribution levels. Thus, due to the abovementioned issues, the mal-operation of conventional relays may occur using the existing methods under fault conditions. Moreover, identifying low and high impedance faults is equally essential in active distribution networks (ADNs). Thus, this article proposes a novel fault detection index for identifying low and high impedance faults. Further, a fault classification index is also proposed for classifying low and high impedance faults. The energy associated with the differential value of the superimposed component of the positive sequence impedance is utilized for the proposed technique. It also accurately discriminates the internal and external faults, switching transients, and non-linear loading conditions. The efficacy of the proposed method is further evaluated in the presence of noise components, and by considering the communication delay from one end. A modified IEEE-13 bus distribution system consisting both single DGR unit and multi-microgrids are considered for simulating these test cases. The simulation is performed using Real Time Digital Simulator (RTDS). The experimental setup is used to validate the proposed method for real-time scenarios.