Modal voltage decomposition-based passive method for islanding detection using variational mode decomposition in active distribution network

•A fast and non spurious IDT using a modal voltage signal has been presented. The islanding/non-islanding condition has been detected without directly impacting the system operation.•The proposed method is well competent in ascertaining the islanding below 2 s in the case of a zero power deficit.•The analysis of NDZ of the proposed VMD based IDT is also carried out using anti-islanding requirements specified by UL 1741 Std.•The proposed IDT is applicable for all types of DG.•A real-time simulation and validation of the proposed method has been carried out on the RTDS/RSCAD and dSPACE platform to reaffirm its efficacy and feasibility on real world problems. Ascertaining unintentional islanding conditions is a challenging task for power utility operators due to the pervasive penetration of Distributed Energy Resources (DER). The presence of DER has a significant adverse impact on islanding detection schemes for various types of Distributed Generators (DG) and inverters. This paper addresses the passive islanding detection mechanism based on the mode energy index using Variational Mode Decomposition (VMD) in an Active Distribution Network (ADN). The prime attributes of VMD are noise immunity, robustness, and non-recursive signal processing, making it more promising and competent for signal decomposition than other extant signal processing methods. In this paper, three-phase instantaneous voltages at the target DG end have been acquired to compute modal voltage signals, and VMD has been utilized to decompose the obtained signals into four modes. Thereupon, the energy was calculated for the selected mode. In the context of threshold selection, a series of simulation is carried out for various islanding and non-islanding events. The energy threshold is then selected by implementing “Otsu thresholding method”. The estimated energy index has ultimately been utilized as an islanding detection indicator. In this work, two different test systems have been modelled and simulated using EMTDC/PSCAD. The simulation result outcomes asserted that the developed approach effectively ascertains the islanding and non-islanding events. Furthermore, the proposed islanding detection technique has been validated using the Real-Time Digital Simulator (RTDS) and dSPACE MicroLabBox based co-simulation platform.