Islanding detection scheme for converter-based DGs with nearly zero non-detectable zone

• Published in: IET generation, transmission & distribution Vol. 13; no. 23; pp. 5365 - 5374
• Main Authors: Gupta, Om Hari, Tripathy, Manoj, Sood, Vijay K
• Format: Journal Article
• Language: English
• Published: The Institution of Engineering and Technology 03.12.2019
• Subjects: converter‐based DGs; different islanding conditions; distributed power generation; embedded converter‐based; fault event; grid‐connected mode; high magnitude; islanded mode; islanding detection scheme; islanding event; laboratory‐based experimental setup; MATLAB‐based simulations; microgrid; nondetectable zone; PCC; power distribution faults; power grids; recently published detection scheme; Research Article; steady‐state magnitude; high magnitude; islanding event; power distribution faults; islanded mode; distributed power generation; PCC; fault event; laboratory-based experimental setup; converter-based DGs; different islanding conditions; grid-connected mode; microgrid; recently published detection scheme; MATLAB-based simulations; islanding detection scheme; steady-state magnitude; power grids; nondetectable zone; embedded converter-based
• ISSN: 1751-8687; 1751-8695; 1751-8695
• DOI: 10.1049/iet-gtd.2018.5168

This study presents a new method for detecting an islanding event in a microgrid with embedded converter-based distributed generation (DG). Unlike other schemes, the proposed scheme injects negligible perturbations into the microgrid after the generation of an alert signal. The proposed scheme then uses another index called superimposed impedance, ΔZ. The ΔZ is characterised by a low steady-state magnitude during the grid-connected mode and a high magnitude during the islanded mode. Furthermore, for a fault at the point of common coupling (PCC), the magnitudes of ΔZ and PCC voltage are both very low – except during the initial transient period, where |ΔZ| momentarily crosses the threshold. Therefore, an islanding event can be detected if the magnitude of ΔZ is high for some specified time. Moreover, a fault event will not be misdirected as an islanding event because the steady-state magnitudes of both the ΔZ and PCC voltage are very low in the case of a fault. The robustness of the proposed detection scheme is evaluated against different islanding conditions and also, for a fault at the PCC, first by using MATLAB-based simulations and later by using a laboratory-based experimental setup. A comparison with a recently published detection scheme shows the superiority of the proposed schemes.