Hybrid Islanding Detection Method of Photovoltaic-Based Microgrid Using Reference Current Disturbance

Abstract

This paper proposes a new hybrid islanding detection method for grid-connected photovoltaic system (GCPVS)-based microgrid. In the presented technique, the suspicious islanding event is initially recognized whilst the absolute deviation of the point of common coupling (PCC) voltage surpasses a threshold. After an intentional delay, a transient disturbance is injected into the voltage source inverter’s d-axis reference current to decline the active power output. As a result, the PCC voltage reduces in islanding operating mode whilst its variation is negligible in the grid presence. Therefore, the simultaneous drop of PCC voltage and active power output is used as an islanding detection criterion. The effectiveness of the proposed algorithm is investigated for various islanding and non-islanding scenarios for a practical distribution network with three GCPVSs. The simulation results in MATLAB/Simulink show successful islanding detection with a small non-detection zone within 300 ms without false tripping during non-islanding incidents. In addition to the precise and fast islanding classification, the presented scheme is realized inexpensively; its thresholds are determined self-standing, and its output power quality degradation is eminently small. Moreover, the active power output is restored to the nominal set after islanding recognition, enhancing the chance of GCPVS generation at its highest possible level in the autonomous microgrid.

Review on islanding detection methods for grid‐connected photovoltaic systems, existing limitations and future insights

“…The combination of both active‐ and passive‐based methods significantly reduces the overall NDZ compared to the pure passive IDM without violating the PQ standards in grid‐connected mode. As an instance of hybrid schemes, the active power output of GCPVS has been reduced through a current injection into I d ,ref during suspicious islanding events, categorised by an absolute voltage deviation index [58]. This power curtailment leads to a further voltage reduction; thus, islanding is recognised when voltage and active power output drop below pre‐defined thresholds simultaneously.…”

“…Therefore, the interaction between these features and islanding detection should draw more attention in future studies. • Several hybrid methodologies employed a voltage-based criterion to identify the suspicious islanding events [58,[62][63][64].…”

“…For example, the MPPT disturbance injection forces the PCC voltage beyond the minimum standard set [62]. Still, most hybrid techniques are designed to slightly change the system conditions of the microgrid/GCPVS for islanding detection without destabilizing the islanded area [58–61, 63, 64]. For example, a slight active power output reduction is ordered in refs.…”

A Review on Artificial Intelligence Applications for Grid-Connected Solar Photovoltaic Systems

“…There is much research on attaining fast detection times with a smaller non-detection zone [98]. Based on the method implemented to identify abnormality, the anti-islanding protection scheme is categorized into active [99], passive [100] and hybrid [101] islanding detection. In active islanding detection, an external perturbation is added into the system, and variation in the signal is observed to identify any abnormality.…”

A Decentralized Passive Islanding Detection Method Based on the Variations of Estimated Droop Characteristics

“…Nonetheless, the method relies on communication infrastructure, hindering its decentralized applicability. Finally, Bakhshi-Jafarabadi & Popov [13] introduced an HDM based on a series PDM-ADM. The PDM is based on the ROCOV at the PCC.…”