A Hybrid Reactive Power Perturbation Islanding Detection Method Based on Double Trigger Conditions

In the context of grid-connected power electronic devices, particularly power conversion systems (PCS), traditional bilateral reactive power perturbation techniques are plagued by challenges associated with unpredictable detection times and pronounced detrimental effects on power quality. Meanwhile, unilateral reactive power perturbation methods encounter similar difficulties in effectively managing detection durations. This paper, taking into account the operational conditions both preceding and following the occurrence of islanding, conducts a thorough analysis of the fundamental principles of reactive power perturbation. It subsequently establishes an approximate linear correlation between reactive power perturbation and the frequency at the point of common coupling (PCC) subsequent to islanding. Building upon this analysis, the paper introduces the design rationale for a dual-trigger mechanism for reactive power perturbations, which integrates the strengths of both perturbation methodologies. Consequently, a novel hybrid reactive power perturbation-based islanding detection method, conditioned upon these dual triggers, is proposed. Through comprehensive hardware-in-the-loop (HIL) simulations, the results conclusively demonstrate that this method exhibits minimal disruption to output power quality, exhibits robust adaptability to grid frequency fluctuations, effectively eliminates detection blind zones, and ensures precise control over the timing of islanding detection.