An Analytical Investigation on Selection of I-APF and R-APF to Mitigate Harmonic Resonance in HVDC Terminal Under Capacity Constraints

With the rapid advancement of power electronics technology, active power filters (APFs) have increasingly become a preferred solution for mitigating harmonic resonance in high-voltage direct current (HVDC) systems. APFs can be broadly categorized into current compensation APFs (I-APFs) and resistive APFs (R-APFs), depending on the control strategies they employ. Although both types have demonstrated effectiveness in practical applications, previous studies have not thoroughly clarified the differences in resonance mitigation performance between these two APF types, especially when operating under the constraint of limited APF capacity. To address this gap, this paper introduces a novel metric, termed capacity utilization efficiency (CUE), to evaluate the resonance suppression effectiveness of APFs. The variation characteristics of CUE are systematically analyzed and compared, considering factors such as resonance frequency, system damping, and APF capacity. The findings provide a general guideline to assist utilities in selecting the optimal APF configuration. The practical value of the proposed guideline is validated using a real-life LCC-HVDC system that exhibits resonance issues.