Enhancing small-signal stability in high-voltage DC systems: supplementary controls for damping inter-area oscillations

Abstract

High voltage direct current (HVDC) transmission systems have emerged as a leading technology for efficient and cost-effective long-distance power transmission, offering significant advantages over traditional high voltage alternating current (HVAC) systems. These benefits include seamless integration of asynchronous grids and renewable energy sources (RES), enhancing the reliability of power supply. However, the dynamic behavior of HVDC systems and their ability to maintain stability under small disturbances introduce challenges to overall system stability.To address these challenges, this study focuses on improving small-signal stability in HVDC systems by exploring supplementary control strategies for damping interarea power oscillations.The proposed strategy was tested using the kundur two-area four-machine (K-TAFM) system modeled in power systems computer-aided design (PSCAD), incorporating case study under a three phase-to-ground fault scenario.The active power imbalance and inter-area oscillations observed during fault conditions highlight the critical need for advanced stability enhancement techniques to effectively mitigate small signal disturbances. This approach significantly improved the small-signal stability of the HVDC system, underscoring its potential to enhance the reliability and resilience of modern power grids.