Enhanced Grid Stability Operation with Plant-Level Control of Generic Inverter-Based Resources in an Embedded HVDC Link

The intermittent nature of renewable energy resources (RESs) poses challenges to network operation, particularly in maintaining frequency stability. To address this issue, the utilization of high-voltage direct current (HVDC) systems for reserve operation balancing has emerged as a viable solution. However, the balancing arrangements implemented through embedded HVDC systems are susceptible to maintaining acceptable voltages at the converter bus. Therefore, it is essential to explore the advanced control of embedded HVDC systems between two regions. Also, plant-level control of inverter-based resources (IBRs) could improve stability by controlling grid functions like emulating active and reactive power. This paper focuses on advanced control operations between embedded HVDC systems and IBRs. The IBR's control operation is based on the 2nd Renewable Energy Generic Modeling (REGM) framework, which was developed by WECC (Western Electricity Coordinating Council) and other research institutes. The proposed control algorithm is shown to effectively mitigate frequency deviations and maintain converter bus voltage regulation in both over- and under-frequency situations, e.g., ± 0.15 Hz and ± 0.1 Per Unit (PU), respectively. Compared to conventional methods, when only one fast frequency control in embedded HVDC or IBRs systems is applied, the frequency deviation increases until ± 0.35 Hz. Additionally, this study examines the provision of replacement reserves for the near future during low inertia stage operations.