Summary
This paper presents an EMT-based frequency stability assessment of a power system with high renewable energy penetration, focusing on the role of grid-forming (GFM) inverters during large disturbances. PSCAD/EMTDC simulations are performed to investigate system frequency responses under three operating scenarios, including load step changes, HVDC line disconnection with different GFM composition ratios, and HVDC disconnection under high renewable penetration. Frequency nadir and rate of change of frequency (RoCoF) are adopted as key performance indices to quantify dynamic stability. The EMT model is established by reflecting projected Jeju Island system conditions based on the 11th Basic Plan for Electricity
Read more Read lessSupply and Demand, including future load growth, renewable energy expansion, and mainlandlinked HVDC operation. The results show that GFM inverters effectively mitigate RoCoF by enabling rapid active power injection immediately after disturbances. However, improvements in frequency nadir are limited when the GFM capacity is small relative to the total system load.
Furthermore, the study reveals that frequency stability depends more on the installed capacity and power capability of GFM inverters than on their proportional share within renewable resources. Specifically, under annual operating conditions, stable operation in 2023 and 2030 was achieved only with sufficiently high GFM penetration, whereas in the 2038 high-load and high-renewable scenario, grid collapse occurred even when 90% of renewable resources were operate with GFM inverters. In addition, under 80% renewable penetration with HVDC disconnection, GFM-dominant operation maintained stable frequency convergence, while
GFL-dominant operation resulted in severe oscillation and collapse. These findings provide practical guidance for system planning and operation in grids with increasing inverter-based resources.
Additional informations
| Publication type | Session Materials |
|---|---|
| Reference | C6_12053_2026 |
| Publication year | |
| Publisher | CIGRE |
| Country | Korea, Republic of (South Korea) |
| Study committees | |
| File size | 1 MB |
| Price for non member | 30 € |
| Price for member | 30 € |
Authors
JI Sanghyuk - Hanyang University; LEE Chaeeun - Hanyang University; JANG Yohan - Hanyang University; CHOUNG Seunghoon - Yonam Institute of Technology; BAE Sungwoo - Hanyang University
Keywords
Frequency stability, Grid-forming inverter, Inertial support, Renewable energy penetration
