COORDINATED FREQUENCY SUPPORT OF GRID FORMING AND GRID FOLLOWING CONVERTER CLUSTERS
Keywords:
Grid-forming converter, Grid-following converter, Frequency support, Battery energy storage, Coordinated controlAbstract
High penetration of inverter-interfaced renewable generation reduces the equivalent inertia of power systems and increases the need for fast frequency support from power-electronic resources. Grid-forming (GFM) converters can provide virtual-inertia and droop responses, whereas grid-following (GFL) converters can contribute additional active power through frequency-dependent control but exhibit different synchronization and response dynamics. This paper develops a reduced-order model for coordinated frequency support of a GFM battery energy storage system (GFM-BESS) cluster and a GFL renewable energy source (GFL-RES) cluster. Particle swarm optimization is used to coordinate the virtual-inertia coefficient and the GFM/GFL active-power support gains. Three strategies, namely Conventional, GFM-only, and Proposed, are compared under a 10 MW load disturbance. Relative to Conventional control, the Proposed strategy reduces the maximum frequency deviation from 0.6084 Hz to 0.4556 Hz and the maximum RoCoF from 0.8331 Hz/s to 0.5188 Hz/s, corresponding to reductions of 25.1% and 37.7%, respectively. Compared with GFM-only control, it reduces the peak GFM support by 18.0% while the GFL cluster provides 2.366 MW of peak support. The results indicate that coordinated GFM/GFL control can improve transient frequency performance while distributing short-term support more effectively between converter clusters.References
[1] Valikhany Mina, Astero Poria, Lehtonen Matti, et al. A review on the suitability of virtual inertia strategies for the next generation of low-inertia power systems. e-Prime - Advances in Electrical Engineering, Electronics and Energy, 2025, 14: 101131. DOI: 10.1016/j.prime.2025.101131.
[2] Li Yalou, Zhao Fei, Fan Xuejun. Review of Grid-Forming Energy Storage and Its Applications. Power Generation Technology, 2025, 46(2): 386-398. DOI: 10.12096/j.2096-4528.pgt.24052.
[3] Guzman Gilberto, Madrigal Manuel, Melgoza-Vazquez Enrique. Grid-Forming Inverters for Frequency Support in Power Grids. Electricity, 2025, 6(4): 65. DOI: 10.3390/electricity6040065.
[4] Liu Hui, Yu Siqi, Sun Dawei, et al. An Overview of Control Technologies and Principles for Grid-forming Converters. Proceedings of the CSEE, 2025, 45(1): 277-297. DOI: 10.13334/j.0258-8013.pcsee.232479.
[5] Wang Guanqi, Pei Wei, Xiong Jiawang, et al. Stability Analysis Method for Hybrid Systems of Grid-following and Grid-forming Inverters. Proceedings of the CSEE, 2025, 45(1): 25-37. DOI: 10.13334/j.0258-8013.pcsee.240374.
[6] Wang Zhen, Shan Yu, Zhu Yue, et al. Spatio-Temporal Frequency Distribution Analysis in Systems With Grid-Forming and Grid-Following Inverters: A New Perspective From Frequency Domain. IEEE Access, 2025, 13: 87999-88011. DOI: 10.1109/ACCESS.2025.3571481.
[7] Mohammed Nabil, Ahmed Shehab, Konstantinou Charalambos. Comparative frequency- and time-domain analysis of four grid-forming inverters: Droop, VSM, matching, and dVOC. International Journal of Electrical Power & Energy Systems, 2025, 172: 111302. DOI: 10.1016/j.ijepes.2025.111302.
[8] Liu Zunzhu, Cheng Zhijiang, Wang Weiqing, et al. Active frequency support control strategy for grid-forming direct-drive wind turbines. Electric Power Engineering Technology, 2025, 44(2): 23-33. DOI: 10.12158/j.2096-3203.2025.02.003.
[9] Wang Weiyu, Wu Gongping, Ke Fei, et al. A power disturbance observer-based sliding mode frequency controller for grid-forming converters. International Journal of Electrical Power & Energy Systems, 2025, 170: 110696. DOI: 10.1016/j.ijepes.2025.110696.
[10] Ndirangu Julius, Nderu John, Irungu George. Adaptive Grid-Forming Controller With Virtual Inertia and Damping for Enhanced Frequency Stability in Renewable Energy Systems. Journal of Electrical and Computer Engineering, 2026, 2026: 4351705. DOI: 10.1155/jece/4351705.
[11] Yu Hengning, Yao Liangzhong, Liang Shuai, et al. Coordinated control of grid-following and grid-forming energy storage for virtual inertia response considering frequency modal characteristics. International Journal of Electrical Power & Energy Systems, 2025, 168: 110686. DOI: 10.1016/j.ijepes.2025.110686.
[12] Zong Qihang, Yao Wei, Zhou Hongyu, et al. Hierarchical optimal frequency support scheme of wind farm with both grid-forming and grid-following wind turbines. International Journal of Electrical Power & Energy Systems, 2025, 165: 110463. DOI: 10.1016/j.ijepes.2025.110463.
[13] Wei Che, Pei Wei, Qiu Yinfeng, et al. A co-configuration method of grid-forming/grid-following energy storage for grid frequency support and wind power consumption in offshore oil and gas fields. Advanced Technology of Electrical Engineering and Energy, 2025, 44(11): 58-71. DOI: 10.12067/ATEEE2501020.
[14] Wang Xiaoyang, Chen Xin. Distributed Coordination of Grid-Forming and Grid-Following Inverters for Optimal Frequency Control in Power Systems. IEEE Transactions on Power Systems, 2026, 41(5): 3831-3846. DOI: 10.1109/TPWRS.2026.3684791.