本論文提出一種混合式離岸再生能源發電系統經由高壓直流輸電系統連接至陸上多機電力系統之系統架構，所建構之混合式離岸再生能源發電系統包含潮汐流發電系統、離岸風力發電系統與海底抽水蓄能系統，並經由基於模組化多階轉換器之高壓直流輸電系統連接至IEEE 14匯流排之陸上多機電力系統。為進一步改善系統穩定度，論文中除根據系統模態設計模組化多階轉換器之輔助阻尼控制器外，還引入重力搜尋演算法最佳化控制器之參數設計，在穩態及小訊號穩定度方面，分別對所研究系統於多種情境下進行分析，而在動態與暫態穩定度方面，針對不同的干擾及故障進行模擬及分析，並比較加入輔助阻尼控制器前後之響應結果。

This paper proposes a system architecture for a hybrid offshore renewable energy generation system connected to an onshore multi-machine power system via a high-voltage direct-current (HVDC) transmission system. The constructed hybrid offshore renewable energy generation system comprises a tidal flow power generation system, an offshore wind power generation system, and an undersea pumped storage hydropower system, and is connected to the IEEE 14-bus onshore multi-machine power system via an HVDC transmission system based on a modular multilevel converter. To further improve system stability, in addition to designing a supplementary damping controller for the modular multilevel converter based on the system's modal eigenvalues, a gravity search algorithm (GSA) is introduced to design the parameters of the supplementary damping controller. The steady-state and small-signal stability of the studied system are analyzed under various scenarios. For dynamic and transient stability, simulations and analyses are performed for different disturbances and faults, and the response results before and after adding the supplementary damping controller are compared.

[1] H. Díaz and C. G. Soares, “Review of the current status, technology and future trends of offshore wind farms,” Ocean Engineering, vol. 209, no. 1, pp. 1-21, Aug. 2020.
[2] S. Paul, A. P. Nath, and Z. H. Rather, “A multi-objective planning framework for coordinated generation from offshore wind farm and battery energy storage system,” IEEE Trans. Sustainable Energy, vol. 11, no. 4, pp. 2087-2097, Oct. 2020.
[3] H. Wang, S. A. Pourmousavi, W. L. Soong, X. Zhang, and N. Ertugrul, “Battery and energy management system for vanadium redox flow battery: a critical review and recommendations,” Journal of Energy Storage, vol. 58, no. 1, pp. 1-21, Feb. 2023.
[4] M. Puchta, J. Bard, C. Dick, D. Hau, B. Krautkremer, F. Thalemann, and H. Hahn, “Development and testing of a novel offshore pumped storage concept for storing energy at sea-Stensea,” Journal of Energy Storage, vol. 14, no. 2, pp. 271-275, Dec. 2017.
[5] A. Mohanty, M. Viswavandya, P. K. Ray, T. K. Panigrahi, and S. Mohanty, “Stability and optimisation of direct drive permanent magnet synchronous generator based tidal turbine,” Vacuum, vol. 166, no. 1, pp. 341-350, Aug. 2019.
[6] M. C. Dinh, M. Park, and T. T. Nguyen, “Simplified floating offshore wind turbine model for time-domain simulation,” in Proc. 2019 International Conference on Renewable Energy Research and Applications (ICRERA), Brasov, Romania, Nov. 03-06, 2019, pp. 270-275.
[7] D. Zhu, X. Guo, B. Tang, J. Hu, X. Zou, and Y. Kang, “Feedforward frequency deviation control in PLL for fast inertial response of DFIG-based wind turbine,” IEEE Trans. Power Electronics, vol. 39, no. 1, pp. 664-676, Jan. 2024.
[8] P. P. Pradhan, B. Subudhi, and A. Ghosh, “A robust multiloop disturbance rejection controller for a doubly fed induction generator-based wind energy conversion system,” IEEE Journal of Emerging and Selected Topics in Power Electronics, vol. 10, no. 5, pp. 6266-6273, Oct. 2022.
[9] K. Su, X. Wang, and X. Xie, “Advanced grid-forming undersea pumped storage to enable 100% renewable offshore oilfield power systems,” IEEE Trans. Sustainable Energy, vol. 16, no. 3, pp. 1791-1805, Jul. 2025.
[10] J. N. Forestieri and M. Farasat, “Integrative sizing/real-time energy management of a hybrid supercapacitor/undersea energy storage system for grid integration of wave energy conversion systems,” IEEE Journal of Emerging and Selected Topics in Power Electronics, vol. 8, no. 4, pp. 3798-3810, Dec. 2020.
[11] H. Wu, J. Yu, J. Liu, R. Mei, X. Ji, and H. Wang, “Voltage control of offshore wind farm considering reactive ability of electrochemical energy storage,” in Proc. 2022 IEEE Sustainable Power and Energy Conference (iSPEC), Perth, WA, Australia, Dec. 04-07, 2022, pp. 1-5.
[12] R. Zeng, G. Pang, L. Yang, M. Lei, and Y. Wang, “Modelling and stability analysis of MMC based wind farm integration system,” in Proc. 2023 IEEE International Conference on Power Science and Technology (ICPST), Kunming, Yunnan, China, May 05-07, 2023, pp. 432-437.
[13] Y. A. Sultan, A. A. Eladl, and S. S. Kaddah, “Artificial neural network-based PI control of battery energy storage system connected with MMC-HVDC system,” in Proc. 2023 24th International Middle East Power System Conference (MEPCON), Mansoura, Egypt, Dec. 19-21, 2023, pp. 1-8.
[14] S. Das, D. Chatterjee, and S. K. Goswami, “A GSA-based modified SVC switching scheme for load balancing and source power factor improvement,” IEEE Trans. Power Delivery, vol. 31, no. 5, pp. 2072-2082, Oct. 2016.
[15] P. S. Kundur and O. P. Malik, Power System Stability and Control, New York, NY, USA: McGraw-Hill, 2022.
[16] IEEE, “Excitation system models for power system stability studies,” IEEE Trans. Power Apparatus and Systems, vol. 100, no. 2, pp. 494-509, Feb. 1981.
[17] P. C. Krause, Analysis of Electric Machinery, New York, NY, USA: McGraw-Hill, 1986.
[18] 潘建銘，利用靜態同步補償器於混合離岸式潮汐場之穩定度改善研究，國立成功大學電機工程學系碩士論文，2015年7月。
[19] M. I. D. M. Norhan, N. A. Salim, Z. M. Yasin, and H. Mohamad, “Tidal energy system based on tidal stream generator with the implementation of permanent magnet synchronous generator,” in Proc. 2022 IEEE International Conference in Power Engineering Application (ICPEA), Shah Alam, Malaysia, Mar. 07-08, 2022, pp. 1-6.
[20] A. G. Abo-Khalil and A. S. Alghamdi, “MPPT of permanent magnet synchronous generator in tidal energy systems using support vector regression,” Sustainability, vol. 13, no. 4, pp. 1-15, Feb. 2021.
[21] T. D. Pham, M. C. Dinh, H. M. Kim, and T. T. Nguyen, “Simplified floating wind turbine for real-time simulation of large-scale floating offshore wind farms,” Energies, vol. 14, no. 15, pp. 1-18, Jul. 2021.
[22] 李冠緯，整合浮動式離岸風場與再生能源場經模組化多階轉換器之多端直流高壓直流鏈饋入多機電力系統之穩定度分析，國立成功大學電機工程學系碩士論文，2025年7月。
[23] 武光山，採用靜態同步串聯補償器於含有雙饋式感應發電機風場之大型電力系統動態穩定度改善，國立成功大學電機工程學系碩士論文，2011年7月。
[24] F. Guo, T. Zheng, and Z. Wang, “Comparative study of direct power control with vector control for rotor side converter of DFIG,” in Proc. 9th IET International Conference on Advances in Power System Control, Operation and Management (APSCOM 2012), Hong Kong, China, Nov. 18-21, 2012, pp. 1-6.
[25] S. Arnaltes, J. L. Rodriguez-Amenedo, and M. E. Montilla-DJesus, “Control of variable speed wind turbines with doubly fed asynchronous generators for stand-alone applications,” Energies, vol. 11, no. 1, pp. 1-16, Dec. 2017.
[26] 柯王君奕，採用全釩氧化還原液流電池及超級電容器於市電併聯型混合再生能源系統之穩定度改善分析，國立成功大學電機工程學系碩士論文，2020年7月。
[27] W.-J. Zou, H.-Y. Jung, and S. Jung, “Modeling and performance optimization of vanadium redox flow batteries,” Journal of Energy Storage, vol. 121, no. 1, pp. 1-13, Jun. 2025.
[28] S. Jafarishiadeh and M. Farasat, “Modeling and sizing of an undersea energy storage system,” IEEE Trans. Industry Applications, vol. 54, no. 3, pp. 2727-2739, Feb. 2018.
[29] A. Kazemian, Y. basati, M. Khatibi, and T. Ma, “Prediction method for the complete characteristic curves of a Francis pump-turbine,” Water, vol. 10, no. 2, pp. 1-20, Feb. 2018.
[30] 李庭佑，以模組化多階轉換器為基礎之多饋入式高壓直流輸電系統連接再生能源之穩定度改善分析，國立成功大學電機工程學系碩士論文，2024年7月。
[31] P. M. Anderson and A. A. Fouad, Power System Control and Stability, Piscataway, NJ, USA: Wiley-IEEE Press, 2003.
[32] E. Rashedi, H. Nezamabadi-pour, and S. Saryazdi, “GSA: A gravitational search algorithm,” Information Sciences, vol. 179, no. 13, pp. 2232-2248, Jun. 2009.
[33] M. S. I. Aziz, S. W. Nawawi, S. Sudin, N. A. Wahab, M. Faramarzi, and M. A. M. Yusof, “Gravitational search algorithm optimization for PID controller tuning in waste-water treatment process,” Jurnal Teknologi, vol. 73, no. 3, pp. 1-7, Mar. 2015.
[34] Y. Liu, Q. H. Wu, and X. X. Zhou, “Co-ordinated multiloop switching control of DFIG for resilience enhancement of wind power penetrated power systems,” IEEE Trans. Sustainable Energy, vol. 7, no. 3, pp. 1089-1099, Jul. 2016.
[35] M. A. Mohamed, T. Chen, W. Su, and T. Jin, “Proactive resilience of power systems against natural disasters: a literature review,” IEEE Access, vol. 7, pp. 163778-163795, Nov. 2019.
[36] H. W. Schmidt-Böcking, G. Luther, M. Düren, M. Puchta, T. Bender, A. Garg, B. Ernst, and H. Frobeen, “Renewable electric energy storage systems by storage spheres on the seabed of deep lakes or oceans,” Energies, vol. 17, no. 1, pp. 1-17, Dec. 2023.
[37] H. Hahn, D. Hau, C. Dick, and M. Puchta, “Techno-economic assessment of a subsea energy storage technology for power balancing services,” Energy, vol. 133, no. 1, pp. 121-127, Aug. 2017.