Mechanism Analysis of Near Fundamental-Frequency Positive/Negative-Sequence Oscillations in MMC-HVDC Connected Direct-Drive Wind Farm

doi:10.12204/j.issn.1000-7229.2024.02.002

Abstract

Abstract:

Positive- and negative-sequence oscillation phenomena close to the fundamental frequency (40-60 Hz) occur in a practical modular multilevel converter-based high-voltage DC (MMC-HVDC) transmission system for new energy integration, which has led to a decrease in the power output of new energy sources. The mechanism of near-fundamental-frequency oscillations is more complex and has more influencing factors than oscillations in other frequency bands. This study focuses on the near-fundamental-frequency oscillation stability of an MMC-HVDC-connected direct-drive wind farm. Refined impedance models of the direct-drive wind turbine and sending-end MMC are established by considering positive and negative sequence controls. Based on the established impedance models, the mechanisms of the near-fundamental-frequency positive- and negative-sequence oscillations between the direct-drive wind farm and the sending-end MMC are revealed. In addition, the parameter phase-margin sensitivity is defined, and the key influencing factors of the near-fundamental-frequency oscillation stability of the interconnected system were analyzed quantitatively. Finally, an electromagnetic transient simulation model of the MMC-HVDC-connected direct-drive wind farm is developed. The near-fundamental-frequency positive- and negative-sequence oscillation phenomena in the actual project are reproduced, and the correctness of the near-fundamental-frequency oscillation mechanism analysis is validated.

Key words: wind farm, flexible DC transmission, near-fundamental-frequency oscillation, negative-sequence control, negative-sequence oscillation, sensitivity

CLC Number:

TM712

YU Jing, LIN Hongfei, WANG Xiao, Lü Jing, WU Linlin, LI Yunhong. Mechanism Analysis of Near Fundamental-Frequency Positive/Negative-Sequence Oscillations in MMC-HVDC Connected Direct-Drive Wind Farm[J]. ELECTRIC POWER CONSTRUCTION, 2024, 45(2): 10-25.

Figures/Tables 26

Fig.1 Structure diagram of an MMC-HVDC connected direct-drive wind farm system

Fig.2 Control diagram of sending-end MMC of MMC-HVDC

Fig.3 Validation for the impedance model of direct-drive wind turbine

Fig.4 Validation for the impedance model of sending-end MMC of MMC-HVDC

Fig.5 Near fundamental-frequency positive-sequence oscillation mechanism of the PMSG-based wind farm-MMC interconnected system

Fig.6 Near fundamental-frequency negative-sequence oscillation mechanism of the PMSG-based wind farm-MMC interconnected system

Table 1 Calculation results of positive-sequence parameter phase margin sensitivity

Fig.7 Analysis results of positive-sequence phase margin sensitivity ratio under different output power of wind farm

Table 2 Calculation results of negative-sequence parameter phase margin sensitivity

Fig.8 Analysis results of negative-sequence phase margin sensitivity ratio under different output power of wind farm

Fig.9 Research ideas of control system interaction

Fig.10 Analysis results of interactive case 1

Fig.11 Analysis results of interactive case 2

Fig.12 Verification results of simulation case 1

Fig.13 Verification results of simulation case 2

Fig.14 Verification results of simulation case 3

Fig.15 Verification results of simulation case 4

Fig.A1 Typical topology and control of PMSG-based power generation system

Fig.A2 Structure of positive and negative sequence separation algorithm

Fig.A3 Typical structure of PLL

Fig.A4 Topology of MMC

Fig.A5 Equivalent circuit of MMC single-phase leg

Table B1 Parameters of the PMSG-based wind turbine system

Table B2 Parameters of the sending-end MMC

Fig.D1 Influences of negative sequence current inner loop of PMSG-based wind farm

Fig.D2 Influences of negative sequence AC voltage outer loop of MMC

References 31

[1]	蔡旭, 杨仁炘, 周剑桥, 等. 海上风电直流送出与并网技术综述[J]. 电力系统自动化, 2021, 45(21): 2-22.
	CAI Xu, YANG Renxin, ZHOU Jianqiao, et al. Review on offshore wind power integration via DC transmission[J]. Automation of Electric Power Systems, 2021, 45(21): 2-22.
[2]	吕敬, 董鹏, 施刚, 等. 大型双馈风电场经MMC-HVDC并网的次同步振荡及其抑制[J]. 中国电机工程学报, 2015, 35(19): 4852-4860.
	LÜ Jing, DONG Peng, SHI Gang, et al. Subsynchronous oscillation and its mitigation of MMC-based HVDC with large doubly-fed induction generator-based wind farm integration[J]. Proceedings of the CSEE, 2015, 35(19): 4852-4860.
[3]	吕敬, 蔡旭, 张占奎, 等. 海上风电场经MMC-HVDC并网的阻抗建模及稳定性分析[J]. 中国电机工程学报, 2016, 36(14): 3771-3781.
	LÜ Jing, CAI Xu, ZHANG Zhankui, et al. Impedance modeling and stability analysis of MMC-based HVDC for offshore wind farms[J]. Proceedings of the CSEE, 2016, 36(14): 3771-3781.
[4]	李浩志, 谢小荣, 刘芮彤, 等. 新能源经柔直送出系统的次同步振荡分析与抑制[J/OL]. 中国电机工程学报. (2023-03-17)[2023-06-10]. https://doi.org/10.13334/j.0258-8013.pcsee.223006.
	LI Haozhi, XIE Xiaorong, LIU Ruitong, et al. Analysis and mitigation of the subsynchronous oscillation in renewable energy system connected to the MMC-HVDC[J/OL]. Proceedings of the CSEE, early access. (2023-03-17)[2023-06-10]. https://doi.org/10.13334/j.0258-8013.pcsee.223006.
[5]	杜镇宇, 阳岳希, 季柯, 等. 张北柔直工程高频谐波振荡机理与抑制方法研究[J]. 电网技术, 2022, 46(8): 3066-3075.
	DU Zhenyu, YANG Yuexi, JI Ke, et al. High frequency harmonic resonance and suppression in Zhangbei Project[J]. Power System Technology, 2022, 46(8): 3066-3075.
[6]	高磊, 吕敬, 蔡旭. 如东海上风电柔直送出系统的中频振荡特性分析[J]. 电网技术, 2023, 47(9): 3495-3509.
	GAO Lei, LÜ Jing, CAI Xu. Analysis of mid-frequency oscillation characteristics in Rudong MMC-HVDC system for offshore wind farms[J]. Power System Technology, 2023, 47(9): 3495-3509.
[7]	赵峥, 李明, 田园园, 等. 江苏如东海上风电柔直工程系统谐振分析与抑制[J]. 电力建设, 2023, 44(6): 144-152. doi: 10.12204/j.issn.1000-7229.2023.06.015
	ZHAO Zheng, LI Ming, TIAN Yuanyuan, et al. Resonance analysis and suppression in Jiangsu Rudong offshore wind power flexible DC system[J]. Electric Power Construction, 2023, 44(6): 144-152. doi: 10.12204/j.issn.1000-7229.2023.06.015
[8]	边晓燕, 丁炀, 买坤, 等. 海上风电场经VSC-HVDC并网的次同步振荡与抑制[J]. 电力系统自动化, 2018, 42(17): 25-33.
	BIAN Xiaoyan, DING Yang, MAI Kun, et al. Subsynchronous oscillation caused by grid-connection of offshore wind farm through VSC-HVDC and its mitigation[J]. Automation of Electric Power Systems, 2018, 42(17): 25-33.
[9]	周彦彤, 郝丽丽, 王昊昊, 等. 大容量风电场柔直并网系统的送/受端次同步振荡分析与抑制[J]. 电力自动化设备, 2020, 40(3): 100-106.
	ZHOU Yantong, HAO Lili, WANG Haohao, et al. Analysis and suppression of SSO at sending/receiving end in VSC-HVDC system connected large-capacity wind farms[J]. Electric Power Automation Equipment, 2020, 40(3): 100-106.
[10]	SHAO B B, ZHAO S Q, YANG Y H, et al. Sub-synchronous oscillation characteristics and analysis of direct-drive wind farms with VSC-HVDC systems[J]. IEEE Transactions on Sustainable Energy, 2021, 12(2): 1127-1140. doi: 10.1109/TSTE.2020.3035203 URL
[11]	KUNJUMUHAMMED L P, PAL B C, GUPTA R, et al. Stability analysis of a PMSG-based large offshore wind farm connected to a VSC-HVDC[J]. IEEE Transactions on Energy Conversion, 2017, 32(3): 1166-1176. doi: 10.1109/TEC.60 URL
[12]	陈宝平, 林涛, 陈汝斯, 等. 直驱风电场经VSC-HVDC并网系统的多频段振荡特性分析[J]. 电工技术学报, 2018, 33(S1): 176-184.
	CHEN Baoping, LIN Tao, CHEN Rusi, et al. Analysis of multi-band oscillation characteristics of direct-driven wind farm through VSC-HVDC grid-connected system[J]. Transactions of China Electrotechnical Society, 2018, 33(S1): 176-184.
[13]	AMIN M, MOLINAS M. Understanding the origin of oscillatory phenomena observed between wind farms and HVDC systems[J]. IEEE Journal of Emerging and Selected Topics in Power Electronics, 2017, 5(1): 378-392. doi: 10.1109/JESTPE.2016.2620378 URL
[14]	孙焜, 姚伟, 文劲宇. 双馈风电场经柔直并网系统次同步振荡机理及特性分析[J]. 中国电机工程学报, 2018, 38(22): 6520-6533.
	SUN Kun, YAO Wei, WEN Jinyu. Mechanism and characteristics analysis of subsynchronous oscillation caused by DFIG-based wind farm integrated into grid through VSC-HVDC system[J]. Proceedings of the CSEE, 2018, 38(22): 6520-6533.
[15]	SUN K, YAO W, FANG J K, et al. Impedance modeling and stability analysis of grid-connected DFIG-based wind farm with a VSC-HVDC[J]. IEEE Journal of Emerging and Selected Topics in Power Electronics, 2020, 8(2): 1375-1390. doi: 10.1109/JESTPE.6245517 URL
[16]	LYU J, CAI X, MOLINAS M. Frequency domain stability analysis of MMC-based HVDC for wind farm integration[J]. IEEE Journal of Emerging and Selected Topics in Power Electronics, 2016, 4(1): 141-151. doi: 10.1109/JESTPE.2015.2498182 URL
[17]	LYU J, CAI X, AMIN M, et al. Sub-synchronous oscillation mechanism and its suppression in MMC-based HVDC connected wind farms[J]. IET Generation, Transmission & Distribution, 2018, 12(4): 1021-1029. doi: 10.1049/gtd2.v12.4 URL
[18]	LYU J, ZHANG X, CAI X, et al. Harmonic state-space based small-signal impedance modeling of a modular multilevel converter with consideration of internal harmonic dynamics[J]. IEEE Transactions on Power Electronics, 2019, 34(3): 2134-2148. doi: 10.1109/TPEL.2018.2842682 URL
[19]	LIN H F, XUE T, LYU J, et al. Impact of different AC voltage control modes of wind-farm-side MMC on stability of MMC-HVDC with offshore wind farms[J]. Journal of Modern Power Systems and Clean Energy, 2023, 11(5): 1687-1699. doi: 10.35833/MPCE.2022.000363 URL
[20]	LYU J, YIN J H, ZHU H, et al. Impedance modeling and stability analysis of energy controlled modular multilevel converter[J]. IEEE Transactions on Power Delivery, 2023, 38(3): 1868-1881. doi: 10.1109/TPWRD.2022.3225640 URL
[21]	宗皓翔, 吕敬, 张琛, 等. MMC多维阻抗模型及其在风场-柔直交互稳定分析中的应用[J]. 中国电机工程学报, 2021, 41(14): 4941-4953.
	ZONG Haoxiang, LYU Jing, ZHANG Chen, et al. MIMO impedance model of MMC and its application in the wind farm-HVDC interaction stability analysis[J]. Proceedings of the CSEE, 2021, 41(14): 4941-4953.
[22]	ZONG H X, ZHANG C, LYU J, et al. Generalized MIMO sequence impedance modeling and stability analysis of MMC-HVDC with wind farm considering frequency couplings[J]. IEEE Access, 2020, 8: 55602-55618. doi: 10.1109/Access.6287639 URL
[23]	JI K, TANG G F, PANG H, et al. Impedance modeling and analysis of MMC-HVDC for offshore wind farm integration[J]. IEEE Transactions on Power Delivery, 2020, 35(3): 1488-1501. doi: 10.1109/TPWRD.61 URL
[24]	PANG B, NIAN H, XU Y Y. Mechanism analysis and damping method for high frequency resonance between VSC-HVDC and the wind farm[J]. IEEE Transactions on Energy Conversion, 2021, 36(2): 984-994. doi: 10.1109/TEC.60 URL
[25]	LI Y F, AN T, ZHANG D, et al. Analysis and suppression control of high frequency resonance for MMC-HVDC system[J]. IEEE Transactions on Power Delivery, 2021, 36(6): 3867-3881. doi: 10.1109/TPWRD.2021.3049973 URL
[26]	苑宾, 厉璇, 尹聪琦, 等. 孤岛新能源场站接入柔性直流高频振荡机理及抑制策略[J]. 电力系统自动化, 2023, 47(4): 133-141.
	YUAN Bin, LI Xuan, YIN Congqi, et al. Mechanism and suppression strategy of high-frequency oscillation caused by integration of islanded renewable energy station into MMC-HVDC system[J]. Automation of Electric Power Systems, 2023, 47(4): 133-141.
[27]	夏玥, 李征, 蔡旭, 等. 基于直驱式永磁同步发电机组的风电场动态建模[J]. 电网技术, 2014, 38(6): 1439-1445.
	XIA Yue, LI Zheng, CAI Xu, et al. Dynamic modeling of wind farm composed of direct-driven permanent magnet synchronous generators[J]. Power System Technology, 2014, 38(6): 1439-1445.
[28]	XUE T, LYU J, WANG H, et al. A complete impedance model of a PMSG-based wind energy conversion system and its effect on the stability analysis of MMC-HVDC connected offshore wind farms[J]. IEEE Transactions on Energy Conversion, 2021, 36(4): 3449-3461. doi: 10.1109/TEC.2021.3074798 URL
[29]	RYGG A, MOLINAS M, ZHANG C, et al. A modified sequence-domain impedance definition and its equivalence to the dq-domain impedance definition for the stability analysis of AC power electronic systems[J]. IEEE Journal of Emerging and Selected Topics in Power Electronics, 2016, 4(4): 1383-1396. doi: 10.1109/JESTPE.6245517 URL
[30]	ZHANG C, CAI X, RYGG A, et al. Sequence domain SISO equivalent models of a grid-tied voltage source converter system for small-signal stability analysis[J]. IEEE Transactions on Energy Conversion, 2018, 33(2): 741-749. doi: 10.1109/TEC.60 URL
[31]	李光辉, 王伟胜, 郭剑波, 等. 风电场经MMC-HVDC送出系统宽频带振荡机理与分析方法[J]. 中国电机工程学报, 2019, 39(18): 5281-5297, 5575.
	LI Guanghui, WANG Weisheng, GUO Jianbo, et al. Broadband oscillation mechanism and analysis method of wind farm sending system through MMC-HVDC[J]. Proceedings of the CSEE, 2019, 39(18): 5281-5297, 5575.