王柯,朱海勇,刘黎,卢宇,董云龙,邹强
WANG Ke,ZHU Haiyong,LIU Li,LU Yu,DONG Yunlong,ZOU Qiang

• 1:南京南瑞继保电气有限公司
• 2:国网浙江省电力有限公司舟山供电公司

摘要(Abstract)：

柔性直流输电系统接入海岛电网后，需根据交流拓扑改变控制方式，在联网、孤岛转换过程中，存在扰动过大、高频失稳等现象。首先，提出了柔性直流系统联网转孤岛的方法，通过电气量与开关量的结合，提升柔性直流联网转孤岛的快速性与准确性。接着，建立了柔性直流系统的简单高频模型，分析联网转孤岛期间高频失稳的原因，利用联网转孤岛过程中出现的高频分量，提出了联网转孤岛优化逻辑及孤岛开环控制策略，提高系统稳定性。然后，设计了基于阀侧电流负荷预测的孤岛转联网策略，避免孤岛转联网过程中的过流跳闸。最后，利用在线仿真模型，结合实际工程控制保护装置，验证了所提策略的有效性和正确性。
The flexible DC transmission system is connected to the island grid, so the control mode needs to be changed according to the AC topology. In the process of grid-connected and island operation conversion, there are phenomena such as excessive disturbance, high frequency instability and so on. Firstly, the transition method from grid-connected operation to island operation is put forward. The speed and accuracy of the transition from gridconnected operation to island operation of flexible DC system can be improved through the combination of electric quantity and switching quantity. Then, a simple high-frequency model of the flexible DC system is established to analyze the causes of high-frequency component during the transition from grid-connected operation to island operation. Combined with the high-frequency instability of the transition from grid-connected operation to island operation, the optimal logic of the transition from grid-connected operation to island operation and the island open-loop control strategy are proposed to improve the stability of the system. Thirdly, the transition strategy of island operation to grid-connected operation is designed based on the load forecasting of valve side current to avoid the overcurrent trip during the process from island operation to grid-connected operation. Finally, the effectiveness and correctness of the proposed strategy are verified by the online simulation model combining the control protection devices in actual engineering.

关键词(KeyWords)： 柔性直流输电;阻抗;联网;孤岛;高频失稳;临时闭锁
flexible DC transmission;impedance;networking;island;high-frequency instability;temporary block

Abstract:

Keywords:

基金项目(Foundation): 国网浙江省电力有限公司科技项目（5211ZS2000GR）

作者(Author): 王柯,朱海勇,刘黎,卢宇,董云龙,邹强
WANG Ke,ZHU Haiyong,LIU Li,LU Yu,DONG Yunlong,ZOU Qiang

DOI: 10.19585/j.zjdl.202307001

参考文献(References)：

• [1]徐政，肖晃庆，张哲任.柔性直流输电系统[M].2版.北京：机械工业出版社，2017.
• [2]邹常跃，韦嵘晖，冯俊杰，等.柔性直流输电发展现状及应用前景[J].南方电网技术，2022,16(3):1-7.ZOU Changyue,WEI Ronghui,FENG Junjie,et al.Development status and application prospect of VSC-HVDC[J].Southern Power System Technology,2022,16(3):1-7.
• [3]徐政，张哲任，刘高任.柔性直流输电网的电压控制原理研究[J].电力工程技术，2017,36(1):54-59.XU Zheng,ZHANG Zheren,LIU Gaoren.Research on voltage control principle of flexible DC transmission power grid[J].Electric Power Engineering Technology,2017,36(1):54-59.
• [4]朱家宁，张诗钽，葛维春，等.海上风电外送及电能输送技术综述[J].发电技术，2022,43(2):236-248.ZHU Jianing,ZHANG Shitan,GE Weichun,et al.Overview of offshore wind power transmission and power transportation technology[J].Power Generation Technology,2022,43(2):236-248.
• [5]汪惟源，窦飞，蔡晖，等.柔性输电技术在江苏跨江输电通道的应用研究[J].电力电容器与无功补偿，2022,43(2):141-146.WANG Weiyuan,DOU Fei,CAI Hui,et al.Research on application of flexible AC/DC transmission technologies in yangtze-river-crossing transmission channels of Jiangsu Province[J].Power Capacitor&Reactive Power Compensation,2022,43(2):141-146.
• [6]杨万开，王兴国，王书扬.渝鄂柔性直流输电接入电网高频谐振与抑制分析[J].发电技术，2022,43(3):492-500.YANG Wankai,WANG Xingguo,WANG Shuyang.Analysis of high frequency resonance and suppression in yu to E VSC-HVDC project connected to power grid[J].Power Generation Technology,2022,43(3):492-500.
• [7]王晖，彭依，杨立敏，等.集群新能源经柔直孤岛送出换流站的功率越限控制研究[J].电力工程技术，2021,40(3):51-59.WANG Hui,PENG Yi,YANG Limin,et al.Research on power overlimit control of cluster new energy sending out of converter station via soft island[J].Electric Power Engineering Technology,2021,40(3):51-59.
• [8]蔡晖，王国腾，刘柏良，等.柔性直流分区技术在多直流馈入的受端电网中的应用研究[J].电力电容器与无功补偿，2021,42(1):108-113.CAI Hui,WANG Guoteng,LIU Bailiang,et al.Study on application of flexible direct-current segmentation technology in multi in-feed DC receiving-end power network[J].Power Capacitor&Reactive Power Compensation,2021,42(1):108-113.
• [9]王庆，卢宇，胡兆庆，等.柔性直流输电系统孤岛运行方式下的故障电流抑制方法[J].电力系统自动化，2018,42(7):56-61.WANG Qing,LU Yu,HU Zhaoqing,et al.Fault Current suppression method for flexible DC transmission system operating in islanded mode[J].Automation of Electric Power Systems,2018,42(7):56-61.
• [10]胡兆庆，毛承雄，陆继明.适用于电压源型高压直流输电的控制策略[J].电力系统自动化，2005,29(1):39-44.HU Zhaoqing,MAO Chengxiong,LU Jiming.A novel control strategy for voltage sourced converters based HVDC[J].Automation of Electric Power Systems,2005,29(1):39-44.
• [11]梁少华，田杰，曹冬明，等.柔性直流输电系统控制保护方案[J].电力系统自动化，2013,37(15):59-65.LIANG Shaohua,TIAN Jie,CAO Dongming,et al.Acontrol and protection scheme for VSC-HVDC system[J].Automation of Electric Power Systems,2013,37(15):59-65.
• [12]王柯，李继红，田杰，等.多端柔性直流故障快速恢复系统控制策略[J].供用电，2017,34(8):2-7.WANG Ke,LI Jihong,TIAN Jie,et al.Control strategy of quick recovery system with multi-terminals HVDC DCfault[J].Distribution&Utilization,2017,34(8):2-7.
• [13]唐庚，徐政，薛英林，等.基于模块化多电平换流器的多端柔性直流输电控制系统设计[J].高电压技术，2013,39(11):2773-2782.TANG Geng,XU Zheng,XUE Yinglin,et al.Control design of multi-terminal HVDC based on modular multilevel converter[J].High Voltage Engineering,2013,39(11):2773-2782.
• [14]刘昇，徐政，唐庚，等.MMC-HVDC联网及孤岛运行状态转换策略[J].中国电机工程学报，2015,35(9):2152-2161.LIU Sheng,XU Zheng,TANG Geng,et al.Study on MMC-HVDC switching scheme between grid-connected and passive islanding mode[J].Proceedings of the CSEE,2015,35(9):2152-2161.
• [15]刘黎，蔡旭，俞恩科，等.舟山多端柔性直流输电示范工程及其评估[J].南方电网技术，2019,13(3):79-88.LIU Li,CAI Xu,YU Enke,et al.Zhoushan multi-terminal VSC-HVDC transmission demonstration project and its evaluation[J].Southern Power System Technology,2019,13(3):79-88.
• [16]尹聪琦，谢小荣，刘辉，等.柔性直流输电系统振荡现象分析与控制方法综述[J].电网技术，2018,42(4):1117-1123.YIN Congqi,XIE Xiaorong,LIU Hui,et al.Analysis and control of the oscillation phenomenon in VSC-HVDCtransmission system[J].Power System Technology,2018,42(4):1117-1123.
• [17]冯俊杰，邹常跃，杨双飞，等.针对中高频谐振问题的柔性直流输电系统阻抗精确建模与特性分析[J].中国电机工程学报，2020,40(15):4805-4820.FENG Junjie,ZOU Changyue,YANG Shuangfei,et al.Accurate impedance modeling and characteristic analysis of VSC-HVDC system for mid-and high-frequency resonance problems[J].Proceedings of the CSEE,2020,40(15):4805-4820.
• [18]郭贤珊，刘泽洪，李云丰，等.柔性直流输电系统高频振荡特性分析及抑制策略研究[J].中国电机工程学报，2020,40(1):19-29.GUO Xianshan,LIU Zehong,LI Yunfeng,et al.Characteristic analysis of high-frequency resonance of flexible high voltage direct current and research on its damping control strategy[J].Proceedings of the CSEE,2020,40(1):19-29.
• [19]WEN B,BOROYEVICH D,BURGOS R,et al.Analysis of D-Q small-signal impedance of grid-tied inverters[J].IEEE Transactions on Power Electronics,2016,31(1):675-687.
• [20]ZOU C Y,RAO H,XU S K,et al.Analysis of resonance between a VSC-HVDC converter and the AC grid[J].IEEE Transactions on Power Electronics,2018,33(12):10157-10168.
• [21]SUN J.Impedance-based stability criterion for gridconnected inverters[J].IEEE Transactions on Power Electronics,2011,26(11):3075-3078.
• [22]年珩，朱茂玮，徐韵扬，等.双闭环定交流电压控制下MMC换流站阻抗建模及稳定性分析[J].电力系统自动化，2020,44(4):81-90.NIAN Heng,ZHU Maowei,XU Yunyang,et al.Impedance modeling and system stability analysis of MMC with double closed-loop AC voltage control[J].Automation of Electric Power Systems,2020,44(4):81-90.
• [23]WU H,WANG X F.Dynamic impact of zero-sequence circulating current on modular multilevel converters:complex-valued AC impedance modeling and analysis[J].IEEE Journal of Emerging and Selected Topics in Power Electronics,2019,8(2):1947-1963.
• [24]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.LI Guanghui,WANG Weisheng,GUO Jianbo,et al.Broadband oscillation mechanism and analysis for wind farm integration through MMC-HVDC system[J].Proceedings of the CSEE,2019,39(18):5281-5297.
• [25]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.LüJing,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.