Assessment and Extension Method for Stable Operation Domain of DFIG in Asymmetric Weak Grid

doi:10.16183/j.cnki.jsjtu.2023.512

Abstract

Abstract:

In asymmetric weak grid, there exists a complex coupling path between the positive- and negative-sequences of the impedance between a doubly-fed wind turbine (DFIG) and the grid, leading to intricate interactions. Since grid codes require wind turbines to provide positive- and negative-sequence dynamic reactive power support, improper settings of these currents may result in system instability and oscillations. Therefore, this paper first develops a sequence impedance model of the DFIG-grid system using a harmonic linearization method, revealing the effects of positive-sequence active current, positive-sequence reactive current, and negative-sequence reactive current on system stability, and analyzes the stability mechanism induced by inter-sequence coupling. Furthermore, considering stability constraints, grid codes, and converter capacity, it characterizes the stable operating domain of the DFIG. To solve the problem of insufficient stable operating range in weak grid, it proposes an adaptive oscillation suppression phase-locked loop (PLL) method, which adaptively suppresses the oscillatory component in the PLL input, thereby extending the stable operating domain of the DFIG. Finally, simulation results verify the correctness of the theoretical analysis and the effectiveness of the proposed control method.

Key words: weak grid, doubly-fed induction generator (DFIG), stability analysis, inter-sequence coupling

CLC Number:

TM614

FEI Renxiang, XU Hailiang, GE Pingjuan, CHEN Xiangyu. Assessment and Extension Method for Stable Operation Domain of DFIG in Asymmetric Weak Grid[J]. Journal of Shanghai Jiao Tong University, 2025, 59(10): 1510-1522.

Figures/Tables 23

Fig.1

Fig.2

Fig.3

Fig.4

Fig.5

Fig.6

Fig.7

Fig.8

Fig.9

Fig.10

Fig.11

Fig.12

Fig.13

Fig.14

Tab.1

Fig.15

Fig.16

Fig.17

Fig.18

Tab.2

Fig.19

Fig.20

Fig.21

References 24

[1]	刘新宇, 逯芯妍, 曾龙, 等. 双馈风电场并网抑制频率振荡控制策略[J]. 上海交通大学学报, 2022, 56(3): 303-311. doi: 10.16183/j.cnki.jsjtu.2021.437
	LIU Xinyu, LU Xinyan, ZENG Long, et al. Control strategies for suppressing frequency oscillation of doubly-fed wind farms connected to grid[J]. Journal of Shanghai Jiao Tong University, 2022, 56(3): 303-311.
[2]	郭祺, 贾文慧, 涂春鸣, 等. 面向暂态电压主动支撑的多功能并网变流器多模式柔性切换策略[J]. 电力系统自动化, 2023, 47(21): 156-164.
	GUO Qi, JIA Wenhui, TU Chunming, et al. Multi-mode flexible switching strategy of multi-functional grid-connected converters for active support to transient voltage[J]. Automation of Electric Power Systems, 2023, 47(21): 156-164.
[3]	年珩, 程鹏, 贺益康. 故障电网下双馈风电系统运行技术研究综述[J]. 中国电机工程学报, 2015, 35(16): 4184-4197.
	NIAN Heng, CHENG Peng, HE Yikang. Review on operation techniques for DFIG-based wind energy conversion systems under network faults[J]. Proceedings of the CSEE, 2015, 35(16): 4184-4197.
[4]	刘新宇, 王森, 曾龙, 等. 双馈风电场抑制电网低频振荡的自适应附加控制策略[J]. 上海交通大学学报, 2023, 57(9): 1156-1164. doi: 10.16183/j.cnki.jsjtu.2022.135
	LIU Xinyu, WANG Sen, ZENG Long, et al. An adaptive additional control strategy for suppressing low-frequency grid oscillations in doubly-fed wind farms[J]. Journal of Shanghai Jiao Tong University, 2023, 57(9): 1156-1164.
[5]	HAMATWI E, BARENDSE P, KHAN A. A case for micromachines in laboratory-based DFIG wind turbine systems for fault studies[J]. IEEE Transactions on Industry Applications, 2023, 59(2): 1754-1764.
[6]	TANG W, HU J B, ZHANG R, et al. Coupling characteristics of DFIG-based WT considering reactive power control and its impact on phase/amplitude transient stability in a rotor speed control timescale[J]. CSEE Journal of Power and Energy Systems, 2022, 8(2): 511-522.
[7]	国家市场监督管理总局, 国家标准化管理委员会. 风电场接入电力系统技术规定第1部分陆上风电: GB/T 19963.1—2021[S]. 北京: 中国标准出版社, 2021.
	State Administration for Market Regulation, Standardization Administration of the People’s Republic of China. Technical specification for connecting wind farm to power system: Part 1—On shore wind power: GB/T 19963.1—2021[S]. Beijing: Standards Press of China, 2021.
[8]	吴瀚, 徐海亮, 张利, 等. 弱电网下含负序控制的双馈风力机阻抗建模及关键致稳因素评估[J]. 高电压技术, 2023, 49(6): 2516-2528.
	WU Han, XU Hailiang, ZHANG Li, et al. Impedance modeling and key stabilizing factor evaluation of DFIG-based wind turbines with negative sequence control during weak power grid[J]. High Voltage Engineering, 2023, 49(6): 2516-2528.
[9]	ALSMADI Y M, XU L Y, BLAABJERG F, et al. Detailed investigation and performance improvement of the dynamic behavior of grid-connected DFIG-based wind turbines under LVRT conditions[J]. IEEE Transactions on Industry Applications, 2018, 54(5): 4795-4812.
[10]	LIU J, YAO W, WEN J Y, et al. Impact of power grid strength and PLL parameters on stability of grid-connected DFIG wind farm[J]. IEEE Transactions on Sustainable Energy, 2020, 11(1): 545-557.
[11]	LIU R K, YAO J, WANG X W, et al. Dynamic stability analysis and improved LVRT schemes of DFIG-based wind turbines during a symmetrical fault in a weak grid[J]. IEEE Transactions on Power Electronics, 2020, 35(1): 303-318.
[12]	GUAN L, YAO J, LIU R K, et al. Small-signal stability analysis and enhanced control strategy for VSC system during weak-grid asymmetric faults[J]. IEEE Transactions on Sustainable Energy, 2021, 12(4): 2074-2085.
[13]	徐海亮, 吴瀚, 李志, 等. 低短路比电网下含负序控制双馈风力机稳定性研究的几个关键问题[J]. 电工技术学报, 2021, 36(22): 4688-4702.
	XU Hailiang, WU Han, LI Zhi, et al. Several key issues on stability study of DFIG-based wind turbines with negative sequence control during low short-circuit ratio power grids[J]. Transactions of China Electrotechnical Society, 2021, 36(22): 4688-4702.
[14]	WANG X F, HARNEFORS L, BLAABJERG F. Unified impedance model of grid-connected voltage-source converters[J]. IEEE Transactions on Power Electronics, 2018, 33(2): 1775-1787.
[15]	张学广, 马彦, 王天一, 等. 弱电网下双馈发电机输入导纳建模及稳定性分析[J]. 中国电机工程学报, 2017, 37(5): 1507-1516.
	ZHANG Xueguang, MA Yan, WANG Tianyi, et al. Input admittance modeling and stability analysis of DFIG under weak grid condition[J]. Proceedings of the CSEE, 2017, 37(5): 1507-1516.
[16]	SHI F, SHU D, YAN Z, et al. A shifted frequency impedance model of doubly fed induction generator (DFIG)-based wind farms and its applications on S2SI analysis[J]. IEEE Transactions on Power Electronics, 2021, 36(1): 215-227.
[17]	LI Z, XU H L, WANG Z X, et al. Stability assessment and enhanced control of DFIG-based WTs during weak AC grid[J]. IEEE Access, 2022, 10: 41371-41380.
[18]	姚骏, 孙鹏, 刘瑞阔, 等. 弱电网不对称故障期间双馈风电系统动态稳定性分析[J]. 中国电机工程学报, 2021, 41(21): 7225-7237.
	YAO Jun, SUN Peng, LIU Ruikuo, et al. Dynamic stability analysis of DFIG-based wind power system during asymmetric faults of weak grid[J]. Proceedings of the CSEE, 2021, 41(21): 7225-7237.
[19]	徐海亮, 李志, 王中行. 低电压穿越期间双馈风电机组稳定性分析与电流分配方法[J]. 电力自动化设备, 2022, 42(8): 198-205.
	XU Hailiang, LI Zhi, WANG Zhongxing. Stability analysis and current distribution method of DFIG during low voltage ride-through[J]. Electric Power Automation Equipment, 2022, 42(8): 198-205.
[20]	年珩, 杨洪雨. 不平衡运行工况下并网逆变器的阻抗建模及稳定性分析[J]. 电力系统自动化, 2016, 40(10): 76-83.
	NIAN Heng, YANG Hongyu. Impedance modeling and stability analysis of grid-connected inverters under unbalanced operation conditions[J]. Automation of Electric Power Systems, 2016, 40(10): 76-83.
[21]	年珩, 胡彬, 陈亮, 等. 无锁相环直接功率控制双馈感应发电机系统阻抗建模和稳定性分析[J]. 中国电机工程学报, 2020, 40(3): 951-962.
	NIAN Heng, HU Bin, CHEN Liang, et al. Impedance modeling and stability analysis of direct power controlled doubly fed induction generator system without phase-locked loop[J]. Proceedings of the CSEE, 2020, 40(3): 951-962.
[22]	CHEN Y H, XU W, LIU Y, et al. Small-signal system frequency stability analysis of the power grid integrated with type-II doubly-fed variable speed pumped storage[J]. IEEE Transactions on Energy Conversion, 2023, 38(1): 611-623.
[23]	王波. 电网故障持续期间双馈风力发电机并网系统小信号建模与分析研究[D]. 武汉: 华中科技大学, 2018.
	WANG Bo. Study of small-signal modeling and analysis of grid-connected doubly-fed wind generator during riding through grid fault[D]. Wuhan: Huazhong University of Science and Technology, 2018.
[24]	GOLESTAN S, GUERRERO J M, MUSAVI F, et al. Single-phase frequency-locked loops: A comprehensive review[J]. IEEE Transactions on Power Electronics, 2019, 34(12): 11791-11812.

系统参数	数值	系统参数	数值
额定功率/ kW	5.5	定子自感/mH	6
额定电压/ V	380	转子自感/mH	6
极对数	3	定子电阻/Ω	1.1
定转子匝比	1∶1.6	转子电阻/Ω	2.3
定转子互感/ H	0.123	直流母线电压/V	600

运行域	正序有功电流	正序无功电流	负序无功电流
A	0.25	0.35	0.25
B	0.25	0.1	0.1
C	0.25	0.1	0.3