|
|
|
| Coupled Response Modeling and Direct Short-Circuit Current Analysis Method for Grid-Forming Converter under Grid Fault |
| Chen Jiyu, Ouyang Jinxin, Mo Fan, Yang Bofei |
| State Key Laboratory of Power Transmission Equipment Technology Chongqing University Chongqing 400044 China |
|
|
|
Abstract With the widespread application of power converters across generation, grid, and load sectors, modern power systems have become increasingly dominated by power electronics. Consequently, traditional fault analysis methods, which are based on synchronous machines and the principle of linear superposition, are often inadequate for accurately characterizing converter responses during grid faults. This limitation challenges the effectiveness of existing grid protection schemes. Current research on the fault response of grid-forming converter (GFC) predominantly focuses on voltage sags at the point of common coupling and controller dynamics. However, it frequently overlooks the coupling between complex power and voltage magnitude-phase of GFC under abrupt changes in grid impedance due to faults, a simplification that compromises model accuracy. Furthermore, the inherent communication delays and refresh cycles associated with real-time topology acquisition raise concerns about the applicability of online short-circuit current calculations in rapidly evolving scenarios, such as frequent network reconfigurations and fluctuating power outputs.
To address these issues, this study focuses on GFC controlled by the virtual synchronous generator strategy. It is found that the controller response of GFC and the complex power interaction with the faulted grid form a closed loop under abrupt impedance changes. This loop jointly determines the dynamic variation of the GFC's port characteristics, exhibiting a coupled response. During the sub-transient stage of this coupled response, the port characteristics are dominated by the reactive power-voltage outer loop, manifesting as variations in active power, reactive power, and AC bus voltage. In the transient stage, the coupling between the active power-phase outer loop and the reactive power-voltage outer loop dictates the port characteristics, leading to dynamic changes in active power, AC bus voltage and power angle, while reactive power tends to stabilize. If the AC current remains within the maximum allowable limit, the AC bus voltage and power angle eventually stabilize under the power outer loop in the quasi-steady state. Conversely, if the AC current limit control is triggered, the AC current magnitude is clamped at the maximum allowable value, with its phase fixed at the AC current saturation angle during this quasi-steady stage of the coupled response.
A method for identifying the complex parameters of virtual short-circuit fault is proposed. By equivalently representing any three-phase grid fault as a virtual fault at the point of common coupling under the condition of constant voltage vector of the point of common coupling, a dimensionality-reduced equivalent model of the faulted grid is obtained. Subsequently, by solving the controller response equations in different time intervals, an equivalent port model of GFC considering the coupled response is established. This model quantifies the evolution of GFC port characteristics from an independent voltage source to a controlled voltage source and finally to a controlled voltage or independent current source. Additionally, a direct analytical method for GFC short-circuit current, independent of actual fault parameters, is introduced. It derives parameters for the reduced-order grid model and the GFC coupled-response model from pre-fault and fault-instant port electrical quantities. Through sequential model pairing and enforcing vector magnitude-phase equality, the fundamental short-circuit current magnitude and phase are directly computed. Simulations confirm the method's accuracy in capturing the coupled fault response and calculating the short-circuit current, with reduced communication dependency.
|
|
Received: 03 June 2025
|
|
|
|
|
|
[1] 欧阳金鑫, 陈纪宇, 李昂, 等. 兼顾直流电压安全与无功支撑的柔性直流输电故障穿越控制[J]. 电工技术学报, 2024, 39(19): 6129-6144.
Ouyang Jinxin, Chen Jiyu, Li Ang, et al.Fault ride-through control method for VSC-HVDC balancing between DC voltage security and reactive power support[J]. Transactions of China Electrotechnical Society, 2024, 39(19): 6129-6144.
[2] 李亚楼, 张星, 胡善华, 等. 含高比例电力电子装备电力系统安全稳定分析建模仿真技术[J]. 电力系统自动化, 2022, 46(10): 33-42.
Li Yalou, Zhang Xing, Hu Shanhua, et al.Modeling and simulation technology for stability analysis of power system with high proportion of power electronics[J]. Automation of Electric Power Systems, 2022, 46(10): 33-42.
[3] 赵冬梅, 宋晨铭, 冯向阳, 等. 100%新能源场景下考虑频率稳定约束的源网荷储一体化系统储能优化配置[J]. 电工技术学报, 2025, 40(7): 2146-2161.
Zhao Dongmei, Song Chenming, Feng Xiangyang, et al.The optimal configuration of energy storage in the source-grid-load-storage integrated system considering frequency stability constraints in 100% new energy scenarios[J]. Transactions of China Electrotechnical Society, 2025, 40(7): 2146-2161.
[4] 郑玉平, 吕鹏飞, 李斌, 等. 新型电力系统继电保护面临的问题与解决思路[J]. 电力系统自动化, 2023, 47(22): 3-15.
Zheng Yuping, Lü Pengfei, Li Bin, et al.Problems faced by relay protection in new power system and their solution ideas[J]. Automation of Electric Power Systems, 2023, 47(22): 3-15.
[5] Fang Yu, Jia Ke, Yang Zhe, et al.Impact of inverter-interfaced renewable energy generators on distance protection and an improved scheme[J]. IEEE Transactions on Industrial Electronics, 2019, 66(9): 7078-7088.
[6] 陈海东, 潘学萍, 黄桦, 等. 分布式光伏与风电机组LVRT及电流限幅环节的等值建模[J]. 电力自动化设备, 2022, 42(7): 25-32, 39.
Chen Haidong, Pan Xueping, Huang Hua, et al.Equivalent modeling of LVRT and current limiting links for distributed photovoltaic and wind turbine generators[J]. Electric Power Automation Equipment, 2022, 42(7): 25-32, 39.
[7] 贾科, 侯来运, 毕天姝, 等. 基于故障区域局部迭代的工程实用化新能源短路电流计算[J]. 电力系统自动化, 2021, 45(13): 151-158.
Jia Ke, Hou Laiyun, Bi Tianshu, et al.Practical engineering calculation of short-circuit current for renewable energy based on local iteration of fault area[J]. Automation of Electric Power Systems, 2021, 45(13): 151-158.
[8] Kim I.Short-circuit analysis models for unbalanced inverter-based distributed generation sources and loads[J]. IEEE Transactions on Power Systems, 2019, 34(5): 3515-3526.
[9] 黄欣然, 王增平, 王彤, 等. 风电经基于虚拟同步机控制的柔直系统送出交流线路故障电流特性分析[J/OL]. 电工技术学报, 2025: 1-18[2025-12-03]. https://doi.org/10.19595/j.cnki.1000-6753.tces.251285.
Huang Xinran, Wang Zengping, Wang Tong, et al. Analysis of fault current characteristics in AC transmission lines for wind power integration through VSC-HVDC system controlled by virtual synchronous generator[J/OL]. Transactions of China Electrotechnical Society, 2025: 1-18[2025-12-03]. https://doi.org/10.19595/j.cnki.1000-6753.tces.251285.
[10] Li Bin, Mu Rui, He Jiawei, et al.Transient fault current calculation method for the PV grid-connected system considering dynamic response of PLL[J]. IEEE Transactions on Industry Applications, 2024, 60(5): 7537-7547.
[11] Shuai Zhikang, Shen Chao, Yin Xin, et al.Fault analysis of inverter-interfaced distributed generators with different control schemes[J]. IEEE Transactions on Power Delivery, 2018, 33(3): 1223-1235.
[12] Chao Pupu, Li Weixing, Peng Simin, et al.Fault ride-through behaviors correction-based single-unit equivalent method for large photovoltaic power plants[J]. IEEE Transactions on Sustainable Energy, 2021, 12(1): 715-726.
[13] 刘岩, 贾科, 毕天姝, 等. 基于末端机组电压前推的逆变型新能源发电场站故障等值计算[J]. 电工技术学报, 2025, 40(1): 96-107.
Liu Yan, Jia Ke, Bi Tianshu, et al.Fault equivalent calculation of inverter interfaced renewable energy generator stations based on extrapolation of terminal unit voltage[J]. Transactions of China Electrotechnical Society, 2025, 40(1): 96-107.
[14] 查晓明, 李锡林, 黄萌, 等. 源-机-网协同视角下电力电子并网装备同步控制方法综述[J]. 高电压技术, 2025, 51(4): 1507-1526.
Zha Xiaoming, Li Xilin, Huang Meng, et al.Review of synchronous control for power electronic grid-connected equipment from the perspective of source-converter-network cooperation[J]. High Voltage Engineering, 2025, 51(4): 1507-1526.
[15] Yu Jiale, Qi Yang, Deng Han, et al.Evaluating small-signal synchronization stability of grid-forming converter: a geometrical approach[J]. IEEE Transactions on Industrial Electronics, 2022, 69(9): 9087-9098.
[16] 朱誉, 华凤林, 杨银国, 等. 基于等面积准则的含电流限幅虚拟同步机控制暂态稳定性分析[J]. 电力自动化设备, 2025, 45(2): 209-216.
Zhu Yu, Hua Fenglin, Yang Yinguo, et al.Transient stability analysis of virtual synchronous generator control with current limiting based on equal area criterion[J]. Electric Power Automation Equipment, 2025, 45(2): 209-216.
[17] 魏凤廷, 张海涛, 王秀丽, 等. 计及电压动态特性的虚拟同步机暂态稳定性分析[J]. 电网技术, 2024, 48(7): 2910-2918.
Wei Fengting, Zhang Haitao, Wang Xiuli, et al.Transient stability analysis of virtual synchronous generator considering voltage dynamic characteristics[J]. Power System Technology, 2024, 48(7): 2910-2918.
[18] Wang Guangyu, Fu Lijun, Hu Qi, et al.Transient synchronization stability of grid-forming converter during grid fault considering transient switched operation mode[J]. IEEE Transactions on Sustainable Energy, 2023, 14(3): 1504-1515.
[19] Luo Cong, Chen Yandong, Liao Shuhan, et al.Design-oriented analysis and transient control for VSG with current saturation unit[J]. IEEE Transactions on Power Electronics, 2025, 40(1): 2472-2483.
[20] Chen Jiyu, Ouyang Jinxin, Huang Fei, et al.Modelling of AC-DC voltage control coupling and adaptive fault ride-through method for VSC-HVDC integrated wind farms[J]. IEEE Transactions on Sustainable Energy, 2025, 16(4): 2533-2546.
[21] 吴成国, 肖仕武. 高比例分布式电源接入电网短路电流的拟牛顿迭代计算方法[J]. 电网技术, 2022, 46(12): 4581-4590.
Wu Chengguo, Xiao Shiwu.Quasi-Newton iterative calculation method for short circuit current of high proportion distributed generation connected to power grid[J]. Power System Technology, 2022, 46(12): 4581-4590.
[22] 郑涛, 马英, 陈云飞, 等. 计及内电势变化影响的VSG不对称短路暂态电流解析计算[J]. 电力系统自动化, 2024, 48(19): 162-170.
Zheng Tao, Ma Ying, Chen Yunfei, et al.Transient current analytic calculation for virtual synchronous generator with asymmetric short circuit considering influence of internal potential change[J]. Automation of Electric Power Systems, 2024, 48(19): 162-170.
[23] 郑涛, 王子鸣, 邹芃蓥, 等. 电网对称短路故障时虚拟同步机电流解析计算及影响因素分析[J]. 电网技术, 2023, 47(4): 1460-1469.
Zheng Tao, Wang Ziming, Zou Pengying, et al.Fault current calculation and influencing factors anslysis of virtual synchronous generator under symmetrical short circuit fault[J]. Power System Technology, 2023, 47(4): 1460-1469.
[24] 高本锋, 陈宗良, 于思奇, 等. 基于等效阻抗的虚拟同步机短路电流解析计算方法及影响因素分析[J]. 高电压技术, 2025, 51(12): 6022-6032.
Gao Benfeng, Chen Zongliang, Yu Siqi, et al.Analytical calculation method of virtual synchronous generator short-circuit current based on equivalent impedance and analysis of influencing factors[J]. High Voltage Engineering, 2025, 51(12): 6022-6032.
[25] 裴金鑫, 姚骏, 黄森, 等. 电网短路故障下新能源并网变换器的暂态同步机制及其自适应稳定控制策略[J]. 中国电机工程学报, 2022, 42(16): 5922-5934.
Pei Jinxin, Yao Jun, Huang Sen, et al.Transient synchronization mechanism and adaptive stability control strategy for renewable energy grid-connected converter under grid faults[J]. Proceedings of the CSEE, 2022, 42(16): 5922-5934.
[26] 贾科, 李佩烨, 毕天姝, 等. 基于电流协同优化的柔直输电系统受端换流站故障穿越控制方法[J/OL]. 中国电机工程学报, 2025: 1-14. [2025-10-11]. https://doi.org/10.13334/j.0258-8013.pcsee.242707.
Jia Ke, Li Peiye, Bi Tianshu, et al. A receiving-end fault ride-through method based on current coordinated optimization control for MMC-HVDC[J]. Proceedings of the CSEE, 2025: 1-14. [2025-10-11]. https://doi.org/10.13334/j.0258-8013.pcsee.242707.
[27] 贺家李. 电力系统继电保护原理: 典藏版[M]. 北京: 中国电力出版社, 2022.
[28] 构网型储能系统并网技术规范:T/CES 243—2023[S]. 北京: 中国电工技术学会, 2023. |
|
|
|
2026, Vol. 41 
