Analysis and stabilization control of a voltage source controlled wind farm under weak grid conditions

Abstract

This paper investigates and discusses the interaction stability issues of a wind farm with weak grid connections, where the wind turbines (WTs) are controlled by a new type of converter control strategy referred to as the voltage source (VS) control. The primary intention of the VS control method is to achieve the high-quality inertial response capability of a single WT. However, when it is applied to multiple WTs within a wind farm, its weak-grid performance regarding the stability remains concealed and needs to be clarified. To this end, a frequency domain model of the wind farm under the VS control is first developed. Based on this model and the application of a stability margin quantification index, not only the interactions between the wind farm and the weak grid but also those among WTs will be systematically assessed in this paper. A crucial finding is that the inertial response of VS control has negative impacts on the stability margin of the system, and the dominant instability mode is more related to the interactions among the WTs rather than the typical grid-wind farm interaction. Based on this knowledge, a stabilization control strategy is then proposed, aiming for stability improvements of VS control while fulfilling the demand of inertial responses. Finally, all the results are verified by time-domain simulations in power systems computer aided design/electromagnetic transients including DC(PSCAD/EMTDC).

Keywords

weak grids / voltage source (VS) control / wind turbine (WT) / stabilization control / wind farm / inertial response

参考文献

[1] Krautz H J, Lisk A, Posselt J, Impact of renewable energies on the operation and economic situation of coal fired power stations: actual situation of coal fired power stations in Germany. Frontiers in Energy, 2017, 11(2): 119–125

[2] Chen X, Wu W, Gao N, Finite control set model predictive control for LCL-filtered grid-tied inverter with minimum sensors. IEEE Transactions on Industrial Electronics, 2020, 67(12): 9980–9990

[3] Li J, Liu G, Zhang S. Smoothing ramp events in wind farm based on dynamic programming in energy internet. Frontiers in Energy, 2018, 12(4): 550–559

[4] Deng F, Chen Z, Khan M R, Fault detection and localization method for modular multilevel converters. IEEE Transactions on Power Electronics, 2015, 30(5): 2721–2732

[5] Heidari A, Esmaeel Nezhad A, Tavakoli A, A comprehensive review of renewable energy resources for electricity generation in Australia. Frontiers in Energy, 2020, 14(3): 510–529

[6] Kundur P.Power System Stability and Control. New York: McGraw-Hill, Inc, 1994

[7] Xi J, Geng H, Zou X. Decoupling scheme for virtual synchronous generator controlled wind farms participating in inertial response. Journal of Modern Power Systems and Clean Energy, 2021, 9(2): 347–355

[8] Huang S, Wu Q, Bao W, Hierarchical optimal control for synthetic inertial response of wind farm based on alternating direction method of multipliers. IEEE Transactions on Sustainable Energy, 2021, 12(1): 25–35

[9] Diaz F G A, Mombello E E, Venerdini G D G. Calculation of leakage reactance in transformers with constructive deformations in low voltage foil windings. IEEE Transactions on Power Delivery, 2018, 33(6): 3205–3210

[10] Sun Y, Ye H, Sun X, Wind power fluctuation mitigation based low-frequency oscillation. Journal of Engineering (Stevenage, England), 2017, 2017(13): 1299–1306

[11] Lyu J, Cai X, Amin M, Sub-synchronous oscillation mechanism and its suppression in MMC-based HVDC connected wind farms. IET Generation, Transmission & Distribution, 2018, 12(4): 1021–1029

[12] Egea-Alvarez A, Fekriasl S, Gomis-Bellmunt O. Advanced vector control for voltage source converters connected to weak grids. In: 2016 IEEE Power and Energy Society General Meeting, Boston, USA, 2016

[13] Davari M, Mohamed Y A R I. Robust vector control of a very weak-grid-connected voltage-source converter considering the phase-locked loop dynamics. IEEE Transactions on Power Electronics, 2017, 32(2): 977–994

[14] Zhang C, Cai X, Rygg A, Sequence domain SISO equivalent models of a grid-tied voltage source converter system for small-signal stability analysis. IEEE Transactions on Energy Conversion, 2018, 33(2): 741–749

[15] Zhang C, Cai X, Li Z, Properties and physical interpretation of the dynamic interactions between voltage source converters and grid: electrical oscillation and its stability control. IET Power Electronics, 2017, 10(8): 894–902

[16] Sang S, Gao N, Cai X, A novel power-voltage control strategy for the grid-tied inverter to raise the rated power injection level in a weak grid. IEEE Journal of Emerging and Selected Topics in Power Electronics, 2018, 6(1): 219–232

[17] Zhou J Z, Ding H, Fan S, Impact of short-circuit ratio and phase-locked-loop parameters on the small-signal behavior of a VSC-HVDC converter. IEEE Transactions on Power Delivery, 2014, 29(5): 2287–2296

[18] Chen X, Zhang Y, Wang S, Impedance-phased dynamic control method for grid-connected inverters in a weak grid. IEEE Transactions on Power Electronics, 2017, 32(1): 274–283

[19] Peña-Alzola R, Liserre M, Blaabjerg F, LCL-filter design for robust active damping in grid-connected converters. IEEE Transactions on Industrial Informatics, 2014, 10(4): 2192–2203

[20] Wang Y, Meng J, Zhang X, Control of PMSG-based wind turbines for system inertial response and power oscillation damping. IEEE Transactions on Sustainable Energy, 2015, 6(2): 565–574

[21] Xu G, Xu L. Improved use of WT kinetic energy for system frequency support. IET Renewable Power Generation, 2017, 11(8): 1094–1100

[22] Xiong X, Wu C, Blaabjerg F. An improved synchronization stability method of virtual synchronous generators based on frequency feedforward on reactive power control loop. IEEE Transactions on Power Electronics, 2021, 36(8): 9136–9148

[23] Chen M, Zhou D, Blaabjerg F. Active power oscillation damping based on acceleration control in paralleled virtual synchronous generators system. IEEE Transactions on Power Electronics, 2021, 36(8): 9501–9510

[24] Yazdani S, Davari M, Ferdowsi M, Internal model power synchronization control of a PV-based voltage-source converter in weak-grid and islanded conditions. IEEE Transactions on Sustainable Energy, 2021, 12(2): 1360–1371

[25] Harnefors L, Rahman F M M, Hinkkanen M, Reference-feedforward power-synchronization control. IEEE Transactions on Power Electronics, 2020, 35(9): 8878–8881

[26] Wu W, Zhou L, Chen Y, Sequence-impedance-based stability comparison between VSGs and traditional grid-connected inverters. IEEE Transactions on Power Electronics, 2019, 34(1): 46–52

[27] Cvetkovic I, Boroyevich D, Burgos R, Modeling of a virtual synchronous machine-based grid-interface converter for renewable energy systems integration. In: 2014 IEEE 15th Workshop on Control and Modeling for Power Electronics, Santander, Spain, 2014

[28] Sang S, Zhang C, Cai X, Control of a type-IV wind turbine with the capability of robust grid-synchronization and inertial response for weak grid stable operation. IEEE Access: Practical Innovations, Open Solutions, 2019, 7: 58553–58569

Acknowledgments

This work was supported in part by the National Key R&D Plan of China (Grant No. 2018YFB1501300), and in part by the Key Laboratory of Control of Power Transmission and Conversion (SJTU), Ministry of Education (2021AC03).

版权

2021 Higher Education Press