Grid-Synchronization Stability Improvement of Large Scale Wind Farm During Severe Grid Fault

Loss of synchronization between wind farm and power grid during severe grid faults would cause wind farm tripping. In this paper, the mechanism of grid-synchronization is uncovered, described as motion of an autonomous nonlinear differential equation with specific initial states. The revealed mechanism indicates that even though steady-state working point exists, improper initial states and poor system dynamic properties could lead to synchronization instability. In order to keep wind farm synchronous with the power grid during severe grid faults, special requirements on system dynamic properties are stated. Moreover, to satisfy all the requirements, a current injecting method is proposed. By adjusting active and reactive output currents of the wind farm, the proposed method could ensure system synchronization stability during severe grid faults. Implementation of the proposed method on PMSG- and DFIG-based wind farm is illustrated. Simulation results validate the analysis and the control method.

[1]  A. Gole,et al.  Impact of Short-Circuit Ratio and Phase-Locked-Loop Parameters on the Small-Signal Behavior of a VSC-HVDC Converter , 2014, IEEE Transactions on Power Delivery.

[2]  Dragan Jovcic,et al.  Phase locked loop system for FACTS , 2003 .

[3]  Luis M. Fernández,et al.  Aggregated dynamic model for wind farms with doubly fed induction generator wind turbines , 2008 .

[4]  Hans-Peter Nee,et al.  A general algorithm for speed and position estimation of AC motors , 2000, IEEE Trans. Ind. Electron..

[5]  J. Morren,et al.  Ridethrough of wind turbines with doubly-fed induction generator during a voltage dip , 2005, IEEE Transactions on Energy Conversion.

[6]  Geng Yang,et al.  Enhanced model of the doubly fed induction generator-based wind farm for small-signal stability studies of weak power system , 2014 .

[7]  Hans-Peter Nee,et al.  Interconnection of Two Very Weak AC Systems by VSC-HVDC Links Using Power-Synchronization Control , 2011, IEEE Transactions on Power Systems.

[8]  Hao Yuan,et al.  Synchronizing stability of DFIG-based wind turbines attached to weak AC grid , 2014, 2014 17th International Conference on Electrical Machines and Systems (ICEMS).

[9]  Luis M. Fernández,et al.  Equivalent models of wind farms by using aggregated wind turbines and equivalent winds , 2009 .

[10]  Hans-Peter Nee,et al.  Power-Synchronization Control of Grid-Connected Voltage-Source Converters , 2010, IEEE Transactions on Power Systems.

[11]  Geng Yang,et al.  An LVRT Control Strategy Based on Flux Linkage Tracking for DFIG-Based WECS , 2013, IEEE Transactions on Industrial Electronics.

[12]  Josep M. Guerrero,et al.  PLL With MAF-Based Prefiltering Stage: Small-Signal Modeling and Performance Enhancement , 2016, IEEE Transactions on Power Electronics.

[13]  A. Mullane,et al.  Wind-turbine fault ride-through enhancement , 2005, IEEE Transactions on Power Systems.

[14]  Mansour Mohseni,et al.  Fault ride-through capability enhancement of doubly-fed induction wind generators , 2011 .

[15]  Claus Leth Bak,et al.  Instability of Wind Turbine Converters During Current Injection to Low Voltage Grid Faults and PLL Frequency Based Stability Solution , 2014, IEEE Transactions on Power Systems.

[16]  Zhen Wang,et al.  Synchronous Instability Mechanism of P-f Droop-Controlled Voltage Source Converter Caused by Current Saturation , 2016, IEEE Transactions on Power Systems.

[17]  Thomas Ackermann,et al.  Wind Power in Power Systems , 2005 .

[18]  Bo Wen,et al.  Grid-synchronization modeling and its stability analysis for multi-paralleled three-phase inverter systems , 2013, 2013 Twenty-Eighth Annual IEEE Applied Power Electronics Conference and Exposition (APEC).

[19]  Bo Wen,et al.  Analysis of Phase-Locked Loop Low-Frequency Stability in Three-Phase Grid-Connected Power Converters Considering Impedance Interactions , 2015, IEEE Transactions on Industrial Electronics.

[20]  D. Boroyevich,et al.  Frequency behavior and its stability of grid-interface converter in distributed generation systems , 2012, 2012 Twenty-Seventh Annual IEEE Applied Power Electronics Conference and Exposition (APEC).

[21]  Bo Wen,et al.  Impedance-Based Analysis of Grid-Synchronization Stability for Three-Phase Paralleled Converters , 2014, IEEE Transactions on Power Electronics.

[22]  Bo Wen,et al.  Influence of phase-locked loop on input admittance of three-phase voltage-source converters , 2013, 2013 Twenty-Eighth Annual IEEE Applied Power Electronics Conference and Exposition (APEC).

[23]  D. Boroyevich,et al.  Decoupled Double Synchronous Reference Frame PLL for Power Converters Control , 2007, IEEE Transactions on Power Electronics.

[24]  Jianbo Sun,et al.  Modeling and Implementation of an All Digital Phase-Locked-Loop for Grid-Voltage Phase Detection , 2013, IEEE Transactions on Industrial Informatics.