Minimum number of permanent-magnet synchronous generators for coordinated low-voltage ride-through of induction generators in hybrid wind farms

Coordinated low-voltage ride-through (LVRT) of induction generators (IGs) utilizing the excessive reactive power of permanent magnet synchronous generators (PMSGs) in hybrid wind farms is attractive due to saving investments on shunt compensators. The existing research is mainly based on dynamic simulations to given scenarios and does not quantify the necessary capacity and number of PMSGs. This paper newly proposes an analytical model to quantify the minimum number of the PMSGs for coordinated LVRT. The critical voltage at the point of common coupling (PCC) leading to slip instability of the IGs is quantified. To avoid instability, necessary var support from the PMSGs to improve the PCC voltage above the critical value is proposed. With the improved var control to the grid-side converter (GSC), the minimum number of PMSGs is determined. Numerical results are provided to validate any error of the proposed model, which shows that voltage drop at the PCC, power capability of the PMSGs, and control strategy of the GSC are the critical factors for coordinated LVRT.

PDF

___

[1] Benchagra M, Maaroufi M, Ouassaid M. A performance comparison of linear and nolinear control of a SCIG-wind farm connecting to a distribution network. Turk J Elec Eng & Comp Sci 2014; 22: 1-11.
[2] Emanuel H, Schellschmidt M, Wachtel S, Adloff S. Power quality measurements of wind energy converters with fullscale converter according to IEC 61400-21. In: International Conference on Electrical Power Quality and Utilisation; 1517 September 2009; Lodz, Poland. New York, NY, USA: IEEE. pp. 1-7.
[3] Amutha N, Kumar BK. Effect of modeling of induction generator based wind generating systems on determining CCT. IEEE T Power Syst 2013; 40: 4456-4464.
[4] Pedra J, C´orcoles F, Monjo LI, Bogarra S, Rol´an A. On fixed-speed WT generator modeling for rotor speed stability studies. IEEE T Power Syst 2012; 27: 397-406.
[5] Samuelsson O, Lindahl S. On speed stability. IEEE T Power Syst 2005; 20: 1179-1180.
[6] Mahfouz MMA, El-Sayed MAH. Static synchronous compensator sizing for enhancement of fault ride-through capability and voltage stabilization of fixed speed wind farms. IET Renew Power Gener 2014; 8: 1-9.
[7] Causebrook A, Atkinson DJ, Jack AG. Fault ride-through of large wind farms using series dynamic braking resistors. IEEE T Power Syst 2007; 22: 966-975.
[8] Abedini A, Nasiri A. Output power smoothing for wind turbine permanent magnet synchronous generator using rotor inertia. Elect Power Compon Syst 2009; 37: 1-19.
[9] Chinchilla M, Arnaltes S, Burgos JC. Control of permanent-magnet generators applied to variable-speed wind-energy systems connected to grid. IEEE T Energy Convers 2006; 21: 130-135.
[10] Kim KH, Jeung YC, Lee DC, Kim HG. LVRT scheme of PMSG wind power systems based on feedback linearization. IEEE T Power Electron 2012; 27: 2376-2384.
[11] Nguyen TH, Lee DC. Advanced fault ride-through technique for PMSG wind turbine systems using line-side converter as STATCOM. IEEE T Ind Electron 2013; 60: 2842-2850.
[12] Li S. Operation region of doubly fed induction generators based on rotor slip under maximum power point tracking control and power dispatch. Elect Power Compon Syst 2014; 42: 808-817.
[13] Li S. Power flow modeling to doubly-fed induction generators under power regulation. IEEE T Power Syst 2013; 28: 3292-3301.
[14] Molinas M, Suul JA, Undeland T. Low voltage ride through of wind farms with cage generators: STATCOM versus SVC. IEEE T Power Electron 2008; 23: 1104-1117.
[15] Teninge A, Roye D, Bacha S, Duval J. Low voltage ride-through capabilities of wind plant combining different turbine technologies. In: European Conference on Power Electronics and Applications; 810 September 2009; Barcelona, Spain. New York, NY, USA: IEEE. pp. 1-9.
[16] Muyeen SM, Takahashi R, Murata T, Tamura J. A variable speed wind turbine control strategy to meet wind farm grid code requirements. IEEE T Power Syst 2010; 25: 331-340.
[17] Sarkhanloo MS, Yazdankhah AS, Kazemzadeh R. A new control strategy for small wind farm with capabilities of supplying required reactive power and transient stability improvement. Renew Energ 2012; 44: 32-39.
[18] Rosyadi M, Muyeen SM, Takahashi R, Tamura J. Stabilization of fixed speed wind generator by using variable speed PM wind generator in multi-machine power system. In: IEEE International Conference on Electrical Machines and Systems; 2124 October 2012; Sapporo, Japan. New York, NY, USA: IEEE. pp. 3292-3301.
[19] Leon AE, Mauricio JM, G´omez-Exp´osito A, Solsona JA. An improved control strategy for hybrid wind farms. IEEE T Sustain Energ 2010; 1: 131-141.
[20] Grilo AP, Mota ADA, Mota LTM, Freitas W. An analytical method for analysis of large-disturbance stability of induction generators. IEEE T Power Syst 2007; 22: 1861-1869.