ACCIONA WINDPOWER WIND POWER PLANTS AND GRID INTEGRATION EXPERIENCE 2010 –Friday 23 th April Óscar Alonso Teresa Arlabán Alberto García Alejandro González

Authors statement As a consequence of the Island volcano ash any author of the present paper has been attending the 2010 EWEC conference in Warsaw. Our commitment with the attendees and conference organizers has lead us to prepare a new presentation with audio tracks where you will hear the voices of Oscar Alonso and Teresa Arlaban introducing and highlighting the most important aspects of our work. We apologize for any inconvenience and hope you find our work interesting and useful. At the end of the presentation you will see our contact . Feel free to contact us for any question or doubt. Our Best Regards. Óscar TeresaAlbertoAlejandro

Introduction -TSO – DSO Grid Requirements: - Voltage support: Normal and Transients. - International approach. - Compliance of: turbines and subs controls -AW turbine capabilities (AW1500/3000) - Reactive power & LV/HV RT capabilities -Substation level voltage control. - Last experience: Waubra - Australia. -Future trends: Preliminary research results.

1 GRID SUPPORT REQUIREMENTS -Every country establishes distinct specs. -Different requirements for transmission or distribution lines. -Current demands mainly focused on following aspects: - Normal operation – small voltage variations. - Transients: LVRT and HVRT. - Quality: Flicker, harmonics, unbalance, etc - Protections. - Metering. 1.- Scope of the current operator demands

1 GRID SUPPORT REQUIREMENTS - Normal demands: - 5% voltage steps response in 1 to 5 s. - Reactive power range: +/- 35% Rated Power. - Operation on voltage range (PCC): +/- 15%. - Set point accuracy higher than 0.5 %. 2.- Voltage Controls

3.- LVRT – International Comparison – Balance/unbalance AWP technology 1 GRID SUPPORT REQUIREMENTS

4.- Implications 1 GRID SUPPORT REQUIREMENTS -Turbine level: - Increased reactive power range (40%). - Efficient reactive power management. - Improved LVRT/HVRT techniques. -Substation Level: - Improved technology (control & comms).

2 -Variable Speed – Low loads -Rated Power: 1500 / 3000 kW -IGBT-Based Power converter. -Doubly Fed Induction generator: - 6 pole – 1000 rpm / 60 Hz -Pitch Control – Hydraulic -Three-bladed. Horizontal Shaft. -High Efficiency: 12 kV supply. ACCIONA WINDPOWER TURBINES: AW1500 / General Characteristics

2 ACCIONA WINDPOWER TURBINES: AW1500 / 3000 Design - Robust – Reliable - Efficient AW1500 AW3000

2 ACCIONA WINDPOWER TURBINES: AW1500 / Extended Reactive Power Range: 40% AW1500 AW3000 Increased Reactive Power capability implies: Increased power converter & generator ratings

3.- LVRT / HVRT New Torque and Pitch strategy -Based on “available active power” (depends on the remaining voltage and reactive current injection) -Available torque is used to damp oscillations. -Fast Pitching to get pre-calculated steady angle. 2 ACCIONA WINDPOWER TURBINES: AW1500 / 3000

Max = rpm Max = rpm 88 rpm 38 rpm 2 ACCIONA WINDPOWER TURBINES: AW1500 / 3000 Example (LVRT test) - 90% Volt depth and 2s long. -Turbine load 90%.

2 ACCIONA WINDPOWER TURBINES: AW1500 / LVRT / HVRT New Torque and Pitch strategy Old Techniques New Techniques Consequences -Longer and deeper voltage dips. -Reduction of oscillations and mechanical loads.

3 VOLTAGE CONTROL – WAUBRA (AUS) 1.- WAUBRA (AUS) Characteristics & Requirements -128 wind turbines model AW POI at 220 kV – 2 transformers 220 kV / 66 kV / 150 MW -Five substations 66 kV / 12 kV. -Two voltage controllers: - Transformer kV side. - Transformer kV side. -Requirements: - Response for voltage steps of 5% in less than 5 secs. - Reactive capacity +/- 30% Rated Power.

2.- Voltage Control Principles Comms: 200 ms polling cycle Parameters: Kp Ti Filter 3 VOLTAGE CONTROL – WAUBRA (AUS)

3.- Set point step tests Set Point steps Pink – Substation Reactive power Blue – Substation Voltage Saturation 3 VOLTAGE CONTROL – WAUBRA (AUS)

4.- Transformer Tap changer tests Transformer Tap changer test Pink – Substation Reactive power Blue – Substation Voltage s max response time 3 VOLTAGE CONTROL – WAUBRA (AUS)

5.- Coordination after LV or HV faults (Now, standard) Smoothed reactive power restoration Ramp up/down 30 to 50 kVAr/s LV event – 0.5 s (real measurement) Sub Control Turb Control 3 VOLTAGE CONTROL – WAUBRA (AUS)

1.- Improved Voltage control -Same control for weak (SCR 10). -Detection of the grid characteristics: - Fast grid impedance selection method. - Fast estimation algorithm of the Thevenin grid voltage. -Principle of operation: Steady-state pre-calculated response. -Accurate, robust and safe even with long polling times. -Patents pending. 4 FUTURE DEVELOPMENTS

4 1.- Improved Voltage control (1 – 2 s response) Set Point changes RX grid change (SCR 20 to less than 4!) Grid voltage changes

4 FUTURE DEVELOPMENTS 2.- Accredited Grid Integration field test report Field tests to demonstrate grid code compliance. Certified Laboratory testing and accredited procedure (international acceptability). -Turbine level: - LVRT and HVRT according to most exigent grid codes. - Active power management: Primary, inertial response, power reserve. - Protections. Harmonics. Flicker. Islanding. Etc. -Substation level: - Voltage control. - Global active power controls: Frequency, others. - Protections. Harmonics. Flicker. Islanding. Etc.

CONCLUSSIONS  AWP Grid Voltage support :  AW1500 and AW3000 Turbines:  Improved LVRT / HVRT behavior.  Extended Reactive Power range.  Substation: Accurate and reliable hardware and controls (improved close future solutions, R&D benefits).  Acciona WindPower commitment to demonstrate Full Grid Code compliance through real and accredited field testing.

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