J. E. Villena Lapaz 1 , A. Vigueras Rodríguez 1 , E. Gómez Lázaro 1 ,

1. Demand Response and Wind Power Ramp Limitation for Reducing Frequency Excursions in Power Systems with High Wind Penetration J. E. Villena Lapaz1, A. Vigueras Rodríguez1, E. Gómez Lázaro1, A. Molina García2, I. Muñoz Benavente2 1Renewable Energy Research Institute (IER), University of Castilla-La Mancha 2Department of Electrical Engineering, Universidad Politécnica de Cartagena EWEA Conference. Brussels, 15th of March, 2010

2. Index • Introduction • Power System model • Simulation and results • Conclusions

3. Index • Introduction • Power System model • Simulation and results • Conclusions

4. Index • Introduction • Power System model • Simulation and results • Conclusions

5. Index • Introduction • Power System model • Simulation and Results • Conclusions

6. Index • Introduction • Power System model • Simulation and results • Conclusions

7. Motivation • Current and future rising of wind power • Stochastic nature of the wind: - Active power fluctuations of the wind farms - Balance between produced and consumed power - Grid frequency excursions • High penetration of cooling and heating loads, which cycle on and off • Grid Code requirements

8. Aim of the work • Studying the contribution of the demand side to the primary frequency control • Assessing the effect of positive ramp limitation (PRL) applied to the active power generated form wind, on both the frequency excursions and the Demand Response

9. Index • Introduction • Power System model • Simulation and results • Conclusions

10. Power System Model • Conventional generation • Wind farm generation • Load • Power System model

11. Power System Model • Conventional generation Thermal Plant

12. Power System Model • Conventional generation Hydraulic Plant

13. Power System Model • Wind power generation (500 MW simulated offshore wind farm)

14. Power System Model • Wind power generation (with PRL)

15. Power System Model • Load - Constant demand (1 GW) - Controllable Load (0.1 pu)

16. Power System Model • Power System - ΔPm , generated power variation - ΔPD , demanded power variation - Δf , frequency error - Df , damping factor - ωk, kinetic energy stored in the rotating masses

17. Power System Model Load - ΔPD ΔPWF + Wind Farm + + Thermal Plant ΔPT + ΔPm-ΔPD - Gain Power System AGC Δf ΔPH + Hydro Plant - Gain AGC

18. Index • Introduction • Power System model • Simulation and results • Conclusions

19. Simulation and Results • 2-hour simulation • Wind farm power between 15 % and 40 % during the simulation • Two conventional plants involved in frequency control • 1 GW constant load • 10 % controllable load (only negative frequency excursions) • PRL (1 % energy losses)

20. Simulation and Results • Scenario 1: Uncontrolled customer-side power demand (constant Load) • Scenario 2: Demand Response facing frequency excursions (variable Load) • Scenario 3: Demand Response & PRL (1 % energy loss)

21. Simulation and ResultsScenario 1 (uncontrollable load)

22. Simulation and ResultsScenario 2 (controllable load)

23. Simulation and ResultsScenario 2 (controllable load) • Example of Demand Response

24. Simulation and ResultsScenarios 1 & 2 • Example of comparison of frequency excursions

25. Simulation and ResultsScenarios 1 & 2 • Comparison of frequency excursions (reduction of 18.15 %)

26. Simulation and ResultsScenarios 1 & 2 • Example of comparison of conventional generators behaviour

27. Simulation and ResultsScenario 3 (PRL)

28. Simulation and ResultsScenarios 2 & 3

29. Simulation and ResultsScenarios 2 & 3 • Example of comparison of Demand Response and frequency excursions

30. Index • Introduction • Power System model • Simulation and Results • Conclusions

31. Conclusions • Demand-side must be considered as a potencial contributor to the primary frequency control. • Simulations have shown a significant reduction of grid frequency excursions for a reasonable amount of controllable loads. • Only negative frequency errors have been considered for the Demand Response model.

32. Conclusions • Regulation techniques such as PRL can be usefull for improving the behaviour of big wind farms in the power system. • A 1% curtailment of the available wind power can reduce significantly the frequency fluctuations caused by wind farms.

33. Thank you very much for your attention!