Smoothing of Wind Farm Output using Short-Term ahead Wind Speed Prediction and Flywheel Energy Storage System

1. Smoothing of Wind Farm Output
using Short-Term ahead Wind Speed
Prediction and Flywheel Energy
Storage System
ROHITH PAUL
S7 F
ROLL NO: 46
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2. CONTENTS
o INTRODUCTION
o NEED FOR SMOOTHING
o MODEL SYSTEM
o DIFFERENT MODELS OF SYSTEM
o SMOOTHING OF OUTPUT POWER
o WIND SPEED PREDICTION
o CONCLUSION
o REFRENCE
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3. INTRODUCTION
o Wind energy is now considered to be the world’s fastest growing renewable energy
o A Renewable Non-Polluting Resource
o Intermittent nature of wind speed makes a big issue in the generation of wind power.
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4. NEED FOR SMOOTHING
o Beneficial for power grid management
o Stabilization of power system
o Matching demand and supply
o To reduce frequency deviation in the grid
o Remove restrictions to install new wind farms.
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5. METHODS
o Smoothing of output power of wind farm is achieved by:
 Battery energy storage system (BESS),
 super conducting magnetic energy storage systems (SME)
 energy capacitor systems (ECS)
 flywheel energy storage system (FEES)
o Forecasting of the wind speed using different techniques
 linear regression analysis,
 time series,
 linear regression method
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6. MODEL SYSTEM
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7. DIFFERENT MODELS OF SYSTEM
1. A. Wind Turbine model
2. Double Fed Induction Generator Model
3. FESS
4. Rotor Side Converter(RSC)
5. Grid Side Converter(GSC)
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8. WIND TURBINE MODEL
o Consists of an Induction Generator and a wind turbine
o The reference power of the WF is adjusted according to the availability of the stored energy in
the FESS
o Wind turbines produce electricity by using the power of the wind to drive an electrical
generator
o Wind turbine extracts kinetic energy from the swept area of the blades
o Generated power is fed to the supply system when the IG is run above synchronous speed
o Generated power is 𝑃 𝑀=0.5∗ 𝜌 ∗ 𝐶 𝑃 ∗ 𝜋 ∗ 𝑅2 ∗ 𝑉 ∗ 𝑊3 ∗ 𝛼
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9. DOUBLE FED INDUCTION GENERATOR
MODEL
o Modelled in the direct (d) and quadrature (q) axis reference frame,
FIG 2.
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10. Contd…
o DFIG supplies the real power and it can compensate reactive power
o when rotor speed is greater than rotating magnetic field from stator, the stator induces a
strong current in the rotor
o power will be transferred as an electromagnetic force to the stator
o converted to electricity which is fed to the electric grid
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11. ROTOR SIDE CONVERTER(RSC)
o Control the active and reactive power control of the stator side
o control the wind turbine output power and the voltage measured at the grid terminals
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12. GRID SIDE CONVERTER(GSC)
o keep the DC link voltage constant at 1 p.u
o Supply additional reactive power into the grid
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13. FESS
o DFIG with secondary excitation system is considered as FESS
o mechanical energy storage system where energy is stored in the form of kinetic energy.
o maximum and minimum energy that can be stored in the FESS is limited to ± 30% of
the rated energy
o The reference of the output power for the secondary excitation circuit is adjusted
according to the availability of the stored energy in FESS and predicted wind speed data.
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14. ADVANTAGES OF FESS
oReliability
olong life
o large energy storage capacity,
oless overall cost
opower compensation is very effective.
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15. SMOOTHING OF OUTPUT POWER BY
USING FESS
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16. Contd…
o reference output (P_ref_1) is generated using low pass filter function
o When the output of the IG is higher than the final output power reference, FESS is in
charging mode and absorbs the active power from the grid.
o when the generated output is lower than the final output power reference, FESS is in
discharging mode and supplies active power to the grid.
o By controlling the rotor speed of FESS in different operating regions, the stored energy in
FESS is utilized to smooth the output power fluctuation
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17. WIND SPEED PREDICTION BY USING
LINEAR REGRESSION MODEL
o Wind speed data is predicted using short-term ahead linear regression model
o The prediction model has been implemented using MATLAB.
o Predicted power is given by:
𝑃𝑝𝑟𝑒𝑑𝑖𝑐𝑡𝑒𝑑=0.5∗ 𝜌 ∗ 𝐶 𝑃 ∗ 𝜋 ∗ 𝑅2
∗ 𝑉 ∗ 𝑉 ∗ 𝑉 ∗ 𝑊 ∗ 𝛼
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18. Contd…
o If predicted power (P_Predict) - actual power (P_IG) is small output power reference remain
unchanged
o P_ref_2 is corrected if the actual stored energy of FESS is not in a range of (45-85)%
o this control scheme will prevent the system from reaching instability
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19. FLOWCHART
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20. Contd…
o Flowchart is used to modify the final output reference (P_ref_final)
o if the rotor speed of the FESS (W) is ≥1.3 p.u. or it is ≤ 0.7 p.u ,no power will be absorbed or
supplied by the FESS.
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21. CONCLUSION
o Proposed a new control strategy of FESS to mitigate the fluctuation in the output power of the
grid
o It has been shown that prediction of the wind speed and modification of the output power
reference accordingly makes the FESS more effective and reduces the fluctuation of output
power efficiently.
o The system cost can also be kept minimum by optimum use of small capacity flywheel energy
storage system
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22. REFRENCES
o “ A New Control Strategy for Smoothing of Wind Farm Output using Short-Term Ahead Wind Speed Prediction
and Flywheel Energy Storage System” Farzana Islam1, Hany. Hasanien2, Ahmed Al-Durra1, S.M.Muyeen1
o X. Wang, G. Siderators, N. Hatziargyrion and L. H. Tsoakalas, “Wind Speed Forecasting for Power System
Operational Planning,” International Conference on Probabilistic Methods applied to Power System, pp 470-474,
o S.M. Muyeen, M.H. Ali, R. Takahashi, T. Murata and J. Tamura,“Wind Generator Output Power Smoothing and
Terminal Voltage Regulation by Using STATCOM/ESS
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