Physics of wind power Wind turbines Parts of a wind turbine Typical power curves Power fluctuations in wind farms Aggregation in the wind farm References ECE 566: Grid Integration of Wind Energy Systems S. Suryanarayanan Associate Professor ECE Dept. Suryanarayanan ECE 566 Lecture/Week 2
Physics of wind power Wind turbines Parts of a wind turbine Typical power curves Power fluctuations in wind farms Aggregation in the wind farm References Reminders and notifications Homework 1: Due on 9.9.2014 at 515pm (mtn time) via 1 RamCT Blackboard. Suryanarayanan ECE 566 Lecture/Week 2
Physics of wind power Wind turbines Parts of a wind turbine Typical power curves Power fluctuations in wind farms Aggregation in the wind farm References Reminders and notifications Homework 1: Due on 9.9.2014 at 515pm (mtn time) via 1 RamCT Blackboard. Due to my travel engagement, the first half of the lecture 2 (from 515pm-630pm) on 9.9.2014 is canceled. Suryanarayanan ECE 566 Lecture/Week 2
Physics of wind power Wind turbines Parts of a wind turbine Typical power curves Power fluctuations in wind farms Aggregation in the wind farm References Reminders and notifications Homework 1: Due on 9.9.2014 at 515pm (mtn time) via 1 RamCT Blackboard. Due to my travel engagement, the first half of the lecture 2 (from 515pm-630pm) on 9.9.2014 is canceled. The second half of the lecture (from 645pm-8pm Mtn 3 time) on 9.9.2014 is as scheduled. You are expected to attend the second half of the lecture. Suryanarayanan ECE 566 Lecture/Week 2
Physics of wind power Wind turbines Parts of a wind turbine Typical power curves Power fluctuations in wind farms Aggregation in the wind farm References Reminders and notifications Homework 1: Due on 9.9.2014 at 515pm (mtn time) via 1 RamCT Blackboard. Due to my travel engagement, the first half of the lecture 2 (from 515pm-630pm) on 9.9.2014 is canceled. The second half of the lecture (from 645pm-8pm Mtn 3 time) on 9.9.2014 is as scheduled. You are expected to attend the second half of the lecture. In lieu of the cancellation of the first half, you will be 4 required to view a seminar on the topic. Link and other information will be provided via RamCT Blackboard. Suryanarayanan ECE 566 Lecture/Week 2
Physics of wind power Wind turbines Parts of a wind turbine Typical power curves Power fluctuations in wind farms Aggregation in the wind farm References From the Week-1 reading material What is the expression for maximum possible power 1 extraction from the wind stream? Suryanarayanan ECE 566 Lecture/Week 2
Physics of wind power Wind turbines Parts of a wind turbine Typical power curves Power fluctuations in wind farms Aggregation in the wind farm References From the Week-1 reading material What is the expression for maximum possible power 1 extraction from the wind stream? What is the maximum power coefficient termed as and 2 what is its numeric value? Suryanarayanan ECE 566 Lecture/Week 2
Physics of wind power Wind turbines Parts of a wind turbine Typical power curves Power fluctuations in wind farms Aggregation in the wind farm References From the Week-1 reading material What is the expression for maximum possible power 1 extraction from the wind stream? What is the maximum power coefficient termed as and 2 what is its numeric value? What is the practical achievable value of this coefficient? 3 Suryanarayanan ECE 566 Lecture/Week 2
Physics of wind power Wind turbines Parts of a wind turbine Typical power curves Power fluctuations in wind farms Aggregation in the wind farm References From the Week-1 reading material What is the expression for maximum possible power 1 extraction from the wind stream? What is the maximum power coefficient termed as and 2 what is its numeric value? What is the practical achievable value of this coefficient? 3 What is the definition of tip-speed ratio? 4 Suryanarayanan ECE 566 Lecture/Week 2
Physics of wind power Wind turbines Parts of a wind turbine Typical power curves Power fluctuations in wind farms Aggregation in the wind farm References From the Week-1 reading material What is the expression for maximum possible power 1 extraction from the wind stream? What is the maximum power coefficient termed as and 2 what is its numeric value? What is the practical achievable value of this coefficient? 3 What is the definition of tip-speed ratio? 4 How do the TSR and the blade pitch angle affect the power 5 coefficient? Suryanarayanan ECE 566 Lecture/Week 2
Physics of wind power Wind turbines Parts of a wind turbine Typical power curves Power fluctuations in wind farms Aggregation in the wind farm References From the Week-1 reading material What is the expression for maximum possible power 1 extraction from the wind stream? What is the maximum power coefficient termed as and 2 what is its numeric value? What is the practical achievable value of this coefficient? 3 What is the definition of tip-speed ratio? 4 How do the TSR and the blade pitch angle affect the power 5 coefficient? What is the definition of capacity factor (CF)? Qualitatively 6 compare the CFs of a nuclear power plant and a wind power plant? Suryanarayanan ECE 566 Lecture/Week 2
Physics of wind power Wind turbines C p v. λ Parts of a wind turbine P(MW) v. ω Typical power curves Wind velocities v. tower height [2] Power fluctuations in wind farms In-class problem Aggregation in the wind farm References C p v. λ (Figure from: [1]) For MOD-2 type turbine 1 λ + 0 . 08 θ − 0 . 035 1 β = 1 + θ 3 C p ( λ, θ ) = − C 6 1 C 1 ( C 2 1 β − C 3 θ − C 4 θ x − C 5 ) e β Suryanarayanan ECE 566 Lecture/Week 2
Physics of wind power Wind turbines C p v. λ Parts of a wind turbine P(MW) v. ω Typical power curves Wind velocities v. tower height [2] Power fluctuations in wind farms In-class problem Aggregation in the wind farm References P(MW) v. ω (Figure from: [1]) For MOD-2 type turbine λ = ω w R υ 1 1 λ + 0 . 08 θ − 0 . 035 1 β = 1 + θ 3 C p ( λ, θ ) = − C 6 1 β − C 3 θ − C 4 θ x − C 5 ) e C 1 ( C 2 1 β Red line represents the maximum power extraction curve. Suryanarayanan ECE 566 Lecture/Week 2
Physics of wind power Wind turbines C p v. λ Parts of a wind turbine P(MW) v. ω Typical power curves Wind velocities v. tower height [2] Power fluctuations in wind farms In-class problem Aggregation in the wind farm References How does tower height affect wind velocities? Wind speeds differ from blades nearest to the ground and the blades at the top of the rotation This may produce flow and power effects on the turbine When wind speeds lie in the operational range of the turbine and exceed 4m/s, the formula for wind speed at height h is: υ w ( h ) = υ 10 ( h h 10 ) a where, υ 10 is the wind speed measured at 10m For onshore wind farms, typical values of the Hellman exponent, a is: | 0 . 14 ≤ a ≤ 0 . 17 Suryanarayanan ECE 566 Lecture/Week 2
Physics of wind power Wind turbines C p v. λ Parts of a wind turbine P(MW) v. ω Typical power curves Wind velocities v. tower height [2] Power fluctuations in wind farms In-class problem Aggregation in the wind farm References The Hellman exponent [3] The Hellman exponent, a , quantifies variation of wind speed with height a depends on: coastal location 1 terrain shape on the ground 2 air stability. 3 Suryanarayanan ECE 566 Lecture/Week 2
Physics of wind power Wind turbines C p v. λ Parts of a wind turbine P(MW) v. ω Typical power curves Wind velocities v. tower height [2] Power fluctuations in wind farms In-class problem Aggregation in the wind farm References The Hellman exponent: Example values from [3] Location Hellman exponent Unstable air above open water surface 0.06 Neutral air above open water surface 0.1 Unstable air above flat open coast 0.11 Neutral air above flat open coast 0.16 Stable air above open water surface 0.27 Unstable air above human inhabited areas 0.27 Neutral air above human inhabited areas 0.34 Stable air above flat open coast 0.4 Stable air above human inhabited areas 0.6 For more on types of air, see [4]. Suryanarayanan ECE 566 Lecture/Week 2
Physics of wind power Wind turbines C p v. λ Parts of a wind turbine P(MW) v. ω Typical power curves Wind velocities v. tower height [2] Power fluctuations in wind farms In-class problem Aggregation in the wind farm References Hellman exponent a =0 . 16 for υ 30 v. υ 10 [2] 12 10 8 υ 30 6 4 2 0 0 2 4 6 8 10 12 υ 1 0 Suryanarayanan ECE 566 Lecture/Week 2
Physics of wind power Wind turbines C p v. λ Parts of a wind turbine P(MW) v. ω Typical power curves Wind velocities v. tower height [2] Power fluctuations in wind farms In-class problem Aggregation in the wind farm References Vertical profile effects on turbines [2], [5] First approximations Figure shows variation of wind speed with tower height for υ 10 = 9 m/s. First approximations: You may assume r =0 . 7 R (i.e., 70% of rotor radius) for calc. purposes. Suryanarayanan ECE 566 Lecture/Week 2
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