-MASTER THESIS- ADVANCED ACTIVE POWER AND FREQUENCY CONTROL OF WIND POWER PLANTS

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1 -MASTER THESIS- ADVANCED ACTIVE POWER AND FREQUENCY CONTROL OF WIND POWER PLANTS C L AU D I U I O N I TA 1, 2, A L I N G EO R G E R A D U C U 1, F LO R I N I OV 2 1 V A T T E N F A L L W I N D P O W E R R & D, J U P I T E R V E J 6, K O L D I N G, D E N M A R K 2 D E P A R T M E N T OF E N E R G Y T E C H N O L O G Y, A A L B O R G U N I V E R S I T Y, D E N M A R K E M A I L : C L A U D I U. I O N I T V A T T E N F A L L. C O M, A L I N G E O R G E. R A D U C V A T T E N F A L L. C O M, F E T. A A U. D K

2 Presentation Layout 1. Motivation and objectives 2. Approach 3. Controller requirements, design and tuning 4. RT implementation and simulation results 5. Conclusion 6. Future work 2

3 Motivation The WF control is typically delivered by the WT manufacturer- so adding WTs with different performance and response times is challenging. Challenges in the Control Center- operators need to handle different controllers- changing parameters and setpoints requires knowledge of all controller types. Vattenfall WFC simulator Project Objectives 1. Develop, implement and tune a WFC with focus on active power and frequency control to fulfil the Danish grid codes. 2. Verify the robustness of the WFC through simulation studies. 3. Implement a suitable dispatch function, which distributes the power reference to the individual wind turbines. 4. Validate the developed WFC using Real-Time Hardware in the Loop (RT-HIL) approach. 3

4 Model Based Design Approach Controller design 1. Plant model 2. Steady-state analysis 3. Plant characterization and simplification 4. Controller design and tuning in s-domain 5. Robustness verification Site testing Controller verification 1. Controller discretization 2. Offline simulation with complete plant 3. RT-simulation with complete plant Generated automatically by Matlab. Time reduction!! Controller validation 1. Plant model in OPAL-RT 2. HIL controller implementation (Bachmann controller) 4

5 Control Architecture and Test Case 80 x 2MW WTs 5

6 Feedback Control and Plant Characterization K P T i s+1 T i s K P τ=15 ms 1 τ m s + 1 K loss τ P s + 1 6

7 PI-controller design PI designed using Modulus Optimum criteria- replacement of the pole with the slowest time constant with pole in the origin- yields closed loop response similar to the open loop. Requirements No overshoot Stable System Steady-state error <2% of P n Settling time <10 s for a step change of 0.1 p.u. 7

8 PI-controller Tuning Determine minimum K which yields a settling time of 10 s K K P T i s + 1 T i s bw = 4 T set bw = 0.4 rad/s 0.4<K<1 K=0.4 8

9 Equal Reference Dispatch P ref WT,i = P ava WF n Equal dispatch is not suitable!!! 9

10 Proportional Reference Dispatch ref = P av WT,i P WT,i av P WF P ref WF 10

11 Discrete Controller Implementation 11

12 Real-Time Implementation 12

13 Following a set-point (active power constraint) OPAL Real-Time Results Frequency response Delta and ramp rate constraint 13

14 HIL Real-Time Implementation 14

15 Conclusion 1. Develop, implement and tune a WFC with focus on active power and frequency control to fulfil the Danish grid codes. 2. Verify the robustness of the WFC through simulation studies. 3. Implement a suitable dispatch function, which distributes the power reference to the individual wind turbines. 4. Validate the developed WFC using Real-Time Hardware in the Loop (RT-HIL) approach. 15

16 Future Work Merge the active power and reactive power controllers (available from another MSc thesis). Develop an optimized dispatch strategy- loss reduction, tower fatigue or another goal. Communication delays/protocol. Investigate the influence of WT type/response. Verify controller suitability for other grid codes. 16

17 Thank you for your attention! Questions? 17