Ancillary services: Research results from wind power plants

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1 Downloaded from orbit.dtu.dk on: Jun 07, 2018 Ancillary services: Research results from wind power plants Sørensen, Poul Ejnar; Cutululis, Nicolaos Antonio; Hansen, Anca Daniela; Altin, Müfit; Zeni, Lorenzo; Basit, Abdul Publication date: 2014 Document Version Peer reviewed version Link back to DTU Orbit Citation (APA): Sørensen, P. E., Cutululis, N. A., Hansen, A. D., Altin, M., Zeni, L., & Basit, A. (2014). Ancillary services: Research results from wind power plants [Sound/Visual production (digital)]. Grid Support And Ancillary Services Forum 2014, Hamburg, Germany, 04/06/2014 General rights Copyright and moral rights for the publications made accessible in the public portal are retained by the authors and/or other copyright owners and it is a condition of accessing publications that users recognise and abide by the legal requirements associated with these rights. Users may download and print one copy of any publication from the public portal for the purpose of private study or research. You may not further distribute the material or use it for any profit-making activity or commercial gain You may freely distribute the URL identifying the publication in the public portal If you believe that this document breaches copyright please contact us providing details, and we will remove access to the work immediately and investigate your claim.

2 Ancillary services: Research results from wind power plants Poul Sørensen, Nicolaos Cutululis, Anca D. Hansen, Müfit Altin, Lorenzo Zeni, Abdul Basit

3 Program outline Ancillary Services: Research Results From Wind Power Plants Characteristics and requirements for ancillary service provision to European power systems - now and in the future Technical capabilities required by wind power plants in order to provide ancillary services - a focus on state-of-the-art industry and R&D (simulation based) perspectives What are the economic incentives and barriers to providing ancillary services? What are the next steps for researchers, developers, system operators and turbine manufacturers to allow further penetration of wind into European grids? 2 DTU Wind Energy, Technical University of Denmark Windpower Monthly - Grid support

4 Definitions of ancillary services CIGRÉ report - overview of International Practices definitions for ancillary services can differ significantly based on who is using the terms. While some definitions emphasize the importance of ancillary services for system security and reliability, others mention the use of ancillary services to support electricity transfers from generation to load and to maintain power quality Some TSOs are including more specific types of ancillary services than others because differences in the definitions (above) some of the required properties of the generation plants are embedded in conventional power plants using directly grid connected synchronous generators. new ancillary service products seem to pop up in power systems with large scale penetration of renewables. 3 DTU Wind Energy, Technical University of Denmark Windpower Monthly - Grid support

5 Requirements for and types of ancillary services Active power reserves (using ENTSO-E glossary) Frequency containment reserves (FCR) Frequency restoration reserves (FRR) Replacement reserves (RR) Properties required to maintain power system stability today (Energinet.dk terminology) Short-circuit power Continuous voltage control Voltage support during faults Inertia Possible new ancillary service products (research references) Fast frequency response (and inertia support) Synchronising power Power oscillation damping Black-start capability 4 DTU Wind Energy, Technical University of Denmark Windpower Monthly - Grid support

6 RESERVICES CONSORTIUM Sharon Wokke Project Manager European Wind Energy Association Rue d Arlon Brussels (Belgium) Tel: sharon.wokke@ewea.org

7 6 DTU Wind Energy, Technical University of Denmark Windpower Monthly - Grid support

8 State of the art technical capabilities in industry Horns Rev 2002 (Kristoffersen et.al.) according to first DK technical requirements Primary frequency control Secondary frequency control Reactive power neutral Today + Continuous voltage control Voltage support during faults Inertia under development verification? REserviceS presentation more details? 7 DTU Wind Energy, Technical University of Denmark Windpower Monthly - Grid support

9 Simulation based verification of ancillary services from wind power Anca D. Hansen, Müfit Altin DTU Wind Energy

10 Background PSO project EaseWind Enhanced Ancillary Services from Wind Power Plants Partners: Vestas Technology R&D DTU Wind Energy DTU Compute AAU IET Objective to develop technical solutions for enabling wind power to have similar power plant characteristics as conventional generation units. Wind power replacing conventional power plants! 9 DTU Wind Energy, Technical University of Denmark Windpower Monthly - Grid support

11 Ancillary services from wind power plants The ancillary services from wind power plants are supported by communication and control at the power plant level. 10 DTU Wind Energy, Technical University of Denmark Windpower Monthly - Grid support

12 Simple generic wind power plant model follows the basic structure of the IEC standard Type IV wind turbine model includes additional adjustments to reflect the dynamics relevant for active power and grid frequency control capabilities. Wind speed filter Optimal speed reference ω rot Wind speed (CorWind) ω gen _ ref v Pitch controller θ v Aerodynamic wt P aero wt P meas Mechanical model Filter ω gen _ filt ω gen _ filt Estimated available power wt P available wt P ref wt P meas ω gen _ filt MPPT ω gen _ filt wt P MPPT wt P WPPC wt Q WPPC Power reference selection wt P ref wt P meas wt Q ref P control LVRT i Pcmd Static generator P, Q measurements wt Q meas Q control i Qcmd 11 DTU Wind Energy, Technical University of Denmark Windpower Monthly - Grid support

13 Short-term overproduction capability Wind speed 0.6pu Aerodynamic Rotor Speed power [pu] Shaft ω Torque gen - ω rot [pu] Electrical power [pu] Pitch Angle [deg] Time [sec] Wind speed 0.93pu Aerodynamic Rotor Speed power [pu] 1.1 [pu] Shaft ω Torque 1.5 gen - ω [pu] rot [pu] Below rated wind speed, the overproduction is followed by recovery period Electrical power [pu] Pitch Angle [deg] Time [sec] Wind speed 1.1pu Electrical power [pu] Aerodynamic Rotor Speed 1.05 power [pu] [pu] Shaft ω Torque gen - ω [pu] 1.4 rot Pitch Angle [deg] Time [sec] The higher the wind speed, the shorter the recovery period The higher the overproduction power: the longer the recovery period and the larger the power underproduction -> frequency stability might be affected the higher the shaft torque -> high mechanical stress of the turbine No power recovery above rated wind speed 12 DTU Wind Energy, Technical University of Denmark Windpower Monthly - Grid support

14 Wind power plant control architecture 13 DTU Wind Energy, Technical University of Denmark Windpower Monthly - Grid support

15 Enhanced ancillary services f df / dt IR controller P IR 1pu P Grid Frequency WPP Power Output time time Active Power or Current Magnitude I Q POD time P POD controller PPOD WPP Active or Reactive Power output time Load Angle δ θ SP controller P SP WPP power output Time Time 14 DTU Wind Energy, Technical University of Denmark Windpower Monthly - Grid support

16 WPP Inertial response capability Grid frequency Without IR With IR [pu] WPP power [pu] Pitch angle 4.00 [deg] Gen. speed [pu] [s] DTU Wind Energy, Technical University of Denmark Windpower Monthly - Grid support

17 WPP synchronise power capability 550 Load change 500 [MW] [deg] Rotor angle deviation δ Without SP With SP WPP power [MW] Time [s] DTU Wind Energy, Technical University of Denmark Windpower Monthly - Grid support

18 OffshoreDC Windpower Monthly - Grid support 17

19 OffshoreDC WP 3 Communication and control in clusters of wind power plants connected to offshore HVDC grids PhD student: Lorenzo Zeni

20 OffshoreDC Results status L. Zeni et.al. From paper in Cigré session 2014 Investigation on system services provision DC voltage control P1,Q1 VSC1 (w chopper) VSC2 (w chopper) P2,Q2 P,Q Bus 1 Bus 2 0.5*Zline SG1 Onshore frequency control and power oscillation damping Grid 1 VDC,1 0.5*Zline SG2 Bus 3 P,Q VDC,WPP PWPP,QWPP VDC,2 Offshore network control P,Q Grid 2 Onshore AC voltage control and LVRT Important results obtained and lines for future work were drawn Windpower Monthly - Grid support 19

21 OffshoreDC Frequency support through HVDC P2P example Two strategies are compared: 1. Communication-based control (with communication delay) 2. Coordinated control mirroring the frequency in DC voltage Windpower Monthly - Grid support 20

22 OffshoreDC On the inertial contribution A2 - P ref [pu] B2 - P ref [pu] (a) (a) (b) (b) Communication Coordinated control Time [s] Power reference to WPP (a) From controller (b) Ramp-limited The initial power support is heavily limited by the ramp limiter (0.1 pu/s): relaxation of this figure? Windpower Monthly - Grid support 21

23 OffshoreDC Conclusions Onshore frequency variations can be mirrored offshore Hence, WPPs can provide frequency control through HVDC with communication-less scheme In a P2P connection, communication-based and coordinated solutions are equivalent, as far as frequency control and inertial response are concerned Fast control actions are inhibited by ramp rate limiters in the WPP Windpower Monthly - Grid support 22

24 Consortium and budget Ireland UCD United Kingdom (2) ALSTOM GRID UNIVERSITY OF STRATHCLYDE France (2) RTE EDF 10 European Member States 1 Associated Country Norway SINTEF Denmark (3) DONG ENERGY ENERGINET DTU ENERGY Portugal INESC-PORTO The Netherlands TENNET Spain (5) RED ELECTRICA DE ESPAÑA IBERDROLA ITT COMILLAS GAMESA ABB S.A. DFFV conference, Herning Total budget: 56.8 M EU contribution: 31.8 M Germany (3) FRAUNHOFER IWES 50 HzT SIEMENS Wind Power Belgium (6) ELIA SYSTEM OPERATOR EWEA CORESO UNIVERSITY LIEGE UNIVERSITY LEUVEN UNIVERSITE LIBRE BRUXELLES Italy RSE 23

25 Demo 4 - The challenge Synchronous Area MW MW Continental 21,421 57,685 Nordic 4,924 14,669 GB 13,711 33,601 Ireland 1,419 3, E 60 N DFFV conference, Herning 2030 map 24

26 Large scale challenge: Adequacy of primary reserves There must be sufficient primary reserves in the power system synchronous area to replace lost production corresponding to dimensioning fault This brings power system from normal state to alert state Frequency restoration (secondary / tertiary) reserves will return system to normal state in 15 minutes Larger faults (loss of generation) may bring system into disturbed (or emergency) state Therefore, maximum 15 minute wind power forecast errors are essential to esure adequacy of primary reserves Synchronous Area Dimensioning faultt MW Continental 3,000 Nordic 1,200 GB 1,800 Ireland 500 Nordic grid code DTU Wind Energy, Technical University of Denmark DFFV conference, Herning

27 Upscaling results and conclusion Result for 2020 indicates that there is sufficient primary reserves with current dimensioning fault to cover offshore wind power variability in the four main European synchronous areas Result for 2030 indicates that there is not sufficient primary reserves with current dimensioning fault to cover offshore wind power variability in Continental and GB synchronous areas Current requirements for primary reserves should be revised by 2030 to maintain secure operation Synchronous Area HWSD HWEP Dimensioning faultt MW MW MW Continental 1,661 1,548 3,000 Nordic ,200 GB 1,212 1,222 1,800 Ireland Synchronous Area HWSD HWEP Dimensioning faultt MW MW MW Continental 4,729 3,933 3,000 Nordic ,200 GB 4,418 4,440 1,800 Ireland DTU Wind Energy, Technical University of Denmark DFFV conference, Herning

28 Simulation of balancing (Simba) Import Simulation of Balancing (Simba) Export Simba idea Simulation of intra hour balancing as supplement to day ahead Uses inputs from day-ahead market model Main imbalance included today is from wind Applications of Simba Planning of investment Assessment of new market designs (e.g. towards real time) Assessment of cost / value of reserves Assessment of needs for reserve capacities Economic optimisation of system services Assessment of flexible demand support to system balancing 27 DTU Wind Energy, Technical University of Denmark Windpower Monthly - Grid support and ancillary services

29 CorWind Simulation of wind power fluctuations and forecast errors 28 DTU Wind Energy, Technical University of Denmark Windpower Monthly - Grid support and ancillary services

30 Modelling chain P w,pos [5m] Wind power model (CorWind) P w,da [1h] P w,ha [5m] Spot market model (e.g. WILMAR) P traded,da [1h] P avail [1h] Intra-hour balancing model (Simba) P w,pos [5m] P plan [5m] Secondary control model (PhD) P w,inst P inst Power system scenario 29 DTU Wind Energy, Technical University of Denmark Windpower Monthly - Grid support and ancillary services

31 Automatic Generation Control in a power system with high wind power penetration Danish case study fnominal + - factual PDCHP + PCHP + + Pwind B PGEN f/r - ACE - P + - PI controller -90 MW +90 MW Pset PCHP pfchp PDCHP pfdchp Pexchange PLOAD + + Model overview AGC model Result: simulated AGC performance 30 DTU Wind Energy, Technical University of Denmark Windpower Monthly - Grid support

32 Wind Power integration into the Automatic Generation Control of power systems SimBa AGC Fmeasure Pmeasure Pavailable + ΔP_WF + Frequency droop Pref Pref (freq) Wind Power Plant Controller Pref_WT Pmeasure Aggregated Wind Turbine model Active power Controller Aggregated WPP model ip_cmd Static Generator Pset Curtailing Power P < 0 dpavailable P < curtailing yes no no P > dp_avail yes yes no P_WF = Pset P_CHP = 0 P_WF = -1* curtailing P_CHP = curtailing - Pset P_WF = dp_avail P_CHP = 0 P_WF = dp_avail P_CHP = Pset - Available Secondary (AGC) dispatch with wind 31 DTU Wind Energy, Technical University of Denmark Windpower Monthly - Grid support

33 Summary and reflections on technical capabilities WPPs can provide basic ancillary services and replace conventional power plants Also possible to provide enhanced ancillary services emulating synchronous generators (inertia-like response, power oscillation damping and synchronizing power) but is this the optimal solution in future systems? Ancillary services can also be provided from HVDC connected WPPs 32 DTU Wind Energy, Technical University of Denmark Windpower Monthly - Grid support

34 Economic incentives and barriers Incentives: Technical requirements for grid connection! Higher prices for reserves than for power (e.g. low and even negative power prices) Co-generation with other production technologies (ramp support) Enables higher wind power penetration Barriers: Symmetric (up/down) requirement (Spain TWENTIES) Downwards reserves from WPPs is feasible with high penetration loads are more feasible as upwards reserves Length (= prediction horizon) of reserve products Development costs for new products Additional hardware costs Verification needs for new products costly certifications 33 DTU Wind Energy, Technical University of Denmark Windpower Monthly - Grid support

35 TPWind Technology Platform New strategic research agenda (SRA) / Market deployment strategy 2014 Issues very similar to REserviceS Frequency support Voltage support System restoration support Research priorities Further development of enhanced wind power capabilities from wind turbine level up to cluster level, including the related design tools and models; Testing and verification of frequency and voltage capabilities, and methods of proving compliance of new solutions for advanced capabilities with Grid Codes and standards; Harmonisation, standardisation and interoperability of methods and technologies for delivering ancillary services with wind power. 34 DTU Wind Energy, Technical University of Denmark Windpower Monthly - Grid support

36 Next steps to allow further penetration of wind into European grids? Researchers Propose strategies for ancillary services to ensure system strategy from wind and other sources Special focus on power system security with increasing levels of non-synchronous generation Not necessarily emulation of synchronous generators!! Develop and implement new controls in simulation tools Simulation based validation of ancillary services from wind Develop tools to assess the value of new ancillary services Developers / owners Assess the value of new ancillary services System operators Propose and verify new strategies to ensure system security Turbine manufacturers Develop and implement new ancillary service capabilities in full WPP scale 35 DTU Wind Energy, Technical University of Denmark Windpower Monthly - Grid support