Ancillary Services from Wind Farms

Transcription

1 Downloaded from orbit.dtu.dk on: Jul 19, 2018 Ancillary Services from Wind Farms Hansen, Anca Daniela; Margaris, Ioannis; Zeni, Lorenzo; Sørensen, Poul Ejnar; Cutululis, Nicolaos Antonio Publication date: 2011 Document Version Publisher's PDF, also known as Version of record Link back to DTU Orbit Citation (APA): Hansen, A. D., Margaris, I., Zeni, L., Sørensen, P. E., & Cutululis, N. A. (2011). Ancillary Services from Wind Farms [Sound/Visual production (digital)]. 5th Wind Energy Systems Workshop, Roskilde, Denmark, 31/03/2011 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 from Wind Farms Anca D. Hansen Ioannis Margaris Lorenzo Zeni Poul Sørensen Nicolaos A. Cutululis (presenter)

3 Ancillary services Ancillary Services are support services in the power system, particularly those which are necessary to support the transmission capacity and are essential in maintaining i i power quality, reliability and security of the grid Classification (Alvarado, 1996): Real vs reactive power, time and insurance Real power: frequency regulation, ramping schedules, energy imbalance, loss compensation and unit commitment Reactive power: voltage regulation, capacitor switching and generator scheduling 2

4 Danish TSO requirements Danish TSOs requirements: Balance control Delta control Power Power Fault Ride Through Capabilities Power control Capabilities: - Active power control functions: Balance control Delta control Power gradient limiter Automatic frequency control - Reactive power control functions: Reactive power control Automatic voltage control Power Frequency control droop + time time Reactive power droop Voltage control droop frequency deadband deadband voltage 3

5 Wind turbine control Traditionally: to produce maximum possible power to reduce the structural loads on the mechanical components and thus theirs costs Additionally now: to optimize the integration of the wind turbines in the power system, in order to secure quality, stability and reliability to reduce the required grid connection costs Wind farm controller Wind turbine controllers Grid support! 4

6 Wind farm hierarchical supervision System operators Demands P ref Wind farm Wind turbine control level controllevel l P avail PCC P meas Q PCC meas Wind farm controller s goal is to meet grid integration challenges! System operators: Supervise the wind farm production : wind farm control level wind turbine control level System Control l functions operators wfc Wind farm control level wfc P ref P ref wfc Q ref Q ref wfc Control wind farm production Wind farm controller wfc P wfc out WT i WT out Main P Dispatch P ref ref controller WT wfc out wfc function Q WT ref Q Q ref out controller maximum production controlled production (control tasks) Wind turbine control level 5 Measurements in PCC Available power f i

7 Wind turbine control level Wind farm control level Wind farm control level Wind farm status Required operation Normal operation Imposed limited operation WT P rated i WT P i available Main controller WF P set + + _ PI Powerramprate limiter Balance Delta Frequecy, voltage droop/deadband Power reference settings WF Q set P freq + Frequency control PCC f meas + PCC P meas + _ PI Q volt + Voltage control U PCC meas Q PCC meas 6 Available powers P i WF ref WT P ref WF ref Dispatch control Q i WT Q ref

8 Power control grid support: ASWT wind farm ASWT equipped with appropriate controller: can provide a relativelly fast response to changes in active power demands. new P setpoint reached within a few seconds Dynamic phase control immediate response to Qdemands d (in the limits of capacitor bank) new Q reference reached in less than 0.5 s. quickly control of voltage DIgSILENT DIgSILENT Power demand 6 MW from system operator Power reference y p reference Wind farm available power Reactive power demand Wind farm reactive power in PCC [MW] [MVar] in PCC MW Power reference MW [MVar] in PCC 0 MW Wind farm PCC power [sec] [sec] 7

9 Power control grid support: DFIG/PMSG wind farm Variable speed wind turbines (DFIG or PMSG) PMSG have better grid support capability than DFIG respond immediately to changes in P and Q demands from power system operator. control independently P and Q can provide ahigher h amount of reactive power can support voltage level to a higher level recovers faster the voltage DIgSILENT DIgSILENT Available power MW 2MW Actual power Balance Balance Max. production Delta control = 0.5 MW down Max. production Delta control = 0.5 MW down Max. production Reactive power [MVar] [pu] Speed Pgrid [Mvar] Pitch angle [deg] Wind speed [m/s] Qgrid [Mvar] Qdemand = 0 Mvar Qdemand= 1 Mvar [sec] [sec] DFIG wind turbine PMSG with full scale converter wind turbine 260.0

10 Voltage control grid support DFIG/PMSG wind farm Variable speed wind turbines (DFIG or PMSG) participate to properly reestablish the grid voltage during a grid fault. can help a nearby active stall wind farm to FRT, without any additional ride through control setup in the nearby active stall wind farm DIgSILENT age WFT [pu] WFT [MW] DIgSILENT a b c d damping effect on ASWF for (b) and (c) Active power WFT [MW] Volta Reactive power WFT [Mvar] Active power c d a b worst case for ASWF is (a) best case for ASWF is (b) [sec] DFIG wind farm without voltage grid support - DFIG wind farm with voltage grid support a - DFIG-WF without / AS-WF without b - DFIG-WF with /AS-WF without [sec] c - DFIG-WF with /AS-WF with d - DFIG-WF without / AS-WF with Reactive po ower WFT [Mvar]

11 Frequency control 10

12 Frequency control primary response (i) Inertia Control ( virtual inertia ) (ii) Droop Control df dt K inertia f K droop 11

13 Frequency control scheme PI PI cascade P r ef gen + + Maximum Power Tracking Po int General frequency control scheme 12

14 Droop control 13 Source :I. Erlich, 2010

15 Kinetic energy 1 (virtual inertia) 14 Source :I. Erlich, 2010

16 Kinetic energy 2 (temporary droop) Source :I. Erlich,

17 Frequency control 16 Source :I. Erlich, 2010

18 t of ancillary services Enhanced Ancillary Services from Wind Power Plants (EASEWIND) To develop, asses and demonstrate technical solutions for enabling wind power to have similar power plant characteristics as conventional generation units. WP0 Management and Coordination with Synergy projects WP4 Operat tional value and cost WP7 Dissemination Partners: Vestas Power Programme Risø DTU VES and IES DTU/IMM AAU/IET

19 DC grids for integration of large scale wind power (OffshoreDC) Overall objective: To develop and apply the Voltage Source Converter (VSC) based HVDC grid technologies in the deployment of offshore wind power. TSO(s) Partners: Risø DTU VES Vestas Technology R&D DTU Elektro ABB DONG Energy EnergiNet.dk Chalmers University SINTEF VTT Wind turbine controller Wind Power Plant Controller Wind turbine controller Wind turbine controller Balancing responsible Central Cluster Controller Wind Power Plant Controller Wind turbine controller Wind Power Plant Controller Wind turbine controller Wind turbine controller Cluster control (Ph.D student): Communication and control in clusters of wind power plants connected to HVDC offshore grids (control system architecture, allocation of control tasks, communication protocol)