AlstomINTEGRATED APPROACH TO FULFILLMENT OF GRID CODE

REQUIREMENTS IN LARGE OFFSHORE WIND FARMS

Marc Sala, Vicenç Casadevall (Alstom Wind)Liangzhong Yao, Norman MacLeod (Alstom Grid)

Brussels, 16/03/11

© ALSTOM 2010. All rights reserved. Information contained in this document is provided without liability for information purposes only and is subject to change without notice. No representation or warranty is given or to be implied as to the completeness of information or fitness for any particular purpose. Reproduction, use or disclosure to third parties, without express written authority, is strictly prohibited.

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Offshore Alstom Wind’s offering

Pushing the limits to become a leader in offshore wind

• Alstom is currently developing an offshore WTG with the following main features:- 6MW- Large rotor diameter- ALSTOM PURE TORQUE™ Direct

Drive and Permanent Magnet generator- Optimized head mass

• Time to market schedule:- Prototype phase: 2011 – 2012- Pre-series: 2013- Serial production: 2014

© ALSTOM 2010. All rights reserved. Information contained in this document is provided without liability for information purposes only and is subject to change without notice. No representation or warranty is given or to be implied as to the completeness of information or fitness for any particular purpose. Reproduction, use or disclosure to third parties, without express written authority, is strictly prohibited.

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Offshore Alstom Grid’s offering

Increased offering to serve the offshore market

Several competences to supply full solution• HV substation equipment and

engineering• Offshore platform engineering• Construction of the topside (shipyard)• Installation at sea• Foundation engineering• Foundation construction

Note: the foundation is often managed separately

• Alstom Grid is a world leader in electrical infrastructure for offshore wind• Experience offshore since 2006, >1,900MW references

© ALSTOM 2010. All rights reserved. Information contained in this document is provided without liability for information purposes only and is subject to change without notice. No representation or warranty is given or to be implied as to the completeness of information or fitness for any particular purpose. Reproduction, use or disclosure to third parties, without express written authority, is strictly prohibited.

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Electrical Infrastructure

• Location offshore substation• Grid code requirements• Type of transmission• Voltage levels• Distance to shore• Subsea soil• Cable routes

Combination of passive and active components (power electronics)

© ALSTOM 2010. All rights reserved. Information contained in this document is provided without liability for information purposes only and is subject to change without notice. No representation or warranty is given or to be implied as to the completeness of information or fitness for any particular purpose. Reproduction, use or disclosure to third parties, without express written authority, is strictly prohibited.

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Grid Code Requirements

• Frequency Control• Active Power Control• Voltage Control• Reactive Power Control• LFRT/HVRT• Stability at grid faults• Power Quality• Provision of Inertia• Compliance tests

Dependency on Reference Point & Connection Network

180MW Robin Rigg Offshore Wind Farm Substation

© ALSTOM 2010. All rights reserved. Information contained in this document is provided without liability for information purposes only and is subject to change without notice. No representation or warranty is given or to be implied as to the completeness of information or fitness for any particular purpose. Reproduction, use or disclosure to third parties, without express written authority, is strictly prohibited.

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Power Control

• Frequency Control- Power reduction with frequency increases- No disconnection in case of frequency drops- Automatic regulation

• Active Power Control- Maximum power limitation- Delta production (reserve)- Start/ stop control- Remote commands

Good potential combination with Energy Storage equipment

Pgenerated

Dead band

Frequency control

50 Hz fgrid

Pgenerated

Dead band

Frequency control

50 Hz fgrid

Ppossible

Reserve provisionPpossible

Reserve provision

PpossibleMax power limitation PpossibleMax power limitation

© ALSTOM 2010. All rights reserved. Information contained in this document is provided without liability for information purposes only and is subject to change without notice. No representation or warranty is given or to be implied as to the completeness of information or fitness for any particular purpose. Reproduction, use or disclosure to third parties, without express written authority, is strictly prohibited.

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Reactive Power Control

• Voltage Control- MVAr control reference at PCC-offshore (MV)- Voltage control at connection onshore (HV)- Combination of reactive power capabilities of wind turbine and

substation level equipments- Automatic regulation

• Reactive Power Control- Minimisation of losses in transmission to onshore- Apparent power limit follow up- External Q set points from operator- Remote commands

Combination of Q capabilities of WT and substation level equipments (on and offshore)

Reactive power delivery

U [pu]

Reactive power consumption

Wind Turbine Control (LFRT mode)

Q [pu]

U/Un4 U/Un5

Wind Farm Control

Wind Turbine Control (LFRT mode)

© ALSTOM 2010. All rights reserved. Information contained in this document is provided without liability for information purposes only and is subject to change without notice. No representation or warranty is given or to be implied as to the completeness of information or fitness for any particular purpose. Reproduction, use or disclosure to third parties, without express written authority, is strictly prohibited.

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Stability against Grid faults/ peaks

• LFRT /HVRT- No disconnection during grid faults or peaks- Current injection during fault / consumption during peak- 3ph, 2ph, 1ph faults- Continue production after clearance- Very fast response required- Can be managed either at WT or at substations level

Response expected at the connection point

WFWF

© ALSTOM 2010. All rights reserved. Information contained in this document is provided without liability for information purposes only and is subject to change without notice. No representation or warranty is given or to be implied as to the completeness of information or fitness for any particular purpose. Reproduction, use or disclosure to third parties, without express written authority, is strictly prohibited.

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Grid Stability

• Comparison of SVC and STATCOM Characteristics

STATCOM

System Voltage (p.u.)

1.0 p.u. 1.0 p.u.Capacitive Current(Leading)

Inductive Current(Lagging)

1.0 p.u.

TSC & TCR

0.4 p.u. The capability of the STATCOM to operate at low voltage allows it to contribute to the low voltage ride through requirement.

© ALSTOM 2010. All rights reserved. Information contained in this document is provided without liability for information purposes only and is subject to change without notice. No representation or warranty is given or to be implied as to the completeness of information or fitness for any particular purpose. Reproduction, use or disclosure to third parties, without express written authority, is strictly prohibited.

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Monitor and control of wind farm

• Control of wind farm operation to meet the grid code requirements- Control of wind turbines- Control of reactive power

compensation device such as SVC, STATCOM

- Control of offshore substation- HVDC converter control

• An integrated control approach can improve the operation performance of wind farm- Real-time data management and

visualisation- More intelligent operation and control

Control room

© ALSTOM 2010. All rights reserved. Information contained in this document is provided without liability for information purposes only and is subject to change without notice. No representation or warranty is given or to be implied as to the completeness of information or fitness for any particular purpose. Reproduction, use or disclosure to third parties, without express written authority, is strictly prohibited.

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HVAC topology- Current Practice

Independency between substation and WF controllers

© ALSTOM 2010. All rights reserved. Information contained in this document is provided without liability for information purposes only and is subject to change without notice. No representation or warranty is given or to be implied as to the completeness of information or fitness for any particular purpose. Reproduction, use or disclosure to third parties, without express written authority, is strictly prohibited.

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HVAC topology- Integrated approach

Optimisation of global response by linking controllers

© ALSTOM 2010. All rights reserved. Information contained in this document is provided without liability for information purposes only and is subject to change without notice. No representation or warranty is given or to be implied as to the completeness of information or fitness for any particular purpose. Reproduction, use or disclosure to third parties, without express written authority, is strictly prohibited.

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HVDC topology

HVDC requires integrated WF approach

© ALSTOM 2010. All rights reserved. Information contained in this document is provided without liability for information purposes only and is subject to change without notice. No representation or warranty is given or to be implied as to the completeness of information or fitness for any particular purpose. Reproduction, use or disclosure to third parties, without express written authority, is strictly prohibited.

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Conclusions

• Fulfilment of Grid Requirements in OWF is obtained by combining capabilities of substation equipment and wind turbines

• Electrical infrastructure and substations equipments are project dependent

• Integration of substation equipment and wind turbines in same algorithms allows:- Optimised response of the whole WF at the

connection points- Reduced losses- Better management of interfaces (WT/substation)- Cost and risk reduction

Customised project approach solutions

Thanks for your attention