The key to successful deployment of High Voltage offshore wind transmission systems

Transcription

1 Peter Jones Technology Strategy Manager ABB The key to successful deployment of High Voltage offshore wind transmission systems All Energy 22 May 2014 Offshore Wind / O&M Seminar Theatre ABB Group June 6, 2014 Slide 1

2 The key to successful deployment of HV offshore transmission systems Typical project Thornton Bank HVAC offshore wind transmission system Electrical system design process Mechanical design considerations Conclusions ABB Group

3 Thornton Bank 325 MW, 150kV AC Turnkey electrical system provider 325 MW Offshore AC platform Supply of 38 km of 150 kv Export sea cable Supply of 55 km of 36 kv Array sea cables Supply and installation of 6 km of 150 kv land cable Completion on time - July 2013

4 The Project ABB Group June 6, 2014 Slide 4

5 HVAC Offshore Transmission System Electrical System Design Steps (Iteration) DESIGN BASIS (WINDFARM CONCEPT & NETWORK) OFFSHORE SYSTEM DESIGN ONSHORE SYSTEM DESIGN DESIGN REPORTS AND VERIFICATION STUDIES ELECTRICAL AND ENVIRONMENTAL CONDITIONS CLIENT DRIVEN REQUIREMENTS eg. SPECIFICATIONS, WINDFARM CONCEPT ABB Group June 6, 2014 Slide 5

6 System Modelling In the UK DigSilent is a widely used system modelling tool Used by many of the host utilities for Grid Code Compliance Allows the modelling of plant Allows modelling of control algorithms Reactive compensation STATCOM/SVCs Turbine reactive contribution and harmonic performance Model total systems with turbines, reactive compensation and plant performance. ABB Group June 6, 2014 Slide 6

7 HVAC Offshore Transmission System Electrical System Design Steps Short-circuit calculation performed for normal and contingency operation Determine the short-circuit current at wind turbine terminal and 33 kv switchgear on platforms (and in HV network). The onshore and offshore transformer impedances are determined to limit the short-circuit current to the desired value. Power flow calculation performed for normal and contingency operation Determine size and rating of reactive power compensation (shunt reactors, filters and dynamic compensation system) equipment and rating of cables and transformers. Determine voltage profiles throughout the windfarm. Result is used to specify electrical data MV & HV cables MV & HV switchgear offshore transformer initial data for onshore transformer Data returned from component designs ABB Group June 6, 2014 Slide 7

8 HVAC Offshore Transmission System Electrical System Design Steps Harmonic calculation performed for normal and contingency operation Fulfill PCC and offshore harmonic distortion requirement Assume preliminary HV filter data. Specify requirement for reactive compensation system Design reactive compensation system Determine configuration Component rating Onshore transformer requirements Data returned from equipment design Final requirements HV filters Shunt reactors Dynamic reactive compensation Onshore transformer New iteration of power flow, shortcircuit and harmonic calculations ABB Group June 6, 2014 Slide 8

9 Transmission Grid VAR Requirements Source National Grid

10 HVAC Offshore Transmission System UK Requirements Reactive Power Capability Rated MW 100% 50% 20% MW Point A is equivalent (in MVAr) to 0.95 leading Power Factor at Rated MW Output Point B is equivalent (in MVAr) to 0.95 lagging Power Factor at Rated MW Output Point C is equivalent (in MVAr) to -5% of Rated MW Output Point D is equivalent (in MVAr) to +5% of Rated MW Output Point E is equivalent (in MVAr) to -12% of Rated MW Output A E C D B MVAr [ Grid Code CC ] ABB Nov 22, 2012 Slide 10

11 HVAC Offshore Transmission System UK Requirements Voltage Control ABB Nov 22, 2012 Slide 11

12 HVAC Offshore Transmission System UK Requirements Transient Response ABB Nov 22, 2012 Slide 12

13 Effect of 400kV fault on the UK System Source National Grid ABB Month DD, YYYY Slide 13

14 HVAC Offshore Transmission System UK Requirements Fault Ride Through Offshore Power Park should remain transiently stable and connected to the system without tripping any module for balanced Supergrid Voltage dips and associated duration on the Onshore Transmission System. ABB Nov 22, 2012 Slide 14

15 Insulation Co-ordination Studies Impact of energisation of the windfarm on the transmission system. P28 Staged energisation if required Transient voltage performance Switching Lightning Design, positioning and rating for surge arrestors Failure to do this reduces the service life of plant ABB Month DD, YYYY Slide 15

16 HVAC Offshore Transmission System Mechanical Design Considerations Offshore S/S Electrical equipment data Environmental conditions Client specifications Onshore S/S Electrical equipment data Environmental conditions Client specifications Subsea export cables Electrical requirements Seabed characteristics Shore-landing characteristics Onshore export cables Electrical requirements Environmental conditions & soil characteristics ABB Group June 6, 2014 Slide 16

17 HVAC Offshore Transmission Systems Conclusions Getting the end-to-end electrical system design correct is fundamental to achieving a grid code compliant outcome. Correct and sufficient input data is essential at the outset of the electrical system design process. The electrical system design process is iterative with design of the individual primary plant components. The UK has a uniquely challenging set of requirements which require thorough and comprehensive modelling and validation to assure compliance. ABB Group

18