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HVDC Grids: A View to Standardisation. Carl Barker. Chief Engineer, Systems. March 2011. Why DC Transmission? . Page 3. What are DC Grids? . Page 6. How will DC Grids Evolve? . Page 11. DC Grid Standardisation . Page 13. Agenda. Charges and Discharges Every Half Cycle. AC. DC.
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HVDC Grids: A View to Standardisation Carl Barker Chief Engineer, Systems March 2011
Why DC Transmission? Page 3 What are DC Grids? Page 6 How will DC Grids Evolve? Page 11 DC Grid Standardisation Page 13 Agenda HVDC Grids: A View to Standardisation – March 2011 - P 2
Charges and Discharges Every Half Cycle AC DC Only Charges the Cable Once Why DC Transmission? • HVDC transmission is the correct technology for bulk submarine energy transfer. HVDC Grids: A View to Standardisation – March 2011 - P 3
Network 2 Idc= V1- V2 R Why DC Transmission? Basic Structure of VSC Transmission System Q Q P 1 2 I C 1 V V 1 2 Network VSC VSC 1 DC transmission Station 1 S tation 2 line i i i Idc Iac Iac t t t HVDC Grids: A View to Standardisation – March 2011 - P 4
Why DC Transmission? Page 3 What are DC Grids? Page 6 How will DC Grids Evolve? Page 11 DC Grid Standardisation Page 13 Agenda HVDC Grids: A View to Standardisation – March 2011 - P 5
What are “DC Grids”? • “DC Grids” – Multiple converters connecting AC power networks to a DC power network • “DC Grids” – Permit the economic transfer of power over buried cables reducing environmental impact • “DC Grids” – Permits economic bulk transfer over large distances • “DC Grids” – Reduce the number of AC/DC Conversions therefore reduce losses HVDC Grids: A View to Standardisation – March 2011 - P 6
DC Grid Configurations: Point-to-point System HVDC Grids: A View to Standardisation – March 2011 - P 7
DC Grid Configurations: Radial System HVDC Grids: A View to Standardisation – March 2011 - P 8
DC Grid Configurations: Meshed System HVDC Grids: A View to Standardisation – March 2011 - P 9
Why DC Transmission? Page 3 What are DC Grids? Page 6 How will DC Grids Evolve? Page 11 DC Grid Standardisation Page 13 Agenda HVDC Grids: A View to Standardisation – March 2011 - P 10
How will DC Grids Evolve? • Large pan-European grids • Strategic all encompassing planning at the outset • Four, five, six terminal grids • Small independent DC grids developing ‘organically’ “DC Grids” require rules in the same way that AC grids operate within “AC Grid Codes” HVDC Grids: A View to Standardisation – March 2011 - P 11
Why DC Transmission? Page 3 What are DC Grids? Page 6 How will DC Grids Evolve? Page 8 DC Grid Standardisation Page 13 Agenda HVDC Grids: A View to Standardisation – March 2011 - P 12
Do We Need to Standardise? • Purpose of Standards • Reduce costs (design one build many, long run cost reductions etc.) • Improve asset availability through improved maintainability (common or interchangeable spares, common tooling etc.) • Support interoperability • Allowing interconnected systems to be built incrementally and by different equipment suppliers, thus support incremental investment plans and avoid “stranded assets” • Allow separation of cable and converter procurement thus allowing buyers to take advantage of the increasing number of HVDC cable manufacturers HVDC Grids: A View to Standardisation – March 2011 - P 13
Functional Specifications Equipment that should have a common functional specification • AC/DC Converters • HVDC Cables • DC Breakers • DC-DC Converters • Dump Resistor HVDC Grids: A View to Standardisation – March 2011 - P 14
Design Specification Equipment that should be defined at the initial design stage • Topology? • Symmetric Monopole • Monopole • Bipole • DC Voltage (nominal, steady-state and transient range) • Fault Current Contribution • Multi-terminal DC Protection • Multi-terminal DC control* *Barker CD, Whitehouse RS, ‘AUTONOMOUS CONVERTER CONTROL IN A MULTI-TERMINAL HVDC SYSTEM’, IET, ACDC 2010 HVDC Grids: A View to Standardisation – March 2011 - P 15
DC Grid Standardisation Activities • International recommendations being created; • CENELEC - Four, five, six terminal grids • Cigrè B4-52 - Large pan-European grids • Cigrè have just approved five further DC grid working groups; • B4-56 Guidelines for the preparation of “connection agreements” or “Grid Codes” for HVDC grids • B4-57 Guide for the development of models for HVDC converters in a HVDC grid • B4-58 Devices for load flow control and methodologies for direct voltage control in a meshed HVDC Grid • B4-59 Devices for load flow control and methodologies for direct voltage control in a meshed HVDC Grid • B4-60 Designing HVDC Grids for Optimal Reliability and Availability performance HVDC Grids: A View to Standardisation – March 2011 - P 16