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ECE 421 Project 1, Group 3 HVDC Brian Beilstein, Robert Germick, James Haney, Alexander Joss, Matt Murphy, Shutang You
ECE 421 Project 1, Group 3HVDCBrian Beilstein, Robert Germick, James Haney, Alexander Joss, Matt Murphy, Shutang You
History and Basic Theory● First HVDC link in Sweden● Mercury Arc Rectifiers● Silicon Thyristors● Capacitor Commutated Converter (CCC)
State-of-the-art Design and Products● DC Breaker
○ Low impedance of HVDC system■ Faster opening speed■ Wider air gap
● Thyristor valves○ Can be used to go from AC-DC or DC-AC○ Used in renewables
Hybrid DC Breaker● Used to overcome issues of breaking DC
o No zero-crossings with voltage as in AC● In the case of a fault
o Load-commutating switch directs current to the main breaker
o Arrestor across the main breaker absorbs currento Ultra fast disconnector opens to isolate the LCSo Main breaker opens a number of IGBT bank
depending on whether interruption or limitation is required
Hybrid DC Breaker Sequence of Events
http://www05.abb.com/global/scot/scot221.nsf/veritydisplay/22d1af449957bf28c1257d070046df97/$file/Technical%20Assessment%20of%20Load%20Commutation%20Switch_IPEC2014.pdf
Thyristor Valve● Typically will use electronically triggered or
light triggered thyristors for control.● Thyristors are typically found in large stacks
and are water cooled
http://www05.abb.com/global/scot/scot221.nsf/veritydisplay/3c981b9078f55447c1256feb0022602a/$file/ett%20vs%20ltt.pdf
Impacts - Benefits● Undersea cables● Useful in connecting remote areas/plants
o End to end long haul bulk transmission● Reduced cost in…
o Increasing capacitance of existing grido Line cost - less wiring, conductors, and lower pylon profile
● AC systems compatibleo Transmission between unsynchronized AC systemso Stabilization of AC grid
● Reduced corona losses
Impacts - Concerns● Higher overall cost
o Expensive inverter stations for connecting to AC grido Requires filter and reactive power compensation unitso Design and operational complexity
● Short circuits in connect AC systems causes HVDC faults● Substation construction limit
o Requires minimal capacity difference● Creates radio noise in communication lines● Current causes electro-corrosion of underground metal pipes● Difficult to ground preventing ‘step voltage’
Challenges- Cost of HVDC components and availability- Conversion from AC to DC
- Cost and losses in conversion may not be offset in by the lower transmission losses and line construction.
- Limited overload capacity - Complex control needed for Multi Terminal
Systems
R&D Development- Offshore HVDC
- Useful for offshore wind-farms- Need for projects with Higher DC voltage
and rating- Improvements in Converting to HVDC
- Voltage Source Converters (VSC)- Multi Terminal HVDC systems- HVDC breakers
Current ApplicationsNorth America
Existing - 12Projects Planned - 4Projects Under Construction - 3
EuropeExisting - 49Projects Planned - 0Projects Under Construction - 2
Current Applications cont.Asia
Existing - 52Projects Planned - 0Projects Under Construction - 0
Red - Existing
Green - Under Construction
Blue - Possible additions
Specific Existing ProjectsOctober 23, 2014 - Alstom announces €800 million in new contracts to build HVDC “Energy highways”.
South Korea - HVDC Line Commutated Converter project
India - ~800kV, 3000MW Ultra-high voltage DC connecting Champa to Kurukshetra
Related ResearchModular Multilevel Converter for HVDC System
HVDC-Station using Modular Multilevel Converter
SM
SM
SM
a) Half-Bridge Submodule (SM) b) Full-Bridge Submodule (SM)
Internal structure of typical submodules
OR
Ref: Marquardt, R. "Modular Multilevel Converter: An universal concept for HVDC-Networks and extended DC-Bus-applications." Power Electronics Conference (IPEC), 2010 International. IEEE, 2010.
Conventional VSC-HVDC convertersThree-level converterTwo-level converter
Ref: http://en.wikipedia.org/wiki/HVDC_converter
Modular Multilevel Converter for HVDC System
Ref: http://en.wikipedia.org/wiki/HVDC_converter
Modular Multilevel Converter for HVDC System
Comparison of the arm currents of Two-Level Converter and the M2C
Comparison of the AC-line voltages of Two-Level Converter and the M2C
Ref: Marquardt, R. "Modular Multilevel Converter: An universal concept for HVDC-Networks and extended DC-Bus-applications." Power Electronics Conference (IPEC), 2010 International. IEEE, 2010.
Two-Level Converter
Modular Multilevel Converter
Two-Level Converter
Modular Multilevel Converter
Ref: Marquardt, R. "Modular Multilevel Converter: An universal concept for HVDC-Networks and extended DC-Bus-applications." Power Electronics Conference (IPEC), 2010 International. IEEE, 2010.
Application of M2C in multi-terminal HVDC
A Multi-terminal HVDC Network with 3 branches
Station 1 Station 2
Station 3Failure current
line-to-line fault
Clamp-Doule submodule
Questions?
