ECE 421 Project 1, Group 3 HVDC Brian 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 No zero-crossings with voltage as in AC o ● In the case of a fault Load-commutating switch directs current to the main o breaker Arrestor across the main breaker absorbs current o Ultra fast disconnector opens to isolate the LCS o Main breaker opens a number of IGBT bank o 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 End to end long haul bulk transmission o ● Reduced cost in… Increasing capacitance of existing grid o Line cost - less wiring, conductors, and lower pylon profile o ● AC systems compatible Transmission between unsynchronized AC systems o Stabilization of AC grid o ● Reduced corona losses
Impacts - Concerns Higher overall cost ● Expensive inverter stations for connecting to AC grid o Requires filter and reactive power compensation units o Design and operational complexity o ● Short circuits in connect AC systems causes HVDC faults ● Substation construction limit Requires minimal capacity difference o ● 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 Applications North America Existing - 12 Projects Planned - 4 Projects Under Construction - 3 Europe Existing - 49 Projects Planned - 0 Projects Under Construction - 2
Current Applications cont. Asia Existing - 52 Projects Planned - 0 Projects Under Construction - 0
Red - Existing Green - Under Construction Blue - Possible additions
Specific Existing Projects October 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 Research Modular Multilevel Converter for HVDC System SM OR SM SM a) Half-Bridge Submodule (SM) b) Full-Bridge Submodule (SM) Internal structure of typical submodules HVDC-Station using 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.
Conventional VSC-HVDC converters Three-level converter Two-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 Two-Level Converter Two-Level Converter Modular Multilevel Converter Modular Multilevel Converter Comparison of the arm currents of Two-Level Comparison of the AC-line voltages of Two-Level Converter and the M2C 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.
Application of M2C in multi-terminal HVDC line-to-line fault Station 1 Station 2 A Multi-terminal HVDC Network with 3 branches Failure current Clamp-Doule submodule Station 3 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.
Questions?
Recommend
More recommend
