High Voltage Direct Current- Powering The Future
Presented at: 2017 Engineering Symposium, IEEE Track Rochester , April 18, 2017 Presented by: Girish Behal, Sr. Project Manager, SNC-Lavalin Presenter:Girish Behal, PMP Sr. Project Manager – SNC-Lavalin Background IEEE IEEE Senior Member Secretary of 15.05.08 WG Member of W.G.’s 15.05.18/15.05.19 Member of Smart Village Development Committee Education History BS in Civil Engineering MS in Electrical Engineering (Power Systems) MBA (‘17) Work Energy industry (13 years) Hydrocarbons (2 Years) 2 Agenda Section 1 - Introduction to HVDC Section 2 - Comparison of HVDC and HVAC grids or AC Vs DC – Part Deux Section 3 – Main Components of HVDC Section 4 - HVDC Grid Drivers
3 Section 1-Introduction to HVDC
Battle of the Currents HVDC Basics Brief History of HVDC Transmission HVDC–Benefits Overview **Questions**
4 AC Vs DC or Battle of the Currents
Westinghouse versus Edison DC Lower voltages (+110/-110 V) Small Distributed Generation 121 DC stations existed in 1887 AC Higher Voltages Pan-Am exposition Contract Niagara falls contract solidifies AC’s role in Electric Grid
5 High Voltage Direct Current Basics
HVDC is the transmission of power using Direct Current (DC) rather than Alternating Current (AC)
It uses two AC-DC converters, the Rectifier and the Inverter
Main components: valves,
transformer and filters Source: GE Grid Solutions
6 Brief History of DC Transmission
Started with Rene Thury in 1880’s Moutiers-Lyon System Mercury Valves in 1914 Elbe Project (Moscow-Kashira HVDC system) Island of Gotland Connection (Uno Lamm) Nelson River Bipole 1 Semiconductor Solid State electronics in 1970’s Thyristor Valves (LCC technology)
7 Brief History of DC Transmission
+/- 800kV
Itaipu, Brazil: 6300 MW – 800km Nelson River, Canada: 3800 MW – 800km First introduced in Sweden in 1954: Three Gorges, China, 3000MW – 1060km Gotland to Sweden Quebec-New England, 2000MW, 1480 km, 3 term. Link 20MW at 100kV Xiangjiaba-Shanghai, China, 6400 MW, 2000 km
8 HVDC: Overview of Benefits
Suitable for transfer of bulk power from point to point
Reliable over very long distances: no substations !
Reduced Environmental Impact
Better Immunization to black outs
Nicolet Converter Station, Quebec –New England Long cables – no reactive power ! Link
9 Questions Who was responsible for widespread growth of AC Systems?
Which innovation in 1970’s made HVDC more accessible?
Which Project equipment was used to build Moscow-Kashira System?
10 Section 2 - Comparison of HVDC and HVAC AC vs DC – Techno-Economic Choice **Questions**
11 AC vs. DC: breakeven distance ?
Converter stations Vs. N substations
Breakeven distance is a moving target
For OH lines: generally accepted figures around 600 km to 800km
For Cables: cost + technical limitations of AC cable interconnections Source: Areva T&D
Choice needs to include many Source: Siemens other aspects
12 AC vs. DC: relative costs M$US
Source: ABB
13 AC vs. DC: ROW + cost reduction
Source: ABB
Source: GE Grid Solutions
14 AC vs. DC: Technical Aspects Firewall against problems associated with synchronous operation ex. U.S.A – Canada - Quebec
Toronto Star: How one power grid kept lights on
Hydro-Quebec built sub-stations where they installed electric buffers, or valves, that convert AC power to DC and back to AC.
[The HydroQuebec system is] very different from New York Ohio the rest of North America, but also, because of its New Jersey Maryland buffers and valves, is very stable and secure Michigan Massachusetts relative to other utility companies” Connecticut Ontario
15 AC vs. DC: Technical Aspects Full control over magnitude and direction of power flow
Various control strategies possible
Reduced voltage operation possible
No Short-Circuit Contribution
Impact on reactive power & power quality
All factors contribute to the choice
16 HVDC vs HVAC grid Comparison Summary
HVDC Advantages ›AC Advantages
Long distance Meshed systems Long distance over cables Easily expandable in stages (more flexible to deal with Large power levels uncertain resource additions) Possible contribution to frequency control and ramping HVDC grids add the expandability
17 Questions What is the generally accepted break even distance for OH transmission line for DC systems to be cost effective?
Which system has higher line losses over long distances?
What is the reduction in the ROW width for two transmission lines at 500kV if DC system is installed?
Which system is better for long distance over cables?
18 Section 3 – Main Components of HVDC Applications and Ratings Converters Semi Conductor Valves Transformers Filters
**Questions**
19 Applications/Ratings of HVDC Transmission
Applications Long Distance, bulk-power OVHD transmission Sea and land cable transmission Asynchronous interconnections Power flow control Congestion relief
Ratings Power range up to 4000 MW at ± 500 kV Power range up to 4800 MW at ± 600 kV Voltage range increasing to ± 800 kV Power range up to 6400 MW at ± 800 kV VSC-HVDC applicable to lower powers as well 6300MW Converter Station – Ibiuna, Brazil
20 Main Components: Converters
HVDC Valve Hall Source: Areva T&D
21 Main Components: Semi-Conductor Valves
HVDC Valve Hall Source: GE Grid Solutions
22 Main Components: Transformers
325 MVA HVDC Converter Transformer Undergoing Factory Testing
Specific to HVDC Applications
Designed to withstand harmonics
Parallel connection so as to cancel major harmonics
23 Main Components: Filters
Reduce harmonics entering AC networks
Reduce interference with phone lines
Improve power quality of neighbouring networks
Provide reactive power support
Source: Siemens
24 Questions What are the main components of an HVDC converter station?
Can HVDC Transformer be designed to withstand harmonics?
Why do we need filters?
25 Section 4 –HVDC Grid Drivers
Emerging Drivers Renewable Resource Maps Transmission Development Trends Vision for the future – DC Grids **Questions**
26 Emerging Drivers Behind HVDC Grids
Integrate utility-scale renewables Wind and solar are intermittent and not dispatchable Diversification of resources The resource rich areas tend to: Require space (wind and solar) Sit away from load centers Siting / Permitting
27 Wind resource potential map
• Wind has exceptional resources in the Central US and Canada • Driving major transmission developments in – MT, KS, OK, ND, SD, TX –ME – Off-shore (East coast)
Courtesy of IRENA
28 Solar resource potential
• Photovoltaics (PV) has been identified as having major potential in CA, AZ and UT • One of the drivers behind the southern California transmission projects
29 Transmission Development Trends
30 Vision for the Future: the DC Supergrid ?
The European Supergrid Concept 31 Vision for the Future: the DC Supergrid ?
Source: NREL
32 Vision for the Future: the DC Supergrid ?
If US states that have significant renewable resources are to export their power to more populated states, the US should build a high-voltage direct current grid – Physics Today (Andy Sibler)
33 Vision for the Future: the DC Supergrid ?
Source: Dale Osborn - Mid Continent Independent System Operator 34 Vision for the Future: Integrating into the Supergrid ?
Needs to be thought of as “continental grid” We will need Multi terminal HVDC Link different types of generation to loads – wind, thermal, solar, etc. Integration of renewable energy sources . Renewable sources generally far from load . Multi-term: mitigate renewable source variability Needs point towards several grid “layers” . LCC for bulk transfer . VSC for voltage support, frequency response etc.
35 36 Questions Where are the bulk of wind resources located in the US?
Where are the bulk of solar resources located in the US?
What are the general Transmission development trends in the US?
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