Advanced AC and DC Power Electronics Based Grid Technologies for the Energy Ecosystem of the Future

2011 T&D SummitMarcus Evans Nov. 3, 201 – Chicago, IL

Dr. Gregory F. Reed

Professor of Electric Power Engineering, ECE Dept.Director, Electric Power & Energy InitiativeAssociate Director, Center for EnergySwanson School of EngineeringUniversity of Pittsburgh

AC and DC TechnologiesAC and DC Technologies

A ‘Back to the Future’ ScenarioA ‘Back to the Future’ Scenario

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Grand Challenges for the Power GridGrand Challenges for the Power Grid

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• Growing constraints on electrical infrastructure• Constant growth in electrical demand

• Transmission congestion in key areas

• ‘Legacy’ century-old system and aging AC equipment

• Increased penetration of renewable generation• Statewide renewable portfolio standards

• Location of renewable supply vs. location of load centers

• Integrating non-dispatchable resources reliably

• Distributed resources and DC loads• High penetration of local generation, within the distribution network

• Consumer and industrial loads are migrating toward DC sysems:

• Data center equipment, e.g. switches, servers, UPS, etc.

• Home computers, TVs, internet routers, cell phones, etc.

• Electronic motor drives, industrial automation equipment, etc.

A New Era Emerging in Power SystemsA New Era Emerging in Power Systems

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• Historically, AC has dominated the power industry• Westinghouse, Tesla, Edison, and others intensely fought the initial

‘AC/DC Wars’ at the turn of the 20th Century (late 1800’s, early 1900’s)

• AC proved superior for all the right reasons at the time

• Today, in 2011, there is continued dependence on a ‘legacy’ century-old AC network, mainly built up through the 1930-1970 time frame

• What has changed in the 21st Century?• The era of Power Electronics Technologies

• Continued improvements and efficiencies in semiconductors, devices, circuits, designs, systems, and applications scaled at all levels

• Consumer electronics, emerging resources, servers, energy storage, EVs, and other systems operating at or supplying absolute DC power

• Grid technologies for the future• FACTS devices has improved the performance of AC systems

• HVDC has proven its merit over AC for certain applications (transmission)

• MVDC has the potential to bridge the gap between supply and demand

Context of Renewable Energy GrowthContext of Renewable Energy Growth

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Statements on Increased Renewable Energy Penetration

• DOE National Electric Transmission Congestion Study:

“…there is transmission congestion at present, but ‘significant’ increases in congestion would result if large amounts of new generation resources were to be developed without simultaneous development of associated transmission capacity.” (2006)

• DOE, National Renewable Energy Laboratory (NREL), and

American Wind Energy Association (AWEA) joint Report:

“….transmission and integration into the U.S. electric system…” is one main hurdle to establishing wind power on the grid.

“….many challenges are inherent in building transmission systems to accommodate wind and solar energy. If electric loads keep growing, extensive new transmission will be required to connect new generation to loads. ….true regardless of the power sources that dominate, whether they are fossil fuels, wind, solar hydropower, etc.” (2008)

Power Electronics Technology ImpactPower Electronics Technology Impact

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Power Electronics Technologies Impact and Growth:

• U.S. Dept. of Energy, Office of Electricity Delivery & Energy Reliability Report (March, 2010):

“Presently 30% of all electric power generated uses power electronics technologies somewhere between the point of generation and end-use. By 2030, 80% of all electric power will flow through power electronics.”

• Reed, et.al. DOE NETL SGA Report (June, 2011): “Advances in power electronics technologies and systems

will be critical to improve electric power flow control, effectively integrate renewable and non-dispatched energy generation resources, implement energy storage solutions and distributed generation, and support an expanding market for plug-in hybrid electric vehicles”

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Geographic Intensity of Highest Penetration Potential

Renewable Resource Location IssuesRenewable Resource Location Issues

Wind Speed Across the US Solar Intensity Across the US

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Renewable Resource CapabilitiesRenewable Resource Capabilities

Wind Potential Across the US – On-Shore and Off-Shore Intenstity

National Transmission NeedsNational Transmission Needsfor Wind Integration – 2030for Wind Integration – 2030

2006 National Electric Transmission Congestion Study (NETCS2006) 9

HV DC/AC Super Grid ConceptsHV DC/AC Super Grid Concepts

HV DC/AC Super-Grid Concept for Efficient Integration of Energy Resources and Power Delivery 10

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HVDC: High Voltage DC Transmission Systems:

More power can be transmitted more efficiently over long distances by applying HVDC

HVDC lines can carry 2 to 5 times the capacity of an AC line of similar voltage

Interconnection of two AC systems, where AC lines would not be possible due to stability problems or both systems having different nominal frequencies

HVDC transmission is necessary for underwater power transfer if the cables are longer than 50km

Power flow can be controlled rapidly and accurately

HVDC SolutionsHVDC Solutions

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HVDC SolutionsHVDC Solutions

Transmission and Back-to-Back Link Configurations

THYRISTORVALVE HALL

CONVERTERSTATION

ACNetwork (A)

ACNetwork(B)

ConverterStation A

Converter Station B

DC Transmission

Lines

~ or ~

BtB DC-Link

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FACTS: Flexible AC Transmission Systems

Greater demands are being placed on the transmission network and will continue. At the same time, its becoming more difficult to acquire new rights of way for new transmission infrastructure/lines.

FACTS create new opportunities in controlling power, enhancing the usable capacity of present and future transmission; improving system performance, reliability and security; and validating the use of power electronics to enhance power systems operation and dynamic performance.

Up to 40% additional capacity of existing grid infrastructure can be realized in some locations through strategic FACTS implementation

FACTS SolutionsFACTS Solutions

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FACTS SolutionsFACTS Solutions

PowerSystem

ConverterTransformer

Converter

Ed

DC VoltageSource

Shunt and Series Connected Configurations

STATCOM

TCSC

Medium Voltage DC Network ConceptMedium Voltage DC Network Concept

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DC

AC

DC

DC

DC

AC

DC

AC

Non-Synchronous Generation (Wind)

Distribution Level Storage

DC

DC

Photovoltaic Generation

DC

DC

Fuel Cells

Electric Vehicle

AC

DC

DC

DC

Distribution DC Load Circuits

Sensitive Load

Electronic and AC Loads

Control Algorithm

Future DC Industrial Facility

DC

DC

AC Transmission Supply

Future DC Data Centers

DC

DC

Existing AC Infrastructure

DC

DC

HVDC / MVDC

HVDC System

Future HVDC Intertie

AC

DC

DC

DC

Motor

Variable Frequency Drives

FACTS Compensation

STATCOM / SVC

Power Electronics TechnologiesPower Electronics Technologies

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My View of the Smart Grid

Voltage ControlPower System Stability

SSSC / TCSC

S/S

UPFC

Power Generation

Load

IncreasedTransmission Capacity

Inter-area ControlInter-tie Reliability

Power Flow ControlSystem Reliability

ImprovedPower Quality

EnhancedImport Capability

Inter-connectedISO/RTO

Inter-connectedPower System

HVDC

HVDC

STATCOM / SVC

S/S

S/S

STATCOM / SVCLoads

EnergyStorage

RenewableInterconnections

VoltageSupport

BTB DC

SVC /STATCOM

BTB DC

StorageIntegration

• Needs are rapidly developing in the electric power sector for improved integrated generation management (IGM) with respect to the increase in green energy resource penetration.

• Many of the challenges faced for IGM and the new green resource portfolios that are emerging are within the power transmission delivery sector. There is a strong need for applying advanced transmission technologies to assure safe, reliable, and efficient electricity delivery.

• Future applications and development requirements for power electronics and control technologies in a diversified generation environment, with respect to power system dynamic performance, are needed.

• In general, the case is made for employing more power electronics control technologies throughout transmission and distribution systems for power delivery and for strategically interconnecting green energy resources.

• Combinations of AC and DC Power Electronics Technologies can provide optimal solutions and enhanced investment for utilities and generation providers alike – we need continued investment, development and deployment.

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SummarySummary

• Commonwealth of Pennsylvania, Department of Community and Economic Development, Office of Technology Investments– Ben Franklin Technology Development Authority

• U.S. Department of Energy – Office of Energy Delivery and Electricity Reliability (OEDER) – Energy Efficiency and Renewable Energy Lab (EERE)– ARPA-E Solar ADEPT (Agile Delivery of Electric Power Technologies)

• ABB, Inc. – U.S. Corporate Research Center

• Eaton Corporation – Electrical Sector, Americas Region

• Mitsubishi Electric Power Products, Inc. – Power Systems Division

• Siemens Energy, Inc. – High Voltage T&D Systems

• Univ. of Pittsburgh Electric Power & Energy Research for Grid Infrastructure (EPERGI) Graduate Student Researchers:– H. Bassi, B. Grainger, H. Chen, J. Coulomb, B. De Courreges, R. Kerestes, R. Khanna, R. Kovacs, M. Korytowski, A. Li, A. Sparacino, E. Taylor 18

AcknowledgmentsAcknowledgments

Contact InformationContact Information

Dr. Gregory Reed

Professor of Electric Power Engineering, ECE Dept.Director, Electric Power & Energy InitiativeAssociate Director, Center for Energy

Swanson School of EngineeringUniversity of Pittsburgh

Tele: 412-383-9862Cell: 412-389-7503E-mail: reed5@pitt.edu

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