The Smart Grid and

Power Quality

Terry ChandlerPower Quality Inc, USA

Power Quality Thailand LTDSept 2009

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DefinitionsA smart grid is an umbrella term that covers

modernization of both the transmission and distribution grids. http://en.wikipedia.org

Smart Grid is a new industry being built around the modernization of the electrical grid, green power generation and more efficient usage of electrical power. Terry Chandler, Power Quality Inc Aug 2009

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NIST SmartGrid Conceptual model

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Taxonomy of SmartGrid ( the practice and science of classification)

Compliments of GTWResearch

Why do we need SmartGrid?

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Andy Tang, an executive at the PG&E utility in California, “ Smart Grid is not a thing or a specific project. It is about how the utilities leverage technology to enhance their entire portfolio of business processes.”

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What is Power Quality?The characteristics of the supply voltage and the electrical system that affect the performance of the load

The characteristics of the load that affect the electrical system or other loads..Terry Chandler PQI 1995

June of 2008, the U.S. Department of Energy list for Smart Grid

1 Optimize asset utilization and operating efficiency.

2 Accommodate all generation and storage

options.

3 Provide power quality for the range of needs in a digital economy.

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PQ/PR issues for Utility sideVoltage stability Voltage sags

From transmission From DistributionFrom other loads

Voltage transientsLightningSwitching gridPower Factor Capacitor switching

Voltage imbalance/unbalanceFrequencyPhase shifts

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Utility PQ issues IIHarmonics (Voltage)

Non-linear loadsSaturated transformersSystem impedanceInterharmonics

FlickerVarying loadsVarying voltage

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Power Quality parameters User Side

Voltage, Sag and surges, micro-outagesSine wave waveshape, transientsVoltage imbalanceHarmonicsElectrical system design and construction.Grounding

What is driving the SmartGrid ?1. Growing Energy Demand2. Energy Security3. GHG Reduction (Green House Gas)4. Economic Growth (Business opportunities)5. Policy and Regulation (Government direction)6. Technology Advancement 7. Increased Efficiency Through Grid Optimization8. Economic stimulus investment9. Digital economy power quality

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The Smart grid utilizes technology in three important ways:• 1) Automating the grid to harden it and make

it less costly to operate.

• 2) Integrating the electric grid to create an end-to-end network for quickly acquiring and transporting data from millions of end points

• 3) Expanding the value of the grid beyond typical utility needs to support new services and new markets offered by energy retailers.

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Event Avoidance to improve PR/PQRemote load profiling/management

Automatic Grid event diagnostics

Advanced data analysis

Grid condition sensing and predictive response

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Self-Healing Grid (improve PR)Improved asset management/visibility

Real-time grid condition monitoring

Automated grid switching to improve reliability and reduce risk of major blackouts.

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Self healing gridMeters as a sensors for the SmartGrid

Transformer load management, near real time

Condition-based crew dispatching with Automatic Fault locating

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Advanced Meter Infrastructure

• Meters, Revenue, Grid monitors and PQMS

• Meter interrogation

• Meter with load connect/disconnect

• Outage notification• Two-way communications with meters• Automated meters a critical role in the

Smart Grid architecture as sensing devices.9/6/2009 17www.powerquality.org all rights reserve

Modern Grid Team 2006 “Reliable with quality” Safe SecureEconomic EfficientEnvironmentally friendly

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Comparison Current Grid to Smart Grid

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Today’s Grid vs Smart Grid

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Compare the reliability

Power not available9's Seconds Minutes2 99.0000000% 315,360.00 5,256 3 99.9000000% 31,536.00 526 4 99.9900000% 3,153.60 53 5 99.9990000% 315.36 5 6 99.9999000% 31.54 7 99.9999900% 3.15 8 99.9999990% 0.32

Fixed line telephony

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How will Smart Grid affect Power QualityFrequent switching of the grid will

Significant increase of switching transients (until solid state switching devices are used) Sensitive loads will experience an increase in

transientsVoltage imbalance/unbalance will change with

switching alternate sources

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Harmonics affected by Smart GridVoltage Harmonic levels

Voltage distortion is a function of Harmonic load current and the source impedance.

As the SmartGrid switches between sources it will change the source impedance. This will cause the Voltage distortion level to change when the Grid Switches.

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SmartGrid and voltage sagsInterconnection of

distribution substations

Increases voltage sags incidents at that voltage level.

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PQ changes with SmartGridPQ parameter Transition to netgrid Smart Grid fully implementedV Harmonics Increase decrease or return existing levelVoltage transients Increase decrease or return existing levelVoltage imbalance Increase decrease or return existing levelVoltage Phase Shifts Increase decrease or return existing levelVoltage Sags Increase depends on implementation

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Conclusions Short term affectsAs the grid changes from Hierarchal to

network configuration the voltage sag incident will increase.

The Voltage harmonics will change frequently as the source impedance changes when the SmartGrid switching.

Voltage waveform transients will occur during the switching and can be sever if the new source is at a different phase angle than the existing source.

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Conclusions Long TermGridSwitching will become more

sophisticated to switch only at zero crossing and when in phase.

Network design will change to reduce voltage sag depth and duration.

Short and medium term Power Quality will deteriorate

Long Term Power Quality should improve to existing levels or better

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ReferencesTHE SMART GRID IN 2010: MARKET SEGMENTS,

APPLICATIONS AND INDUSTRY PLAYERSDAVID J. LEEDS | GTM RESEARCH

http://www.leonardo-energy.org/what-definition-smart-grid

http://www.utilitiesproject.com/documentshttp://www.smartgridnews.com/artman/publis

h/article_177.htmlwww.Gridwise.org

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Thank YouTerryc@powerquality.org

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