Chulalongkorn University
Department of Electrical Engineering
The Impacts of Smart Grid
Technologies on Power Quality
Asst. Prof. Thavatchai Tayjasanant, Ph.D.
(Thavatchai.T@chula.ac.th or taytaycu@gmail.com)
Sept 27-28, 2010 @ Grand Sukhumvit Hotel, Bangkok, Thailand
Presentation Outline
Smart Grid
Smart Grid Technologies
Examples and Impacts on PQ
Conclusions
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1. Smart Grid
• Smart Grid (SG)
- Other names: Intelligent grid, Modern grid
and Future grid
- Various definitions [1]
USA: self-healing, active participation by
consumers, operate resiliently, provide
quality power, accommodate all generation
and storage options, optimize asset utilization
and operate efficiency.
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1. Smart Grid
The Department of Energy’s (DOE)
Smart Grid Task Force defines 7
characteristics of smart grid:
1. Enable active participation by consumers
2. Accommodate all generation and storage options
3. Enable new products, services, and markets
4. Provide power quality for the range of needs in a digital economy
5. Optimize asset utilization and operating efficiency
6. Anticipate and respond to system disturbances in a self-healing
manner
7. Operate resiliently against physical and cyber attacks, and natural
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disasters
1. Smart Grid
Europe (European Commission report):
flexible, accessible, reliable an economical.
China: An electricity transmission and
distribution system that incorporates elements of
traditional and cutting-edge power engineering,
sophisticated sensing and monitoring technology,
information technology, and communications to
provide better grid performance and to support a
wide range of additional services to consumers.
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1. Smart Grid
• Main challenges of power grids
– Deguration  uncertain power flow scenarios
– Increasing penetration of renewable energy 
uncertainty in power supply
– Require a supply of high quality and availability
– Need to achieve sustainable growth and minimize
environment impact by energy conservation 
increase energy efficiency, reduce peak demand
and maximize the use of renewable energy
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1. Smart Grid
SG challenges: Deliver both energy and information [2]
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1. Smart Grid
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Source: European Smartgrids Technology Platform [3]
1. Smart Grid
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Source: European Smartgrids Technology Platform [3]
1. Smart Grid
• Power grid has to be more active and
dynamic in its configuration and its
operational condition.
• Smart grid technologies are required
to answer these challenges.
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2. Smart Grid Technologies
• Technology layers of smart grid [1]
 Human brain
 Nerves that transmit
perception and motor signals
 Body’s sensory and
motor nerves
 Body’s muscles
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2. Smart Grid Technologies
• Smartness of the smart grid lies in
the decision intelligence layer (L4).
• Advanced algorithms such as
–
–
–
–
Events and faults diagnosis
Load balancing and management
Adaptive protection
Energy management systems
are required for this layer.
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2. Smart Grid Technologies
• Grid data need to be transferred from the
connected devices to the controllers that
process the information and transmit the
control directives back to the devices.
• This task can be performed by
communication layer (L3) with the help
from advanced information and
communication technology (ICT).
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2. Smart Grid Technologies
• One example of ICT is from ZigBee which
was launched in 2002 to develop open
standard for wireless sensor networks.
• Home Area Network (HAN)  Home
automation piece
• ZigBee Smart Energy was released in 2008
with following benefits: metering, pricing,
support for distributed generation, demand
response and load control, security level
options for data and so on [2].
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2. Smart Grid Technologies
ZigBee Home
Area Network
(HAN) [2]
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2. Smart Grid Technologies
• Advanced metering is one part of the
sensor/actuator layer (L2).
• Two-way communication is needed.
• An example is Advanced Metering
Infrastructure (AMI): Full measurement and
collection system that includes meters at the customer site,
communication networks between the customer and a
service provider, such as an electric, gas, or water utility,
and data reception and management systems that make the
information available to the service provider [4].
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2. Smart Grid Technologies
• Advanced Metering Infrastructure (AMI)
Customers are
equipped with
smart meters
which transmit
data via
communication
network to AMI
host managed by
MDMS.
Two-way communication between meter and utility 17
2. Smart Grid Technologies
• An example of
smart meter
from Freescale [5]
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2. Smart Grid Technologies
• Technologies for the physical layer (L1):
– Solid-state technology (e.g. SiC IGBT [6])
– Power electronics–based building blocks
(e.g. HVDC)
– Superconducting materials
(e.g. superconducting cables)
– New battery storage technologies
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3. Examples and Impacts on PQ
• Application examples are [1]:
1) Equipment monitoring and diagnostic systems
(asset management)
2) Wide-area monitoring, protection, and control
3) Voltage and var optimization (energy efficiency
and demand reduction)
4) Intelligent load balancing and feeder reconfiguration (energy efficiency)
5) Self-setting and adaptive relays (protection)
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3. Examples and Impacts on PQ
• Application examples (cont.):
6) Online system event identification and alarming
(safety and reliability)
7) Voltage collapse vulnerability detection
(security)
8) Autonomous outage detection and restoration
(self-healing)
9) Dynamic power compensation, using energy
storage and voltage source inverters (efficiency
and stability)
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3. Examples and Impacts on PQ
• Major PQ issues
1) Harmonics and Interharmonics
2) Voltage dips (sags) and Interruptions
3) Voltage fluctuation and Flicker
4) Voltage transients
5) Voltage unbalance (imbalance)
6) Power-frequency variation
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3. Examples and Impacts on PQ
• Impacts on PQ
1) PQ monitoring will be more
informative and reliable provided
from advanced communication
technologies. System characteristics
can be fully analyzed from AMI data.
However, large amount of information
has to be processed.
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3. Examples and Impacts on PQ
2) Outage Management System (OMS) +
Distribution Management System (DMS) 
Distribution Network Management System
(NMS), e.g. switch order management and
operation.
3) On-line disturbance detection, classification,
location and event notification can be
achieved through advanced smart meters.
Proper measures can be taken effectively.
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3. Examples and Impacts on PQ
4) In order to accommodate many
distributed energy sources (DERs), the
system protection has to be adaptive.
This modification will affect voltage dips
or sags issue. In addition, harmonic and
voltage fluctuation levels can be
increased from these DERs and other
interconnection issues need more
attention.
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3. Examples and Impacts on PQ
5) For self-healing purpose, the network
configuration requires changing and
switching, this results in higher number
of switching transients in the system.
6) Better control of the power system
(stability, security, reliability, optimization
and load balancing) and energy
management (efficiency) can be achieved
through smart grid technologies. These
benefits increase PQ of the system.
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4. Conclusions
• Smart grid technology is a collection of
existing and emerging standards-based,
interoperable technologies working together.
• Technology layers of smart grid can be
divided into 4 layers: 1) Power transport/
storage, 2) Sensor, 3) Communication and
4) Decision intelligence.
• Various impacts on PQ from smart grid
technologies need to be investigated.
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References
[1] E. Santacana, G. Rackliffe, L.Tang and X. Feng, “Getting
Smart,” IEEE Power & Energy magazine, March/April
2010.
[2] B. Heile, “Smart grids for green communication,” IEEE
Wireless communications, June 2010.
[3] European SmartGrids Technology Platform, European
Commission, 2006.
[4] Advanced Metering Infrastructure (AMI), EPRI, Feb 2007
[5] Freescale semiconductor (http://www.freescale.com)
[6] J. Wang, A. Q. Huang, W. Sung, Y. Liu, and B. J. Baliga,
“Smart Grid Technologies,” IEEE Industrial Electronics
Magazine, June 2009.
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Thank You
End of the presentation
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