Division of
POWER
ENGINEERING
DIVISION OF
POWER
ENGINEERING
13
INTRODUCTION
E
lectric power is by far the most utilized form of energy.
It pervades all areas of modern society from the point of
view of power generation, transmission, and distribution to
the utilization of electrical energy in industrial, medical and
consumer applications. With the recent increase in oil prices
and awareness of global climate change, research interest
has also intensified in areas of renewable energy, its sources
and management. The Division of Power Engineering
comprises 20 academic staff actively involved in research
in one or more of these areas. With the diversity in power
and its applications, the division’s research activities are
categorized into several research thrusts actively pursued
in its flagship research center, the Centre for Smart Energy
Systems (CSES). These thrust areas combine closely the
disciplines of Power Systems, Power Markets, Power
Electronics, Power Monitoring and Control.
http://www.ntu.edu.sg/eee/eee1/research.asp
This research thrust looks into the design and analysis
of market institutions, mechanism and computational
tools, risk analysis and financial engineering. Research in
the required technology is also pursued in areas such as
intelligent energy metering with power-line and wireless
communications.
• Energy Efficiency in Utilization. The final research
thrust focuses on the state of the art technology required
for energy efficiency. Research pursued includes energyefficient power converters, solid-state lighting systems,
electric motor drives, land-air-marine transportation
energy systems, new power semiconductors and power
integrated circuits.
Highlights of Research Activities
The Division’s research activities have been continuously
reported through publications in refereed international
Having as prime objective the development of intelligent
systems for the efficient and clean harvesting, storage,
delivery and utilization of energy, CSES research thrusts
are in the following areas:
• Smart Distributed Generation (DG) of Clean Energy.
With the increased usage of solar panels and other microsources, distributed generation becomes a reality. This
would require flexible transmission-distribution grids,
smart network control and communications. Issues of
power quality and system integration also arise. This
research thrust thus pays particular attention to the needs
in renewable/clean energy systems.
journal papers and conference proceedings. To synergize
our research with external bodies, research collaborations
have been forged with research institutes, multinational
companies, Small and Medium Enterprises (SMEs) as well as
foreign universities.
Three articles are presented here to highlight some of the
interesting activities being pursued in the Division. The
first article is on Microgrid Energy Management Systems
(MEMS). This article describes the algorithm design and
control schemes that can minimize the scheduling cost
or maximize the revenue of MEMS while ensuring their
secure operation. The second article features research in
• Electrical Energy Storage Systems. Several main
renewable energy sources are often characterized by
fluctuating generated power. Energy storage is thus
a necessity. This research thrust looks into advanced
batteries, fuel cells, flywheels, ultra-capacitors, superconducting magnetic energy storage systems as well
as the power electronic converters for interfacing these
storage systems.
Energy Storage for Clean Energy Applications. This includes
research in electrochemical batteries, solid-oxide fuel cell
and rotating flywheel. Collaborative work here is also done
with the global wind turbine manufacturing giant Vestas.
The third article features the area of Intelligent Power
Quality Monitoring and Estimation. The article describes
how advancements in computer technologies are changing
the way in which the status of a power system network
• Energy and Power Markets. With the advent of a
liberalized power market with multiple sources, new
mechanisms of transaction and operation are required.
is being monitored. It also describes how the wealth of
resources in information technologies can be applied in this
very critical area.
[ Nanyang Technological University • School of Electrical & Electronic Engineering ]
14
DIVISION OF
POWER
ENGINEERING
CENTRE FOR SMART ENERGY SYSTEMS
Microgrid Energy
Management Systems
MEMS can operate in interconnected or autonomous
modes. In the autonomous mode, an MEMS is disconnected
OBJECTIVE
The objective of this research program is to
design software algorithms and control schemes
that can be used for minimizing the scheduling
cost or maximizing the revenue of Microgrid
Energy Management Systems (MEMS) while
ensuring the secure operation of MEMS.
from the main grid and operates as an isolated power
system. When operated in the interconnected mode, the
MEMS may be connected to the LV (e.g. 400 V in Singapore)
network, which in turn is connected to the upstream MV
(e.g. 6.6 or 22 kV in Singapore) and HV (e.g. 66 kV and
above in Singapore) networks. The control architecture
detailing the relationship between MEMS, Distribution
Management System (DMS) and Energy Management
Highlights of Research Activities
System (EMS) is shown in the accompanying figure.
The restructuring of the electricity supply industry in many
MEMS not only can provide customers’ electricity and
parts of the world has gradually introduced a competitive
thermal needs but can also be operated as a single
electricity market in which generators offer to sell their
aggregated interruptible load to participate in the spinning
generated electricity and consumers bid to buy the
reserve market. Given the attractive pricing of electricity,
electricity. However, active participation by the demand
MEMS can participate in the electricity energy market and
side remains low. Microgrids represent the next evolved
provide reactive power as ancillary services. Other options
stage which will incentivize consumers to participate in
such as enhancing supply reliability of a specific customer,
the electricity market. A microgrid, by definition, is an
reducing emissions and improving power quality of the
integrated energy system consisting of interconnected loads
supply are also possible.
and distributed energy resources (DERs). As an integrated
PSO
system, it can operate in parallel with the grid or in an
MO
intentional islanded mode. To operate such an integrated
system, MEMS are required.
Each MEMS consists of one or several
distributed energy resources (DERs), one or
several price-sensitive loads, interruptible
loads, fixed loads and energy storage devices.
HV Network
EMS
MV Network
DMS
DERs may include diesel generators, micro turbines, fuel cells
LV
for combined heat and power (CHP)/electricity production,
solar photovoltaic (PV), and wind turbines. Price-sensitive loads
MEMS A
MEMS B
...
may be disconnected when electricity price becomes too high.
Within MEMS, demand side bidding (DSB) is supported. This
Network
Loads
DERs
MEMS C
...
Loads
DERs
Loads
means that some of the customer loads may be equipped with
load controllers and customers may bid not to be served if the
Control Architecture of MEMS
price of electricity is high.
[ Nanyang Technological University • School of Electrical & Electronic Engineering ]
DERs
DIVISION OF
POWER
ENGINEERING
Unlike traditional EMS where energy production and
consumption are centrally balanced, renewable energy
resources (RES) such as solar and wind are non-dispatchable
because they lack primary energy movers and cannot
be centrally controlled. Hence they need to be treated
differently depending on weather conditions. DERs usually
have different owners and some of them are required to
produce heat and/or steam for local installations. All these
constraints favor decentralized control for operating DERs.
1.3 Advanced Sensing and
Communication System
1.1 Scheduling and Forecasting
Functions
generation management.
15
The advanced sensing and communication system focuses
on the deployment of MEMS in the existing distribution
network via wireline or wireless communication and
control. The system includes computer software programs
that manage sensing information and perform load and
1.4 Energy Sources and Conversion
The Scheduling and Forecasting functions consist of the
Load Forecasting (LF) function which predicts the halfhourly (or quarter-hourly) fixed and price-sensitive load for
the next 4 to 24 hours. The forecast values are needed for
Various DERs are considered in this project. They usually
have certain output voltage and current. To match the
the execution of Unit Commitment (UC) which determines
actuator’s required voltage and current, power converters
the half-hourly (or quarter-hourly) on/off schedules of DERs
such as DC-DC converters and DC-AC Inverters are used in
and their MW generation for the next 4 to 24 hours. Within
this project. These power converters have the advantages
the UC, the MW dispatch is determined via the Economic
of high power factor, high efficiency, small size, small power
Dispatch function. RES such as solar and wind can increase/
losses, low cost, high reliability and flexibility.
decrease their output due to weather conditions, wind
speed or nightfall. They are inflexible and their output
unpredictable. Uncertainties are observed in both demand
and generation and a probabilistic approach is most suited
for the modeling and prediction of load and generation.
1.2 Network Applications Functions
The Network Applications functions consist of (i) Security
Assessment (SA) which monitors the on-line security
and robustness of MEMS for possible generation and
line outages and (ii) Optimal Power Flow (OPF) which
recommends MW/MVar rescheduling to MEMS if such
The accompanying figure illustrates the proposed
framework of MEMS, in the context of the Singapore
network. Individual DERs within the MEMS are monitored
by system-state sensors through the MEMS server. The
MEMS server obtains energy production and power flow
information from the sensors placed at DERs and LV feeders
respectively. It controls the output of power from each
dispatchable DER through the power converter. With the
MEMS server, the generated power from each individual
DER can be distributed over the electrical grid or stored in
the energy storage for future supply.
outages or unplanned events should occur. The OPF’s
recommendations are implemented via the On-line Tap
This research led by Assoc Prof Gooi HB, So PL and Luo FL
Changers [OLTC] and raise/lower unit setpoints after
aims at analyzing various control schemes and designing
emergency control to shed load and/or to start standby
software algorithms that can predict total customer (fixed
units has stabilized. The two functions work hand in hand to
and variable) loads and perform economic scheduling
ensure that MEMS can survive unpredicted events such as a
of distributed energy resources and security monitoring
sudden disconnection of the MV network.
within MEMS.
[ Nanyang Technological University • School of Electrical & Electronic Engineering ]
16
DIVISION OF
POWER
ENGINEERING
Wind
Photovoltaics
Fuel Cell Energy Storage
Distributed Generation
(DG - Jurong Island)
Communication &
Control Network
Jurong Island
Electrical Load
PC
PC
PC
PC
Electrical Network
Power Flow Sensor
Power Converter
PC
PC
Jurong Island
DG Server
PC
MEMS
Centralized Server
PC
PC
PC
PC
HDB DG
Server
PC
Ayer Rajah
DG Server
PC
Ayer Rajah
Industrial Load
MEMS Framework
[ Nanyang Technological University • School of Electrical & Electronic Engineering ]
DIVISION OF
POWER
ENGINEERING
17
Energy Storage
for Clean Energy Application
Modeling of lithium-ion batteries and their variations such
as iron-phosphate and nano-titanate batteries are being
OBJECTIVE
The objective of this strategic research thrust
is to develop energy storage solutions for the
future energy infrastructure made possible by the
emergence of various clean energy technologies.
done for power quality and UPS applications.
Another competing technology being studied is the solidoxide fuel cell, which requires energy to be converted
to hydrogen first. On a smaller scale, the permeable
membrane fuel cell is being analyzed for automotive
Highlights of Research Activities
applications. These studies are focused on energy
management, electrical characterization and modeling for
The sustainability of energy and environment in the future
power electronic simulations.
depends on four strategic thrusts: the harvesting of clean
energy, the ability to store energy on a large scale, the
Besides the more conventional energy storage media,
smart distribution of energy, and the efficient utilization of
members of the CSES also research into more unusual
energy. Progress
in clean and renewable energy
production such as solar, wind and tidal energy
would be hampered if the ability to store vast
amounts of excess energy is not developed in
tandem. Realizing this challenge, the Centre for Smart
ways to store energy effectively. One of these is the
Energy Systems (CSES) under the direction of its Director
its energy storage capacity does not deteriorate with
Dr Tseng King Jet has been pushing for more externally
time. Suspending the rotating flywheel in a magnetic
funded programs and projects in this area.
novel “mechanical” battery which consists of a highspeed rotating flywheel suspended in a magnetic field.
The faster the flywheel rotates the more energy it stores.
A flywheel typically has a life-span of twenty years and
field reduces the friction, thus improving its efficiency. A
self-levitating flywheel energy storage system has been
A preliminary project to comprehensively review energy
designed and is currently being prototyped.
storage solutions and to chart its technology roadmap
has been commissioned by the global wind turbine
Another area of research is the concept of energy buffer
manufacturing giant Vestas. With the corporate research
in power systems, such as those utilized in wind farms to
agreement recently signed between NTU and Vestas, more
attenuate the generated power fluctuation. An objective
projects in energy storage are in the pipeline.
function is formulated in terms of the dispatch level and
amortized BESS capital cost. From the planning point of
Electrochemical batteries have been the technology of
view, the output power from the wind farm is assumed
choice when it comes to energy storage, though there
to be constant. By optimizing the objective function,
are considerable difficulties when trying to scale up the
the dispatch level is optimized and the BESS capacity in
storage capacity. One of the projects being undertaken by
power-and energy-specifications is appropriately sized.
the CSES is the detailed simulation and analysis of lead-
Such a BESS can accommodate the power imbalance
acid and sodium-sulpfur batteries for large scale battery
during fluctuation of wind speed, thus keeping the output
energy storage systems (BESS) in load-leveling applications.
of the wind farm stable.
[ Nanyang Technological University • School of Electrical & Electronic Engineering ]
18
DIVISION OF
POWER
ENGINEERING
Battery voltage versus SOD at different temperature
4.5
4.3
45ºC
34ºC
23ºC
10ºC
0ºC
-10ºC
-20ºC
45ºC
23ºC
0ºC
-10ºC
-20ºC
Battery Voltage (V)
4.1
3.9
3.7
3.5
3.3
3.1
2.9
2.7
2.5
0.0
0.2
0.4
0.6
0.8
1.0
Self-Levitating Axial-Flux Flywheel
Energy Storage System
1.2
State of Discharge
Accurate Modeling of Lithium-Ion Battery
Intelligent Power Quality
Monitoring and Evaluation
Highlights of Research Activities
OBJECTIVE
Advancement in computer technologies is
changing the way in which the status of a power
system network is being monitored. As networks
become more diverse with new generation,
transmission and distribution equipment that
enable bidirectional power flows, monitoring
systems have to keep up with the increasing
demand for up-to-date information. This
requires new design methodology instead of the
traditional installation and duplication of metering
across the network. This project aims to employ
the wealth of resources in available information
technologies in monitoring and evaluation of
power system quality.
Today’s electrical power infrastructure is designed to
transmit electrical power from bulk generations at remote
locations to urban customers in a unidirectional manner.
This assumption that power always flows in one direction
has served the industry well as it has helped to simplify
many of the control and operational functions. Accordingly,
the handling of power quality (and many other) issues also
takes advantage of this assumption where solutions are
implemented to prevent voltage transients and variations
from affecting sensitive loads, while preventing harmonic
distortions and power fluctuations from deteriorating
system quality. However, this layout is increasingly being
deemed inadequate as new, smaller and often cleaner
[ Nanyang Technological University • School of Electrical & Electronic Engineering ]
DIVISION OF
POWER
ENGINEERING
19
generations are installed electrically close to the customer
coordinating body, typically equipped with centralized data
loads resulting in reverse power flows and change in
storage, must be able to handle this dynamic situation. In
propagation of various power quality phenomena.
addition, it is expected that different makes, models and
The new generations typically use variable energy
sources, thereby presenting themselves as new
causes of voltage fluctuations and variations.
versions of the units will coexist together at any one time,
In addition, the heavy use of power electronics makes them
and upgraded incrementally, in a more manageable and
new sources of harmonic distortions. In such a scenario,
cost effective manner.
thereby requiring the system to be backward compatible.
This would also allow the monitoring system to be improved
these power quality problems are propagating in the
same direction as the active power to the loads, violating
the existing assumption of opposite direction. It is widely
Integrated Environment of
Monitoring Units
accepted that new design methodologies are needed
to ensure that the power quality at the load terminals is
One potential concept to manage the changing
still maintained at all times. Similarly, the design of the
environment of monitoring system is to treat each of
monitoring system also needs to be revised to ensure that it
the units as a separate object with the system taken
continues to measure and keep track of the system quality
as a collection of objects of various functions and of
accurately.
different data types. With sound design, the objects
can be connected and disconnected in a plug and play
Another aspect of the electrical power industry that affects
manner. Resembling the object-oriented programming
the operation and maintenance of the power network is
(OOP) methodology, each entity or object contains the
the divided ownership (and blurred responsibilities) as a
attributes or properties, functions or methods and event
result of deregulation. As new distributed generations are
handlers pertaining to the operation of the particular
added to the network, control and monitoring equipment
entity. As expected, communications are essential so that
often need to be upgraded too. The increasing number of
the control and display of results can be done remotely.
such small generations makes it impractical to handle the
changes in the traditional manner. New designs such as
The above requirements can be easily met by adopting the
“plug-and-play” measurement units would provide more
CORBA (Common Object Request Broker Architecture)
flexibility and are more conducive to the new distributed
technology. Using CORBA, the functional objects and
environment.
the displays are designed in pairs as shown in the
accompanying diagram.
This article describes using several approaches to
support the impending heterogeneous environment of
future monitoring systems. Firstly, new monitoring units
are expected to be added alongside new generation
systems. At the same time, other units may be removed
for maintenance or after the associated generation is
decommissioned. The system architecture must allow these
units to “join” and “leave” on an adhoc basis. The central
[ Nanyang Technological University • School of Electrical & Electronic Engineering ]
20
DIVISION OF
POWER
ENGINEERING
Common Object Request Broker
Architecture for PQ Monitoring
DAQ Card
overall performance and also to pinpoint the location of
the disturbance source. Utilising the CORBA technology,
corresponding analysis and display objects are created for
Server
each of the data-gathering server objects.
Power Quality Analysis Objects
DAQ Card
Object
Harmonic
Analysis
Object
Harmonic
Analysis
Object
There are many technical strengths provided by this
design. Firstly, CORBA objects are remote objects with
inbuilt communications over the Internet. This avoids the
painstaking process of developing a communication link
CORBA Middleware
(over Intranet/Internet)
between the objects, especially the server objects and their
corresponding analysis objects. In addition, it is supported
by many vendors and can be programmed to work on
different operating systems. As users may use different
DAQ Card
Setup GUI
Harmonic
Analysis
GUI
Voltage Sag
Analysis
GUI
operation systems, the display and analysis units are best
Client
programmed in Java, making these functions to be platform
independent. On the other hand, the server objects should
In this design, the monitoring units are considered as
be designed using C or C++ since there is a need to interact
servers where the measurement data originates. In power
with the data acquisition hardware. With the DAQ software
quality monitoring, they are made up of the DAQ (data
drivers typically given for C or C++ codes, this would very
acquisition) object and the respective processing objects.
much simplify the development of these objects.
The former interfaces to the DAQ hardware and is
responsible for collecting the raw samples and converting
Power Quality State Estimation
them into the appropriate format for processing. The
number of processing objects depends on the number
Traditionally, power quality information is only available
and type of power quality phenomena to be monitored.
at points where there is a monitoring unit. Those
They are generally divided into steady-state and transient
locations without monitoring units are deemed unknown
phenomena, with the first group recording the trend of
in terms of their quality status or performance. At times
some averaged information at regular intervals while the
such as those involving transient disturbances, the power
second group saves the raw samples in an ad hoc manner
system is modeled on a computer and simulations are
whenever an event occurs.
undertaken with the assumption of the cause and its
location. The simulated waveform is then compared to
Through the CORBA layer, these server objects are
the measurement data. Once matched, the cause and
connected to their corresponding remote entities where
location are taken as the reason behind the disturbance.
the data is further used or displayed. This could include
This is a laborious process as there is much guess work
storage objects where the processed and captured
and it relies heavily on human experiences. An alternative
information are stored for future reference and use. In
to such a process is using an estimation technique to
addition, data collected from multiple units spreading
derive the status at unmonitored points. This is termed
over a power network may be used to evaluate the system
generally as power quality state estimation.
[ Nanyang Technological University • School of Electrical & Electronic Engineering ]
DIVISION OF
POWER
ENGINEERING
21
State estimation has been used in power systems for many
solution in these under-determined cases. The method
years. The basic objective is to formulate all the unknown
can also easily identify the solvable portions of the results
states in the following general measurement equation,
from those that are unsolvable. One promising use of the
SVD method is in measurement placement, which helps
z^ = [h] x^ + e^
to decide where in the network to install the monitoring
where
unit and what quantities to measure. This is of particular
importance for deploying the limited monitoring units for
^
z
is vector of measurements
^
x
is vector of unknown states
e
is vector of measurement errors, and
^
[h] is termed as the measurement matrix.
power quality.
The above formulation is suitable for estimating steadystate phenomena such as fundamental frequency power
flow and harmonic distortions. However, many power
There are many techniques for solving the above equation,
quality phenomena are transient and the network is also
depending on the situation of the measurements with
dynamic, making it necessary to employ methods capable
respect to the unknown states.
of tracking time-varying information. One such well-known
method is the Kalman filtering, shown on the accompanying
Traditionally, state estimation is used in power systems
diagram, for use in estimating the RMS voltage magnitude
to predict the status at the fundamental frequency
when an upstream fault causes a voltage dip. Prof. S Chen
only. In such a scenario, the power network is equipped
and his associates are actively pursuing this area of work.
with many meters measuring the various fundamental
frequency parameters in large quantities, giving an overdetermined situation. Estimations are therefore applied
to sift out bad data as an accurate status of the network
at the fundamental frequency is critical to the stability of
the system. However, in power quality monitoring, the
measurement units are costly and therefore only a very
limited number of units is installed, typically at strategic
locations according to engineers’ experiences. This
Kalman filtering method for dynamic
estimation of power system states
results in an under-determined situation, which is much
more difficult to solve.
With sound engineering judgements and available
supplementary information, the measurement equation can
be transformed into a fully determined one by reducing
the number of unknown variables to solve. This, however,
can become erroneous if prior information is not accurate.
Alternatively, a well-known method called the SVD (singular
value decomposition) can be used to provide partial
[ Nanyang Technological University • School of Electrical & Electronic Engineering ]
22
DIVISION OF
POWER
ENGINEERING
Staff
Members
1st Row (From left to right)
Head of Division
Lalit Goel, Professor
Professor
Choi San Shing
2nd Row (From left to left)
Associate Professors
Chen Shiun
Choo Fook Hoong
Gooi Hoay Beng
Mohammed Hamidul Haque
3rd Row (From left to right)
Associate Professors
Lie Tek Tjing
Luo Fang Lin
Ali Iftekhar Maswood
[ Nanyang Technological University • School of Electrical & Electronic Engineering ]
DIVISION OF
POWER
ENGINEERING
23
Staff
Members
1st Row (From right to left)
Associate Professors
Govinda Bol Shrestha
Program Director,
MSc (Power Engineering)
So Ping Lam
Tan Yoke Lin
Tseng King Jet
2nd Row (From right to left)
Associate Professors
Don Mahinda Vilathgamuwa
Wang Peng
Wang Youyi
3rd Row (From right to left)
Assistant Professors
Loh Poh Chiang, Andrew
R.M.A. Sumedha Rajakaruna
Sng Eng Kian, Kenneth
Zhang Daming
4th Row (From right to left)
Associate Professorial Fellows
Chan Tat Wai, David
Lee Tat Man
[ Nanyang Technological University • School of Electrical & Electronic Engineering ]
24
DIVISION OF
POWER
ENGINEERING
Research
Interest
POWER ENGINEERING
1
Ali Iftekhar Maswood
Associate Professor
Advanced switching techniques, Unity PF converter, Harmonics and Power
quality.
2
Chan Tat Wai, David
Associate Professorial
Fellow
Power system protection,Power system simulation and analysis.
3
Chen Shiun
Associate Professor
Power quality, PQ Instrumentation, Transient simulation, Harmonic/
interharmonic analysis, PLC.
4
Choi San Shing
Professor
Control of networks, Power quality, FACTS, Custom Power, Distributed
generation, Energy storage systems.
5
Choo Fook Hoong
Associate Professor
Robotics control, Electric vehicles, Power electronics and drives.
6
Don Mahinda Vilathgamuwa
Associate Professor
Modelling and control of power electronic converters, Electric Drives,
Distributed Generation.
7
Gooi Hoay Beng
Associate Professor
Unit commitment, Power market, Power system operation, Economics and
computation.
8
Govinda Bol Shrestha
Associate Professor
Power markets, Power system operation and planning,
Alternate/Renewable energy.
9
Lalit Kumar Goel
Professor
Power system reliability and Deregulated power markets.
10
Lee Tat Man
Associate Professorial
Fellow
Power-frequency electro-magnetic interference, Power system
disturbances and harmonics.
11
Lie Tek Tjing
Associate Professor
Power system control and Stability. Deregulated power markets.
12
Loh Poh Chiang, Andrew
Assistant Professor
PWM/Control techniques, Converter design, Motor drives, Power quality,
Renewable Technology.
13
Luo Fang Lin
Associate Professor
Analogue and digitally-controlled power electronics, Electrical machine
drives systems.
14
Mohammed Hamidul Haque
Associate Professor
Steady state and dynamic analyses of power systems, FACTS devices.
15
R M A Sumedha Rajakaruna
Assistant Professor
Distributed generation, Energy storage, Induction generators, Power
electronic converters.
16
Sng Eng Kian, Kenneth
Assistant Professor
Reliability in converters, Passives optimization, LTCC applications in power
electronics.
17
So Ping Lam
Associate Professor
Power system stability and control, FACTS, Power quality, Power line
communications.
18
Tan Yoke Lin
Associate Professor
Resistivity measurement, Earthing, High voltage engineering, System
planning, design & control, FACTS.
19
Tseng King Jet
Associate Professor
Power electronics, Semiconductor devices, Electrical machines, Electrical
energy systems, Electromagnetics.
20
Wang Peng
Associate Professor
Power system reliability and security analysis, Power market operation and
pricing, Time-of-use energy metering system.
21
Wang Youyi
Associate Professor
Robust control, Nonlinear control, Power system transient stability
enhancement, Voltage stability, FACTS, Data storage systems, Microdrive
systems.
22
Zhang Daming
Assistant Professor
Computational magnetics and EMI/EMC in power system.
[ Nanyang Technological University • School of Electrical & Electronic Engineering ]
DIVISION OF
POWER
ENGINEERING
25
PhD & MEng
Degrees Awarded in 2007
PhD - POWER ENGINEERING
S/NO.
PROJECT TITLE
STUDENT
SUPERVISOR/CO-SUPERVISOR
1
Optimal generation scheduling with demand-side bidding
Bai Jie
Gooi Hoay Beng
2
Aspects of generation planning in competitive electricity markets
Bikal Kumar Pokharel
Govinda Bol Shrestha
3
Fault control for paralleled DC-DC converters and novel common mode current
based communication strategy for decentralized control of paralleled inverters
Cheng Yeong Jia
Sng Eng Kian, Kenneth
4
Nodal reliability and nodal price in deregulated power markets
Ding Yi
Wang Peng
5
Advanced nonlinear control of complex power systems
Li Hongyin
Wang Youyi
6
Investigation of hybrid multilevel dc/ac inverters
Liu Yu
Luo Fang Lin
7
Reliability evaluation of deregulated power systems using monte carlo simulation
Viswanath Padmavati
Aparna
Lalit Kumar Goel
Wang Peng
8
Flexible control of transmission and distribution networks through applications of
power electronics technology
Wang Qi
Choi San Shing
9
Power quality enhancement of isolated power systems through series
compensation
Wang Tongxun
Choi San Shing
10
Investigations into new concept of inductively-driven centrifugal blood pumps
Wu Peng
Tseng King Jet
11
Congestion management in restructured power systems
Xiao Yu
Wang Peng
12
On the control characteristics of power electronic converters supplied by
ultra-capacitor energy storages
Yogama Ralalage
Laksumana
Jayawickrama
R M A Sumedha
Rajakaruna
13
Study of energy storage system based on axial-flux flywheel-rotor electrical
machines
Zhang Chi
Tseng King Jet
14
Global control design and its applications to power systems
Zhang Guohua
Wang Youyi
MEng - POWER ENGINEERING
S/NO.
PROJECT TITLE
1
Reliability constrained multi-commodities dispatch in restructured power system
Liu Yong
Wang Peng
2
Static and dynamic voltage stability analysis
Pothula Uma
Maheswararao
Mohammed Hamidul
Haque
STUDENT
SUPERVISOR/CO-SUPERVISOR
Selected
Publication in 2007
List of Selected Publications - POWER ENGINEERING
1
A. I. Maswood and F. Liu, "A Unity Power Factor Converter Using the Synchronous Reference Frame Based Hysteresis Current Control",
IEEE Trans. on Industry Applications, vol.43, no. 2, March/April 2007.
2
A. I. Maswood and F. Liu, "A Near Unity PF Rectifier-Inverter Structure Operation Under Non-Ideal Conditions", accepted, IEEE Trans.
on Power Electronics, July 2007.
3
A. I. Maswood and Z. K. Yong, "Switching Loss Reduction Through Digital Burst Technique in a TV Power Supply", accepted, IEEE
Industrial Electronics Magazine, 2007.
[ Nanyang Technological University • School of Electrical & Electronic Engineering ]
26
DIVISION OF
POWER
ENGINEERING
Selected
Publication in 2007
List of Selected Publications - POWER ENGINEERING
4
J. Wang, S. Chen and T. T. Lie, "A systematic approach for evaluating economic impact of voltage dips", Electric Power Systems
Research, vol. 77, no. 2, pp. 145 - 154, February 2007.
5
S. Chen and H. Y. Zhu, "Wavelet Transform for Processing Power Quality Disturbances", EURASIP Journal on Advances in Signal Processing,
Vol. 2007, Special issue on Emerging Signal Processing Techniques for Power Quality Applications, Article ID 47695, 20 pp, 2007.
6
H. Y. Zhu and S. Chen, "Identification of Capacitor Switching Transients with Consideration of Uncertain System and Component
Parameters", accepted, IEEE Trans. On Power Delivery, 2007.
7
T. X. Wang, S. S. Choi, E. K. K. Sng, "Series Compensation Method to Mitigate Harmonics and Voltage Sags/Swells", IET Proc.
Generation, Transmission and Distribution, vol. 1, no. 1, pp. 96 - 103, January 2007.
8
T. X. Wang and S. S. Choi, "Enhancement of Voltage Quality in Isolated Power Systems", IEEE Trans. on Power Delivery, vol. 22, no. 2,
pp. 1160 - 1168, April 2007.
9
Y. H. Li, S. Rajakaruna and S. S. Choi, "Control of a Solid Oxide Fuel Cell Power Plant in a Grid-Connected System", IEEE Trans. on
Energy Conversion, vol. 22, no. 2, pp. 405 - 413, June 2007.
10
C. J. Gajanayake, D. M. Vilathgamuwa, P. C. Loh, "Development of comprehensive model and multi-loop controller for Z-source
inverter", IEEE Trans. on Industrial Electronics, vol. 54, no. 4, pp. 2352 - 2359, August 2007.
11
Y. W. Li, D. M. Vilathgamuwa and P. C. Loh , "Robust Control Scheme for a Microgrid with PFC Capacitor Connected", IEEE Trans. on
Industry Applications, vol. 43, no. 5, pp. 1172 - 1182, September - October 2007.
12
Y. W. Li, D. M. Vilathgamuwa, P. C. Loh, F. Blaabjerg, "A Dual-Functional Medium Voltage Level DVR to Limit Downstream Fault
Currents", IEEE Trans. on Power Electronics, vol. 22, no. 4, pp. 1330 - 1340, July 2007.
13
X. Han and H. B. Gooi, "Effective Economic Dispatch Model and Algorithm", International Journal of Electrical Power & Energy Systems,
vol. 29, no. 2, pp. 113 - 120, February 2007.
14
B Venkatesh, T Jamtsho and H.B. Gooi, "Unit Commitment – A Fuzzy Mixed Integer Linear Programming Solution", IET Proc.
Generation, Transmission and Distribution, vol. 1, no. 5, pp. 836 - 846, September 2007.
15
J. Bai, H.B. Gooi, L. Xia, "Probabilistic Reserve Schedule with Demand-side Participation", accepted, Electric Power Components and Systems, 2007.
16
G. B. Shrestha, P. A. J. Fonseka, "Optimal Transmission Expansion under Different Market Structures", IET Proc. Generation,
Transmission and Distribution, vol. 1, no. 5, pp. 697 - 706, September 2007.
17
G. B. Shrestha, B. K. Pokharel, T. T. Lie and S. E. Fleten, "Price Based Unit Commitment for Bidding under Price Uncertainty", IET Proc.
Generation, Transmission and Distribution, vol. 1, no. 4, pp. 663 - 669, July 2007.
18
G. B. Shrestha, B. K. Pokharel, T. T. Lie and S.E. Fleten, "Management of Price Uncertainty in Short-Term Generation Planning",
accepted, IET Proc. Generation, Transmission and Distribution, 2007.
19
L. Goel, P. A. Viswanath, P. Wang, "Reliability evaluation of hybrid power markets based on multiple transaction matrix and optimal
transaction curtailment", IET Proc. Generation, Transmission and Distribution, vol. 1, no. 1, pp. 65 - 71, January 2007.
20
L. Goel, P. A. Viswanath, P. Wang, "A Framework to Implement Supply and Demand Side Contingency Management in Reliability
Assessment of Restructured Power Systems", IEEE Trans. on Power Systems, vol. 22, no. 1, pp. 205 - 212, February 2007.
21
Y. Ding, P. Wang, L. Goel, R. Billinton and R. Karki, "Reliability Assessment of Restructured Power Systems Using Reliability Network Equivalent
and Pseudo-sequential Simulation Techniques", Electric Power Systems Research Journal, vol. 77, no. 12, pp. 1665 - 1671, October 2007.
22
S. Y. Ruan, G. J. Li, L. Peng, Y. Z. Sun, and T. T. Lie, "A Nonlinear Control for Enhancing HVDC Light Transmission System Stability",
Electrical Power and Energy System, vol. 27, pp. 565 - 570, 2007.
23
G. J. Li, X. P. Zhang, S. S. Choi, T. T. Lie, and Y. Z. Sun, "A Control Strategy for Dynamic Voltage Restorers to Achieve Minimum Power
Injection and without Introducing Sudden Phase Shift", IET Proc. Generation, Transmission and Distribution, vol. 1, no. 5, pp. 847 - 853, 2007.
24
P. C. Loh, S. W. Lim, F. Gao & F. Blaabjerg, "Three-Level Z-Source Inverters using a Single LC Impedance Network", IEEE Trans. on Power
Electronics, vol. 22, pp. 706 - 711, March 2007.
[ Nanyang Technological University • School of Electrical & Electronic Engineering ]
DIVISION OF
POWER
ENGINEERING
27
Selected
Publication in 2007
List of Selected Publications - POWER ENGINEERING
25
F. Gao, P. C. Loh, R. Teodorescu, F. Blaabjerg & D. M. Vilathgamuwa, "Topological Design and Modulation Strategy for Buck-Boost
Three-Level Inverters", accepted, IEEE Trans. on Power Electronics, 2007.
26
F. Gao, P. C. Loh, R. Teodorescu & F. Blaabjerg, "Diode-Assisted Buck-Boost Voltage Source Inverters", accepted, IEEE Trans. on Power Electronics, 2007.
27
M. Zhu and F. L. Luo, "Graphical Analytical Method for Power DC/DC Converters: Averaging Binary Tree Structure Representation", IEEE
Trans. on Power Electronics, vol. 22, no. 2, pp. 701 - 705, March 2007.
28
F. L. Luo and H. Ye, "Small Signal Analysis of Energy Factor and Mathematical Modeling for Power DC/DC Converters", IEEE Trans. on
Power Electronics, vol. 22, no. 1, pp. 69 - 79, January 2007.
29
F. L. Luo and H. Ye, "Investigation of DC-Modulated Single-Stage Power Factor Correction AC/AC Converters", (Invited paper) Trans. of
China Electrotechnical Society, vol. 22, no. 5, pp. 18 - 32, May 2007.
30
M.H. Haque, "Best Location of SVC to Improve First Swing Stability Limit of a Power System", Electric Power Systems Research, vol. 77,
no. 10, pp. 1402 - 1409, 2007.
31
S. S. Choi, T. X. Wang, E. K. K. Sng, "Series Compensation Method to Mitigate Harmonics and Voltage Sags/Swells", IET Proc.
Generation, Transmission and Distribution, vol. 1, no. 1, pp. 96 - 103, January 2007.
32
K. Y. See, P. L. So, and A. Kamarul, "Feasibility study of adding a common-mode choke in PLC modem for EMI suppression", IEEE Trans.
on Power Delivery, vol. 22, no. 4, pp. 2136 - 2141, October 2007.
33
T. S. Pang, P. L. So, K. Y. See, and A. Kamarul, "Modeling and analysis of common-mode current propagation in broadband power line
communication networks", accepted, IEEE Trans on Power Delivery, 2007.
34
Y. H. Ma, P. L. So, and E. Gunawan, "Comparison of CDMA and OFDM systems for broadband power line communications", accepted,
IEEE Trans. on Power Delivery, 2007.
35
H. Liu, Y. Sun, P. Wang, L. Cheng, and L. Goel, "A Novel State Selection Technique for Power System Reliability Evaluation", accepted,
Electric Power Systems Research, 2007.
36
Yi Ding, P. Wang, L. Goel, R. Billinton and R. Karki, "Reliability Assessment of Restructured Power Systems Using Reliability Network
Equivalent and Pseudo-sequential Simulation Techniques", Electric Power Systems Research, vol. 77, no. 12, pp. 1665 - 1671, October 2007.
37
P. Wang, W. Li, "Reliability Evaluation of Distribution Systems Considering Optimal Restoration Sequence and Variable Restoration
Times", accepted, IET Proc. Generation, Transmission and Distribution, 2007.
38
D. Wu, G. Guo and Y. Wang, "Reset Integral-Derivative Control for HDD Servo Systems", IEEE Trans. on Control System Technology, vol.
15, no. 1, pp. 1 - 7, 2007.
39
Y. Li, V. Vnkataramanan, G. Guo and Y. Wang, "Dynamic Nonlinear Control for Fast Seek-settling Performance in Hard Disk Drives", IEEE
Trans. on Industrial Electronics, vol. 54, pp. 951 - 962, 2007.
40
Y.Q. Guo, Y. Wang, L. Xie and J. Zheng, “Stability Analysis and Design of Reset Systems: Theory and an Application”, accepted, Automatica, 2007
41
R. F. Huang, D.M. Zhang, "Experimentally Verified Mn-Zn ferrites’ Intrinsic Complex Permittivity and Permeability Tracing Technique
Using Two Rectangular-shaped Ferrite Capacitors", IEEE Trans. On Magnetics, vol. 43, no. 3, pp. 974 - 981, March 2007.
42
D. M. Zhang, "Permeability Enhancement by Induced Displacement Current in Magnetic Material with High Permittivity", Journal of
Magnetism and Magnetic Materials, vol. 313, no. 1, pp. 47 - 51, June 2007.
43
R. F. Huang, D. M. Zhang, "Using a Single Toroidal Sample to Determine the Intrinsic Complex Permeability and Permittivity of Mn-Zn
Ferrites", IEEE Trans. on Magnetics, vol. 43, no. 10, pp. 3807 - 3815, October 2007.
44
C. E. Chong and Y. L. Tan, "A New Geometric Factor for In Situ Resistivity Measurement using Four Slender Cylindrical Electrodes",
accepted, IEEE Trans. on Biomedical Engineering, May 2007.
45
Y. L. Tan and C. E. Chong, "Resistivity Measurement of a Small-Volume Sample using Two Planar Disc Electrodes and a New Geometric
Factor", accepted, IEEE Sensors Journal: Special issue on Sensors for Microfluidic Analysis Systems, January 2007.
46
C. Zhang, and K.J. Tseng, "A Novel Flywheel Energy Storage System with Partially-Self-Bearing Flywheel-Rotor", IEEE Trans. on Energy
Conversion. vol. 22, no. 2, pp. 477 - 487, June 2007.
[ Nanyang Technological University • School of Electrical & Electronic Engineering ]