Advanced Power Technologies
Table of Contents
- Distribution System Reliability Analysis
and Design, Phase III - Richard Christie and S.S. Venkata
- Visualization of Large Scale Power
Systems - Richard Christie
- Operator Centered Emergency Control of
Power Systems - Richard Christie
- Mechanisms and Controllability Using the
Theory of Foliations - Chen-Ching Liu
- Advanced Alarm Processing (AAP) in an
On-Line Control Center Environment - Chen-Ching Liu
- On-Line Intelligent Alarm Processing (IAA)
Using Sequence-of-Events Recorder (SER) Information - Chen-Ching Liu
- Optimal Strategies for Electric Energy
Contract Decision Making - Chen-Ching Liu, Jacques Lawarree, Norris
Peterson and Robert Dahlgren
- Data Analysis for Power Quality Assessment
- Chen-Ching Liu and Gerald T. Heydt
- Device Modeling for Power Electronic Circuit
Simulation - Peter O. Lauritzen
- Adaptive Sequential Controller -
Mohamed El-Sharkawi
- Short Winding Assessment Technique
(SWAT) - Mohamed El-Sharkawi and Robert J. Marks
- Computational Intelligent Applications
to Transmission and Distribution - Mohamed El-Sharkawi and Robert Marks
- Dynamic Security Assessment (DSA)
- Mohamed El-Sharkawi, Robert Marks and Russell Reed
Electric
Energy is the backbone of our industrial productivity and, consequently,
our economic health since it is a significant energy source for a broad
spectrum of industries. The 1965 electricity blackout in New York City,
followed by the oil embargo of the 1970s, motivated electric utilities
to take a long, hard look at the way they generate, transmit and distribute
this important resource. The challenge of delivering a reliable electric
supply at minimum cost has been intensified by the pressures of environmental
and productivity concerns, and more recently, the deregulation of generation
and open transmission access. Simultaneously, electric power consuming
industries have been faced with the same productivity and environmental
challenges.
The research group on Advanced Power Technologies conducts state-of-the-art
research to meet future needs in power systems and power electronics. The
primary impetus for the research projects undertaken stems from the technological
innovations and developments that have taken place in the last two decades
in the areas of computers, communications, control and materials technology.
The quality of this research program is in the top five in the country.
The Advanced Power Technologies Group, consisting of seven faculty members,
has been developing state-of-the-art techniques in the following five major
areas:
Distribution system planning and operation: The advent of
Geographic Information Systems and other technological developments have
opened avenues for automating the planning and operation of distribution
systems.
Intelligent systems applications to power systems: The emphasis
is on the investigation of modern methods such as expert systems, neural
networks, intelligent decision support systems, and evolutionary algorithms
for a host of power system problems.
Industrial power electronic applications: The design, development,
modeling, simulation, and field testing of custom power devices such as
Adaptive Var Compensators has been underway. In addition, research on better
methods for solid-state control of motors and other industrial applications
are being investigated.
Power electronic modeling and simulation: Detailed modeling of
the latest power electronic devices such as diodes, thyristors, MOSFETs,
IGBTs and MCTs, in conjunction with development of improved forms of these
devices, is the thrust of this research specialty.
Power system planning and operation: The focus in this area has
been in the use of newer visualization and mathematical techniques and
theories in economics to improve the planning and performance of power
systems.
Electric Energy Program at UW during the Period of January 1995 -
January 1997
Education
2 Ph.D. completed per year
2.5 M.S. completed per year
16 B.S. completed per year
Research
6 Government sponsored research projects totalling approximately $331,000
per year
11 Industry sponsored research projects totally approximately $653,000
per year
7 Technical papers published in technical conference proceedings per year
Number of Professional Societies/Conferences/Journals Served by EEIC
Faculty:
1 Governing Board of IEEE Societies
2 International conference steering committees
8 Technical journal editorial boards
26 IEEE working groups and task forces
1 IEEE Seattle Section
Summary details on each of these projects is provided in this chapter.
Further details on the Group's research activities are presented in the
Electric Energy Industrial Consortium's Brochure.
Summary details on each of these projects is provided in this chapter.
Further details on the Group's research activities are presented in the
Electric Energy Industrial Consortium's Annual Report.
APT ADVANCED POWER
TECHNOLOGIES
Arizona State University (ASU), Iowa State University (ISU), University
of Washington (UW), and Virginia Polytechnic Institute (VPI) and State
University, are forming a multi-institutional engineering research team
for advanced research and educational innovation in Electric Power Engineering.
We envision that advanced technology is a key factor to achieve a high
level of efficiency and meet the rapidly increasing customer needs in energy
and power production, control, transmission, distribution and utilization
in the next decades. The Advanced Power Technologies (APT) collaboration
is aimed at becoming a world leader in (1) Development of advanced and
innovative technologies for high quality, performance and efficiency in
electric energy systems of the future, (2) Multi-dimensional technological
innovation with associated technologies in information, communication,
sensors, monitoring, nondestructive testing, and advanced control, (3)
Innovation of power engineering education to develop future engineers with
the leadership and engineering skills to meet the challenges in a broad
context of the industry and society and, (4) Development of a close partnership
with the power industry in technology transfer and educational innovation.
The coordinators of the APT team are Chen-Ching Liu, University of Washington;
Gerald T. Heydt, Arizona State University; Vijay Vittal, Iowa State University;
and Arun G. Phadke, Virginia Tech.
Distribution System Reliability Analysis and
Design, Phase III
Advanced Power Technologies (APT) Laboratory
Principal Investigators: Richard D. Christie and S. S. (Mani)
Venkata (Iowa State University)
Sponsor: Snohomish Public Utilities District No. 1
Abstract: The reliability of current distribution systems is
hard to quantify from the customer's point of view. Further, the reliability
evaluation methods currently in use consider only sustained outages, while
customers regard momentary outages and power quality problems (voltage
sags, spikes, harmonics, etc.) as indications of unreliable service. Lastly,
the ability to translate from reliability to dollars when making design
decisions for distribution systems is presently very poorly developed.
The objective of this project is to address these problems by proposing
new ways of measuring reliability that take into account the power quality
and economic aspects, and to build a computer program capable of predicting
the expected reliability of any given distribution system design. Building
on a successful implementation of reliability assessment using Hierarchical
Modeling, further extended by a Monte Carlo modeling of windstorm related
outages, the current phase of the project includes integration of switch
placement for reliability, optimal reliability-based tree trimming scheduling,
and inclusion of loading limits in post-fault switching sequences probability
of successful switching.
References:
R.E. Brown, S. Gupta, R.D. Christie, S.S. Venkata, and R. Fletcher,
"Automated Primary Distribution System Design: Reliability and Cost
Optimization," Presented at the IEEE T&D Conference, Los Angeles,
CA, September 1996. To appear in IEEE Transactions.
R.E. Brown, S. Gupta, R.D. Christie, S.S. Venkata, R. Fletcher, "Distribution
System Reliability Assessment: Momentary Interruptions and Storms,"
Presented at the IEEE PES Summer Meeting, Denver, Colorado, July, 1996.
To appear in IEEE Transactions.
R.E. Brown, S. Gupta, R.D. Christie, S.S. Venkata and R. Fletcher, "Distribution
System Reliability Assessment Using Hierarchical Markov Modeling,"
IEEE Transactions on Power Delivery, Vol. 11, No. 4, October 1996,
pp. 1929-34.
Visualization of Large Scale Power Systems
Advanced Power Technologies (APT) Laboratory
Principal Investigator: Richard D. Christie
Sponsor: Tokyo Electric Power Company
Abstract: A carefully selected subset of scientific visualization
techniques has been successful in communicating power system operating
state information in graphical form for systems as large as 300 buses.
However, real power systems are an order of magnitude larger. For systems
of this size, the resolution of available display real estate causes a
breakdown in the readability of previous visualization techniques. In this
work, a color scale for voltage representation based on the concept of
"kansei" engineering (engineering based on the user's perception
rather than abstract logic) has been developed, tested and shown to be
somewhat superior to the previous technique.
References:
H. Mitsui and R.D. Christie, "Visualization of Large Scale Power
Systems," to appear in the July, 1997 IEEE Computers and Power.
Operator Centered Emergency Control of Power
Systems
Advanced Power Technologies (APT) Laboratory
Principal Investigator: Richard D. Christie
Sponsor: National Science Foundation and Cegelec ESCA Corp.
Abstract: Most power system analytical tools are designed around
their computational algorithm. It is something of a miracle that the algorithm
can compute solutions to large and difficult power system analysis problems.
When computation was slow and expensive, the relatively few results were
valuable no matter what form they took. However, as computation becomes
ever faster and cheaper, the ability to compute these problems in real
time has led to a desire to use analytical tools on line. The most severe
on line test is emergency control, where a computer program tries to recommend
corrective action to an operator before the power system blacks out. While
the basic ability to arrive at some form of solution for these problems
in a timely way has existed for some time, such tools are simply not used
by power system operators. This research is an attempt to determine the
reasons why the tools are not used, and to address them. The working theory
is that the tools are not used because they are centered around the demands
of their algorithms rather than the needs of the operator. By building
tools centered on operator needs, more useable and therefore more useful
on line tools should result.
The current work has built an emergency control process capable of utilizing
a number of heterogeneous corrective action tools (CATS) (programs that
can recommend one type of corrective action), with the problem to be fixed
and the action to fix it selected using fuzzy sets. The approach follows
the operator-centered model of "one problem at a time, one control
at a time", and includes consideration of how long it takes to compute
a corrective action and to implement it in its decision making process.
References:
R. Khare and R.D. Christie, "Prioritizing Overload and Voltage
Problems With Fuzzy Sets," Presented at the IEEE PES Summer Meeting,
Denver, Colorado, July, 1996. To appear in IEEE Transactions.
R. Khare and R.D. Christie, "On Designing a Better Operator Assistant
for Emergency Control in Power Systems," Proceedings of the
1996 International Symposium on Intelligent System Application to Power
Systems (ISAPS'96), Orlando, FL, January 28-February 2, 1996.
R. Khare and R.D. Christie, "Towards an Ideal Operator's Assistant:
Development of a Framework," Proceedings of the IEEE International
Conference on Systems, Man and Cybernetics, Vancouver, BC, October
22-25, 1995.
R.D. Christie, "Towards a Higher Level of User Interaction in the
Energy Management Task," Proceedings of the 1994 IEEE International
Conference on Systems, Man and Cybernetics, San Antonio, TX, October,
1994.
Mechanisms and Controllability Using the Theory of
Foliations
Principal Investigator: Chen-Ching Liu
Sponsor: National Science Foundation
Abstract: In this research, we have developed a new theory for
the complete controllability of power systems. Within a complete controllability
region, the power system can be steered from a state to any other state
with the available controls. We analyzed complete controllability based
on N-bus nonlinear, dynamic power system models. The major results are
(1) local controllability criteria, (2) construction of complete controllability
region for unbounded controls using the foliation theory, (3) properties
of the complete controllability region, (4) characterization of the complete
controllability region for bounded controls, and (5) computation of the
complete controllability regions for simple power system models.
Future work in this research includes the development of techniques
for decomposition of the nonlinear dynamic mechanisms and handling of uncertainties
for controllability in a less-regulated power industry environment.
Figure 1. An n-bus power
system model.
Figure 2. A complete controllability region with bounded controls.
Advanced Alarm Processing (AAP) in an On-Line
Control Center Environment
Principal Investigator: Chen-Ching Liu
Sponsors: Electric Power Research Institute and Puget Sound Power
and Light Co.
Abstract: An Advanced Alarm Processor (AAP) has been developed
in this research project. The AAP is a model-based reasoning system that
incorporates transformers, communication systems, and the power network
in its model base. A unique feature of the AAP is a power flow relation
model that provides knowledge on the relations linking network variables
(e.g., voltages and power flows) with the status changes. The AAP prototype
was demonstrated at the EPRI Workshop on Advanced Alarm Processing organized
by the University of Washington.
Future work includes the development of a power system protection module
that can be used to analyze alarms resulting from operations of the protective
devices. A methodology for integration of the AAP modules will be developed.
On-Line Intelligent Alarm Processing (IAA) Using
Sequence-of-Events Recorder (SER) Information
Principal Investigator: Chen-Ching Liu
Sponsor: Automation Research Center, ENEL, Italy
Abstract: The ability to locate faults or malfunctioning devices
depend on the availability of data and information. In a typical energy
management system in the U.S., relay or SER information is not available
on-line. As a result, the fault diagnosis capability is quite limited.
Relay operations can help identify the power system components that may
be faulted. To achieve pinpoint accuracy, however, the SER information
with a precision level within milli seconds is essential. In this project,
we have selected the SER information that can be used to pinpoint the fault
location(s) and malfunctioning device(s). This logic-based system is implemented
in an object-oriented software environment.
The IAA prototype resulting from the Phase I research has been demonstrated
at the National Control Center of Italy in Rome. In Phase II, the tasks
to be performed include network status processing, SER data preprocessing,
thorough testing and functionality enhancement, computational performance
enhancement, and development of the ability to handles multiple hypotheses.
Optimal Strategies for Electric Energy Contract
Decision Making
Principal Investigators: Chen-Ching Liu, Jacques Lawarree (Economics),
Norris Peterson and Robert Dahlgren (Celegec ESCA).
Sponsors: National Science Foundation GOALI Program and Celegec
ESCA.
Abstract: This research deals with two important aspects in the
emerging industry environment: power engineering and economics.
From a power engineering point of view, a new challenge is to maintain
the reliability of the power networks given higher levels of uncertainties.
Traditionally, generation units are owned and scheduled by the utilities.
However, in the emerging environment, the available generation depend primarily
on the contracts established by various purchasing-selling parties. Since
a high reliability level has to be maintained for the power systems, new
techniques for operation and decision making will be desirable. Engineering
constraints on the power systems such as available transfer capabilities
have to be met as energy transactions are implemented. The proposed research
incorporates power system engineering constraints into a contract decision
making method.
Economics is an important consideration in contract decision making.
The new electric energy market involves multiple players, each performing
one of more functions such as generation, transmission, distribution, brokering
and marketing. Each player tries to optimize his/her own strategy given
the available information. In this proposal, the methods of Markov Decision
Process and game theory are proposed. The Markov Decision Process provides
a systematic algorithm for computation of the optimal policy that maximizes
the expected reward over a planning horizon. The approach takes uncertainties
into account. The other method proposed in this research uses a game theoretic
approach that includes players' models. Critical economic issues such as
contract terms and collusion will be investigated in the proposed research.
Data Analysis for Power Quality Assessment
Principal Investigators: Chen-Ching Liu and Gerald T. Heydt (EE,
Arizona State University)
Sponsor: Pacific Gas and Electric Co., San Francisco, CA.
Abstract: Power quality is an important issue to power companies
and their customers. Typical power quality problems include momentary voltage
sags and outages. They are usually the results of a fault somewhere in
the subtransmission or distribution system. The resulting fault currents
can cause low voltages over regions of the distribution network and bus
voltage sags at some customer sites. Also, capacitor switching is commonly
performed to maintain feeder voltages or power factors. These switching
actions may lead to transients in the voltage and current waveforms. Other
power quality problems include voltage swells, flickers, harmonics, frequency
deviations, and spikes/notches. Poor power quality has a negative impact
on the customer equipment/appliances, manufacturing process, or motor performance.
At PG&E, numerous measurements have been acquired from the distribution
system. Since the amount of available data and information is large, it
can be time-consuming for PG&E division specialists to analyze the
acquired data. This purpose of this project is to analyze the data collected
by PG&E and evaluate the power quality on the PG&E feeders. During
this project, we will develop performance measures, such as indices on
voltage sags or transients, for power quality assessment. Data analysis
can be performed effectively by intelligent system techniques.
Device Modeling for Power Electronic Circuit
Simulation
Principal Investigator: Peter O. Lauritzen
Sponsor: National Science Foundation-Center for the Design of
Analog Integrated Circuits (CDADIC) University/Industry Research Center
For abstract on this project please see Modern VLSI, Sensors and Semiconductors.
Adaptive Sequential Controller
Computational Intelligent Applications Laboratory
Principal Investigator: Mohamed A. El-Sharkawi
Sponsor: Southern California Edison Company, Bonneville Power
Administration
For abstract on this project please see Applied Signal and Image Processing
Short Winding Assessment Technique (SWAT)
Computational Intelligence Applications Laboratory
Principal Investigator: Mohamed A. El-Sharkawi and Robert J.
Marks II
Sponsor: National Science Foundation and Electric Power Research
Institute
For abstract on this project please see Applied Signal and Image Processing
Computational Intelligent Applications to Transmission
and Distribution
Computational Intelligent Applications Laboratory
Principal Investigator: Mohamed A. El-Sharkawi and Robert J.
Marks II
Sponsor: Southern California Edison Company
For abstract on this project please see Applied Signal and Image Processing
Dynamic Security Assessment (DSA)
Computational Intelligent Applications Laboratory
Principal Investigators: M. A. El-Sharkawi, Robert J. Marks II
and Russell Reed
For abstract on this project please see Applied Signal and Image Processing
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