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| 97-01 | The dynamics of power system markets
Market equilibrium conditions can be
derived from more general
dynamic equations describing the
marketplace. Dynamic market
equations provide additional
insights into the behavior and stability
of markets which are not
available from static models. For
example, markets with a single
supplier with declining linear cost
may or may not be stable,
depending on specific cost
charactertics.
Markets with more than one
supplier with declining linear cost are
always unstable. Energy imbalance
requires careful design: a
combination of aggressive energy
imbalance regulation and rapid
response of the market can lead
to unstable market conditions.
Congestion has the potential of
substantially altering the market
equilibrium point. However, if
properly handled, it does not affect
market stability.
| Fernando L. Alvarado | 7/27/1998 | 217.5k | PDF |
| 97-02 | Simulation of the Multi-Node Open Access Same-Time Information System
This paper describes a Web-based
simulator of the Federal
Energy Regulatory Commission
(FERC) mandated Open Access
Same-Time Information System
(OASIS) network. The purpose
of the simulator is to provide a
tool for study of the various aspects
of an OASIS network and to gain a
strong intuitive feel for its
operations. For a specified
simulation period, the OASISNET
simulator reproduces an OASIS
network of multiple nodes using
the same communications medium as
the actual system, the
Internet, and with multiple
players using the simulator
simultaneously. Salient features
of the simulator are its modular
architecture, the ability to
simulate multi-node OASIS network
operations and to accept
simultaneous access from remote users
through use of client/server
technology. The simulation focuses on
the dissemination and use of the
available transmission capability
information. Sample applications
of the new simulator are
discussed.
| Yong Tian, George Gross | 7/27/1998 | 144.7k | PDF |
| 97-03 | A Simulation Tool for Analysis of Alternative Paradigms for the New Electricity Business
This paper provides preliminary results
on the development of a
simulation tool to perform
analysis alternative paradigms. Since
power systems are ultimately
governed by the laws of physics, the
heart of the tool is a power
system simulation engine, valid over a
simulated time frame of minutes
to days. The modular structure of
the tool then allows other
packages to be superimposed on this
structure to represent different
proposed paradigms.
| Thomas J. Overbye, Peter W. Sauer, George Gross, Mark J. Laufenberg, Jamie D. Weber | 7/27/1998 | 154.8k | PDF |
| 97-04 | Technical Challenges of Computing Available Transfer Capability (ATC) in Electric Power Systems
This paper discusses the ATC definitions
and determination
guidelines approved by the North
American Electric Reliability
Council (NERC) and presents
several concepts for dealing with the
technical challenges of
computation. areas of the interconnected
network and this required the
consideration of a third limiting
phenomena. The introduction of
St. Clair curves were one of the
first attempts to include
thermal, voltage, and stability
constraints
into a single transmission line
loading limitation [1]. These results
were later verified and extended
from a more theoretical basis in
[2]. This "single rating" concept
is extremely valuable from a
computational point of view.
| Peter W. Sauer | 7/27/1998 | 31.6k | PDF |
| 97-05 | Unbundling Power Quality Services: Technical Issues
The modern industrial facility depends
on sensitive elec-tronic
equipment that can be shut down
suddenly by severe power
system disturbances. A large
number of these disturbances on the
power system are a result of line
faults which can cause
momentary voltage sags. This
results in equipment malfunctioning
and high cleanup cost. This
papers describes some of the emerging
oppor-tunities for new services
to users of electrical power. In
particular the focus is on the
need for improved quality of power
and methods for providing this
new service.
| Robert Lasseter, Clark Hochgraf | 7/27/1998 | 128.1k | PDF |
| 97-06 | MinISO: A Minimal Independent System Operator
The Independent System Operator or ISO
is the lead actor in the
various proposals for a
deregulated, com- petitive electric
power
industry. The ISO has three pos-
sible objectives: security
maintenance, service quality
assurance, and promotion of
economic. To achieve these
objectives the ISO may be au-
thorized to set the rules for
transactions between sup- pliers and
consumers, scheduling and
dispatch of gen- erators, loads and
network services, and energy mar-
kets.
| Pravin Varaiya and Felix Wu | 7/27/1998 | 168.8k | PDF |
| 97-07 | Sensitivity of the loading margin to voltage collapse with respect to arbitrary parameters
Loading margin is a fundamental measure
of proximity to voltage
collapse. Linear and quadratic
estimates to the variation of the
loading margin with respect to
any system parameter or control are
derived. Tests with a 118 bus
system indicate that the estimates
accurately predict the
quantitative effect on the loading
margin of
altering the system loading,
reactive power support, wheeling, load
model parameters, line
susceptance, and generator dispatch. The
accuracy of the estimates over a
useful range and the ease of
obtaining the linear estimate
suggest that this method will be of
practical value in avoiding
voltage collapse.
| Scott Greene, Ian Dobson, Fernando L. Alvarado | 7/27/1998 | 116.6k | PDF |
| 97-08 | Contingency Ranking for Voltage Collapse via Sensitivities from a Single Nose Curve
The change in the loading margin to
voltage collapse when line
outages occur is estimated. First
a nose curve is computed by
continuation to obtain a nominal
loading margin. Then linear and
quadratic sensitivities of the
loading margin to each contingency
are computed and used to estimate
the resulting change in the
loading margin. The method is
tested on a critical area of a 1390
bus system and all the line
outages of the IEEE 118 bus system.
The results show the effective
ranking of contingencies and the
very fast computation of the
linear estimates.
| Scott Greene, Ian Dobson, Fernando L. Alvarado | 7/27/1998 | 63.3k | PDF |
| 97-09 | Initial Concepts for Applying Sensitivity to Transfer Capability
The available transfer capability
indicates how much interarea
power transfers can be increased
without compromising system
security. The paper addresses
transfer capabilities caused by
voltage magnitude or voltage
collapse limits. It suggests how the
sensitivity of the transfer
capability can be computed and used to
estimate the effect on the
transfer capability of variations in
parameters such as those
describing other transfers, operating
conditions or data. A
continuation method is used to find the
transfer capability due to
voltage magnitude or voltage collapse
limits. The first order
sensitivity of this transfer capability
to a wide
range of parameters can then be
quickly computed. The objective
is to use these sensitivities to
quickly extract the maximum possible
engineering information from each
continuation. The sensitivity
methods could contribute to the
quick update of transfer capabilities
when operating conditions or
other transfers change and to the
computation of a transfer reserve
margin.
| Scott Greene, Ian Dobson, Fernando L. Alvarado, Peter W. Sauer | 7/27/1998 | 109.6k | PDF |
| 97-10 | PowerWeb User's Manual
PowerWeb is an environment for testing
various power exchange
auction markets. It is
interactive, distributed and web-based.
It is
designed to host simulations of a
competitive "day-ahead" electric
energy market in the context of a
restructured electric power
industry. See also the PowerWeb
Home Page.
| Robert J. Thomas, Ray D. Zimmerman, Robert Ethier | 7/27/1998 | 233.1k | PDF |
| 97-11 | An Internet-Based Platform for Testing Generation Scheduling Auctions
This paper describes the uses and
architecture of a
network-centered computing-rich
software platform called
PowerWeb. PowerWeb was designed
and built as a simulation
environment for experimentally
testing various power exchange
auction markets through
tournaments. It is designed to host
simulations of a competitive
"day-ahead" electric energy market in
the context of a restructured
electric power industry. The
PowerWeb environment is meant to
be flexible so as to
accommodate different "rules of
the game". In this paper we
describe its interactive,
distributed and web- based character.
| Ray Zimmerman, Robert Thomas, Deqiang Gan, Carlos Murillo-Sanchez | 7/27/1998 | 454.7k | PDF |
| 97-12 | Thermal Unit Commitment Including Optimal AC Power Flow Constraints
We propose a new algorithm for unit
commitment that employs a
Lagrange relaxation technique
with a new augmentation of the
Lagrangian. The new augmentation
involves a duplication of
variables that allows relaxation
of the coupling between generator
time- spanning constraints and
system-wide instantaneous
constraints. This framework
allows the possibility of committing
units that are required for the
VArs that they can produce, as well
as for their real power.
Furthermore, although the algorithm is
very
CPU- intensive, the separation
structure of the Lagrangian allows
its implementation in parallel
computers. Our work builds upon that
of Batut & Renaud, as well as
that of Baldick.
| Carlos Murillo-Sanchez, Robert J. Thomas | 7/27/1998 | 231.0k | PDF |
| 97-13 | An Importance Sampling Application: 179 Bus WSCC System under Voltage Based Hidden Failures and Relay Misoperations
Recent studies have shown that power
systems protection
mechanisms have played a major
role in propagating disturbances.
Out of the last five major
Western Systems Coordinating Council
(WSCC) events (the North Ridge
earthquake, December 14th
1994, July 2nd & 3rd 1996, and
August 10th 1996), the latter three
involved false trips with line
protection relays and generators. Using
an importance sampling based
algorithm on the 179 bus WSCC
equivalent system, we modeled the
sequence of rare events under
generator trips and zone 3 relay
misoperations. The resulting
sequence of rare events and its
corresponding probability are used
to detect weak links in the
system.
| Koeunyi Bae and James S. Thorp | 7/27/1998 | 146.6k | PDF |
| 97-14 | A Transmission-Constrained Unit Commitment Method
This paper presents a
transmission-constrained unit commitment
method. The transmission
constraints are modeled as linear
constraints based on a DC power
flow model. The transmission
constraints, as well as the
demand and spinning reserves
constraints, are relaxed by
attaching Lagrange multipliers. In this
paper we take a new approach in
the algorithmic scheme. A
three- phase algorithm is devised
including dual optimization, a
feasibility phase and unit
decommitment. A test problem involving
more than 2500 transmission lines
and 2200 buses is tested along
with other test problems.
| Chung-Li Tseng, Shmuel S. Oren, Carol S. Cheng, Chao-an Li, Alva J. Svoboda, Raymond B. Johnson | 7/27/1998 | 207.9k | PDF |
| 97-15 | The Efficiency of Multi-unit Electricity Auctions
Using a complete information,
game-theoretic model, we analyze
the performance of different
electricity auction structures in
attaining efficiency (i.e., least
cost dispatch). We find that an
auction structure where
generators are allowed to bid for load
"slices" outperforms an auction
structure where generators submit
bids for different hours in the
day.
| Wedad Elmaghraby and Shmuel Oren | 7/27/1998 | 198.3k | PDF |
| 97-16 | A Simulation Based Approach to Pricing Reactive Power
In this paper we investigate the
simulation of real and reactive
power spot markets. While spot
pricing of real power remains a
viable option for the creation of
a power system market, the future
of a reactive power spot market
remains cloudy. The large capital
investment portion needed in
pricing reactive power as well as the
highly volatile nature of
reactive power spot prices makes the
creation of such a market
difficult. In spite of this, a portion
of the
pricing scheme that is used for
reactive power will likely be based
on the spot pricing approach as
this provides the most accurate
signal for near real-time system
operation. This paper will build on
a simple modification to the
standard optimal power flow (OPF) in
order to simulate the spot
markets for real and reactive power. To
achieve this, price-dependent
load models are introduced for both
real and reactive power.
| J.D. Weber, T.J. Overbye, P.W. Sauer, C.L. DeMarco | 7/27/1998 | 97.9k | PDF |
| 97-17 | Inclusion of Price Dependent Load Models in the Optimal Power Flow
In this paper we investigate the
inclusion of price- dependent loads
into the traditional Optimal
Power Flow algorithm. The
development of the model will be
based on the solution of the OPF
using an objective function for
maximization of social welfare. The
paper will show that a
traditional OPF algorithm that minimizes
supplier costs can be modified to
solve the social welfare
maximization problem by including
price- dependent load models.
This modification to the standard
OPF is intuitive and very simple.
We will show this modified OPF
formulation facilitates simulation of
a spot market for electricity.
While the development in this paper
will account for both real and
reactive power supply and
consumption, the examples in the
paper will concentrate on real
power markets. The algorithm will
be demonstrated on a range of
practical examples, including
several small systems, and on a
system with over a hundred buses.
The impact of such price
dependent loads on congestion and
bus marginal costs is
highlighted.
| J.D. Weber, T.J. Overbye, C.L. DeMarco | 7/27/1998 | 117.1k | PDF |
| 97-18 | Underlying Technical Issues in Electricity Deregulation
This paper reports on the results of a
recent attempt by the Power
Systems Engineering Research
Center (Pserc) and EPRI to
determine the technical tools
missing in currently unfolding electric
power restructuring scenarios.
| Robert J. Thomas and Thomas R. Schneider | 7/27/1998 | 58.5k | PDF |
| 97-19 | Solving Unit Commitment by a Unit Decommitment Method
We present a new unit commitment
algorithm which is initialized
with a solution having all
available generation units on-line. The
solution is successively improved
by decommiting units one at a
time. The optimal decommitment
strategy employed is based on a
decommitment algorithm introduced
by the first author in an earlier
paper as a post processing
algorithm for improving the results of a
traditional Lagrangian Relaxation
(LR) algorithm. We show that the
proposed method may in fact be
viewed as an approximate
implementation of the LR
approach. Furthermore, we show that the
number of iterations required by
the method is bounded by the
number of units. Empirical tests
suggest that the proposed method
is more efficient and robust than
the LR approach.
| Chung-Li Tseng, Chao-an Li, Shmuel Oren | 7/27/1998 | 214.5k | PDF |
| 97-20 | The Impact of Generation Mix on Placement of Static Var Compensators
This paper looks at the problem of
placing Static Var Compensators
to provide the maximum transfer
capability for all possible
generation mixes. The margin to
low voltage limit is one of the
quantities used to determine
power system transfer capability. Fast
methods for finding the location
of SVC systems that will have the
greatest impact on low voltage
margin will be shown. The IEEE 24
bus system will be used to
demonstrate this method over a wide
range of generation patterns.
| Robert H. Lasseter and Ronghai Wang | 7/27/1998 | 251.5k | PDF |
| 97-21 | StatCom Controls for Operation with Unbalanced Voltages
Voltage Sourced Static Var Compensators
such as the StatCom need to be able to
handle balanced voltages. Mild Imbalance
can be caused by unbalanced loads while
severe short-term imbalance can he
caused by power system faults. A
synchronous frame voltage regulator is
presented that works even when three
phase symmetry is lost. This regulator
addresses voltage imbalance by using
separate regulation loops for the
positive and negative sequence
components of the voltage. The regulator
allows the
StatCom to ride through severe transient
imbalance withoutdisconnecting from the
power system and, further, to assist in
rebalancing voltages. The regulator
maintains sufficient bandwidth to
perform flicker compensation.
The controllers performance is simulated
for a StatCom in a model distribution
system where it is subjected to a severe
single line to ground fault and a
rapidly varying three phase load.
| Clark Hochgraf & Robert Lasseter | 7/27/1998 | 99.2k | PDF |
| 97-22 | Re-Dispatching Generation to Increase Power System Security Margin and Support Low Voltage Bus
This article proposes a new method to
increase a power system's
security margin and/or support
its low voltage buses by re-
dispatching generator outputs,
using a normal vector found at a
voltage collapse boundary or a
low voltage boundary (LVB). This
method uses the normal vector as
an indicator to change the
generation direction so that more
power can be transferred before
reaching a boundary of a critical
limit such as the voltage collapse
boundary or the LVB, etc. The
method has been tested in
simulation on several systems and
shown predicted results. It can
be applied to many practical
power systems to enhance the
system's security and
reliability, so as to increase the
system's
transfer capability. It also
provides technical guidance for open
access transmission in a
deregulated environment, when bidding
results are shown as generation
directions (patterns).
| Ronghai Wang & Robert H. Lasseter | 7/27/1998 | 84.6k | PDF |
| 97-23 | Power System Bidding Tournaments for a Deregulated Environment
In this paper we describe certain tools for understanding and operating power systems in a deregulated environment. Many of the current models for this competitive market that employ an independent system operator (ISO) for controlling transmission, ensuring fair
access and security and providing a spot market for power will be studied. This centrally- dispatched power pool also ensures that generation meets demand based on bids submitted daily from independent generators (and from customers offering interruptible loads). Currently, most ISO bidding models allow only a single bid per day. In this paper, we present an asynchronous bidding scheme as a possible alternative. In particular, we examine the effects of feedback mechanism such that upon receiving generation levels from the ISO, independent generators (IGs) be allowed to modify their bid if they so desire. This competitive or ‘sequential’ bidding process should be allowed to hopefully optimize their profit margins. This paper also discusses the development tools necessary for examining the effects of different bidding processes on the ISO model and evaluation their capability of driving the market to an efficient state of operation.
Proceedings of the 30th Hawaii International Conference on System Sciences, Vol. 5, pp. 681-686, Jan. 7-10, 1997. Uploaded: June 27, 2006. | E. Sakk, R. Thomas, R. Zimmerman | 6/27/2006 | 641.3k | PDF |
