UWPFLOW
Continuation and Direct Methods to Locate Fold Bifurcations
in AC/DC/FACTS Power Systems
Claudio A. Canizares
University of Waterloo
Waterloo, Ontario N2L-3G1
CANADA
ccanizar@uwaterloo.ca
http://www.power.uwaterloo.ca
Fernando L. Alvarado
University of Wisconsin-Madison
Madison, Wisconsin 53706
USA
alvarado@ece.wisc.edu
Shu Zhang
University of Waterloo
Waterloo, Ontario N2L-3G1
CANADA
syzhang@engmail.uwaterloo.ca
Mario Watson
University of Waterloo
Waterloo, Ontario N2L-3G1
CANADA
mawatson@engmail.uwaterloo.ca
April 9, 2010
(First Version: December 20, 1996)
This program is provided without charge for research purposes only. The program
or any of its parts may not be used for any commercial applications.
The authors would appreciate any comments and suggestions on how to improve the
program. Any reports of problems should be directed to the authors, who reserve
their right to modify the program at any time without previous notification.
DISCLAIMER: THE AUTHORS DO NOT GUARANTEE THE ACCURACY OF THE RESULTS OBTAINED
WITH THIS PROGRAM, NOR ITS PERFORMANCE.
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BRIEF PROGRAM DESCRIPTION:
UWPFLOW is a research tool that has been designed to calculate local
bifurcations related to system limits or singularities in the system Jacobian.
The program also generates a series of output files that allow further analyses,
such as tangent vectors, left and right eigenvectors at a singular bifurcation
point, Jacobians, power flow solutions at different loading levels, voltage
stability indices, etc.
The program reads ac/dc power flow data in WSCC/BPA/EPRI formats [1,3] or IEEE
common format [2]; FACTS devices data in a special format described in the on-
line help file (WINDOWS) and using the models described in [5]; steady-state
load model data in OH format [4]; and steady-state generator data in a simple
free format as explained in the on-line help. The program also reads ac data in
other formats of interest to only some particular users (see on-line help).
Additional unformatted data is required for bifurcation analysis, such as the
direction of generation change, direction of load change, and maximum generator
powers. The program assumes that one parameter, the "loading factor," is
allowed to change. All steady state system controls remain operational unless
otherwise specified through the program options.
The program has been developed in C and C++ and runs under WINDOWS 7 (and other
previous versions of WINDOWS) and UNIX environments. It has no limitations on
system size, other than those imposed by memory limitations in the corresponding
environment, i.e., RAM and swap space in UNIX and WINDOWS. The program has been
successfully used to study a real 3000+ bus system in PCs and a variety of UNIX
servers.
For more details about the program capabilities, models and the techniques used
refer to [5,6,7,8,9,10,11,12]. For a PDF copy of most of these documents access
the WEB server URL: http://www.power.uwaterloo.ca
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FILES:
To get a hold of the program, look under "downloads" at the following URL:
http://www.power.uwaterloo.ca
The following directories and files form part of the distribution package:
uwpflow/-> Executable files needed to run the program. In UNIX these files
must be built from the source code using a C compiler, by
running the "makefile" with the command "make all". Script
(batch) AWK files for post-processing of output files are also
included in this directory.
The executable "maxim" file is used to determine the maximum
entries in the output vectors (tangent, eigenvectors, mismatches)
A DOS executable public domain version of AWK is also included,
so that the AWK file "tomatlab.awk" can be run in DOS and UNIX
to transform the output Jacobians to MATLAB format for matrix and
eigenvalue analyses.
Add this directory to the path to have access to all the files
needed to run the program, especially when running the script
(batch) files.
uwpflow/source/-> UWPFLOW C (*.c) and C++ code files (*.cpp), headers (*.h),
and other necessary files, including make and project files.
uwpflow/examples/-> Input data for 2 examples, a 173 bus ac/dc system (WSCC-
EPRI format) with a SVC, a TCSC and a STATCOM (the format
is described on the data files and the on-line help), and
the IEEE 300 bus ac test system (IEEE common format).
Additional input files needed for bifurcation studies are
also included in this directory.
The script (batch) files "173sys" and "ieee300", which
explain some test cases and the files needed for the
studies, are included in this directory also. These files
are used to automatically run the given examples (in
WINDOWS XP and UNIX). The script files are shown below.
uwpflow/examples/ -> The following files are needed for Cygwin AWK:
awk.exe, cyggcc_s-1.dll, cygiconv-2.dll, cygintl-8.dll,
cygwin1.dll. These are needed to run the examples
(not really needed for the program).
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INSTALLATION:
To install the program:
* WINDOWS 7 (Also tested on some WINDOWS XP & VISTA
machines):
1.- Download "UWPflow_setup.msi".
2.- Run UWPflow_setup.msi. Follow the steps in the setup file.
The setup will allow you to create a start menu and a desktop shortcut.
3.- Open the desktop shortcut "UWPflow".
4.- Now you are ready to run the examples in the EXAMPLES subdirectory.
The batch files IEEE300.BAT and 173SYS.BAT are provided to demonstrate
the program features, and to test the program in your system.
To run these files use the Batch/Script File option (F6) under the Execute
Menu option.
5.- To uninstall it, please use the software management files found
under the Control Panel.
* UNIX:
1.- Copy the compressed "tar.Z" file "uwpflow.tar.Z".
2.- Uncompress the file by typing 2 commands: uncompress uwpflow.tar
tar xf uwpflow.tar
This creates a "uwpflow" directory with the corresponding subdirectories
"source" and "examples", and other UNIX and AWK utilities.
3.- Compile UWPFLOW and other routines by running "make all" in the
subdirectory "source". If you have problems, check the "makefile" file
to see whether the compiler name and options are appropriate for your
system.
4.- Make sure that the uwpflow directory is added to the PATH so that the
files needed for running the program can be accessed.
5.- Run the script files "ieee300" and "173sys" in the "examples"
subdirectory to see whether the program operates properly in your system,
and to familiarize yourself with the program.
To run these files type the file name preceded by the "source" command,
e.g., "source ieee300".
Study and run the script (batch) files to familiarize yourself with the
program.
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REFERENCES:
[1] "Extended Transient-Midterm Stability Package: User's Manual for the Power
Flow Program," EPRI computer code manual EL-2002-CCM, January 1987.
[2] "Common Format for Exchange of Solved Load Flow Data," IEEE Trans. Power
Apparatus and Systems, Vol. 92, No. 6, Nov./Dec. 1973, pp. 1916-1925.
Working Group report.
[3] "Methodology for the Integration of HVDC Links in Large AC Systems-Phase 2:
Advanced Concepts," Vol. 1, EPRI technical report EL-4365, April 1987.
[4] "Small Signal Stability Analysis Program Package," Version 2, EPRI user
manual EL-6678, January 1990.
[5] C. A. Canizares, M. Pozzi, S. Corsi, and E. Uzunovic, "STATCOM Modeling
for Voltage and Angle Stability Studies," International Journal of
Electrical Power & Energy Systems, Vol. 25, No. 6, June 2003, pp. 431-441.
[6] C. A. Canizares and F. L. Alvarado, "Point of Collapse and Continuation
Methods for Large AC/DC Systems," IEEE Trans. Power Systems, Vol. 8, No. 1,
February 1993, pp. 1-8.
[7] C. A. Canizares, F. L. Alvarado, C. L. DeMarco, I. Dobson, W. F. Long,
"Point of Collapse Methods Applied to AC/DC Power Systems," IEEE Trans.
Power Systems, Vol. 7, No. 2, May 1992, pp. 673-683.
[8] C. A. Canizares, "On Bifurcations, Voltage Collapse and Load Modeling,"
IEEE Trans. Power Systems, Vol. 10, No. 1, February 1995, pp. 512-522.
[9] C. A. Canizares, A. Z. de Souza and V. H. Quintana, "Improving
Continuation Methods for Tracing Bifurcation Diagrams in Power Systems,"
Bulk Power System Voltage Phenomena-III Seminar, ECC Inc., Davos,
Switzerland, August 1994.
[10] A. Z. de Souza, C. A. Canizares and V. H. Quintana, "New Techniques to
Speed Up Voltage Collapse Computations Using Tangent Vectors," IEEE
Trans. Power Systems, Vol. 12, No. 3, August 1997, pp. 1380-1387.
[11] C. A. Canizares and Z. Faur, "Analysis of SVC and TCSC Controllers in
Voltage Collapse," IEEE Trans. Power Systems, Vol. 14, No. 1, February
1999, pp. 158-165.
[12] C. A. Canizares, editor, "Voltage Stability Assessment: Concepts, Practices
and Tools," IEEE-PES Power Systems Stability Subcommittee Special Publication,
SP101PSS, August 2002.