TRANSIENT STABILITY PROGRAM
The traditional purpose of a transient stability program is to determine the ability of a transmission network to withstand major faults without the generators connected to the network losing synchronism. Transient stability studies are typically required whenever a generator or transmission line is added to the system. Operations personnel may want to make transient stability studies to determine whether certain network configurations might lead to stability problems in the event of a fault.
Because the TRANSMISSION 2000® Transient Stability (TS) program is capable of solutions up to 600 cycles, it is possible to study the stability of the system after the first swing. Even if your system doesn't have a "stability problem," this capability and the wide range of models in TS may make it useful for studying many different conditions. Motor starting and load shedding are two examples.
Available Models and Switching Actions
TS is capable of modeling all standard power system components. The models available include:
- five synchronous (motor or generator) machine models ranging from the classical model to models that include the effect of damper windings on both axes;
- a generalized load model that allows both the real and reactive portions of the load to be parametrized by voltage and frequency coefficients. Thus, loads may be modeled as constant current, constant power, constant impedance, or with any other exponent for the voltage;
- two induction motor models. The detailed model is sufficiently accurate for starting and stopping studies;
- all of the IEEE (1968) exciter models;
- two power system stabilizer models;
- prime mover models for steam, hydraulic, and combustion turbines and diesel engines;
- five static compensator models developed by one of the largest users of compensators in the world;
- a series capacitor line compensation model;
- impedance, low-frequency, and low-voltage relays.
Solution Method
The underlying solution method used by TS to solve the differential equations is the implicit trapezoidal rule. The numerical characteristics of this method are such that the solution is always numerically stable. This also permits a large amount of flexibility in the program. For instance, it is possible to use a small step size during time periods when switching operations are occurring and larger step sizes when there are no large disturbances. With this method the differential and algebraic equations are solved simultaneously, eliminating interface errors between the machine and network equations.
Post-Processing Module
The Transient Stability Post-Processor (TP) is a tool for the examination and display of results produced by the TS solution module. TP displays results files containing variables monitored during the TS solution in the form of graphs and lists. TP was designed to take advantage of the advanced user-interface features of Microsoft Windows. TP supports (and uses the features of) virtually all common graphics cards and output devices. This program enhances the user's ability to analyze large amounts of output and produce visually appealing graphs for inclusion in reports for management or clients. TP offers the user many options for viewing, comparing, and manipulating TS results in a graphical format. Instant and easy access to context-sensitive on-line help is always available. Additional features include:
- The ability to simultaneously plot up to ten different "curves." The curves may come from up to 10 different results files.
- Easy selection of the data to be plotted. An enhanced data selection screen allows the user to view all the available data from the results file on a single display.
- Automatic creation of axes divisions with optional user control over the scaling. Options include the ability to specify the amount of an axis a curve must occupy before TP places the curve on its own axis and the ability to specify that TP include zero on the axis.
- User specification of the curve "style" and color so that curves can be easily distinguished. The user can specify the extent of the curve shown.
- Automatic creation of the legend and title based on the selected results and curves. The user may change the legend and title content and location.
- User-definable comments and event lines that you can place anywhere on the graph. Along with the legend, you can move these "objects" using a mouse to "click and drag" them anywhere on the graph.
- A facility to list data to the screen, a printer, or a file for use with other programs such as dBASE, Lotus 1-2-3, or Excel.
- A full-function calculator that allows the user to manipulate curves arithmetically. For instance, you can subtract one generator angle from another to display the relative angle between them. The calculator includes the arithmetic operators +, -, *, /; the transcendental functions sin, cos, tan, arcsin, arccos, arctan, natural logarithm and exponential; a power function; and even the ability to do integration! The calculator uses the Reverse Polish Notation (RPN) or Postfix notation made popular by HP calculators. In math mode, you can use the calculator as a standard calculator.
- Parametrized variables that allow you to plot one curve against another (parametrized with respect to time). For example, you can graph an apparent resistance curve against an apparent reactance curve and obtain an R/X diagram. Additionally, you can plot relay characteristics on graphs of parametrized variables.
- The ability to paste graphs into other applications such as Microsoft Paint or Microsoft Write via the Windows Clipboard.
- Support for dozens of printers and plotters. TP supports any output device supported by Microsoft Windows.
Hard-Copy Capabilities
The TRANSMISSION 2000® TP supports all the hard-copy output devices supported by Microsoft Windows. At the current time this list has over 100 devices on it. Additionally, many manufactures support Windows by supplying a device driver with the hardware. Supported devices include:
- Apple LaserWriters
- Epson Printers
- Hewlett-Packard Plotters (using HPGL)
- Hewlett-Packard LaserJets
- IBM Printers
- Okidata Printers
- Toshiba Printers
In addition to the output produced by TP, the solution module produces a complete range of traditional tabular reports.
Operating Requirements
The TRANSMISSION 2000® TS program is designed to run on Intel-based personal computers under Microsoft Windows. You will also need:
- MB of memory
- a hard disk
The TRANSMISSION 2000® Power Flow program is required to generate initial conditions for TS.
Pricing Information
The single-copy price of the TRANSMISSION 2000® TS program includes one year of warranty, maintenance, and upgrade service. Multiple copy discounts, corporate licenses, short- and long-term rentals, and follow-on maintenance contracts are available. The program is supplied under an irrevocable, restricted license; copies of the license agreement are available for review. A demonstration package is available within the United States and Canada and elsewhere, and includes a sample copy of the program, instructions, and a User's Tutorial. Please call us for up-to-date prices.
Training
Training on the operation and use of this program is available at either our location or yours. CAI will also provide consulting services related to the program. For example, you may find it desirable to have CAI personnel help construct your initial machine models since this is a one-time investment of labor. Please call us for more information and pricing.
Other Programs in the TRANSMISSION 2000® Series
The TRANSMISSION 2000® TS program is only one of the programs CAI offers for personal computer use. Power Flow, Short Circuit, Protection Analysis, Line Constants, Power Flow Reduction and Data Conversion, Constrained Economic Dispatch, Short Circuit Reduction, and One-Line Diagram programs are also available.
Ordering and Additional Information
To place an order or obtain additional information, please contact:
- Stephen S. Miller, P.E.
- Commonwealth Associates, Inc.
- P.O. Box 1124
Jackson, MI 49204-1124 - Tel.: (517) 788-3676
Fax: (517) 788-3003 - E-mail: Stephen S. Miller