What is PSCAD?

PSCAD is the professional's simulation tool for analyzing power systems transients. It is also known as PSCAD/EMTDC.  EMTDC is the simulation engine, which is now the integral part of PSCAD. PSCAD is most suitable for simulating the time domain instantaneous responses, also popularly known as electromagnetic transients of electrical systems.

The PSCAD Graphical Interface greatly enhances the power and efficiency of your simulation.  It allows the user to schematically construct a circuit, run a simulation, analyze the results, and manage the data in a completely integrated graphical environment.

The following are some of the common components found in systems studied using PSCAD:

• Fixed and variable resistors (R), inductors (L) and capacitors (C)

• Mutually coupled windings, such as transformers and saturable inductors

• Frequency dependent transmission lines and cables

• Current and voltage sources

• Switches and breakers with optional pre-insertion resistance

• Diodes, thyristors, GTOs, IGBTs, and other power electronic switching devices

• Analog and digital control functions, Laplace functions and signal generators

• AC and DC machines, exciters, governors, stabilizers and inertial models

• Meters and measuring functions

• Most commonly used relay components

• Generic DC and AC controls

• HVDC, SVC, FACTS and Power Electronic Converters and their control circuits

Typical Studies Conducted Using PSCAD

The PSCAD/EMTDC users' spectrum includes engineers from utilities, manufacturers, consultants, and research and academic institutions. It is used in planning, operation, design, commissioning, preparation of tender specifications, teaching and research. The following are samples of types of studies routinely conducted using PSCAD:

• Find over-voltages in a power system due to a fault or breaker operation. Transformer non-linearities (i.e. saturation) are a critical factor and are represented. Multiple run facilities are often used to run hundreds of simulations to find the worst case when varying the point on wave of the fault, type of fault, or location of the fault.

• Find over-voltages in a power system due to a lightning strike. This simulation would be performed with a very small time step (nano-seconds).

• Find the harmonics generated by a SVC, HVDC link, STATCOM, machine drive (virtually any power electronic device) using accurate models of thyristors, GTOs, IGBTs, diodes, etc. along with the detailed control systems, analog or digital.

• Find the maximum energy in a surge arrester for a given disturbance.

• Tune and design control systems for maximum performance. Multiple run facilities are often used here as well to automatically adjust gains and time constants.

• Investigate the Sub-Synchronous Resonance (SSR) effect when a machine and a multi-mass turbine system interact with series compensated lines or power electronic equipment. Control systems can also be modified to investigate possible SSR mitigation methods.

• Modeling of STATCOMs or Voltage Source Converters with their detailed control models.

• Study interactions between SVCs, HVDC and other non-linear devices.

• Investigate instabilities due to harmonic resonance or control interactions.

• Investigate the pulsing effects of diesel engines and wind turbines on the electric network.

• Perform Insulation coordination studies.

• Variable speed drives of various types including cycloconverters and transportation and ship drives.

• Industrial systems including compensation controllers, drives, electric furnaces, filters, etc.

• Feeds to isolated loads.

• Study the transient effects of distributed generation such as wind and micro-turbines on the grid.

• Capacitor switching transients.

• Effect of transmission line imbalances on the system performance during contingencies.

Click here for lists of publications using PSCAD.

What is New in PSCAD V4?

PSCAD V4 is a completely redesigned Windows application built on our decades of experience in delivering previous versions of PSCAD on UNIX and Windows platforms.  The following is a list of some of the major features in PSCAD V4:

• PSCAD Graphical User Interface:

• Multi-platform: PSCAD V4 is available for use on all the latest versions of MS Windows.

• Totally Integrated: You can put run-time plots alongside the circuit or arrange them on a separate page. Circuits, plots and descriptive comments can all be printed together.

• Modular: Electrical systems can be split into different modules (or pages) without having to connect them using transmission lines. Control systems can be modeled in separate modules as in earlier versions.

• Hierarchical: Circuits assembled using basic building blocks can be contained inside modules (also called pages), which can in turn contain more such modules. Simply double-click on one these modules to see the circuit inside.

• Online Information: Point to any circuit component and you will get useful information about such topics as; the circuit connection, short component help, simulation data such as node voltage if the case is running, etc. - all in a concise context sensitive window called a Flyby window.

• Online Help: All the detailed online help is available in native windows help format. It is fast and easy to use.

• Graphical Component Design Tool: You can design your PSCAD components in a completely graphical environment called the Component Workshop. This is the tool used to write/edit all of the components in the Master library.

• Multiple Libraries and Cases in a Project: Now you can easily build cases that depend on multiple libraries and simultaneously load multiple cases. Thus, you can copy circuit components from one case and paste them into another easily.

• Multilevel Zoom Views: You can zoom in on the entire circuit as well as selectively zoom in on selected plots.

• Sequencer Components : You can now monitor and control a sequence of events easily using the library of Sequence Components. They can be used to set up complex sequences to control the application of faults, opening/closing of breakers, and waiting for events (such as a zero crossing).  The sequences visually indicate their progress during a run.

• Single Line Diagrams: You an draw the circuit either in single line or three phase view. You can mix these modes on a page as well.

• Global Constants: Now you can define global constants such as system frequency, MVA base. These constants are available to all pages within the case.

• PSCAD Numerical Solution Engine (EMTDC):

• Faster Solution and Memory Efficient Storage: Computationally intensive parts of EMTDC are rewritten to maximize the speed. Network branch models and transmission line models are internally reorganized to provide memory efficient storage.

• Dynamic Dimensioning: EMTDC is written in a FORTRAN 77 and FORTRAN 90 compliant model.  When used in FORTRAN 90 mode, it dynamically allocates network dimensions to exactly fit the simulation requirements.  This enables you to model much larger cases compared to FORTRAN 77 mode before you run out of computer memory.

• Ideal Branches: You can model infinite voltage sources, infinite transmission lines and cables, ideal ammeters and zero resistance switches.  There is no restriction on how many such elements you can have in series and parallel.

• Interpolation with Instantaneous Switch Algorithm:  EMTDC interpolates the solution between two time steps to find the solution at the exact instant of the event.  The Instantaneous Switch algorithm virtually eliminates losses due to interpolation, producing very accurate results.

• Many New Models: There are many new models and improvements to existing models. See the online help for a list of available models and features after you install PSCAD.

• MATLAB Interface: You can simulate all or part of the controls in MATLAB and interface it to the rest of the system simulation in PSCAD/EMTDC.  You can process or plot EMTDC results in MATLAB interactively.

• C Interface: In addition to the standard FORTRAN interface, users can now write custom models in C and interface them to PSCAD. This opens up the possibilities of using controls written using other simulation programs such as MATLAB and Saber, which have the ability to export the controls in C.

Extensive Online Help

PSCAD includes an extensive context sensitive online help system.  The PSCAD Installation and Setup document from Start=>PSCAD V4 menu is useful in answering most of the frequently asked questions. The online help system has extensive information on the PSCAD interface and EMTDC simulation engine. You should also use the context sensitive online help while you are working within the PSCAD environment. Right click on any component and select help to view information related to that component.

Example Cases

The PSCAD/EMTDC software comes with an excellent collection of example cases, which can be used as the starting point for many of your projects.  They are also used as example cases to illustrate the usage of certain complicated models, which are described best using a working example. You can also copy parts of these examples to quickly assemble your own circuits. For details on available templates see the online help system.  These cases are available in your PSCAD installation directory under Examples. There is also a set of Tutorial examples in this directory. You will find example cases illustrating the following:

• Transmission lines

• Synchronous machines, exciters, governors, stabilizers

• Induction machines

• Multiple run and parametric optimization for batch processing

• Frequency scanning methods for harmonic analysis

• HVDC and FACTS (SVC, ASVC, TCSC, UPFC, etc.)

• Power electronic drives (PWM, vector control drives, etc.)

• Steep front studies

• MATLAB, FORTRAN and C Interface

FREE PERSONAL EDITION

More product information and a free PSCAD Personal Edition download can be found at http://www.pscad.com.

**For a price quote and further information please contact sales@nayakcorp.com