The PSCAD Environment
The term ‘PSCAD Environment’ refers not only to how the PSCADgraphical users interface is organized visually, but also to naming conventions, utilities and other features that facilitate creativity and design. As you may notice, a lot of effort has gone into enhancing the work environment in PSCAD V4. We have however, tried to maintain the look and feel of the previous versions, preserving the most popular functions and enhancing others.
This chapter discusses a wide range of introductory topics ranging from simple terms and definitions, to a general overview of most im- portant functions in PSCAD. The tutorial section My First Simulation is a must read for new PSCAD V4 users.
For a more detailed description of basic functions and operations, see Chapter 5 - Features and Operations.
TERMINOLOGY AND DEFINITIONS
In order to fully appreciate the PSCAD User’s Guide and Online Help System, a quick review of the following common terms is suggested. Due to the environmental changes implemented since PSCAD V3, there have been several changes in the terminology used to describe some new and old features as well.
Components
A component (sometimes referred to simply as a ‘block’) is essen- tially a graphical representation of a device model, and is the basic building block of circuits created in PSCAD. Components are usu- ally designed to perform a specific function, and can exist as either electrical, control, documentary or simply decorative in type.
Components usually posses inputs and outputs and can be pieced together with other components to form larger systems. Model pa- rameters, such as input variables and constants, can also be manu- ally entered through the component.
Definitions
A definition is essentially the underlying ‘blueprint’ of a component. Accessed through the Design Editor, the compo- nent definition is where all aspects of the component design are defined. This can include graphical appearance, connection nodes, input dialogs and model code.
Component definitions are not graphical entities, and are usually stored in library projects. Definitions stored in a library project can be used to create component instances in any case project, includ- ing that library project itself. However, definitions stored in a case project are local to that case and cannot be used in other projects.
Instances
A component instance is a graphical ‘copy’ of the component defini- tion, and is normally what is seen and used in a project. An instance is not exactly a copy, in that many component instances, based on the same definition can exist simultaneously. Each instance is its own entity, and can have different parameter settings, or even ap- pear graphically different from other instances.
Since all instances are based on a single definition, any design changes to a component definition will affect all instances. Modules
Modules are a special type of component, where the basic func- tion of the component model is described using a combination of other basic components, rather than code. Modules can contain other modules within them and thus provide a hierarchical model- ing capability. Also referred to as ‘sub-pages’ or ‘page components,’ modules are also defined by a definition, but presently may only pos- ses one instance per definition. A module behaves very much like an ordinary component except that it does not allow input parameter entry.
Projects
PSCAD allows the user to store everything involved in a particular simulation (except output files) into one file called a project. Projects can contain stored component definitions, on-line plots and controls,
and of course the graphically constructed system itself. There are two types of projects in PSCAD: Library and Case projects.
NOTE: Component definitions stored in case projects are local to that case and cannot be used in other projects. Library projects should not contain components defined in other cases or libraries.
Case
Case projects (or simply ‘cases’) are where most work is performed in PSCAD. In addition to performing the functions of a library proj- ect, cases may be compiled, built and run. Simulated results can be viewed directly within the project through on-line meters and/or plots. Case projects are saved with the file extension ‘*.psc.’
Library
Library projects are used primarily to store component definitions and viewable component instances. Instances of component defini- tions stored in a library, can be used in any case project, provided that the library is loaded first. Library projects are saved with the file extension ‘*.psl.’
TUTORIAL: MY FIRST SIMULATION
This tutorial is designed to give new users a ‘jump start’ in learn- ing how to use PSCAD, as well as to give you a chance to try out a PSCAD simulation before proceeding further in this chapter.
In this tutorial you will learn:
• How to Load a Case Project • How to Run a Simulation • How to Print
If you can successfully run this example Project at the end of this chapter, it will also mean that your installation was successful. So let’s begin!
Starting PSCAD
To start PSCAD, go to Start | Programs | PSCAD in the Windows Start Menu, and select whichever PSCAD Edition you are licensed for. This will open the main PSCAD environment, as shown below.
You should see a list of items across the top of the environment (File, Edit, etc.). These items are part of the Main Menu. The but- tons directly below the main menu are part of the Main Toolbar. Title, Menu and Main Tool Bar
The image below shows the PSCAD V4 Title and Menu Bars.
Title Bar and Active Project
The top most part of the window that displays PSCAD [Edition] is called the Title Bar. The Title Bar will also include the Project page that is currently being viewed in the Design Editor, once a Project is opened.
Menu Bar and Menu Items
The area under the Title Bar, consisting of menu items and menu buttons, is called the Main Menu. All main menu items are drop down menus, so when you left-click with your mouse pointer over top of one of these menus, you will see a list appearing below it.
To select an item from this list, first move the pointer onto that item (the item becomes raised) and then click the left mouse button. The following menu shows how to load a project using the File menu from Main Menu bar.
Toolbar Buttons
The row of buttons directly below the Main Menu bar comprises the Main Toolbar.
While menu items are a two-stage process, a toolbar offers a single- click alternative. The Main Toolbar buttons initiate actions as soon as you click on them and hence are easier to use. For this reason, most frequently used operations have toolbar button equivalents. After you become more familiar with the program, you may begin to use the many keyboard shortcuts available. See the section entitled ‘Keyboard Shortcuts’ in this chapter for more details.
Workspace and Output Windows
If you take a look at the top left-hand corner of the PSCAD Environment, you should see a smaller window referred to as the Workspace window. If it is not visible, go to the main menu bar and click on View | Workspace.
The Workspace gives you an overall view of any library and/or case projects loaded. You can use it to select components and perform many other activities.
Directly below the Workspace window, you should see another win- dow referred to as the Output window. If the Output window is not visible, click on View | Output.
All the status, warning and error messages involved in both Build and Runtime procedures are logged in this window - so it is a good idea to keep this window open and visible at all times.
Both the Workspace and Output windows are based on a tree-type structure, where branches can be expanded and collapsed at will. Loading a Case Project
We will start with the most simple of example cases for this tutorial. This exercise will help us to ensure that PSCAD and any Fortran compilers being used are installed correctly. We will learn to create a case from scratch in ‘Creating a New Project’ tutorial of Chapter 5.
To load an existing Case Project, click on File from the Main Menu bar and select Load Project... You can also either press Ctrl + O or click the Load button in the Main Toolbar.
You should see the Load Project dialog pop up on your screen. By default, the selected file type is ‘PSCAD Files (*.psc, .psl)’ at the bot- tom of the dialog. With this type selected, you will see only PSCAD Project files that have ‘*.psc’ or ‘*.psl’ extension and directories. The file extensions stand for pscad case or pscad library.
Navigate to the ‘tutorial’ directory inside your PSCAD installation directory (i.e. C:\Program Files\PSCAD4xx\examples\tutorial). Click on the ‘vdiv_1.psc’ file and then click on the Open button to load this Case Project into PSCAD.
The Workspace window will now list a second project entitled ‘vdiv_1 (Single Phase Voltage Divider)’ directly under the Master Library Listing. Double-click on the Project title (or right-click and select Open) in the Workspace window to open and view the main page of the Project in the Circuit window of the Design Editor.
You should see the assembled voltage divider circuit as shown below, which is located at the top left corner of the main page of the project that you just opened. The plots are situated directly to the right of the circuit.
The circuit consists of a single-phase resistive voltage source con- nected to a resistive load. Since the magnitude of the source re- sistance (1 Ω) and the load resistance are the same, the voltage at the load terminal is half that of the voltage behind the source resistance. This voltage is measured using a voltmeter called ‘Vmid’ connected to the node between the source and the load. The current in the circuit should be:
The plot and graphs will contain the values of the voltage at the mid- point of the circuit, and the current flowing through the circuit when the project is run.
Running a Simulation
Before we run the simulation we will do a simple calculation to find out what load current and mid-point voltage we should be expecting. Double-click on the source component to open and view its properties - note that the source voltage magnitude is 70.71 kV RMS (or 100 kV peak). Close this dialog by clicking on the Cancel button at the bottom of the dialog and left-click anywhere in an empty space on the page, to de-select the selected source component (this will stop the component from blinking). For a 100 kV source voltage, we know that the mid-point voltage should then be 50 kV peak, and the load current should be 50 kA peak. Now let us run the simulation and actually verify the current and voltage waveforms.
To run a case, simply click on the Run button in the Main
Toolbar. When this button is pressed, PSCAD will go through sev- eral stages of processing the circuit before starting the EMTDC simulation. You should see a message in the status bar at the bottom of the PSCAD window, related to various stages of the process. Depending on how fast your computer is, you may not be able to read these.
Watch the graphs as the simulation progresses. If you look near the bottom-right corner of the PSCAD Environment, you will see a message ‘xx% complete’ where ‘xx’ represents the percentage of the total simulation length. To the right of it you will also see the current simulation time, which changes with the simulation. Once again, depending on the speed of your computer, the simulation may finish
This tutorial case is set up to run for 0.2 seconds. At the end of the run you will see the message ‘EMTDC run completed’ in the status bar. Your plots should look similar to the following - depending on your plot settings:
Make sure that your simulation produces the same result as shown here. This is one step towards ensuring that your PSCAD is installed correctly.
Click again on the Run button to see the run once again. PSCAD will go through all three stages (i.e. compile, build and run), however, you may not be able to detect the first two stages, as they pass by very quickly. This is because PSCAD performs them only if changes have been made to the circuit.
Printing the Circuit
To print the circuit along with the graph you just simulated, click the right mouse button on the background of the main circuit page and either select Print Page or Print Preview Page items.
This should bring up either the Print dialog or the Print Preview Viewer. The contents of the Print dialog depends on what you are printing - click the OK button to proceed. The Print Preview Page allows you to view your page before printing.
THE WORKSPACE
Formally known as the ‘Project Tree’ in PSCAD V3, the Workspace has matured into a central project database for PSCAD. The Workspace not only provides an overview of all projects currently loaded, but also organizes data files, signals, controls, transmission line and cable objects, display devices, etc. within an easily naviga- ble environment. Features such Drag and Drop may also be utilized from the Workspace.
NOTE: The PSCAD Master Library is always the first project loaded into the Workspace. The Master Library cannot be unloaded.
The Workspace window is divided into four tabular sections:
• Projects • Runtime • TLines/Cables • Files
Moving and Resizing the Workspace Window
The Workspace window may be moved and dropped anywhere in the PSCAD environment. To do this, click and hold the left mouse button with the mouse pointer directly over the top window bar.
Drag the window to where you want it placed (you should see a boxed outline of the window) and let go of the mouse button. De- pending on where the window outline is when the mouse button is released, the window will either dock itself into position or appear as a floating window.
The Workspace window can be resized by moving the mouse pointer over one of the four window edges until the pointer changes to that shown below:
or
Click and hold the left mouse button and drag the mouse pointer to resize in either the horizontal or vertical direction as shown above. The Projects Section
When a Case or Library Project is loaded into PSCAD, the Project filename and description will appear in the Projects section of the Workspace window. It is possible to load multiple Projects – and if this happens – the Projects will be listed in the order in which they were loaded.
The Projects section is used mainly for navigating either between Projects or within Projects; including direct access to Modules and
Definitions. A simple double-click on a listed Module, for instance, will bring you directly to that page in Circuit view.
Icons are included for easy visual differentiation between Case and Library Projects. These are listed below:
• Library Project • Inactive Case Project • Active Case Project
As mentioned above, each project listed in the Projects section con- tains information regarding any stored Definitions, as well as Module hierarchy, organized into a standard tree-type structure. This struc- ture is referred to as the Project Tree.
You can expand and detract each branch in the project tree by click- ing on either the [+] or the [-] symbols respectively.
Main Page Branch
This branch lists the various Module instances in the project. Start- ing with the main page, any existing Modules are organized as they exist in the Project, not only making navigation simple, but providing an overview of the Project structure.
For example, the Case Project above (called ‘test’) contains a main page with two Modules called ‘net1’ and ‘net2.’ The Module ‘net1’ contains another Module called ‘sub1.’
A simple double-click on a particular Module will bring you directly to that page in the Circuit window of the Design Editor. Right-click- ing on a Module will bring up a menu where you can either compile that particular Module, or change the Module page set-up. See ‘Compiling an Individual Module’ or ‘Editing the Page Setup’ in Chapter 5 for more details on these menu functions.
Icons are included in this branch for visual representation and are listed below:
• Main Page • Module Instance
Definitions Branch
The Definitions branch contains a list of all definitions that are stored within that particular Project. Instances of component Definitions that are defined in other Projects (such as Master Library components) do not appear here.
The image below shows the list of component Definitions for the same Case Project discussed in the previous section. In addition to the definitions of each Module, the existence of a component Definition (called ‘user_comp’) is also indicated.
NOTE: This example is for illustrative pur- poses only. It is not usually a good idea to define component Definitions within a Case Project, as they can then only be used in that Project. All component Definitions should exist exclusively in Library Projects.
A simple double-click on a Module Definition will bring you directly to that page in the Circuit window of the Design Editor, whereas double-clicking on a component Definition will bring you directly to the Graphic view.
There are a couple of right-click menu functions involved with the Definitions branch, as well (some of these functions are not available anywhere else). Right-clicking directly over the Definitions branch will bring up a menu as shown below:
The following list describes the functions of this pop-up menu:
• Paste Definition: This function can be used to paste a
another Project currently loaded in the Workspace (see the Copy Definition menu function described below).
• Import Definition(s)...: This function is used to import
stored Definition Files (*.cmp). See ‘Importing/Exporting Definitions’ in Chapter 5 for more details.
• Copy to Clipboard: This option allows the user to copy
the entire Definitions list (i.e. names only) to the Windows clipboard as ASCII text.
• Sort By Name: Select this option to sort the Definitions list
by name. Continually selecting this option will toggle the alphabetical order from A to Z or Z to A.
• Sort By Description: Select this option to sort the
Definitions list by description. Continually selecting this option will toggle the alphabetical order from A to Z or Z to A.
If you right-click with the mouse pointer over a specific component Definition in the list, the following menu will appear:
The following list describes the functions of this pop-up menu:
• Properties...: This brings up the Definition Properties dialog
window for editing the definition Name and Description. See ‘Editing Definition Properties’ in Chapter 5 for more details.