The following comprises the most popular terms used when discussing the PSCAD environment. It is important to become familiar with this terminology, as it will help greatly in the comprehension of topics discussed hereafter.
A component (sometimes referred to simply as a block) is a graphical representation of a device model, and is the basic building block of all circuits created in PSCAD. Components are usually designed to perform a specific function, and can exist as either electrical, control, documentary or simply decorative in type.
Single-Phase Transformer component in PSCAD
Components usually possess input and output connection ports and can be pieced together with other components to form larger system models. The user may interface directly to the model through input parameters.
Modules (sometimes referred to as sub-pages or page components) are a special type of component, where the functionality of the component model is defined by constructing a circuit, using a combination of other components. Modules possess their own canvas, as opposed to a hard-coded script interface in regular components. Modules can even contain other modules within their canvas, thus providing a hierarchical modeling capability.
All components and modules possess a single definition, from which many instances may be created.
A definition is the underlying 'blueprint' of a component or module, and is where all design aspects of the associated model are defined. This may include graphical appearance, port connections, input parameters and model code and/or circuit layout. Only one definition can exist for every unique component or module.
Definitions are normally stored in library projects, and are a basis from which to create multiple instances (or copies) of a component or module to be used in any project loaded in the workspace.
An instance is a graphical 'copy' of the definition, and is normally what is seen and manipulated by the user. An instance is not exactly a copy; each instance is its own entity, and may have different input parameter settings, or even appear graphically different from other instances.
Since all instances are based on a single definition, any design changes to a definition will affect all instances.
Everything involved in a particular simulation (except output files) is harboured within a single file called a project. Projects can contain stored definitions, on-line plots and controls, and of course the schematically constructed system itself. There are two types of projects in PSCAD: Library and case projects.
Case projects (or simply 'cases') are where most work is performed in PSCAD. In addition to performing the functions of a library project, 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 *.pscx.
Library projects are used primarily to store definitions. Instances of definitions stored in a library, can be used within any case project. Library projects are saved with the file extension *.pslx.
The namespace is a project attribute, used to provide a stable source name for functions such as definition referencing. The namespace is separate from the project filename, which can be modified outside of the application (in File Explorer for example).
Namespace and filename may be different in library projects only. In case projects, the namespace and filename are kept synchronized in order to avoid confusion. For example, if you save a case project as another name, the namespace attribute will be modified as well.
The namespace is what is displayed in the workspace projects branch.
The workspace is the central operating hub within the PSCAD environment. It not only provides an overview of all projects currently loaded, but also organizes simulation sets, data files, signals, controls, transmission line and cable objects, display devices, etc. within an easily navigable environment.
Although only a single workspace can be present in the application, workspaces may be exchanged at any time. See Loading a Workspace for details.