Graphic Editor Guide

InterPSS provides a graphic editor for user to draw One-line diagram and enter study case data. Currently it has basic functions to create a simple power system one-line diagram, input data, perform analysis and generate analysis reports. The one-line diagram and data can be saved into a file and then reloaded into the editor for further analysis.

InterPSS Graphic Editor

As shown in the following diagram, the editor has two main areas: 1) Workspace/Project Explorer; and 2) One-line graphic editor. You can work on multiple projects simultaneously. InterPSS uses a separate Java runtime thread to run simulation cases, which means you can work on another case while waiting for the completion of a long running analysis/simulation process, such as a transient stability simulation.

InterPSS organizes projects under its workspace. You can hide/resume workspace/project explorer, as follows:

The One-line diagram can be exported as PDF, SVG and other formats.

InterPSS Workspace

InterPSS uses computer file system and an internal database to persist its documents. These documents are organized under the workspace concept. Currently InterPSS supports two workspaces: 1) Ipss/User Workspace; and 2) Sample Workspace.

• Ipss/User Workspace : For user projects. We recommend you put all your actual projects in this workspace. When you perform a new InterPSS release installation, you have the option to keep this workspace untouched.
• Sample Workspace : For InterPSS samples. This workspace will be constantly modified/updated by the InterPSS development team with new samples to showcase InterPSS features. You should only put your temporary data, for example testing cases, in the workspace.

You can make switch between these two workspace by click the Select Workspace/* Workspace menu item. InterPSS will shutdown after the switch. You have to restart InterPSS to continue your work.

Under a workspace, projects are organized into project folders. Project related documents, such as reports, scripts, are put under the parent project. As a user, you do not need to worry about how documents are internally organized and stored. We do not recommend make any change to the document file structure.

Create InterPSS Project

To create a new InterPSS project, first create a new project folder, for example, MyFolder. You can also add a new project under an existing project folder.

To create a new InterPSS project into, for example, MyFolder, right click the project folder, and select Add InterPSS Graphic File, as follows:

Enter project name : MyProject and click OK. At this time you can also create project based on an existing project, see more in the late section on how to import an existing project into InterPSS.

After clicking the OK button, the InterPSS project data editor dialog box will automatically popup.

Enter necessary project info and click Save to complete the new project creation process. You should see the new project listed in your workspace.

Edit One-line Diagram

InterPSS currently provides basic functions for user to create a power network for Loadflow, Short circuit, transient stability or distribution system analysis. Currently available drawing tools are listed in the following figure:

Using the graphic drawing tools, one can quickly create a power network, such as the one shown in the following diagram:

The "InterPSS Graphic Editor User Tips" document, contributed by an InterPSS user, has more detailed information regarding how to use InterPSS graphic editor.

An asterisk in the one-line diagram, as shown in the above diagram, indicates that the network under editing has been changed (dirty). You may want to save the project before moving to other tasks.

InterPSS Network Model

The foundation of InterPSS is an object-oriented power network model proposed in "Object-oriented Programming, C++ and Power System Simulation" (IEEE Trans. on Power Systems, Vol.11, No.1, Feb. 1996 pp206-216). The basic idea could be summarized by the following sentence (quoted from the original paper):

"A network container for the simulation purpose should be designed as if it is a

place where buses can be defined, and branches can be connected between the defined

buses to form a network."

InterPSS assumes that all simulation algorithms are based on the node admittance Y-matrix. This also means that InterPSS could be extended to implement any Y-matrix based power system simulation algorithm. Bus and branch inside InterPSS simulation model are modeled as objects. These objects have types, such as AclfBus, AclfBranch, applicable to different type studies, such as Loadflow. However, these objects share certain common features. These features are captured in the Bus object and Branch object.

Bus Object (JavaAPI)

A unique bus sequence number, starting from 0001, is be assigned by InterPSS to each bus object when it is created and added on to the One-line diagram. This bus sequence number is used as the bus object id. A bus object also has BusName (optional), Base Voltage, Area number, Zone number. If the In Service checkbox is unchecked, the Bus object will not participate in the simulation.

To retrieve a bus object from the network object, the following Java statement could be used:

Bus bus = net.getBus("0001");

where, net is a Network (JavaAPI) object, "0001" is the Bus object id.

Branch Object (JavaAPI)

A branch object, in the InterPSS simulation model, is always connected between two buses - from-bus and to-bus. When you draw a branch from one bus to another bus, system will automatically connect the branch object to the two buses. After the branch creation, the connection relationship cannot be modified. InterPSS branch id takes the following format:

fromBusId->toBusId(Branch Circuit number)

For example, branch id 0001->0002(1) indicates the branch connected to from-bus (0001) and to-bus(0002). Its circuit number is 1.

To retrieve a branch object from it parent containing network object, there are three ways, as follows:

Branch branch = net.getBranch("0001", "0002"); // use this approach when there is no parallel branch between two buses

Branch branch = net.getBranch("0001", "0002", "1"); // "1" is the branch circuit number

Branch branch = net.getBranch("0001->0002(1)"); // retrieve branch by branch id

where, net is the parent Network object, "0001" is the Branch from bus object id, "0002" is the Branch to bus object id and '1' branch circuit number.

A unique branch sequence number, starting from 0001, is assigned by InterPSS to a branch object when it is created and added on to the One-line diagram. A branch object also has BranchName (optional), Area number and Zone number. If the In Service checkbox is unchecked, the Branch will be treated as an open branch in the simulation process.

Edit Project Data

InterPSS divides power system simulation into two main categories (Application Type): 1) Transmission System and 2) Distribution System. Transmission System concept is more applicable to high-voltage utility system studies where network data are expressed in per unit. Distribution system concept is more applicable to medium and low-voltage distribution system studies where network data are expressed in nameplate values, such as Ohms, or Housepower.

For transmission system application type, a network could be further categorized into three Network types:

• ACLF – For describing steady state, positive sequence power networks. It is applicable to AC Loadflow, DC Loadflow, Voltage stability and other analysis where steady-state positive sequence power network data are needed.
• ACSC – For describing steady state power networks with positive, negative and zero sequence network data. It is applicable to Short Circuit analysis.
• TranStability – For describing dynamic power networks for transient stability simulation.

These three types of networks have an inheritance relationship, as shown in the above diagram. It is assumed that all transmission system network data are entered based on the BaseKVA (Base Kva) and BaseFreq (Base system frequency) defined in the InterPSS project dialog box.

Please note: after a project has been created, its application type cannot be changed. You cannot change, for example, from a transmission system to a distribution system, since their underlying data structures are quite different. Within the same application type, you can only change the network type downward in the inheritance hierarchy, for example, from ACLF to ACSC network. Changing from ACSC network to ACLF network will result data loss, which is the reason why it is not allowed. Please note: you can perform Loadflow analysis on an ACSC network, if Loadflow data has been entered into the network.

Edit Bus Data

By double-clicking a bus symbol on the one-line diagram, you can edit bus data. Depending on the type of network you are working on, corresponding bus data editor will be launched for you to edit the data.

Edit Branch Data

By double-clicking a branch symbol on the one-line diagram, you can edit branch data. Depending on the type of network you are working on, corresponding branch data editor will be launched for you to edit the data.

Please note:

• InterPSS power system object model allows multiple parallel branches be defined between two buses. However, the current One-line diagram can only allow you to draw one branch between two buses. The limitation will be removed in the near future.
• InterPSS has no limit on number of buses and branches. Memory necessary to store simulation information is dynamic allocated during the simulation process. Also, it will only allocate memory for the exact network size. For example, if you have a 5-bus system with 4 branches, InterPSS will only allocate memory for 5 Bus objects and for 4 Branch objects.

Run Analysis

After creating a project and entering the data, you can run analysis. Depending on the type of network created, corresponding analysis menu items will be enabled for you to perform appropriate analysis.

Assume you selected run Loadflow Analysis, you will be presented with the following dialog box:

• AddCase - You might want to an project in multiple ways, for example, run 3Phase, Single Phase short circuit analysis. Using the AddCase button, you can add more study cases for the project.
• DeleteCase - Delete an existing study case. Make sure you have at least one study case for your project
• ViewXml - InterPSS run is controlled by an underlying xml document. ViewXml allows you to view the xml document.

• Import - Import an InterPSS run xml document.

Please note: The above feature is available in InterPSS Release 1.5.

Select run options and enter necessary data, then click the Run button to run Loadflow analysis. A Loadflow summary will be presented after successfully completing the run.

If the run process is rather long, such as a transient stability simulation, the progress bar will display the percentage of simulation completed.

In some unusual cases, the simulation thread is continuously running. You can click the green button to stop.

Custom Run Scripting

InterPSS allows you to run its simulation engine in your own way by providing your own custom run scripts.

Please see How to Script Custom Analysis Run for details.

Analysis/Simulation Result

InterPSS analysis/simulation results could be output in different format, including One-line diagram annotation, curve plotting and InterPSS report.

Result Annotation

InterPSS currently supports annotate Loadflow and Short Circuit results onto the One-line diagram after a simulation run.

The following is sample of Loadflow result annotation.

You can use mouse to adjust annotation text position on the One-line diagram. InterPSS will remember the location change. You can also select the clear annotation menu item to clear the annotation text on the diagram.

InterPSS in the future will allow user to have more control over the annotation content and style.

Plot Transient Stability Simulation Result

After completing a transient stability simulation, right-click a bus, you can have choice to plot any state variable associated with the bus.

Generate Report

After an analysis run, appropriate reports could be generated.

The following is a sample Loadflow analysis report.

Report is always saved under the parent project as shown in the following diagram.

The report could be also exported to pdf, rtf or html format.

InterPSS report is template based. You can create your own report template and plug into InterPSS to create your own custom report. Please see How to Customize InterPSS Report for details.

Import Existing Project

Import InterPSS Project

When you create a new InterPSS project, you can optionally import an existing InterPSS project. InterPSS will make a copy of the existing InterPSS project file *.ipss and import the copy into the new project.

Import Custom Data File

To import a custom data file, such a PSS/E raw file, right-click a project folder, the select Add/Add Custom Data File.

Currently, InterPSS supports the following custom file formats.

The following is an example to import a date file in IEEE Common Format into InterPSS.

InterPSS uses custom data file adapters to import data in a particular formal into InterPSS. You can find more information on this subject by reading the InterPSS Custom Data File Adapter Source Code. You can also create your own custom data file adapter and plugin to InterPSS to import your data into InterPSS. The InterPSS Development Guide Develop Custom Data File Adapter could walk you through steps to implement such a adapter.

Import Transient Stability Study Data Files

(This feature is only available currently in InterPSS Dev Release)

BPA transient stability study case info are normally stored in two files: 1) *.dat for Loadflow info; and 2) *.swi for dynamic data. To import the info into InterPSS, select adapter type = BPA Format DStab, and study case files, as shown in the above figure.

The BPA *.dat file is imported in to InterPSS with an extension *.bpa_lf, *.swi with an extension *.bap_dstab, as shown in the above figure.

Getting Help

You can access InterPSS help information under the Help menu. For example, by clicking the User Guide -> English User Guide, InterPSS will launch your default browser and load this user guide into the browser, as shown in the following figure.

Debug InterPSS

Sometime your simulation results may be obviously wrong. Chances are that your input data may not be entered correctly. While InterPSS tries to check input data before running an analysis, it is impossible to catch all possible mistakes. At this point, you can send your case to the InterPSS Support or you can debug yourself.

By clicking the Tools/Debug/SimuContextInfo, you can list the states of all objects of the current project in memory. You may need to consult InterPSS Core API to interpret the information. For example, the following is AclfBus object info:

id: 0001

name: Bus-1

desc:

status: true (sortNumber: 2)

baseVoltage: 132000.0

genCode: Swing

loadCode: NonLoad

voltageMag: 1.06

voltageAng: 0.0

gen: 1.06

load: 0

shuntY: 0

LF Results :

voltage : 1.0600 pu 139920.0000 v

angle : 0.0000 deg

gen : 2.32 - 0.21i pu 232,402.29 - 20,675.75i kva

load : 0 pu 0 kva

Resources

• InterPSS Graphic Editor User Tips