Select The Buses

The Bus Selection page is currently used with two displays:

The Equivalencing Display, to partition the system into the study subsystem ("Study") and the external subsystem ("External").
The Facility Analysis Dialog, to determine the buses in the external subsystem from which the buses in the facility would be isolated.

The following description concerns the Equivalencing Display, but the functionality of the Bus Selection Page is similar for both applications.

Buses, Areas, and Zones lists

For both equivalencing and facility analysis, use these lists to manually change the system designation of individual buses, areas, or zones. Note that changing the system designation on the area or zone tab is just another form of changing the designation of study / external system of individual buses. Click on the Which System? field in each of these tables to toggle the object’s affiliation with the study or external systems, subject to the values of the Filter by kV option and the Include how many tiers of neighbors? field.

In addition, the bus selection table for facility analysis contains one additional column labeled Selected. This Yes or No field indicates which buses in the Study system belong to the Facility being analyzed. Double-clicking one of the fields in this column will toggle the value of the field between Yes and No.

External

Use these fields to specify a range of areas, zones, or buses to be added to the external system. The Filter by kV and Include how many tiers of neighbors? controls will also shape the selection of buses to add to the external system.

Study

Use these fields to specify a range of areas, zones, or buses to be added to the study system. The Filter by kV and Include how many tiers of neighbors? controls will also shape the selection of buses to add to the study system.

Include how many tiers of neighbors?

This value indicates the number of tiers of neighbors to carry with each selected bus when adding the selected bus to either the study or external system. For example, if Neighbor Tiers is 1 and we elect to add bus X to the external system, both bus X and its first tier of neighbors will be added to the external system. If Neighbor Tiers is 0, only bus X will be added to the external system.

Filter by kV

If the Filter by kV box is checked, then only buses having a nominal voltage level between the values given in the Max kV and Min kV fields can be selected.

Set All As External

Click this button to assign all buses to the external system.

Set Branch Terminals External or Study

Clicking either of these two buttons allows setting advanced filter criteria which define a branch or group of branches. Once the criteria are set, clicking Filter will select the terminal buses of all branches meeting the filter criteria, and set those buses to either the External or Study system, depending on which button was pressed.

Select Buses using a Network Cut

A custom network cut can be defined for choosing which buses should remain in either the Study or External system.

Save Buses to File

Once the system has been partitioned, this command allows you to store the numbers of the buses of the study system in a text file.

Load Buses from File

Click on this button to load a listing of the buses to be included in the study system from a text file. You will be prompted to select the text file. The format of this text file is such that one bus number occupies each line. Any buses not identified in this file are defined as being in the external system.

Example

Assume you would like to create an equivalent containing all the buses in areas 1-5 and 10, plus any tie buses, and bus number 2050.

Since initially all buses are in the study system, first enter 1-1000 in the Areas field of Add to External System. Since the area of every bus is within this range, this places all the buses in the external system. Alternatively, click Set All as External to accomplish the same objective.
Set Include how many tiers of neighbors? to 1. This indicates that all subsequent selections will affect the specified buses and their first tier of neighbors.
In the Areas field of Add to Study System, enter 1-5,10. This places all the buses in these areas, plus any tie buses (since Neighbor Tiers is 1), into the study system.
In the Buses list, double-click in the Which System field for bus 2050 to change its status from External back to Study.