Line and Transformer Display

See Also

 

The Line/Transformer Display presents data describing each transmission line and transformer in the case. The Line/Transformer Display is a class of Case Information Display and therefore can be used in a manner consistent with all other case information displays. It has a local menu from which you can print, copy, and modify its information as well as view the information dialog of its associated branches. The local menu also affords the opportunity to insert new lines or transformers into the model or to delete existing ones. Moreover, it enables you to invoke the Quick Power Flow List and Bus View Display for each branch’s terminal buses. You can also sort the line and transformer information by clicking on the heading of the field by which you want to sort. Additionally, you can choose to restrict the information shown by the Line/Transformer Display according to the constraints of the area/zone/owner filters.

To show the line/transformer display, select Network > Branches Input or Network > Branches State from the Model Explorer.

The contents of the display depends upon the application’s operating mode.

 

The line/transformer display shows the following fields by default:

From Bus Number and Name

From Bus number and name. For transformers, the from bus is the tapped side. Right-clicking on either of these fields brings up the display’s local menu from which you may select Quick Power Flow List or Bus View Display to obtain more information about the from bus.

To Bus Number and Name

To Bus number and name. Right-clicking on either of these fields brings up the display’s local menu from which you may select Quick Power Flow List or Bus View Display to obtain more information about the to bus.

Circuit

Two-character identifier used to distinguish between multiple lines joining the same two buses. Default is ‘1’.

Status

The service status of the branch. This field is toggleable.

Branch Device Type

Identifier for the type of branch. Options are: Line, Series Cap, Breaker, Load Break Disconnect, Disconnector, ZBR, Fuse, and Ground Disconnect. The type of branch can be changed through this field except that a line cannot be changed from or to a Transformer. To make that change, use the Branch Options dialog in Edit mode. The type of branch becomes very important when using Integrated Topology Processing. Breakers and Load Break Disconnects are treated as special switching devices which can be controlled automatically through special actions, such as "Open with Breakers" and "Close with Breakers".

Xfrmr

Yes or no field signifying if the branch is a transformer or transmission line. This field cannot be changed.

MW From, Mvar From, MVA From (State display default)

Real, reactive, and complex power flowing into the line at the from bus.

In versions of Simulator prior to version 14, these values were always calculated based on the present voltage at a bus and other branch parameters each time they were displayed. This means that a user could change the bus voltage, or impedance, and see a corresponding change in the line flow values. These values are no longer calculated each time that they are displayed. They are updated following a power flow solution, loading in a case, following an update to the system due to OPF control changes, and after creating an equivalent. The exception to this is that when loading in a PowerWorld Binary (*.pwb) file and the flows are stored in the file, the stored flows will be retained instead of updating them based on the present system state. The MW and Mvar values can be set to user-specified values using an auxiliary file or pasting from Excel. This will allow the contouring of flows based on some external source.

Four additional fields have been added that will update each time they are displayed. This means that they will be updated following a voltage change for a bus or other relevant parameter (i.e. impedance) change for a branch. These fields take on the functionality of the flow fields prior to version 14 and are calculated each time that they are displayed. These fields are MW From (Calculated), MW To (Calculated), Mvar From (Calculated), and Mvar To (Calculated). These fields cannot be changed by the user.

Lim MVA, % of MVA Limit (Max) (State display default)

The current MVA limit of the branch, and the amount of the actual flow as a percentage of the MVA limit.

MW Loss, Mvar Loss (State display default)

Real and reactive power losses on the transmission line or transformer. Since reactive power losses include the effect of line charging, the reactive power losses may be negative.

R, X, B (Input display default)

Indicates the branch’s resistance, reactance, line charging susceptance in per unit on the system base.

Lim A MVA, Lim B MVA, Lim C MVA (Input display default)

Identifies the first three limit settings. Five additional limits can be set, for which the columns can be added using the Display/Column options from the local popup menu. All limits are expressed in MVA.

See Transformer Display for viewing transformer specific fields.