See Also
The Run Mode version of this dialog is very similar in content to its Edit Mode counterpart.
The Branch Information Dialog sports the following fields:
From Bus Number and Name
From Bus number and name. For transformers, the from bus is the tapped side.
To Bus Number and Name
To Bus number and name.
Circuit
Find By Number
To find a line or transformer by its bus numbers, enter the from and to bus numbers and the circuit identifier. Then click this button. Use the spin button to cycle through the list of lines and transformers in the system.
Find By Name
To find a line or transformer by the names of its terminal buses, enter the from and to bus names and the circuit identifier. Then click this button.
Find…
If you do not know the exact from and to bus numbers or names you are looking for, you can click this button to open the advanced search engine.
From End Metered
This field is only used for lines and transformers that serve as tie lines, which are lines that join two areas. If this field is checked for a tie line, the from end of the device is designated as the metered end. Otherwise the to end is metered. By default, the from end is metered. The location of the metered end is important in dealing with energy transactions because it determines which party must account for transmission losses.
From and To Bus Area Name
Names of the areas in which the From and To buses are located.
From and To Bus Nominal kV
From and To bus nominal voltage levels.
From and To Bus Voltage (p.u.)
The actual terminal bus voltages of the transmission element, in per unit.
Labels
Clicking on this button will open the Labels dialog listing all the labels for the selected branch.
Parameters
Status
Current status of the device.
Energized
Indicates if the branch is energized. This is not the same as the Open or Closed status. A branch may be in-service itself (closed) but not be energized, based on the statuses of other devices around the branch. For example, in a full topology model, it is not uncommon for a branch of type Line has a status of Closed, but the branch is not energized if branches of type Circuit Breaker at both ends of the Line are Open.
Per Unit Impedance Parameters
The resistance, reactance, the total charging susceptance (that is, B, not B/2), and the total shunt conductance of the device (in per unit). Magnetizing conductance and susceptance is included if the branch is a transformer.
Line Shunts
Select to view the Line Shunt Dialog. This dialog is used to create or modify line shunts. Line shunts cannot be created or deleted while in Run Mode. Line shunts are expressed in terms of the per-unit conductance and susceptance at each end of the line or transformer. If the line has shunts, the check box Has Line Shunts is checked.
MVA Limits
Ratings for the transmission line or transformer in MVA. Eight different limits are allowed.
Flows
These next fields show the actual real and reactive power flow at both ends of the device (because of real and reactive losses these numbers may be different), and its percentage MVA loading. The line losses are summarized as well.
D-FACTS Devices on the Line
Transformer
The tab is only visible if the branch is a transformer. See the Transformer Control help for more information on transformer types and controls.
Series Capacitor
The OPF tab is only visible if you have the OPF (Optimal Power Flow) add-on tool for PowerWorld Simulator.
Enforce Line Flow Limit
This check box must be checked if the branch limit is going to be enforced when running an OPF solution. If this box is not checked, the OPF routine will allow the branch to violate its branch limits.
Treat Limit as Equality Constraint
If checked, the OPF solution will attempt to solve the load flow while keeping the flow on the branch at its limit.
Maximum MVA Flow
The largest MVA flow value measured on the line, either at the From or To bus.
Present MVA Limit
The limit enforced by the OPF for the branch. This is set in the OPF constraint options, and is related to the original branch limits.
Maximum Percentage
The highest percentage of flow measured on the line, either at the From or To bus.
Limit Marginal Cost
The cost of enforcing the branch MVA limit.
Included in LP
Specifies whether or not the branch flow and limit was included as a constraint in the OPF solution. In general, branches that are not near their limit and do not appear to be changing flow dramatically towards their limit will be ignored in the OPF calculation to speed up the solution. No and Yes indicate whether or not the OPF process determined that the line needed to be included. The user can initially force the branch to be included or not included with these two fields. By choosing Always, the branch will be included in the OPF solution constraints regardless of the propensity of the line to be approaching it's limit.
MVA Flow Constraint Status
The constraint status for the line in the OPF solution will be shown here with the corresponding boxes checked by Simulator. These check boxes cannot be changed manually by the user.
From/To Bus MW Marginal Costs
Displays the marginal costs of the branches terminal buses, following the solution of the OPF.
Fault Info
The parameters on this tab are used when running a fault analysis study. The values represent the zero sequence impedance and zero sequence line shunt admittances for the analysis. By default, the positive and negative sequence line impedances and line shunt admittances are the same as the load flow impedance. The same fields are used for transformers, along with the configuration field. The configuration field defines the winding type combinations for the transformer (wye, delta, etc.) As a default, Simulator assumes an ungrounded wye to ungrounded wye transformer, which has the same model as an open circuit. Usually transformers are not of this type, and the proper type would need to be defined either manually or loaded from an external file in order for the fault analysis to be accurate.
Owner, Area, Zone, Sub, PTDF
The Default Owner (Same as From Bus) read-only check-box indicates whether the line’s owner is the same than the from bus’ owner. Transmission elements can have up to four different owners, each with a certain owner percentage. To add an owner of a transmission element, change one of the Owner fields to a new owner number, and update the owner percentages accordingly. Note that if you do not set the new owner percentages of all specified owners such that the total is 100%, Simulator will normalize the percentages such that the total is 100% when you click Save or OK on the branch dialog.
The area, zone and substation to which the From and To buses belong, are also shown. If a PTDF calculation has been performed, the PTDF values for the viewed line will be displayed as well.
Custom
This page of the dialog contains two sections: custom fields and memo.
The custom fields section allows access to setting and changing the values for custom fields that have been defined for the branch. Defining custom fields is detailed in Custom Field Descriptions.
The Memo section of the dialog is simply a location to log information about the branch. Any information entered in the memo box will be stored with the case when the case is saved to a PWB file.
Stability
This tab is only visible with the Transient Stability Add-On tool. Any branch-specific transient stability modeling information is contained on this tab. For more information see the Transient Stability Data: Object Dialogs.