Three Winding Transformer Display

See Also

 

The Three Winding Transformer Display shows information about all the three winding transformer devices in the case. Three winding transformers are modeled in Simulator as a grouping of two winding transformers, connected at a common midpoint or "Star" bus. The Three Winding Transformer Display is a way to view all the terminal connection points for the three winding transformers and the power delivered at each of the terminals.

Depending on how the three winding transformer was loaded into Simulator, the star bus may be dynamically created for the three winding transformer, with Simulator choosing the star bus number and name. If the star bus numbers and names of three winding transformers need to be changed, an option exists to load the new star bus numbers and names from a file. This option can be selected from the Three-Winding Transformer display in the Model Explorer by right-clicking on the table and choosing 3W Transformer Records > Renumber Star Buses while in edit mode. The format for the text file is one record per row, with six fields for each record. The first four fields are primary bus number, secondary bus number, tertiary bus number, and circuit ID. These fields identify for which three winding transformer the star bus is being changed for that record. The last two fields for each record will be the new star bus number and new star bus name. If the new bus number specified is already in use in the case, the record will be ignored and the star bus will not be renumbered for that three winding transformer record. Note that the first three fields can be specified as the "name_kv" of each of the three winding transformer terminal buses instead of the bus numbers.

The Three Winding 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 three winding transformers. When in Edit Mode, you can define new three winding transformers using the Insert option, or delete existing three winding transformers using Delete. You can also sort the three winding transformer information by clicking on the heading of the field by which you want to sort.

To show this display, open the model explorer and click on Network > Three Winding Transformers.

 

This display contains the following fields by default:

Pri Bus Num, Sec Bus Num, Ter Bus Num

These are the primary winding, secondary winding and tertiary winding terminal bus numbers for the three winding transformer connections.

Circuit 

The circuit identifier for the three winding transformer.

Pri, Sec and Ter MW and MVAr

These fields display the real and reactive power delivered at each of the three winding transformer terminals.

Star Bus Number and Name

These two fields provide the number and name of the internal node star bus used in the three winding transformer equivalent model.

 

While in Edit mode, the local menu allows an option that is specific to three-winding transformers. The option is found on the 3W Transformers records > menu item:

Renumber Star Buses...

This option allows renumbering the star buses of three-winding transformers to user-specified values. This is done via a text file that is loaded with the new designations. The format of the text file is the following:

 

Primary bus, Secondary bus, Tertiary bus, circuit, new star bus number, new star bus name

 

Either the bus number or name_nominal kV (secondary key field) combination may be used to identify the buses. Each bus may be identified using either method even for the same three-winding transformer. Use double slashes (//) to indicate a comment in the file. Any text past the double slashes will be ignored. The file may be either space or comma delimited. If the tertiary bus does not exist, this entry should be either a 0 or empty string enclosed in double quotes. If the new star bus number already exists and is the star bus of another three-winding transformer, the star bus number of the other three-winding transformer will be reassigned and the current transformer will take the specified number. If the specified new star bus number already exists and is not taken by another star bus, the three-winding transformer will not be updated with the specified new star bus number.