ATS - Connection Information

Uniquely identifies the equipment item. The program automatically assigns a name, but you can change it, if needed. The name can be up to 30 characters long.

For automatic transfer switches, the program automatically assigns the names ATS-1,ATS-2, ATS-3, and so on.

Base kV for the ATS. An ATS has three buses as shown by the nodes in the symbol. Note that the bus must have a kV entered before equipment can be connected to the bus. Anything less than 1kV is considered low voltage, anything 1kV or more is high voltage.

The base kV displays the highest voltage between the current carrying conductors. For 3-phase or line-to-line connected single-phase equipment, the base kV is the line-to-line (LL) voltage. For line-to-neutral (LN) connected single-phase equipment, the base kV is the line-to-neutral voltage.

The list of base kV values comes from the table in Tools > Options > System. You can choose from the list or manually type in a value.

The phase type for this item:

• 3PH: 3 phase
• 1PH: 1 phase

The service for this item.

• For three phase, the options are 3PH-3W (3-phase, 3-wire) or 3-PH-4W (3-phase, 4-wire).
• For single phase, the options are 1PH-2W (1-phase, 2 wire) or 1PH-3W (1-phase, 3-wire). See 1PH-3W Systems for more information.

When you create a one-line, it is important to set the service for the ATS before you connect the ATS to other equipment.

Service Type and Phase Connection: A single-phase ATS will have the same service type on all terminals (Source 1, Source 2 and Load). It is possible for the two sources to have different phase connection types upstream. When the source data is changed in the ATS dialog box, or when the ATS position is toggled in any analysis mode (such as in Short Circuit), the program automatically propagates the phase connection type to all of the downstream equipment. This action also makes the necessary changes to update the per-unit calculations for analysis or to update the load calculations.