Setting Bus kV
When you add a bus to the one-line, you must provide the kV of that bus before you can attach anything to it. You can either set a default kV ahead of time (before adding the bus to the one-line) by clicking Tools > Equipment > Bus and specifying the base kV, or you can set it afterward by double-clicking on the bus to bring up its data dialog box.
EasyPower also allows you to set the kV of more than one bus at a time by using Copy and Paste as described in Copying an Item's Database Information.