This feature class/shapefile represents electric power substations primarily associated with electric power transmission. In this layer, substations are considered facilities and equipment that switch, transform, or regulate electric power at voltages equal to, or greater than, 69 kilovolts. Substations with a maximum operating voltage less than 69 kilovolts may be included, depending on the availability of authoritative sources, but coverage of these features should not be considered complete. The Substations feature class/shapefile includes taps, a location where power on a transmission line is tapped by another transmission line. The following updates have been made since the previous release: 6,359 features added.