A substation is a high-voltage power system facility that connects parts of the grid and helps transform voltage, switch circuits, isolate faults, measure power, and control electricity flow. View of a 50 Hz electrical sub station in Australia, showing three 220 kV/66 kV (150 kVA) transformers. Steel lattice structures support strain bus wires and apparatus, and transformer fire barriers prevent catastrophic failure of any one transformer from damaging adjacent units. A substation has protection devices that safeguard the. In a less simple way, substation is the key part of electrical generation, transmission, and distribution systems.