A substation is a critical node in the electricity grid that performs a variety of functions, but its primary role is to change voltage levels. It houses a range of specialized equipment, with the transformer being the most important component for this transition.

• Step-Down Voltage: At a substation, large step-down transformers receive electricity at high or extra-high voltages (e.g., 500 kV) and reduce it to a lower voltage (e.g., 33 kV or less) for the distribution network. This allows the electricity to be safely transported through smaller, local power lines.

• Switching and Protection: Substations also contain switchgear, circuit breakers, and relays. These devices allow operators to control power flow, isolate faults (like short circuits or line failures), and protect the entire system from damage, ensuring reliability and safety.

Without substations, the modern power grid would not be able to function, as there would be no way to safely deliver electricity to end-users.