Transmission Substation Equipment includes...

• A. Breakers, disconnects, grounds, transformers between transmission voltages, relays, and indications.
• B. Only transformers.
• C. Only protective relays.
• D. Voltage regulators only.

Answer: (A)

Transmission substation equipment comprises the switching, protection, and monitoring devices that handle high-voltage power, enable safe operation, and allow maintenance. It includes breakers to interrupt fault currents, disconnectors (isolators) to isolate parts of the circuit for service, and grounding devices to provide a safe fault path and protect personnel. Between transmission voltage levels, transformers connect different voltage levels and integrate the grid. Protective relays monitor current, voltage, and other signals to detect faults and trigger protective actions, while indications (status lights, gauges, alarms) give operators visibility into the substation’s condition. Together, these elements form the set of equipment used in a transmission substation.

Options that mention only a single type—transformers, or protective relays, or voltage regulators—don’t capture the full scope, since a transmission substation relies on the coordinated presence of switching, protection, and monitoring devices in addition to transformers.