Major components of a power station

A power station converts primary energy into electrical energy and delivers it to the grid. Its major electrical components are:

1. Alternator (synchronous generator): Converts mechanical energy from the turbine into 3-phase electrical energy, usually at 6.6–11 kV (up to 25 kV in large plants).
2. Excitation system: Supplies DC to the rotor field (static or brushless exciter) and, with the AVR, controls the terminal voltage and reactive power.
3. Governor (control): Adjusts the turbine input to hold speed/frequency and share active power.
4. Generator step-up transformer: Raises the voltage from generator level to transmission level (e.g. 11/132 kV).
5. Busbars: Conductors that collect power from generators and distribute it to outgoing feeders.
6. Switchgear: Circuit breakers (SF₆/vacuum), isolators and earthing switches to connect, disconnect and protect equipment.
7. Protective relays and instrument transformers: CTs and PTs feed relays (differential, overcurrent, distance) and meters.
8. Lightning arresters: Protect equipment from lightning and switching surges.
9. Station auxiliary transformer and auxiliaries: Supply pumps, fans, lighting, cooling inside the plant.
10. Control room, metering and SCADA: Monitor and control the plant; energy meters record export.
11. Battery bank and DC system: Supplies relays and breaker trip coils even during AC failure.
12. Earthing system: Safe path for fault currents and personnel safety.

 Turbine--[G]--[CB]--[GT 11/132 kV]--[CB]--Bus--Lines
           |                                 |
        Exciter/AVR                     LA, CT, PT