Industry glossary
Terms you will meet in the documents, systems and scenarios.
Combined cycle
A plant arrangement where gas turbine exhaust heat raises steam in a heat recovery steam generator to drive a steam turbine, increasing overall efficiency.
Heat recovery steam generator (HRSG)
The boiler that recovers heat from gas turbine exhaust to produce steam for the steam turbine.
Permit to work
A written authorisation that defines the work, the isolations and the controls before anyone works on plant.
Proving dead
Testing an isolated electrical circuit with a tested instrument to confirm no voltage is present before work begins.
Synchronisation
Matching a generator's voltage, frequency and phase to the grid before closing its circuit breaker.
Dispatch
The instruction from the market operator that sets the output a generating unit must provide for a trading interval.
Exhaust temperature spread
The difference between the highest and lowest exhaust thermocouple readings on a gas turbine, used to detect combustion problems.
Piezometer
An instrument installed in a dam or its foundation that measures water pressure at a point.
Pitch system
The mechanism in a wind turbine hub that rotates each blade to control power and to stop the rotor.
Outage
A planned or forced period when a generating unit is out of service for maintenance or repair.