A method for operating start-up of a compressor train is disclosed. The train includes a driver machine and at least a centrifugal compressor drivingly coupled to the driver machine. The centrifugal compressor in turn includes a plurality of compressor stages and at least a first set of variable inlet guide vanes at an inlet of one of the compressor stages. The method includes at least partly closing the first set of variable inlet guide vanes; when the first set of variable inlet guide vanes is at least partly closed, starting rotation of the centrifugal compressor and accelerating the centrifugal compressor up to a minimum operating speed; opening the at least one set of variable inlet guide vanes to increase the gas flow through the centrifugal compressor once the minimum operating speed has been achieved.

Electrical systems for connecting rotary electric machines with gas turbine spools are provided. One such electrical system comprises: a first rotary electric machine mechanically coupled with a first gas turbine spool and a second rotary electric machine mechanically coupled with a second gas turbine spool, each said electric machine having an identical even number N≥4 of phases, each phase having a respective index n=(1, . . . , N), and each phase comprising an identical number P≥1 of coils wound in a P-plex configuration in which adjacent phases are radially separated by 2π/NP mechanical radians; a first set of N bidirectional converter circuits for conversion of alternating current (ac) to and from direct current (dc), each converter circuit having a respective index n and being connected with the P coils in the nth phase of the first rotary electric machine; and a second set of N bidirectional converter circuits for conversion of ac to and from dc, each converter circuit having a respective index n and being connected with the P coils in the nth phase of the second rotary electric machine. For all n, a dc side of the nth converter circuit in said first set is connected with a dc side of the nth converter circuit in said second set to facilitate dc power transfer between the first gas turbine spool and the second gas turbine spool.

A combined cycle plant includes: a gas turbine having a compressor, a combustor, and a turbine; a supplementary firing burner configured to raise a temperature of an exhaust gas of the gas turbine; a heat recovery steam generator configured to generate a steam using an exhaust heat of the exhaust gas; a steam turbine configured to be driven by the steam generated by the heat recovery steam generator; and a control device configured to change both an output of the combustor and an output of the supplementary firing burner when an output of the combined cycle plant is to be changed.

A combined cycle plant includes: a gas turbine having a compressor, a combustor, and a turbine; a supplementary firing burner configured to raise a temperature of an exhaust gas of the gas turbine; a heat recovery steam generator configured to generate a steam using an exhaust heat of the exhaust gas; a steam turbine configured to be driven by the steam generated by the heat recovery steam generator; and a control device configured to change both an output of the combustor and an output of the supplementary firing burner when an output of the combined cycle plant is to be changed.

Methods and systems for starting an engine are described. The method comprises a manifold purging phase where the at least one fuel manifold is filled with an inert gas; a manifold fuel filling phase, where fuel flows into the at least one manifold and blends with the inert gas as the engine rotates, and the inert gas is subsequently turned off; and an ignition phase, where the fuel flowing from the at least one manifold into the combustor is ignited and light-up is detected.

A method of identifying a fuel contained in a fuel tank of an aircraft and arranged to power a gas turbine engine of the aircraft is performed by processing circuitry of the aircraft and includes: obtaining at least one fuel characteristic of any fuel already present in the fuel tank prior to refuelling; determining at least one fuel characteristic of a fuel added to the fuel tank on refuelling; and calculating at least one fuel characteristic of the resultant fuel in the fuel tank after refuelling. The method may further controlling the propulsion system of the aircraft based on the calculated at least one fuel characteristic of the resultant fuel in the fuel tank after refuelling.

A method for block loading an electrical grid with a combined cycle power plant (CCPP) includes operating a gas turbine system of the CCPP in an islanding mode with a steam turbine system of the CCPP off line with turning gear rotating only; loading the steam turbine system accordingly to temperature matching conditions of the steam turbine system, the loading of the steam turbine system includes controlling gas turbine exhaust fed to the steam turbine system and the gas turbine exhaust temperature heats the steam turbine system and to meet temperature matching conditions of the steam turbine system; wherein controlling gas turbine exhaust includes controlling fuel flow and air flow to the gas turbine system; and operating at least one of the gas turbine system and steam turbine system to block load the electrical grid from a load on at least one of gas turbine system and steam turbine system.

A method for block loading an electrical grid with a combined cycle power plant (CCPP) includes operating a gas turbine system of the CCPP in an islanding mode with a steam turbine system of the CCPP off line with turning gear rotating only; loading the steam turbine system accordingly to temperature matching conditions of the steam turbine system, the loading of the steam turbine system includes controlling gas turbine exhaust fed to the steam turbine system and the gas turbine exhaust temperature heats the steam turbine system and to meet temperature matching conditions of the steam turbine system; wherein controlling gas turbine exhaust includes controlling fuel flow and air flow to the gas turbine system; and operating at least one of the gas turbine system and steam turbine system to block load the electrical grid from a load on at least one of gas turbine system and steam turbine system.

The invention relates to a device for the rapid reactivation of a helicopter turbine engine (6), characterised in that it comprises a pneumatic turbine (7) mechanically connected to said turbine engine (6) so as to be able to rotate it and ensure reactivation thereof; a pneumatic storage (9) connected to said pneumatic turbine (7) by means of a pneumatic circuit (10) for supplying pressurised gas to said pneumatic turbine (7); a controlled fast-opening pneumatic valve (11) arranged on the pneumatic circuit (10) between said storage (9) and said pneumatic turbine (7) and suitable for being on demand placed at least in an open position in which the gas can supply said pneumatic turbine (7), or in a closed position in which said pneumatic turbine (7) is no longer supplied with pressurised gas.

The invention relates to a device for the rapid reactivation of a helicopter turbine engine (6), characterised in that it comprises a pneumatic turbine (7) mechanically connected to said turbine engine (6) so as to be able to rotate it and ensure reactivation thereof; a pneumatic storage (9) connected to said pneumatic turbine (7) by means of a pneumatic circuit (10) for supplying pressurised gas to said pneumatic turbine (7); a controlled fast-opening pneumatic valve (11) arranged on the pneumatic circuit (10) between said storage (9) and said pneumatic turbine (7) and suitable for being on demand placed at least in an open position in which the gas can supply said pneumatic turbine (7), or in a closed position in which said pneumatic turbine (7) is no longer supplied with pressurised gas.