Dear sir,

Can you plz explain the operation of GT-ST single shaft configuration? Just in brief..

Thanks n regards,
Wasim Shaikh

 

Wasim Shaikh,

Your question is a little unclear.

Both steam- and gas turbines are torque-producing devices and a generator is a device for converting torque into amperes.

A single-shaft steam- and gas turbine driving a generator is just what is says it is: a steam turbine, gas turbine and generator all coupled together (directly) all rotating at the same speed.

During starting, the generator is used as a motor to accelerate the "train" (as it's commonly called"; the steam turbine, the gas turbine and the generator). As the gas turbine accelerates the train to rated speed the exhaust hear from the gas turbine starts to make steam in the heat recovery steam generator. Once there is sufficient steam pressure at the proper temperature steam is admitted to the steam turbine.

Both turbines will contribute to the total torque applied to the generator rotor to be converted into amperes when the generator is synchronized and contributing to powering the electrical load on the grid.

Now, there may be some single-shaft designs where there is some kind of "clutch" between the steam turbine, or even the gas turbine, but I don't think they're very common. In such a configuration, the turbine that is directly coupled to the generator would accelerated the generator to rated speed, and then the turbine coupled through the clutch could be brought up to rated speed and as the energy flow-rate into that turbine was increased it would be adding to the total torque applied to the generator rotor.

If you require more information or this is not the information you were inquiring about, please clarify your query.