Longannet Power Station – Turbines

Back to Longannet main page
The turbine hall at Longannet housed four cross-compound generating units arranged in eight turbine lines. There were eight 300 MW generators – one per turbine line. Each of the four units manufactured by English Electric / GEC therefore had a total capacity of 600 MW.

Cross Compound Turbine Arrangement

Longannet utilised a cross-compound arrangement of turbines. Each unit had two turbine lines and therefore two generators per unit. One line incorporated a high-pressure (HP) turbine and two low-pressure (LP) turbines. The second line incorporated two intermediate-pressure (IP) turbines followed by two low pressure turbines. The steam was fed into the HP turbine first, then reheated and fed into the two IP turbines on the second line. After expansion in the IP turbines, the steam was finally divided equally between the four LP turbines. This arrangement has advantages in that the individual casings of the turbines can be smaller and has improved efficiency overall.

The boiler feed pumps were supplied by G&J Weir. Each unit had two starting/standby feed pumps and one primary feed pump driven by a steam turbine utilising steam bled from the high-pressure line.

Longannet Generating Units

List of power generating units at Longannet Power Station:

Turbine Pictures

Boiler Feed Pump Pictures

Back to Longannet main page