Case Studies

Swedish 220

Synchronous Condensing, Peaking Turbine Plant
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Photo courtesy of Svenska Kraftnat

After more that 50 years trouble free operation, this clutch was recently refurbished and returned into service demonstrating how SSS Clutches are “Fit and Forget”.

The plant is a reserve power plant for Svenska kraftnät designed to quickly start and deliver electricity in the event of a disturbance in the electrical system. The power plant consists of a block of Aero derivative jet engine-type gas turbine units where exhaust gases from the engines drive generators that produce electrical power.

The system includes 2 Rolls Royce AVON Gas Turbines each producing 15MW at 3000rpm driving a power turbine connected to an SSS 220FT clutch rated at 30MW.

These were always planned to be peaking plant generating active power for only a few hours per year, but when the designers of these gas turbine generators were planning them in the 1970’s who would have thought they would still be in use and relevant 50 years later?

However the fundamental physics of grid/electrical transmission hasn’t changed, so maintaining reactive power levels, grid frequency and security of supply is as important now as it was then - though the challenges are different

…the original clutches are still in service and after they were returned to SSS for overhaul (the first time in 50 years) no major parts were replaced....

Despite the age of the turbines and their relatively low efficiency by today’s standards, these machines have been overhauled recently with a minimum projected life extension of 20 years, providing a cost- effective use of existing assets and security of supply for the Swedish grid.

The longevity of these clutches demonstrates the ‘Fit & Forget’ attributes that characterise SSS Clutches when they are provided with clean oil supply and good alignment by the operators.