Hawthorne, Kansas City, Missouri
In the middle 1990’s one of the units of the Hawthorn Power Station was replaced by a new peak load Siemens V84.3A gas turbine generator (rated at 172 MW and 200 MVA). As the foreseen power generation time was only 500 hours per year, the unit was equipped with an SSS Clutch installed between the generator and the gas turbine to enable synchronous condensing for about two months in winter and three months in summer. The generator of this machine is used to accelerate the gas turbine for start, has variable frequency, and can be accelerated to full speed (3600 rpm) for synchronous condensing without starting the turbine. Since plant startup in 1997, its capacity has been 170 MW of power and, with turbine stopped and generator functioning as a synchronous motor, a range of 150 and -87 MVAR.