Abstract: In a liquid cooled thyristor stack in which a plurality of disk thyristors are stacked between a plurality of cold plates such that each thyristor has a cold plate on either side thereof, relatively rigid tubular connectors are provided which extend between the cold plates and an associated coolant header. The connectors are provided at first ends with reduced diameter portions for receiving electrically non-conductive insulating bushings which are, in turn, received within ports of the coolant header.

Abstract: In a combined cycle power plant comprising a steam turbine and gas turbine connected through a heat recovery steam generator, the start-up mode for a steam turbine is based upon the shell metal temperature of the steam turbine. In some combined cycle plants, the output of the gas turbine is reduced so as to more closely match the output steam temperature of the heat recovery steam generator to the steam turbine metal temperature. This arrangement can be disadvantageous for several reasons and so it is proposed that a spray attemperator or desuperheater be incorporated between the heat recovery steam generator outlet and the steam turbine inlet. Moreover, control means are indicated for controlling the fluid input into the attemperator.