Abstract: A cross compound turbine apparatus and method of operating the same wherein the apparatus includes a first turbine generator having a high pressure turbine and a first low pressure turbine connected to a first generator driving shaft, with the second turbine generator having an intermediate pressure turbine connected to a second generator driving shaft. Driving steam is supplied to the high pressure turbine and a primary steam line communicates exhaust steam from the high pressure turbine to drive the intermediate pressure turbine during a steady state operation of the first and second turbine generator sections. A bypass steam line communicates steam from the system supplying driving steam to the high pressure turbine to the intermediate pressure turbine in a bypassing relationship to the high pressure turbine.

Abstract: In a plant of a composite cycle which includes a steam turbine having a high pressure portion and a low pressure portion, a gas turbine, and a waste heat boiler having heat exchangers producing high pressure steam and low pressure steam to be fed to the steam turbine, by the use of exhaust gas from the gas turbine as a heat source; there are provided steam valves on steam passages through which steam is fed from the heat exchangers of waste heat boiler to the steam turbine; a detecting device for detecting the condition of steam flowing into the steam valve; and another detecting device for detecting the r.p.m. of the steam turbine; whereby the opening and closing of the steam valves are controlled by means of a selecting device which preferentially selects either of signals from the aforesaid detecting devices to adjust the quantity of steam to be fed to the steam turbine for controlling the steam turbine.