Operating Characteristics of a 420-MW Combined Cycle Heat and Power Plant^1,2

Thermal tests of the combined cycle (steam-gas) unit at the CHPP No. 26 Mosenergo have been carried out, with measurements of the power and efficiency of the steam-gas unit, as well as the flow rates and parameters of the heat transfer media (air, combustion products, water, and steam) over a wide range of electrical loads and ambient air temperatures. The maximum electric power of the combined cycle unit was varied from 430 MW in the winter with ambient temperatures below –10°C to 380 MW in the summer at 30°C. The efficiency ranged from 59.8 to 58%. The performance indicators of the combined cycle unit were also determined for combined electricity and heat production. For a guaranteed thermal load of 140 Gcal/h, the electrical power of the steam turbine is reduced by 17 MW, the power of the combined cycle plant is about 400 MW, and its electrical efficiency is 57%. The performance characteristics of the combined cycle unit and the gas-turbine unit are given for different operating modes, together with data on the steam capacity, the parameters of the steam in the boiler-utilizer loops, and the efficiency of the cylinders of the steam turbine.