Guide for the Evaluating of Thermal Performance Index and Optimizing of Thermal Performance for Gas-Steam Combined Cycle Power Generation Unit

This document applies to thermal performance indicator evaluation and thermal performance optimization for gas-steam combined cycle power generation units of all capacity classes; other types of gas turbine generating units may apply it by reference. It specifies the contents and correction methods for combined-cycle unit performance indicators, covering gross and net thermal efficiency, auxiliary power consumption rate, comprehensive thermal efficiency, and indicators for gas turbines, heat recovery steam generators, steam turbines, pipeline systems and other subsystems. Operating entities should conduct evaluations using corrected indicators and may improve unit performance through intake-system cleaning and upgrading, compressor water washing, hot-gas-path maintenance, heat recovery steam generator sealing optimization, steam-turbine flow-path and cold-end optimization, insulation improvement, auxiliary-power saving, waste-heat recovery, thermal-system drainage optimization, and energy-saving management during start-up, shutdown and standby.