ARCHIVED REPORTS LEC APPLICATION FOR CERTIFICATION

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SECTION 2.0:PROJECT DESCRIPTION 2.5.2.1 Combined-Cycle Power Block One combustion turbine/HRSG power generation train is designed for the LEC combined-cycle power block. The combustion turbine will provide approximately 60 percent of the total unfired combined-cycle power block output. The heat input from the exhaust gas from the combustion turbine will be used in the steam generation system to produce steam. Heat input to the HRSG can be supplemented by firing the HRSG duct burners,which will increase steam flow from the HRSG. Thermal energy in the steam from the steam generation system will be converted to mechanical energy and then to electrical energy in the STG subsystem. The expanded steam from the steam turbine will be condensed and recycled to the feedwater system.Power from the STG subsystem will contribute approximately 40 percent of the total unfired combined-cycle power block output. The combined-cycle power block comprises the major components described below. 2.5.2.2 CTG Subsystems The combustion turbine subsystems will include the combustion turbine,inlet air filtration, evaporative cooling water wash injection, generator and excitation systems,and turbine control and instrumentation. The combustion turbine will produce thermal energy through the combustion of natural gas. The thermal energy will be converted into mechanical energy through rotation of the combustion turbine,which drives the compressor and generator. Exhaust gas from the combustion turbine will be used to produce steam in the associated HRSG. The CTG generator will be totally enclosed,hydrogen cooled. The generator excitation system will be a solid-state static system. Combustion turbine control and instrumentation(interfaced with the DCS) will cover the turbine governing system,the protective system,and the sequence logic. 2.5.2.3 HRSG Subsystems The steam generation system will consist of the HRSG and blowdown systems. The HRSG system will provide for the transfer of heat from the exhaust gas of the combustion turbine and from the supplemental combustion of natural gas in the HRSG duct burner for the production of steam. This heat transfer will produce steam at the pressures and temperatures required by the steam turbine. The HRSG system will consist of ductwork, heat transfer sections, duct burners, an SCR system, and an oxidation catalyst module, as well as safety and auto-relief valves and processing of continuous blowdown drains. 2.5.2.4 STG Subsystems The steam turbine will convert the thermal energy to mechanical energy to drive the STG shaft to produce electrical energy in the generator. The basic subsystems will include the steam turbine and auxiliary systems,turbine lubrication oil system, and generator/exciter system. The steam turbine's generator will be totally enclosed and hydrogen-cooled. 2.5.2.5 Plant Distributed Control System The DCS will be a redundant microprocessor-based system and will have a functionally distributed architecture comprising a group of similar redundant processing units;these units will be linked to a group of operator consoles and an engineer work station by redundant data highways. Each processor will be programmed to perform specific dedicated tasks for control information, data acquisition, annunciation, and historical 2-38 SAC/371322/082340003(LEC_2.0_PROJECT_DESC.DOC)