Laserfiche WebLink
SECTION 2.0:PROJECT DESCRIPTION <br /> inverter, a static transfer switch, a manual bypass switch, an alternate source transformer, <br /> and two or more panelboards. <br /> The normal source of power to the system will be from the 125-volt DC power supply <br /> system through the inverter to the panelboard. A solid-state static transfer switch will <br /> continuously monitor both the inverter output and the alternate AC source. The transfer <br /> switch will automatically transfer essential AC loads without interruption from the inverter <br /> output to the alternate source upon loss of the inverter output. <br /> A manual bypass switch will also be included to enable isolation of the inverter for testing <br /> and maintenance without interruption to the essential service AC loads. <br /> The distributed control system(DCS) operator stations will be supplied by UPS power. The <br /> continuous emission monitoring system (CEMS) equipment,DCS controllers,and <br /> input/output (I/O) modules will be fed using either UPS or 125-volt DC power directly. <br /> 2.1.8 Fuel System <br /> The CTG will be designed to burn natural gas only.The natural gas requirement during <br /> base load operation at annual average ambient temperature is approximately <br /> 1,857 MMBtu/hr (higher heat value [HHV] basis). The maximum natural gas requirement, <br /> experienced during low ambient-temperature operation,is approximately 2,079 MMBtu/hr <br /> (HHV basis). <br /> Natural gas will be delivered from PG&E's Line#108 to the site via a new 2.5-mile-long <br /> pipeline,which will be adjacent to the existing natural gas pipeline used to serve the STIG <br /> plant. At the plant site,the natural gas will flow through a flow-metering station,gas <br /> scrubber/filtering equipment, a gas pressure control station,and a steam-heated fuel gas <br /> heater prior to entering the combustion turbine. <br /> Historical data indicate that the fuel gas pressure on PG&E's Line#108 generally varies <br /> between 300 and 400 pounds per square inch gauge (psig). Two 100-percent-capacity, <br /> electric-driven fuel gas compressors will be provided to boost the fuel gas pressure to about <br /> 500 psig,which is the pressure required by the combustion turbine. The gas compressors <br /> will be located outdoors and will be treated acoustically either by acoustical enclosures or a <br /> soundwall to reduce the compressor noise level. <br /> 2.1.9 Plant Cooling Systems <br /> The steam turbine cycle heat rejection system will consist of a deaerating steam surface <br /> condenser,cooling tower, and cooling water (circulating water) system. The heat rejection <br /> system will receive exhaust steam from the low-pressure steam turbine and condense it to <br /> water (condensate) for reuse. A surface condenser is a shell-and-tube heat exchanger;the <br /> steam condenses on the shell side, and the cooling water flows through the tubes,making <br /> one or more passes. The condenser will be designed to operate at a pressure of <br /> approximately 2 inches of mercury, absolute at an ambient temperature of 61.2°F. <br /> Approximately 542 MMBtu/hr of heat will be transferred from condensing steam to cooling <br /> water in the condenser. <br /> The cooling water will circulate through a counter-flow, 7-cell,mechanical draft cooling <br /> tower that uses electric motor-driven fans to move air in a direction opposite to the flow of <br /> SACI371322I082340003(LEC_2.0_PROJECT_DESC.DOC) 2-19 <br />