Standard Technical Features of BTG System for Supercritical 660 ...
Standard Technical Features of BTG System for Supercritical 660 ...
Standard Technical Features of BTG System for Supercritical 660 ...
Create successful ePaper yourself
Turn your PDF publications into a flip-book with our unique Google optimized e-Paper software.
<strong>Standard</strong> <strong>Technical</strong> <strong>Features</strong> <strong>of</strong> <strong>BTG</strong> <strong>System</strong> <strong>for</strong> <strong>Supercritical</strong> <strong>660</strong>/800 MW Thermal UnitsThe insulation shall have sufficient dielectricstrength to withstand rated phase to earthvoltage in slot portion and phase to phasevoltage in end windings. The insulation materialshall not have any tendency <strong>for</strong> plasticde<strong>for</strong>mation even under extreme operatingcondition like the conductor temperature,mechanical <strong>for</strong>ces, vibrations etc.The cooling circuit shall be provided withasuitable device to guard against any rise inpressure. Power & instrumentation leads shallbe taken out <strong>of</strong> the motor through water tightsealing glands & shall be run in flexible metalconduits or metal cable sheathing along thelength <strong>of</strong> the pump body.4. CoolingsystemThe design <strong>of</strong> the seals shall allow <strong>for</strong> effects <strong>of</strong>differential expansion between insulationconductor and pressure casing, over the entirerange <strong>of</strong> operating temperature.One number external high pressure cooler <strong>for</strong>each motor rated <strong>for</strong> 100% duty shall beprovided to remove the heat generated by themotor and bearings during operation. Thetemperature <strong>of</strong> high pressure cooling waterleaving the motor cavity to the cooler shall notexceed 60 0 C. The cooler shall be adequatelysized to reduce this temperature to 50 0 C.The design shall be such that during hot standbyservice <strong>of</strong> the pumping unit, sufficient coolingeffect is provided by natural circulation <strong>of</strong> thecoolant so as to prevent over heating <strong>of</strong> themotor.6.5.6 Superheaters & reheatersi) Superheaters and reheaters shall be designed, suitably sectionalized andpositioned to comply with the following, <strong>for</strong> the specified load(s),coal(s) and <strong>for</strong> normal, upset, most adverse and other operatingconditions:a) Rated steam temperature As indicated at clause 6.2 above.b) Maximum average flue 10 m/sec (maximum localized velocitygas velocity in section/ across the cross-section not to exceedtube banks with 12 m/sec)transverse tube pitching For high GCV low ash (say 10% and<strong>of</strong> 600 mm or less and below) coals: 12 m/sec (maximumwith 25% excess air at localized velocity across the crosssectionnot to exceed 14 m/sec)economizer outlet37
Change language