Standard Technical Features of BTG System for Supercritical 660 ...
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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 ...

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Standard Technical Features of BTG System for Supercritical 660/800 MW Thermal Unitsmanufacturer. In such case VWO shall mean wide open condition of theturbine main control valves and the overload valves.ii)iii)iv)The turbine- generator set shall be capable of continuous TMCR outputunder rated steam conditions, 89 mm Hg (abs) 3 condenser pressure, 1%make-up and 47.5 Hz grid frequency.The steam turbine generator unit shall be suitable for direct connectionto steam generator having no inter connection with other units either onthe boiler feed water side or main steam side.The steam turbine shall have preferably seven uncontrolled extractionsfor regenerative feed heating based on optimized cycle and shall besuitable for satisfactory operation under tropical conditions. The cycleshall consist of minimum 3 nos. of HP heaters with extraction for top HPheater from HP turbine, one no. of deaerator and minimum 3 nos. of LPheaters.12.1.4 Operational capabilitiesi) Overpressure Operation (if applicable): Turbine overpressure capability(under VWO) shall be indicated along with corresponding continuousoutput of TG set. The Turbine shall be capable of accepting variation insteam pressure as per IEC-45.ii)iii)iv)HP Heaters Out of Service: Turbine shall be capable of continuousoperation under all HP heaters out of service with maximum output notless than rated output.Variable Pressure Operation: Turbine shall be capable of operating onvariable pressure mode during part load and start-up operation.Two Shift & Cyclic Load Operation: The Turbine shall be suitable fortwo-shift operation & cyclic load variations.v) Fast Start- up and Loading/ Unloading Rate: The TG set shall becapable of being started from cold condition to full load operatingconditions in as short time as possible. The TG set shall be designed forminimum rate of loading/ unloading mentioned below withoutcompromising on design life of the machine:a) Step load change : Minimum ± 10% to facilitate fast loading/unloading of the unit.b) Ramp Rate : Minimum ± 3% per minute above 30% load.3 70mmHg (abs) for sea water based once through CW system89

Standard Technical Features of BTG System for Supercritical 660/800 MW Thermal Unitsvi)vii)House- load Operation: The TG set shall be capable of operating onHouse load using HP-LP bypass system during sudden total exportload throw off. Unit shall not trip on overspeed in the event of totalexport load throw-off.No. of Start- ups: Expected number of turbine generator start-upsduring design life of minimum 25 years shall be as under. The designof turbine generator and the associated systems shall take care of thesestart ups without affecting the life of equipment adversely. Nocomponent shall be stressed beyond acceptable safe stress and fatiguelevels when operating under the stated duty conditions.a) Cold Start (after shut down period exceeding 72hours)b) Warm Start (after shut down period between 10hours and 72 hours)c) Hot Start (after shut down period less than 10hours)1501000400012.1.5 Material requirementsThe steam turbine shall be built-up using materials which are field proven.12.1.6 Maintenance requirementsi) Wet Steam Washing (if applicable): Necessary stubs/ connections onturbine/piping shall be provided for future connection to wet steamwashing system, if applicable, as per standard practice of turbinemanufacturer.ii) Fast Cooling of Turbine: Provision shall be made to facilitate fastcooling of turbine during emergency condition for quick access.iii)iv)Boroscopic Inspection: Boroscopic Inspection ports shall be provided inturbine for in situ inspection of turbine internals as per standard practice.The inspection ports shall cover turbine internals as maximum aspossible as per manufacturer Standard practice. The inspection portshould be designed for ease of accessibility with leakage proof featureswhile in operation.Preservation System: Turbine preservation system shall be provided toprotect against corrosion during idle periods as per OEM practice.12.2 Turbine CasingThe turbine casing design shall have following features:i) Symmetrical in design to minimize effects of thermal stress and creep.90

<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 Unitsmanufacturer. In such case VWO shall mean wide open condition <strong>of</strong> theturbine main control valves and the overload valves.ii)iii)iv)The turbine- generator set shall be capable <strong>of</strong> continuous TMCR outputunder rated steam conditions, 89 mm Hg (abs) 3 condenser pressure, 1%make-up and 47.5 Hz grid frequency.The steam turbine generator unit shall be suitable <strong>for</strong> direct connectionto steam generator having no inter connection with other units either onthe boiler feed water side or main steam side.The steam turbine shall have preferably seven uncontrolled extractions<strong>for</strong> regenerative feed heating based on optimized cycle and shall besuitable <strong>for</strong> satisfactory operation under tropical conditions. The cycleshall consist <strong>of</strong> minimum 3 nos. <strong>of</strong> HP heaters with extraction <strong>for</strong> top HPheater from HP turbine, one no. <strong>of</strong> deaerator and minimum 3 nos. <strong>of</strong> LPheaters.12.1.4 Operational capabilitiesi) Overpressure Operation (if applicable): Turbine overpressure capability(under VWO) shall be indicated along with corresponding continuousoutput <strong>of</strong> TG set. The Turbine shall be capable <strong>of</strong> accepting variation insteam pressure as per IEC-45.ii)iii)iv)HP Heaters Out <strong>of</strong> Service: Turbine shall be capable <strong>of</strong> continuousoperation under all HP heaters out <strong>of</strong> service with maximum output notless than rated output.Variable Pressure Operation: Turbine shall be capable <strong>of</strong> operating onvariable pressure mode during part load and start-up operation.Two Shift & Cyclic Load Operation: The Turbine shall be suitable <strong>for</strong>two-shift operation & cyclic load variations.v) Fast Start- up and Loading/ Unloading Rate: The TG set shall becapable <strong>of</strong> being started from cold condition to full load operatingconditions in as short time as possible. The TG set shall be designed <strong>for</strong>minimum rate <strong>of</strong> loading/ unloading mentioned below withoutcompromising on design life <strong>of</strong> the machine:a) Step load change : Minimum ± 10% to facilitate fast loading/unloading <strong>of</strong> the unit.b) Ramp Rate : Minimum ± 3% per minute above 30% load.3 70mmHg (abs) <strong>for</strong> sea water based once through CW system89

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