Appendix E-2.c.i Energy Plan 2004-2013 Follow-up Studies and ...

Re-powering Study for the Northport and Port Jefferson Power Stations
Appendix II Northport System Descriptions
Low point drains are in accordance with ASME TPD, “Recommended Practices for the Prevention of
Water Damage to Steam Turbines Used for Electric Power Generation”.
1.4 Low Pressure Steam
Refer to PID-03-04A and PID-03-4B in Appendix III.
The LP steam system directs superheated steam from the LP superheater outlet of each HRSG to the
steam turbine low pressure admission valves.
The LP steam line from each HRSG contains a flow orifice, a bypass branch, and a motor operated stopcheck
valve. For Northport Hybrid Option, the HRSG lines combine into a common header en route to
the steam turbine. The common header connects to a single connection in the intermediate pressure (IP)
steam turbine outlet. Admission stop and control valves are installed in the LP steam piping near the
steam turbine. The LP steam combines with the IP turbine exhaust steam and travels through the
crossover into the LP section of the steam turbine.
The LP steam bypass valves provide a means for bypassing LP steam to the condenser during startup and
during steam turbine trip conditions. The LP steam lead from each HRSG is equipped with a steam
conditioning valve (bypass valve) to lower the steam pressure and temperature to acceptable condenser
design levels. Attemperating water for the steam conditioning valves is from the condensate system
through temperature control valves.
Low point drains are in accordance with ASME TPD, “Recommended Practices for the Prevention of
Water Damage to Steam Turbines Used for Electric Power Generation”.
1.5 Auxiliary Steam
Refer to PID-03-05A in Appendix III.
1.5.1 General
The auxiliary steam system provides 150 psig steam at 520ºF to the condenser steam jet holding air
ejector, and the steam turbine gland steam system. The source of the steam for the auxiliary steam system
is from the cold reheat system. During start up steam is provided to the auxiliary steam system from the
main steam system. Both sources of steam are each provided with pressure reducing valves to lower
steam pressure to the correct auxiliary steam pressure. Two desuperheater stations are provided to
condition the auxiliary steam from either source.
The Auxiliary Steam System also provides cooling steam to the M501G during startup and shutdown as
per MHI requirements. This steam is generated by the Auxiliary boiler in accordance with MHI quality,
flow, pressure, and temperature requirements.
During short duration outages, typically overnight and weekends, or whenever it is desired to maintain the
plant in a hot or warm condition and during normal plant start-ups, steam is supplied by the auxiliary
boiler.
The system is equipped with roof mounted safety valves, system traps and drains, as well as suitable nonreturn
valves and isolation valves to prevent steam back flow during unit trips. The source of the
desuperheater water is from the condensate pump discharge.
The Auxiliary steam system contains the following major components:
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