10-04-2017, 07:26 PM
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P&I OF BOILER AUXILLARIES A. FD FAN
START PERMISSIVES
Blade pitch position minimum.
Discharge damper fully closed.
Lube oil pressure adequate.
Control oil pressure adequate.
Oil tank level normal.
Bearing temperature not high.
One ID Fan running AND other FD fan not running.
OR Both ID Fan running
TRIPS
Fan bearing temperature very high
Post purge furnace pressure very high/ very low
Outlet damper fail to open in set time (3 min)
No ID fan running or one ID fan and one FD fan already in service.
PA FAN
START PERMISSIVES
Blade pitch minimum
Lube oil pressure adequate
Control oil pressure adequate
Bearing temp. not high
Discharge damper closed.
Lube oil tank level adequate
No MFT & Cold air damper closed
At least one FD fan is running and
PAPH A/B in service & respective air inlet/ outlet dampers are open
TRIPS
Fan bearing temperature very high.
Trip from FSS (MFT).
Discharge damper fails to open.
ID FAN
START PERMISSIVES
Hyd. coupling Scoop position minimum.
Inlet guide vane position minimum.
Bearing temperature not high.
Oil temp. and oil level in Hyd. coupling OK.
Lube oil pressure adequate.
Both inlet and outlet dampers closed.
Other ID fan not running or Any FD fan running.
TRIP CONDITION
Fan/Motor bearing temperature very high.
Lube oil pressure very low.
Post purge furnace pressure Hi/Low from FSS.
Discharge dampers/ suction damper fail to open within specified time (3 min.)
Hydraulic coupling bearing temp. very high
Hydraulic coupling oil temp. very high.
SGWC PUMPS: (CC Pumps)
PERMISSIVES
Discharge valve 1 open.
Discharge valve 2 open.
Motor cavity temp. not high.
Pump cavity suction manifold differential temp. not high.
Motor cooling water flow adequate.
TRIPS
Any of the discharge valves not fully open.
Motor cavity temp. high (60 deg. C) for more than 5 Sec.
Electrical protection trip/ EPB pressed.
Run back operation
Tripping of PA Fan or FD Fan
PA header pressure low/very low
Sequential tripping of Mills/Feeders
Flame sensing
Safe scan(visible light)
Intensity and frequency components
Discriminating flame sensing(oil flame)
Fire ball flame sensing(coal flame)
2/4 corner flame voting
The system has ten (10) independently controlled identical controllers. Of these, two (02) are meant for supervising main boiler protections, known as the Unit Processor . Remaining eight (08) are meant for supervising coal firing elevations and oil firing elevations, known as Elevation Processor . Each controller is connected to its respective input/ output module through a separate I/O power supply (P421) in local configuration mode. It has the facility to configure in remote mode also.