Boiler (master fuel trip)
Steam Generator ( boiler ) is very important equipment at thermal power units , Boiler is the steam supply for the unit to rotate the turbine's rotor , hence produce electricity at Generator's stator.
Boiler usually equipped with solar and Main gas firing equipments , and you can imagine that huge boiler disappear in seconds unless operator take his precaution from operation hazards., hence Boiler always equipped with a protection relays to trip the boiler out of service if hazards conditions has happened , these relays are enclosed at huge protection system is called ( Master Fuel Trip ).
From its name ( Master Fuel Trip ) , it produces trip signal for fuel systems from operation , then trip the boiler out of service away from danger. this relay needs many conditions to operate , these conditions will be found at the following figure.
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MASTER FUEL TRIP , CONDITIONS :-
1-REHEATER PROTECTION
2-DELAYED LIGHTING
3-LOSS OF ALL FUEL INPUT
4-DRUM LEVEL HI HI
5-DRUM LEVEL LOW LOW
6-ALL FD FAN STOP
7-FURNACE PRESSURE HI HI
8-CCS WATCHDOG ABNORMAL
9-COMBUSTION AIR FLOW LOW LOW
10-CONDENSER PROTECTION
11-PARTIAL LOSS OF FLAME
12-BOILER EMERGENCY TRIP
13-LOSS OF ALL FLAME
14-HP/LP BYPASS VALVE ABNORMAL CLOSE
15-ALL FUEL TRIP DELAY TRIP