Dear friends as i told you PPI & C is a vast field to learn,so let us see the protection & control related to thermal power plant
1. Close Loop Control - a) Hotwell Level Control b) CEP re - circulation control c) HPH normal & emergency drain level control, d) Gland steam temp PRDS control , e) Lube oil temp control

2. Governer Control (Wood ward-505)- a) Speed control , b)Load control , c) Frequency control.

3. Boiler Control - a) 3/1-Element Drum level control , b) Temp control for final stem control with attemperator , c) CBD tank level control , d) Combustion control including excess air control based on oxygen level of flue gas , e) Furnace draft control , f) LDO tank level control , g) Dearator header pressure & level control , h) Start up vent control , i) Air heater bypass control

4. Protections - a) Lub oil pressure Low-Low (2/3 voting logic) - Direct Trip
b) Control Oil pressure  Low-Low (2/3 voting logic) - Direct Trip 
c) Trip oil pressure  Low-Low (2/3 voting logic) - Direct Trip 
d) Rotor Axial Displacement High High  (1/2 voting logic) - Direct Trip 
e) Condenser pressure  High High  (2/3 voting logic) - Advice Trip 
f) Exhaust steam temp  High High  (2/3 voting logic) - Direct Trip 
g) Generator class B trip (to be discuss later posts ) - Direct trip
h) Over speed trip from gov controller (dual sensor) - Direct trip
i) Over speed trip from TSI(TURBO SUPERVISORY INSTRUMENT- like vibration of generator)- Direct Trip  
j) Main steam temp/pressure Low-Low - Advice trip
k) Turbine Bearing temp High-High -Direct Trip 
l) Bearing vibration High-High -  Direct Trip  
m) High temp in alternator before & after cooler - Advise trip
n) Hot well level High-High-  Direct Trip.  
o) Gear box temp very High - Direct trip

TSI(TURBO SUPERVISORY INSTRUMENT )- Bently Navada -Model 3500 panel monitors the STG, Gearbox & Generator vibrations, & the rotor axial shift ,turbine speed.