UPS Invertors Failed & UPS By-PASS Supply is not available.

UPS Battery Charger/ or Battery Banks Failed & UPS By-PASS Supply is not available.

FAILURE OF UPS POWER

Consequences: No control from DCS. No Alarm will come in LVS, UCP & ECP. No control from UCP 220 V A.C UPS Supply Fail means –110V A.C Fail. 24V D.C Fail. 230V A.C Fail.

What will happen after Failure of UPS Power : Boiler will trip through Loss of 24V D.C (i.e. MFT WILL OCCUR THROUGH HARDWIRE) MFT All running Coal Feeder will trip due to FAIL SAFE Logic ( Loss of 110 V AC ) FEEDER

HOTV/ LOTV will trip due to FAIL SAFE Logic. HORV will not change the state. TRIP VALVE

Mill & PA FAN not tripped through Logic. To be tripped manually. PA FAN

ID/ FD / CEP/ BFP will not trip. To be tripped as per System requirement

Slide 3

FEEDER

LOTV/HOTVDC HEALTHY 36,46,56 ENERGIZE 1&3 ARE CONNECTED

3

LOTV

OYVHOTV

110V AC RELAY

SYSTEM POWER 24 V DC

PSS AB

PSF AB

3

SADC will open fully.

SH/ RH Block Valve will not close.

Burner Tilt to be minimum.

All CV, Blade Pitch of Fans, IGV, and SCOOP will come down to Minimum.