FD FAN STEAM TURBINE EMERGENCY SHUTDOWN Low Low Lube oil pressure with 2oo3 voting logic (UY P0554 T1/T2/T3) - Steam turbine governor trip (UY S0540 S hardwired signal from governor) Natural Draft Turbine Emergency Shut-Down from local (UY S0540 SE), triple contact (2oo3) configured In case at least one of the following events occurs the emergency trip solenoid valve UY S0540 VS1 AND VS2 will be de-energized and the steam turbine will be tripped. The UY H0053 V will be closed by de-energizing UYH0555VS in order to block the steam to the turbine.

FD FAN ELECTRIC MOTOR EMERGENCY SHUTDOWN Low Low Lube Oil Pressure (UY P0554 T1/T2/T3) In case the above events occurs the electric motor will be tripped (hardwired signal UY M0083 SS2) The FD Fan electric motor start permissive (hardwired signal UY M0083 SX2 from BMS to MCC) are the following: FD Fan inhibit Electric Motor Permissive to start (UY M0083 SX2).

Automatic change-over from Steam Turbine to electric motor or viceversa is foreseen in case of loss of the actual driver of the FD Fan in operation.Remote (from DCS system) Over-speed test will be available in order to test periodically the steam turbine.The Steam turbine governor is hardwired interface with the following equipment: - SIS for safety purpose - DCS for monitoring, automatic change-over and over-speed test The following indication are provided on DCS: Over-speed test enabled UY S0540 ZX The following command are provided from DCS: Speed Raise (increase) UY S0540 XX3 Over-speed test enable UY S0540 HS Turbine Idle / Run UY S0540 SR32

Steam turbine Permissive to start:

Steam turbine slow roll condition (at 500 rpm) set locally through Turbine Governor panel

High Instrument air pressure (UY P0065 T) Steam turbine Auto-start (automatic change-over): Change-over from Electric motor to Steam turbine is allowed provided that Steam turbine is running on idle mode (slow roll condition at 500 rpm). Starting from idle mode, the Steam turbine will be automatically ramped up (IDLE/RUN signal) to nominal speed (4500 rpm) in case of:

Electric motor running (UY M0083ZR3) AND FD FAN Low Speed (UY S0051 T) detected The digital signal IDLE/RUN (UY S0540 SR32) is activated in order to switch the Steam turbine from IDLE to RUN by a rump-up implemented on Turbine Governor panel software. Remote Over-speed Test: The operators will be able to perform periodically the over-speed test from DCS system. The remote over-speed test will be as follow:

DCS system will send to Governor the Over-speed test enable (UY S0540 HS) command

Governor will send back to DCS the confirmation signal Over-speed test enabled (UY S0540 ZX) and when this confirmation is received:

DCS will give the Speed Raise (UY S0540 XX3) command and consequently the Governor will raise the speed until the over-speed system will trip the Steam turbine

After that the Steam turbine is tripped. The Governor will be reset locally and the related logic will be reset according to SIS trip reset philosophy of SEP. Emergency trip (by SIS): The FD Fan steam turbine will be automatically tripped and inhibited to restart in case of

Natural Draft (SIS to de-energize the steam turbine emergency trip solenoid valves UY S0540 VS1 and UY S0540 VS2)

Governor (Governor will sent the trip signal to the SIS that deenergize the steam turbine emergency trip solenoid valves UY S0540 VS1 and UY S0540 VS2)

Low Low Lube oil Pressure (UY P0554 T1/T2/T3)

By Local Emergency push-button (UY S0540 SE) that de-energize the steam turbine emergency trip solenoid valves (UY S0540 VS1 and UY S0540 VS2)

FD Fan Electric Motor (UY M 10A Logic reference no. UY71) (ref. doc. N. 1101-S-082 sheet 210 - 209) The FD Fan electric motor is used when the steam turbine is not available (i.e. for HP steam not available or steam turbine in maintenance) or in case of FD Fan steam turbine loss. Automatic change-over to steam turbine is foreseen in case of electric motor loss (refer to sheet 26). The FD Fan electric motor can be operated from local (local motor control station in field) of from remote (DCS). From remote the FD Fan electric motor can be operated manually by means of the following commands (software switches) available on DCS console: START command UY M0083 SR3 STOP command UY M0083 SS3 PERMISSIVE command UY M0083 ZX3 The following indications are provided on DCS: FD Fan electric motor RUNNING UY M0083 ZR3 FD Fan electric motor IN AUTO MODE UY M0083 ZA3 FD Fan electric motor TRIP UY M0083 SS2 Permissive to start: FD Fan electric motor not running AND FD Fan control damper closed (UY F0057 ZC) AND FD Fan not in service (Low Low FD Fan speed UY S0550 T1/T2/T3) Natural draft not activated by SIS (UY X0552 ZX) The FD Fan electric motor will be automatically started (automatic changeover) in case of: Low FD Fan speed (UY S0051 T) detected AND FD Fan in service driven by steam turbine (Steam Turbine in Run status at 4500 rpm) Emergency trip (by SIS): The FD Fan electric motor will be automatically tripped and inhibited to restart in case of Natural Draft (UY X0552 ZX hardwired from SIS). The FD Fan electric motor will be automatically tripped in case of Low Low Lube Oil Pressure (UY P0554 T1/T2/T3 UY M0083 SS2 from SIS to MCC).

FD Fan and Drivers Vibration MonitoringLUBE OIL SYSTEM AUTOMATION (LOGIC REFERENCE NO. UY54 UY55 AND UY71 - P&ID N. 1101-S-018)The boiler is equipped with 1 (one) Lube Oil System for FD FAN steam turbine and relevant gear reducer bearing lubrication. The Lube Oil system is equipped with 1 (one) Main Lube Oil pump (UY FAN 10A P1A) mounted on turbine shaft, plus 1 (one) auxiliary lube oil pump driven by electric motor (UY FAN 10A P1B M). Before to start-up the steam turbine, the operator shall put in operation the Lube Oil System so that a correct pressure (UY P0059 T) is established in the circuit. During the start-up, the electric motor pump shall be put in service first and switched-off manually by the operator when the steam turbine is verified working as the lube oil flow can be sustained by the Main Lube Oil pump (UY FAN 10 P1A) coupled with turbine shaft. Moreover the electric motor pump will be stopped automatically in case of high pressure (shaft driven pump is working). As soon as the shaft driven pump has started to operate and the correct pressure is established in the circuit, the auxiliary pump will be ready to start automatically in case of lube oil low pressure (UY P0059 T). 3.2.1 Auxiliary Lube Oil Pump Electric Motor (UY FAN 10A P1B M Logic reference no. UY55 and UY71) (see doc. N. 1101-S-082 sheet 194 - 198) The auxiliary pump electric motor can be manually started and stopped from remote (DCS console): START command UY M0080 SR3 STOP command UY M0080 SS3 AUTO/MAN selector UY M0080 SX The auxiliary pump electric motor (UY FAN 10A P1B M) will start automatically by DCS through MCC in case of: Lube Oil Low Pressure (UY P0059 T) detected Low Low Lube Oil Reservoir Level (UY L0053 T) NOT detected The auxiliary pump electric motor (UY FAN 10A P1B M) will be stopped automatically by DCS through MCC in case of: Lube Oil High Pressure (UY P0059 T) detected Low Low Lube Oil Reservoir Level (UY L0053 T) detected The following indication are provided on DCS:

Pump electric motor RUNNING UY M0080 ZR3 3.2.2 Lube Oil Air coolers (UY FAN 10A E1 Logic Reference no. UY55) (see doc. N. 1101-S-082 sheet 194 - 198) The Lube Oil system is equipped with 2 (two) lube oil air coolers, 100% duty each driven by electric motors (UY FAN 10A E1 M1 / M2). During normal operation one air cooler will be in operation, while the second will be in stand-by and ready to start in case the running cooler will fault. 3.2.2.1 Lube Oil Air cooler (UY FAN 10A E1 Logic Reference no UY55) The Lube Oil Air cooler 1 can be operated only from remote (DCS). From remote the Lube Oil Air cooler 1 can be operated manually by means of the following commands (software switches) available on DCS console: START command UY M0081 SR3 STOP command UY M0081 SS3 The following indications are provided on DCS: Lube oil Air cooler RUNNING UY M0081 ZR3 The lube oil Air cooler 1 will be automatically started in case of: Lube oil Air cooler 2 (UY FAN 10A E1) running AND electrical fault detected High high oultlet Temperature (UY T0063 T) The Lube oil Air cooler 1 will be automatically stopped in case of: Low low inlet Temperature (UY T0070 T) or Low low outlet Temperature (UY T0063 T) 3.2.2.2 Lube Oil Air cooler (UY FAN 10A E2 Logic Reference no. UY55) The Lube Oil Air cooler 2 can be operated only from remote (DCS). From remote the Lube Oil Air cooler 2 can be operated manually by means of the following commands (software switches) available on DCS console: START command UY M0082 SR3 STOP command UY M0082 SS3 The following indications are provided on DCS: Lube oil Air cooler RUNNING UY M0082 ZR3 The lube oil Air cooler 2 will be automatically started in case of: Lube oil Air cooler 1 (UY FAN 10A E1) running AND electrical fault detected High high oultlet Temperature (UY T0063 T) The Lube oil Air cooler 2 will be automatically stopped in case of: Low low inlet Temperature (UY T0070 T) or Low low outlet Temperature (UY T0063 T) 3.2.3 Lube Oil Electric Heater (UY FAN 10A E2 Logic Reference no. UY54) (see doc. N. 1101-S-082 sheet 198) The lube oil reservoir is equipped with an electric heater to achieve the correct lube oil temperature before starting lube oil pumps. The lube oil reservoir electric heater is provided with integrated on/off and cut-out safety thermostats. The Lube Oil Electric Hater will work as follow: in case of Lube oil Heater High High temperature (UY T0052 SHH) the heater will be forced to stop automatically in case of Lube oil Heater High temperature (UY T0051 SH) the heater will start automatically in case of Lube oil Reservoir Low Low Level (UY L 0053 T) the heater will be forced to stop automatically.