Control Desc(#5)

8/8/2019 Control Desc(#5)

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CONTROL DESCRIPTIONFor

FORT GEORGE POWER STATION EXTENSIONUNIT 5

1999. 06.


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Subject : Starting Air Pressure (Dwg. No. : FGP5-M0 -101)

1. The pressure in the starting air system is maintained by mean of thecompressors CO-A0-02/10/18. Signals for start/stop are given by thepressure transmitter PT-A0-07. One compressor is defined as mastercompressor(s) and the other two as standby compressors.

- At pressure control Low, the master compressor is started- At pressure control L/Low, the two stand-by compressors are started- At pressure control High, all compressors in operation are stopped

When the starting air systems for DE3, DE4 and DE5 are normaloperating, the starting air compressors are operating by the pressuretransmitter PT-A0-07 as per above sequence.But when the starting air system of either DE3 or DE4 or DE5 wasstopped for maintenance, the valve VA-A3-17 or VA-A4-02 or VA-A5-02

is closed and the signal from the pressure transmitters PT-A3-06 or PT-A4-001 or PT-A5-001 should be ignored .

2. At pressure drop in the starting air receiver TA-A5-02 below stand-bystart of compressors, a pressure alarm Low is given for warning by PT-A5-001.

3. For safety protection of the starting air receiver, the safety valve VA-A5-10 is provided. At pressure alarm H/High in the starting air system,an alarm will be send to the PPC by PT-A0-07 and/or PT-A4-001 and/orPT-A5-001. The transmitters have the same setpoint as the safetyvalve.

4. For safety protection of the compressors, the following safety valvesare provided:

- 1st stage VA-A0-01/107/115- 2nd stage VA-A0-02/108/116- 3rd stage VA-A0-10/109/117

5. At fire or other extremely high temperature, the fusible plug in VA-A5-

04 will melt and release all the compressed air from the starting airsystem.The released air will, by pipeline, be led to the roof on the mechanical

annexes.

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Subject : Control Air Pressure (Dwg. No. : FGP5-M0-102)

1. The pressure in the control air system is maintained by mean of thecompressors CO-A0-36/44. Signals for start/stop of the control aircompressor units are given by the pressure transmitter (PT-A0-19/21).One compressor unit is defined as master unit and the other as stand-by unit.

- at pressure control Low, the master unit is started- at pressure control L/Low, the stand-by unit is started and a pressure

alarm low is given for warning- at pressure control High, all unit(s) in operation is (are) stopped- At pressure alarm H/High, an alarm is given for warning

When the control air systems for DE3, DE4 and DE5 are normaloperating, the starting air compressors are operating by the pressure

transmitter PT-A0-07 as per above sequence.But when the control air system of either DE3 or DE4 or DE5 wasstopped for maintenance, the valve VA-A3-114 or VA-A4-48 or VA-A5-48 is closed and the signal from the pressure transmitters PT-A3-15 orPT-A4-021 or PT-A5-021 should be ignored .

2. For supervision of the pressure in the G5 control air system, a pressuretransmitter (PT-A5-021) is provided.

- at pressure alarm Low, an alarm is given for warning- at pressure alarm High, an alarm is given for warning

3. By pressure control High (PT-A0-19/21) at the air outlet from thecompressors, the corresponding compressor unit will be tripped and acommon alarm from the compressor unit is given for warning.

4. For safety protection of the compressors, the safety valves (VA-A0-67/88) is provided.

5. For safety protection of the control air receivers, the safety valves VA-A0-78, VA-A3-114, VA-A4-49 and VA-A5-49 are provided.

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Subject : Control Air Alarm/Safety Functions (Dwg. No. : FGP5-M0-102)

In order to protect the compressor units and the control air system, thefollowing safety functions are provided:

1. At fire or other extremely high temperature, the fusible plug in VA-A0-77/VA-A4-50/VA-A5-50 will melt and release air from the compressedair from the control air system. The released air will be led, by apipeline, to the roof on the mechanical annex.

2. At temperature control High (TE-L0-46/48) in the internal lub. oilsystem for the compressor, the existing corresponding compressor unitwill be tripped, and a Common alarm from the compressor unit is givenfor warning.

3. At temperature control High (TE-A0-18/20) at the air outlet from the

compressor, the existing corresponding compressor unit will betripped, and a Common alarm from the compressor unit is given forwarning.

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Subject : Centrifugal Drain Pump Control (Dwg. No : FGP5-M0-111)

The control description is similar for all the centrifugal drain pumps PU-K5-13. The description below is only made for PU-K5-13.

1. At level control High (LS-K0-002), the pump is started. The level switchis of the floating type, having its own hysteresis, adjusted by the cablelength from fixing point of the cable to the floating switch. Loweringthe level in the pit by pumping, the floating switch will open and thepump will stop.

2. By level alarm H/High (LS-K0-001), an alarm is given for warning.

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Subject : LO Transfer Pumps (Dwg. No. : FGP5-M0-121)

1. The transfer pumps can transfer LO:- from new or existing LO storage tank- to main LO tank for DE3/DE4/DE5

2. One of the transfer pumps is started - manually only:a. at visual monitoring the main LO tank on the local level (gauge)

indicator.b. following main LO tank Low level alarm (LT-L5-002 for DE5).

3. Both transfer pumps are stopped/tripped:a. manually by visual level monitoring the main LO tank on the local

level (gauge) indicator.b. manually following Low level of storage tanks (LT-L0-17, LS-L0-73).c. automatically at main LO tank High level (LS-L5-002).

d. automatically at storage tanks L/Low level (LT-L0-17/LS-L0-74) tosafeguard the pump from dry-running.

4. The H/High level alarm on each main LO tank safeguards overfilling,(LS-L5-002 for DE5).

5. The position of the outlet valve on each storage tank is guarded bylimit switches (GS-LO 36/37) to:a. interlock the connected storage tank's L/Low level signal with the

transfer pump.b. give alarm if more than one tank outlet is open.

6. The position of the filling valve for each main LO tank shall be guardedby limit switches (ZS-L5-001 for DE5) to:

a. interlock the connected main LO tank's level signals with the transferpumps.

b. give alarm if more than one filling valve is open.

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Subject : Cyl. Oil Transfer Pumps (Dwg. No. : FGP5-M0-122)

1. The transfer pumps can transfer LO:- from new or existing CYL. oil storage tank- to CYL. oil service tank for DE3/DE4/DE5

2. One transfer pump is defined as master pump, and one is stand-by,which is activated manually at master pump failure.

3. In sequence the filling valve (VA-L5-61 for DE5) is auto-opened, andafter delay the transfer master pump is auto-started:a. at Low level of a service tank (LT-L5-032 for DE5).

The transfer master pump is controlled by all service tank leveltransmitters (LT-L3-02 for DE3, LT-L4-032 for DE4 and LT-L5-032 forDE5) and even though either a service tank is at high level for DE3 or

for DE4 or for DE5, only the filling valve (VA-L3-19 or VA-L4-61 or VA-L5-61) which is related to the service tank at high level is automatically-closed and the transfer master pump is stopped at the present level.

4. Both transfer pumps are auto-stopped/tripped:a. at service tank High level (LT-L5-032 for DE5).

b. at storage tanks L/Low level (LT-L0-02/LS-L0- ) with alarm.c. in case of loss of control air pressure and/or control power.

5. The H/High level alarm (LS-L5-032 for DE5) on the service tankmonitors overfilling.

6. The position of the outlet valve on each storage tank is guarded bylimit switches (GS-L0-38/39) to:

a. interlock the connected storage tank's Low level signal with thetransfer pump.

b. give alarm if more than one tank outlet is open.

7. The filling valve (VA-L5-061) closes in case of loss of control airpressure and/or control power.

8. The duplex transfer filter signals clogging at High differential pressure.

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Subject : Steam/Water Drum Pressure (Dwg. No. : FGP5-M0-131)

1. The pressure in the steam/water drum is controlled by the dampers VA-C5-19 and VA-C5-20.

VA-C5-19 is controlling the exhaust gas flow to the boiler and VA-C5-20is controlling the flow through the by-pass duct.

2. The dampers are electrically interlocked in order to secure that aconstant area is always available for the exhaust gas.

3. When the pressure in the steam/water drum is increasing, the damperVA-C5-19 is moving towards the closed position and the damper VA-C5-20 is moving an equal part towards the opened position.

When the pressure is decreasing, the damper VA-C5-19 is movingtowards the opened position and the damper VA-C5-20 is moving an

equal part towards the closed position.

4. The pressure switches PS-S0-20/21 are indicating abnormal operation,respectively low pressure alarm by PS-S0-20 and high alarm by PS-S0-21.

5. For safety protection of the steam/water drum the pressure relief valves VA-S0-25/26 are provided. Set point is 12 bar G.

6. During start-up of the boiler the movement of the dampers are limitedin order to obtain a steady heat-up of the boiler, the drum, the wateretc.

When the pressure reach a pre-set value the control returns to normaloperation as described in item 3.

The damper VA-C5-19 is limited to 30% open and VA-C5-20 is limited to30% closed.

7. During stop of engine the damper VA-C5-19 moves to closed positionand the damper VA-C5-20 moves to open position.

By stop of the engine the control as described in above item 3 is notactive and can be activated only after the start-up of the boiler asdescribed in above item 6.

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Subject : Steam/Water Drum Safety Functions (Dwg. No. : FGP5-M0-132)

In order to protect the steam/water drum the following safety functionsare provided:1. By level alarm high high, manual operation by the personal is required.

2. By level control high, the make-up water valve (VA-W0-22) is closedtotally (overruling the other control) and a level alarm high is given forwarning.

3. By level control low, the make-up water valve (VA-W0-22) is openedtotally (overruling the other control) and a level alarm low is given forwarning.

4. By level alarm low low, the boiler plant is shut-down, i.e.The boiler circulation pumps, the existing oil fired circulation pump (PU-

S0-05) and super heated water distribution pumps (PU-S0-02/03/12)are stopped.

Furthermore, damper VA-C5-19 is totally closed and damper VA-C5-20 istotally opened (overruling other control).

VA-S0-22 remains open.

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Subject : HFO Supply Pump (Dwg. No. : FGP5-M0-141)

1. The pump (PU-F5-16) is auto-started by the aux. start sequence priorto diesel engine operation on HFO, and is running continuously atoperation on HFO, i.e. HFO/DO change-over valve (VA-F5-36/ZT-F5-036) is open (to HFO).

See also Control description HFO/DO Auto change-over/ Viscositycontrol.

2. The pump is auto-stopped/tripped:a. after change-over to DO, i.e. (VA-F5-36/ZT-F5-036) is fully closedb. with PPC alarm at Low pressure at inlet (PT-F5-002) to safeguard the

pump from dry-running.c. by the diesel engine stop sequence.

3. PPC-alarm is given if one of the Service tanks Low level (LS-F0-85/87)

are low., more than 10 min., to monitor the pump for dry-running.

4. The supply pressure (PT-F5-052) at the FO booster unit is kept constantby the control valve VA-F5-12, by-passing excess FO/pressure to theservice tank.

5. The non-return valve (VA-F5-10) provides by-pass if the gravitypressure is sufficient, and the pump is not operating.

6. The duplex filter signals clogging at High differential pressure alarm(PS-F5-001).

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Subject : DO Supply Pump (Dwg. No. : FGP5-M0-142)

1. The pump (PU-F5-20) is auto-started:a. by the aux. start sequence prior to the diesel engine operation on

DO, and runs continuously, during operation on DO, i.e. HFO/DOchange-over valve (VA-F5-36/ZS-F5-036) is closed (to HFO).See also Control description HFO/DO Auto change-over / Viscositycontrol.

b. in case of failure of HFO supply pump (PU-F5-16) during dieselengine operation on HFO.

2. The pump is auto-stopped/tripped:a. after change-over to HFO, i.e. (VA-F5-36/ZT-F5-036) is fully open.b. with PPC alarm at L/Low level (LS-F0-97) of the DO storage tank to

safeguard the pump from dry-running.c. by diesel engine stop sequence.

3. The supply pressure (PT-F5-051) at the FO booster unit is kept constantby the control valve VA-F5-23, by-passing excess DO/pressure to theDO tank.

4. The non-return valve (VA-F5-21) provides by-pass if the gravitypressure is sufficient, and the pump is not operating.

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Subject : HFO/DO Auto Change-Over / Viscosity (Dwg. No. : FGP5-M0-143)

1. The HFO/DO change-over valve (VA-F5-36) directs the fuel to supplythe diesel engine.

The position of the change-over valve is controlled via the positioner (IP-F5-036) and monitored by the position transmitter (ZT-F5-036).

The FO change-over valve stays in position in case of loss of control airpressure and/or control power by means of the solenoid air block valve.See item 7.

The FO change-over valve can be operated manually by handwheel.

2. HFO viscosity is controlled by regulating the HFO temperature (TE-F5-071) via the SHW control valve (VA-S5-118) to the pre-heater in 4operation situations:

. Continuous operation on HFOThe viscosity is controlled by the viscorator VT-F5-062, i.e. the pre-heater control operates in viscosity mode.

In case of viscosity transmitter/mode failure, temperature modecan be used as back-up.

. Continuous operation on DOThe viscosity is determined by the temperature of the DO supply, i.e.

the pre-heater is out of operation.

. Change-over from DO to HFO

Assuming that the HFO service tank temperature: 80 - 85 Engineload needs no reduction.

The viscosity is controlled in one step:

Start HFO supply pump (PU-F5-16).Start SHW pre-heater control in viscosity mode.

Auto-open change-over valve to 100% (open to HFO) as fast as

possible. . Change-over from HFO to DO

The following procedure shall be valid also in emergency in case of failure of HFO supply pump (PU-F5-16).

Assuming that the HFO service tank temperature: 80 - 85Engine load needs no reduction.

The viscosity is controlled in one step:11


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Start DO supply pump.(PU-F5-20)Stop SHW pre-heater control in viscosity mode, auto-close SHW

supply valve to pre-heater.Auto-close change-over valve to 0% (100% DO) as fast as possible.

3. The FO viscosity is monitored by High and Low PPC alarms.

4. The inlet FO temperature is monitored by High and Low PPC alarms(deviation from mean operating temp.).

5. The 3-way SHW valve VA-S5-118 by-passes SHW around the pre-heater in case of loss of control air pressure and/or control power.

The 3-way SHW valve can be operated manually by handwheel.

6. The safety valve VA-F5-56 protects the pre-heater from overpressure.

7. The solenoid air block valve shall always be activated during DE

operation, but isolates the actuator at loss of control power or controlair pressure. The control air pressure failure set point is mechanicallyadjustable.

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Subject : HFO Booster Pumps (Dwg. No. : FGP5-M0-144)

1. One of the booster pumps (PU-F0-06/07) is defined as master pump,and one as standby.

2. The master pump is started prior to the diesel engine by the aux. startsequence (if not already running for FO circulation), and is runningcontinuously during diesel engine operation.

3. The standby pump is started, and the master pump stopped at Lowpressure (PT-F5-055) with PPC alarm.

4. The FO (booster) inlet pressure on the diesel engine is safeguarded byblocking start of engine at Low pressure (PT-F5-071) with PPC alarm,

5. The booster pump is kept running at diesel ENGINE STOP, if FO

operation is selected.

6. The booster pump is stopped at diesel ENGINE STOP, if DO operation isselected.

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Subject : FO 3-Way Inlet Valve (Dwg. No. : FGP5-M0-145)

1. The 3-way valve (VA-F5-67) is continuously open for FO to the dieselengine during normal operation of the engine.

2. The 3-way valve (VA-F5-67) closes and bypasses FO around the dieselengine in case of:

a. trip of the engine (at shut-down and overspeed).b. loss of control air pressure and/or control power to the valve.

3. The limit switch (ZS-F5-067) ensures, that the valve is open for FObefore starting engine, and closed during blocking of engine.

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SUEUECT : FO Drain tank temperature (DWG. No. : FGP5-M0-146)

1. The tank temperature is regulated by thermostat TC-F5-081 via valveVA-S5-154.

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Subject : FO Drain Pump (Dwg. No. : FGP5-M0-147)

1. The pump(PU-F5-12) is auto-started at High level (LS-F5-081) of the FOdrain tank.

2. The pump is auto-stopped/tripped at:a. Low level (LS-F5-081) of the FO drain tank.b. H/High level (LS-F0-91) of HFO buffer tank with PPC alarm.

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Subject : Main LO Pump/Pressure (Dwg. No. : FGP5-M0-151)

1. The Main LO pump is auto-started prior to the diesel engine by the aux.start sequence, and is running continuously during normal engineoperation.

2. The Main LO inlet pressure is monitored by Low pressure alarm (PT-L5-018) and safeguarded by Low pressure shut-down (PS-L5-018).

3. The Piston Cooling Oil inlet pressure is monitored by Low pressurealarm (PT-L5-017).

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Subject : Main LO Temperature (Dwg. No. : FGP5-M0-152)

1. The 3-way LO valve(VA-L5-15) keeps the temperature on the set pointvia the temperature sensor TE-L5-007.

2. The inlet temperature to the engine is monitored by High and Lowtemperature alarms (TE-L5-017).

3. The 3-way valve can be operated manually by lever.

4. The 3-way LO valve stays in position in case of loss of control airpressure and/or control power.

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Subject : Camshaft LO Pump/Pressure (Dwg. No. : FGP5-M0-153)

1. The camshaft LO pump is auto-started prior to the diesel engine by theaux. start sequence, and is running continuously during normal engineoperation.

2. The inlet pressure at the engine (PT-L5-016) is kept constant by thecontrol valve(VA-L5-25), by-passing excess LO/pressure to the pumpsuction side.

3. The LO control valve stays in position in case of loss of control airpressure and/or control power.

4. The valve (VA-L5-30) provides by-pass of the Camshaft LO pump incase of pump failure, provided the Main LO pump delivers sufficientpressure.

5. The Camshaft LO inlet pressure is monitored by Low pressure alarm(PT-L5-016) and safeguarded by Low pressure shut-down (PS-L5-016).

6. The duplex filter signals clogging at High differential pressure (PS-L5-013).

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Subject : Stuffing Box Drain Cir. Pump (Dwg. No. : FGP5-M0-154)

1. The pump(PU-L5-19) is manually started following High level alarm (LS-L5-021) of the LO drain circulation tank.

2. The pump is auto-stopped at:a. Low level (LS-L5-021) of the LO drain circulation tank.b. H/High level alarm (LS-L5-002) of the main LO tank.

3. Overfilling of the Main LO tank is monitored by High level alarm LT-L5-002.

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Subject : Stuffing Box LO Drain Tank Temperature (DWG. No. : FGP5-M0-155)

1. The tank temperature is regulated by thermostat TC-L5-021 via valveVA-S5-140.

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Subject : Scavenge Oily Drain Tank Temperature (Dwg. No. : FGP5-M0-156)

1 The tank temperature is regulated by thermostat TC-L5-020 via valveVA-S5-168.

2. The constant determined by the orifice (XF-L5-24).

3. Max. pressure is protected by the safety valve (VA-L5-33).

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Subject : LO Separator/Tanks (Dwg. No. : FGP5-M0-157)

1. The separator with supply pump is started/stopped manually.The tank to be serviced is selected by operation of the manual

inlet/outlet valves.

2. For servicing the Stuffing box LO drain unit:a. inlet/outlet valves (VA-L5-37/46) must be open, interlocked by limit

switches (ZS-L5-37/46).b. other inlet/outlet valves (VA-L5-40/47) must be closed, interlocked by

limit switches (ZS-L5-40/47).

The manual 3-way valve (VA-L5-36) selects one of two tanks on theunit:

. collecting tank, typically following High level alarm (LS-L5-022). . circulating tank, if required.

The separated LO is always led to the circulating tank.

3. For servicing the Main LO tank:a. inlet/outlet valves (VA-L5-40/47) must be open, interlocked by limit

switches (ZS-L5-40/47).b. other inlet/outlet valves (VA-L5-37/46) must be closed, interlocked

by limit switches (ZS-L5-37/46).

4. Overfilling of the Stuffing box LO circulating tank shall be safeguardedby High level (LS-L5-021) tripping the LO separator and supply pump.

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Subject : LO Separator Sludge Pump (Dwg. No. : FGP5-M0-158)

1. The suction is opened and the pump(PU-L5-103) is started manually:a. following High level alarm (LS-L5-078) of the sludge tank.b. following High level (LS-L5-020) of the scavenge oily drain tank.c. for emptying of the Stuffing box LO drain tanks, when required.

2. The pump is manually stopped by visual monitoring of level in thevarious tanks.

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Subject : T/C Main Oil Tank Temperature (Dwg. No. : FGP5-M0-159)

1. The tank temperature is regulated by thermostat TC-L5-101 via valveVA-S5-161.

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Subject : T/C Oil Pumps (Dwg. No. : FGP5-M0-160)

1. The T/C oil pump is auto-started prior to the diesel engine by the aux.start sequence.

2. One pump is defined as master pump, and one is stand-by. At Lowpressure (PS-L5-106) alarm is given, and the stand-by pump is started.

3. The pump (and system as such) is monitored by Low level alarm (LS-L5-101) of the T/C Main LO tank.

4. The duplex supply filter signals clogging at High differential pressure.

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Subject : T/C Oil Temperature (Dwg. No. : FGP5-M0-161)

The oil temperature is regulated by thermostat TC-L5-109 via valve VA-L5-124.

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Subject : T/C Oil Inlet Pressure (Dwg. No. : FGP5-M0-162)

1. The T/C Oil head tank must be filled prior to start of the diesel engine,by the aux. start sequence.

For filling the head tank the pressure control valve (VA-L5-128) is auto-opened.

2. To allow start/normal operation of diesel engine:a. LO head tank must be full i.e. Low level (LS-L5-115) off.

b. Pressure control valve (VA-L5-128) is in control mode by inletpressure (PT-L5-120).

c. The inlet pressure (PT-L5-120) is above alarm settings.

3. During normal operation, T/C inlet pressure is kept by the pressurecontrol valve (VA-L5-128), by-passing excess LO/pressure to the head

tank.In case of control valve failure, pressure can be adjusted on the manualby-pass valve (VA-L5-130).

4. In case of LO pumps failure, LO is supplied from the head tank.The inlet pressure is adjusted on the manual regulating valve (VA-L5-106).

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Subject : Fresh Cooling Water Pressure (Dwg. No. : FGP5-M0-171)

A: High temperature (HT) cooling water line

1. Circulation in the HT cooling water system is maintained by thepump PU-W5-13. Allowance to DE start is given by PT-W5-031 atsufficient pressure (flow).

PU-W5-13 is started prior to the DE by the aux. start sequence.

2. At pressure drop at inlet of DE (jacket cooling water), a pressurealarm Low is given for warning by PT-W5-031. At low diff. pressureover DE (jacket cooling water), a diff. pressure (flow) alarm Low isgiven for warning by PS-W5-036.

3. At too low pressure at inlet of DE (jacket cooling water), the DE will

be shut down by PS-W5-035.

B: Low temperature (LT) cooling water line

1. Circulation in the LT cooling water system is maintained by the pumpPU-W5-14. Allowance to DE start is given by PT-W5-001. PU-W5-14 isstarted prior to the DE by the aux. start sequence.

2. At pressure drop in the LT cooling water line, a pressure alarm Low is

given for warning by PT-W5-001.

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Subject : HT Cooling Water, Temperature (Dwg. No. : FGP5-M0-172)

1. Start/stop of the Jacket Water Preheater Pump (PU-W5-15) and HTpump (PU-W5-13) is an integrated part of the start/stop sequence forthe diesel engine (DE5).

At start of DE the inlet from the radiator coolers to the 3-way regulatingvalve VA-W5-68 will be closed and the inlet of the cooling water fromthe engine jacket cooling and the HT scav. air coolers will be fully open.

2. Regulation of the cooling water temperature is done by the 3-wayregulating valve VA-W5-68 by mean of the IP-converter IP-W5-068.Inlet signal to IP-W5-068 is given by the temperature sensor TE-W5-036, in order to keep the jacket water outlet temperature constantly at80.

3. At low jacket water inlet temperature, an alarm Low will be sent to the

PPC for warning by TE-W5-031.

4. At high jacket water outlet temperature, an alarm High will be sent tothe PPC for warning by TE-W5-041049, located in cylinder 19 outletpipeline and/or by TE-W5-036, located in the common outlet pipeline.

5. At too high jacket water outlet temperature, the diesel engine, DE5,will be shut down by TS-W5-037 in order to protect the engine.

6. TE-W5-027 is monitoring the inlet temperature of the cooling water tothe HT scav. air coolers, and TE-W5-060 is monitoring the inlettemperature of the cooling water to the HT radiator coolers.

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Subject : LT Cooling Water Temperature (Dwg. No. : FGP5-M0-173)

1. At temperature alarm High from scav. air coolers inlet (TE-W5-013), analarm will be sent to the PPC.

2. Alarms will be sent as individual alarms to the PPC at the followingobservations from the generator coolers:

- warm air temperature High alarm(TE-A5-091/092)- cold air temperature High alarm (TE-A5-093/094)- humidity High alarm in cold air (XT-A5-093/094)

3. ZS-W5-055/064 is monitoring the open/closed position of the coolingwater shut-off valves VA-W5-55/64 for the generator coolers.

4. TE-W5-010 is monitoring the cooling water temperature to the LTradiator coolers.

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Subject : Cooling Water Levels (Dwg. No. : FGP5-M0-174)

A: HT cooling water level:

1. In normal operation the level will be maintained by automatic make-up water filling up via the floating valve VA-W5-90.

2. At Low level, an alarm will be sent to the PPC for warning either byLT-W5-040 (HT expansion tank) and/or by LS-W5-041 (chamber forlevel switch). Block DE start at low level.

B: LT cooling water level:

1. In normal operation, the level will be maintained by automaticmake-up water filling up via the floating valve VA-W5-95.

2. At Low level, an alarm will be sent to the PPC for warning by LS-W5-011. Block DE start at low level.

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Subject : Radiator Coolers (Dwg. No. : FGP5-M0-175)

Start/stop of the radiator cooling fans common for LT and HT radiatorbundles will normally be controlled by the set point for the HT radiatorwater outlet temperature (TE-W5-052).

Start/stop of the radiator cooling fans RF-W5-40 to RF-W5-45 will becontrolled of the set point for the LT radiator water outlet temperature (TE-W5-054).

A: Common HT/LT radiator coolers:

1. Start/stop sequence for the cooling fans RF-W5-32 to RF-W5-39 ischanged regularly in order to obtain equal operating time for all thefans. All the fans are of the two-speed type.

2. Reaching the set point (TE-W5-052) the first fan will start at lowspeed. After a time delay, the process value (PV) is compared withthe set point (SP). If the process value still is higher than the setpoint value, then another fan will start at low speed, e.t.c.

When all the fans are in operation at low speed, the next step will beto increase the speed at the first started fan, then the next startedfan e.t.c.. The highest step is defined as all fans in operation at highspeed (PV > SPmax, = > n + 1 step).

3. The set point shall have a hysteresis. When the process valuebecomes lower than the set point, then the fan that first wasstarted, shall be stopped. After a time delay the process value willbe compared with the lower set point value.

If the process value is still lower than the lower set point value, thenthe step shall be reduced e.t.c. (PV < SPmin, = > n - 1 step).

B: LT radiator coolers:

Start/stop sequence for the cooling fans RF-W5-40 to RF-W5-45 ischanged regularly in order to obtain equal operating time for all thefans. All the fans are of the two-speed type.

C: Switching change from high speed to low speed in cooling fan

1. Timer should be installed to avoid too high difference from highspeed to low speed.

2. Time setting shall be around 15 seconds.

Documents

Control Desc(#5)