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DIESEL ENGINE POWER PLANT

ME 521 – POWER PLANT DESIGN2014

Aljon M. AlticheEfrel John L. ManlapazRomyrick L. GliponeoEmannoel M. Brimon

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Diesel Engine Power Plant

In a diesel power station, diesel engine is used as the prime mover. The diesel burns inside the engine and the products of this combustion act as the working fluid to produce mechanical energy. The diesel engine drives alternator which converts mechanical energy into electrical energy.

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Applications of Diesel power plant

Diesel power plants is in the range of 2 to 50 MW capacity. They are used as central station for small or medium power supplies.

They can be used as stand-by plants to hydro-electric power plants and steam power plants for emergency services.

They can be used as peak load plants in combinations with thermal or hydro-plants.

They are quite suitable for mobile power generation and are widely used in transportation systems such as automobiles, railways, air planes and ships.

Now-a-days power cut has become a regular feature for industries. The only solution to tide over this difficulty is to install diesel generating sets.

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Diesel plant Equipment:

Diesel Engine Air intake system Exhaust system Fuel supply system Cooling system Lubricating system Starting system

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General Layout:

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DIESEL ENGINE

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What is a Diesel Engine?

A diesel engine (also known as a compression-ignition engine) is an internal combustion engine that uses the heat of compression to initiate ignition and burn the fuel that has been injected into the combustion chamber. This contrasts with spark-ignition engines such as a petrol engine(gasoline engine) or gas engine (using a gaseous fuel as opposed to gasoline), which use a spark plug to ignite an air-fuel mixture.

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How it converts the chemical energy stored in the diesel fuel into mechanical energy?

This occurs in two steps. First, the fuel reacts chemically (burns by self ignition) and releases energy in the form of heat. Second the heat causes the gasses trapped in the cylinder to expand, and the expanding gases, being confined by the cylinder, must move the piston to expand. The reciprocating motion of the piston is then converted into rotational motion by the crankshaft.

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v

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Ignition Process of a Diesel Engine

1. Suction stroke, with inlet valve open, fills cylinder with air.

2. Compression stroke raises pressure to about 35kg/cm2.

Fuel injection starts at or near end of compression stroke.

3. High air temperature caused by compression ignites fuel.

Burning mixture expands, pushing piston down on working stroke.

4. Exhaust valve open: rising piston clears cylinder.

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Thermal Cycle of a Diesel Engine

The ideal thermal cycle of the Diesel engine begins with the working medium at state 1, it is first polytropically compressed to state 2, then heat is added during a limited isobaric expansion, after which a polytropic expansion to the initial volume reduces pressure to state 4. The ideal work produced by the cycle is represented by its area, and the mean effective pressure is its average height.

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PV diagram of Diesel Engine ignition

a

b c

d

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4 Stroke Diesel Engine is an internal combustion engine in which

the piston completes four separate strokes which comprise a single thermodynamic cycle

2 Stroke Diesel EngineLike the four-stroke engine, the two-stroke engine must go

through the same four events: intake, compression, power, and exhaust. But a two-stroke engine requires only two strokes of the piston to complete one full cycle(crankshaft).

Types of Diesel Engine

INTAKE

EXHAUST

Two stroke diesel engine:

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AIR INTAKE SYSTEM

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What is an Air Intake System?

A system with air filters, ducts and supercharger that supplies necessary air to the engine for fuel combustion. It consists of pipes for the supply of fresh air to the engine manifold. Filters are provided to remove dust particles from air which may act as abrasive in the engine cylinder.

It also improves the turbocharged or supercharged engine’s efficiency, and it cools the compressed air after being compressed.

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Two types of Air intake system

Dry Filter – A type of system where paper, cloth, or a metal screen material is used to catch and trap dirt before it enters the engine.

Wet Filter – In this system the air is sucked or bubbled through a housing that holds a bath of oil such that the dirt in the air is removed by the oil in the filter. The air then flows through a screen-type material to ensure any entrained oil is removed from the air.

18Wet Filter Air Intake System

To E

ng

ine

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EXHAUST SYSTEM

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What is an Exhaust System?

A system that leads the engine exhaust gas outside the building and discharges it into atmosphere. A silencer is usually incorporated in the system to reduce the noise level. It is mainly composed of manifold, cylinders, muffler and exhaust pipe.

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Exhaust System Layout:

Silencer

Expansion Joint

Exhaust manifoldCylinders

Diesel Engine

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Functions of an Exhaust system

First, the exhaust system routes the spent combustion gasses away from the engine, where they are diluted by the atmosphere. This keeps the area around the engine habitable.

Second, the exhaust system confines and routes the gases to the turbocharger, if used.

Third, the exhaust system allows mufflers to be used to reduce the engine noise.

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Factors in designing an Exhaust System

a. The noise should be reduced to a tolerable degree.

b. It should be exhausted well above the ground level to reduce the air pollution at breathing level.

c. The pressure loss in the system should be reduced to minimum.

d. The vibrations of exhaust system must be isolated from the plant by use of flexible exhaust pipe.

e. A provision should be made to extract the heat from exhaust if the heating is required for fuel oil heating or building heating or process heating.

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Air Intake System and Exhaust System Layout:

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FUEL SUPPLY SYSTEM

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What is a Fuel Supply System?

A system consists of storage tank, strainers, fuel transfer pump and all day fuel tank.

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Basic process of Supply system

a. The fuel oil is supplied at the plant site by rail or road. The oil is stored in the storage tank.

b. From the storage tank, oil is pumped to smaller all day tank at daily or short intervals.

c. From this tank, fuel oil is passed through strainers to remove suspended impurities.

d. The clean oil is injected into the engine by fuel injection pump (fuel injection system).

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Day tanks

Fuel Supply System Diagram:

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Types of a Supply System

Simple Suction systemIn a simple suction system, the oil is taken by a suction

pump driven by engines from service tank located a few cm below the engine level. Such pump delivers constant volume of fuel, therefore, an overflow line is required back to the tank. This system is used for small capacity plant.

Transfer system

In transfer system, the motor driven pump takes the oil from main storage and supply to the day storage tank. The oil from day-storage tank flows under gravity to the engine pump.

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Transfer System Diagram:

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COOLING SYSTEM

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What is a Cooling System?

A system that includes water circulating pumps, cooling towers or spray ponds and water filtration plant. Small engines may be served with a cellular heat exchanger (radiator), through which the air is drawn by means of fan.

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Importance of a Cooling System

If the engines are not properly cooled, the temperature existing inside engines would disintegrate the film of lubricating oil on the liners and wrapping of valves and pistons takes place. The proper cooling of the engine is absolutely necessary to extend the life of the plant. Therefore, exit temperature of the cooling water must be controlled. If it is too low, lubricating oil will not spread properly and wearing of piston and cylinder takes place. If it is too high, the lubricating oil burns. Therefore, the maximum exit temperature of the water is limited to 70°C.

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Basic process of Cooling

The temperature of the burning fuel inside the engine cylinder is 15000C to 20000C. In order to lower this temperature water is circulated around the engine.

The hot water leaving the jacket is passed through the heat exchanger.

The heat from the heat exchanger is carried away by the raw water circulated through the heat exchanger and is cooled in the cooling tower

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to OilCooler

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2 types of Cooling System

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LUBRICATING SYSTEM

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What is a Lubricating System?

A system that includes the oil pumps, oil tanks, filters, coolers and connecting pipes. The function of the lubrication system is to reduce the friction of moving parts, reduce the wear and tear of the engine parts and also helps to cool the engine .

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Importance of a Lubricating System

The role played by the lubrication system in diesel power plant is more important than any other plant because of very high pressures and small clearance in these engines. The life of the engine, the overall efficiency of the plant and possible continuous service of the plant are dependent on the effectiveness of the lubrication system.

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Parts to be Lubricated

Piston and cylinders Crankshaft and connecting rod bearings Gears or other mechanism designed to transmit

motion to auxiliaries. Integral injection or scavenging air compressors.

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General Outline of Lubrication System:

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STARTING SYSTEM

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General types of Starting the Engine

Engine Starting by an auxiliary small engine Compressed air system Starting by electric motor

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Engine Starting by an Auxiliary Small Engine

It is composed of two engine:

1. Diesel engine that is main engine.

2. Small petrol engine.

Joining:• Diesel engine and petrol engine are joined by clutch and gear

arrangements.• Small petrol engine can be easily started by means of manual

operations

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Working process:

• First clutch is disengaged and petrol engine is started by hand operated system.

• Then clutch gradually engaged and the power is transferred to diesel engine.

• Automatic disengagement of clutch takes place after main engine has started.

• The capacity of the starting petrol engine is just sufficient to overcome the friction of the main diesel engine.

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Compressed Air System

The compressed air system is generally used for starting large diesel engine employed for power plant. In this system compressed air a pressure of 17 bar is supplied from an air bottle to the engine cylinder either through a distributor or directly through inlet manifold.

In case of multicylinder engines, at least one cylinder remains on the suction stroke.

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Working process:• When compressed air under the pressure enters cylinder, it

pushes the cylinder thereby causing entire engine crankshaft assembly to rotate.

• Meanwhile the suction stroke of some other cylinder takes place and the compressed air again pushes the piston of this cylinder and causes the engine crank assembly to rotate.

• Gradually the engine gains momentum and by turning on the fuel supply, engine will start running.

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Starting by Electric Motor

This system consists of an electric motor which is drives pinion which engages a gear toothed rim on engine.

A storage battery of 12 to 36 volts is used to supply power to an electric motor.

The main advantages of electric starting are its simplicity and effectiveness. This system is used for small diesel engine.

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Engine Stopping System

The engine should not be stopped abruptly. In order to stop engine, the speed should be decreased gradually until no power is delivered by generator .Then the engine is disconnected from the bus bars and is allowed to run idle for some time.

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Engine can be shut down with of the any one of the following methods:

Stopping fuel supply Keeping exhaust valve open Shutting of air supply Stopping the action of injection pump.

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Advantages of diesel power plant

Plant layout is simple. Hence it can be quickly installed and commissioned, while the erection and starting of a steam power plant or hydro-plant takes a fairly long time.

Quick starting and easy pick-up of loads are possible in a very short time.

The load operation is easy and requires minimum labours. Efficiency at part loads does not fall so much as that of a

steam plant. Fuel handling is easier and no problem of ash disposal

exists. The plant is smaller in size than steam power plant for

same capacity.

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Disadvantages of diesel power plant

Plant capacity is limited to about 50 MW of power. Diesel fuel is much more expensive than coal. The maintenance and lubrication costs are high. Diesel engines are not guaranteed for operation under

continuous, while steam can work under 25% of overload continuously.

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DMPC – CATAINGAN SATELLITE PLANT

DMPC – AROROY SATELLITE PLANT

DMPC – MAIN PLANT

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Power Plants Installed and Operated by

DMCI Masbate Power Corporation

2 x 6.2MW HFO Gensets2 x 2.0MW Diesel Gensets 1 x 2.0MW Diesel Gensets

2 x 1.0MW Diesel Gensets

1 x 2.0MW Diesel Gensets1 x 1.0MW Diesel Gensets

1 x 1.0MW Diesel GensetsMobo Power Plant

Cataingan Satellite Plant

Aroroy Satellite Plant

24.4 MW Total Plant Capacity

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MAIN PLANT

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MAIN PLANTCAPACITY & CONFIGURATION

GENERATOR UNITS Speed (Category) Installed MW CapacityDependable MW

Capacity

NIIGATA 1 600 RPM (Medium Speed) 6.2 5.8NIIGATA 2 600 RPM (Medium Speed) 6.2 5.8CATERPILLAR 1 1800 RPM (High Speed) 2.0 1.6CATERPILLAR 2 1800 RPM (High Speed) 2.0 1.6MITSUBISHI 3 1800 RPM (High Speed) 1.0 0.8

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CATAINGAN SATELLITE PLANT

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CATAINGAN SATELLITE PLANTCAPACITY & CONFIGURATION

GENERATOR UNITS Speed (Category) Installed MW CapacityDependable MW

Capacity

CATERPILLAR 3 1800 RPM (High Speed) 2.0 1.6MITSUBISHI 2 1800 RPM (High Speed) 1.0 0.8MITSUBISHI 4 1800 RPM (High Speed) 1.0 0.8

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AROROY SATELLITE PLANT

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AROROY SATELLITE PLANTCAPACITY & CONFIGURATION

GENERATOR UNITS Speed (Category) Installed MW CapacityDependable MW

Capacity

CATERPILLAR 4 1800 RPM (High Speed) 2.0 1.6MITSUBISHI 1 1800 RPM (High Speed) 1.0 0.8

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DIESEL ENGINES

Main Plant,

Mobo

(MW)

Curvada,

Cataingan

(MW)

Bangon,

Aroroy

(MW)

TOTAL

(MW)

NIIGATA 1 6.2 6.2NIIGATA 2 6.2 6.2CATERPILLAR 1 2.0 2.0CATERPILLAR 2 2.0 2.0CATERPILLAR 3 2.0 2.0CATERPILLAR 4 2.0 2.0MITSUBISHI 1 1.0 1.0MITSUBISHI 2 1.0 1.0MITSUBISHI 3 1.0 1.0MITSUBISHI 4 1.0 1.0

TOTAL INSTALLED CAPACITY (In MW) 17.4 4.0 3.0 24.4

POWER PLANT’S INSTALLED CAPACITY

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DIESEL ENGINES

Main Plant,

Mobo

(MW)

Curvada,

Cataingan

(MW)

Bangon,

Aroroy

(MW)

TOTAL

(MW)

NIIGATA 1 5.8 5.8NIIGATA 2 5.8 5.8CATERPILLAR 1 1.6 1.6CATERPILLAR 2 1.6 1.6CATERPILLAR 3 1.6 1.6CATERPILLAR 4 1.6 1.6MITSUBISHI 1 0.8 0.8MITSUBISHI 2 0.8 0.8MITSUBISHI 3 0.8 0.8MITSUBISHI 4 0.8 0.8

DEPENDABLE CAPACITY (In MW) 16.4 2.4 2.4 21.2

POWER PLANT’S DEPENDABLE CAPACITY

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Why Satellite Plant Exists?

1. It is the DMPCs alternative solution in the absence of NPCs 69 KV Transmission Line (A government’s unfinished project).

2. Due to a long extended 13.8 KV Distribution Line of MASELCO which resulted in a “Low Voltage” in the far end of the DT.

What are its Primary Purposes?

1. To correct “Low Voltage” Problem at far end.2. To minimize “System Loss” of the Off taker.3. To minimize prolong “Brownouts” at areas affected by

Line Repair Maintenance.4. To bring more “Reliable Power” to the consumers.

NIIGATA GENSET

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NIIGATA ENGINE:

Model: 18V32CLX-1M.C.R. output: 6.2MWNo. of cycles: 18Cylinder bore: 320MMPiston stroke: 420MMRated speed: 600RPMTurbocharger: NR34/RMax speed: 25400RPM

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CATERPILLAR GENSET

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MITSUBISHI GENSET

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AIR INTAKE SYSTEM

AIR INTAKE FILTER

“Auto-mazed Air Filter”

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LUBE OIL SYSTEM

2 X 10KL STORAGE TANK

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2 X 10 KL SUMP TANK

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LUBE OIL PURIFIER

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LUBE OIL HEATER MODULE

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COOLING SYSTEM

COOLING SYSTEM

100KL RAW WATER STORAGE TANK

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H2O TREATMENT

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PRIMARY COOLING SYSTEM

20KL SOFT H2OSTORAGE TANK

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PRIMARY COOLING SYSTEM

JACKET H2O PUMP – 30KW

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SECONDARY COOLING SYSTEM

LIANGCHI COOLING TOWER

MODEL: LBC 500NOMINAL H2O FLOW: 6500L/M AIR VOLUME: 2600M3/M

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SECONDARY COOLING SYSTEM

AIRCOOLER

RAW WATER IN

RAW WATER OUT

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SECONDARY COOLING SYSTEM

LUBE OIL COOLER

RAW WATER IN

RAW WATER OUT

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FUEL SYSTEM

100KL DIESEL STORAGE TANK

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2.5 KL LFO DAY TANK

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FUEL SYSTEM DRAIN

FUEL DRAIN TANK: 500L

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SLUDGE SYSTEM

SUMP PIT

SUMP PIT PUMP

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BLACKSTART GENSET

EG – 160 (438 KVA)

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SLUDGE STORAGE AREA

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The Niigata Alternator

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MEDIUM VOLTAGE SWITCHGEAR

BUS PT PANEL

NII-2 PANEL

NII-1 PANEL

20-MVA X’FORMER

PANEL

1.5-MVA AUX.

X’FORMER PANEL

Single Line Diagram

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CONTROL ROOM

2 X 6.2MW CONTROL PANEL

ENGINE-1 ENGINE-2

SYNCHRONIZING PANEL

AMC-1 /

AMC-2

ANCILIARY CONTROL

PANEL

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Actual Flow of Power Distribution

69-KV TRANSMISSIONLINENPC 69KV POWER SUB-STATION

WITH 10MVATRANSFORMER

13.8KV DISTRIBUTIONLINE

CONSUMERS

DMCI MASBATE POWER PLANT

20MVA STEP-UP POWER SUB-STATION

F1 & F3

F2

F1 – FEEDER 1

F2 – FEEDER 2

F3 – FEEDER 3

STEP-DOWN DIST. TRANSFORMER

DMPC

DMPC

MASELCO

MASELCO

DMPC

NPC

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TARLAC POWER CORPORATION

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At shaft under ISO conditions = 6600 kWNumber of strokes = 4 (four)Cylinder Power = 550 kW/cylinderNumber of cylinders = 12Nominal speed = 600 rpmDiesel Engine Unit = 3Capacity Installed = 18.9 MWCapacity Dependable = 14.9 MW

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OPERATION PROCEDURES

Pre-Operation Procedures

Verify order of operation with Shift Supervisor On-duty prior to carrying out pre-startup procedures.

Visually check the Jacket Water [JW] and Injector Cooling [IC] Water expansion tanks for proper level.

Check inlet and outlet valves of Nozzle and Jacket Waters systems for proper open or close positions.

Press JW and NC water pumps start button located on the Engine Control Panel [ECP].

Energize JW and IC water heaters by pressing the “ON” button located on the Heaters Control Panel [HCP].

Check the level of the various engine tanks and auxiliary equipment. Cooling Tower Pond Oil Sump Tank Cylinder Lubricating Oil Tank Bunker fuel service and settling tank Diesel storage tanks Turbocharger oil level Governor oil level Outboard bearing oil level Air pressure for 30 and 8 bar tanks

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Verify that fuel control linkages and injection pump plunges moves freely. Manually lubricate cylinder liners by turning the hand crank of the cylinder

lubricators and check that excessive force is not needed to turn the cranks. Check that the various valves for the engine cooling, lubrication, fuel system and

air system are in the correct position. Verify with Auxiliary Operator/Maintenance that the lube oil separator/centrifuge

of engine in schedule has been running normally. (The separator must be put in operation at least four hour before engine operation to remove accumulated dirt or settled water, if any).

Run bunker fuel centrifuge (if no engine running). Start the Pre-lubricating oil pump. Open the indicator cocks in the cylinder heads and rotate the engine several

times with the turning gear to make sure that no water, oil, or fuel has collected in the cylinder.

Switch “OFF” the JW and IC heaters and switch-off the injector and jacket water-circulating pumps.

Switch “OFF” the turning gear motor, disengage the turning gear, and lock the operating lever.

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Start-Up Procedure

Energize main power supply for the engine alarm. Start up the following and adjust the pressures: Pre-lubricating oil pump (manual position) Diesel transfer pump Fuel booster module Nozzle cooling water pump Jacket water pump Fuel service pump

Check that the turning gear is disengaged and that the operating lever is locked. Open all the indicator cocks. Check starting air tank pressure gauge for the proper pressure of 25 to 30 bar. Set the governor load limit to “0” position, and rotate the speed setting knob for at

least five [5] revolutions from zero. Set the governor speed droop to “40” position. Move each individual fuel pump rack in and out a few times to ensure rack is free

and not binding. Press the emergency stop button. Open the starting air valve. Get clearance and “GO” signal with Shift Supervisor On-duty for startup activation.

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Gradually unload (300 KW/min) the generator to avoid extreme thermal stressing.

Open/trip the generator circuit breaker just before the KW-hr meter reaches 200 KW.

Let the generator run for at least 10 to 15 minutes to cool down the engine. Set alarm power switch to “DISABLE” position. Bring down the engine speed gradually and press the emergency stop button. Open all indicator valves to release air from the cylinders. The engine should

stop running after 20 to 30 seconds. Push control buttons of the following to “OFF” position.

Raw water pump Cooling tower fan motor Jacket water pump njector cooling water pump

Switch “OFF” the chemical feed pump Close the starting air main valves. Switch “OFF” the pre-lube pump. Switch “OFF” main power supply of ECP.

Stopping Procedures

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MAINTENANCE PROCEDURES

The maintenance work to be carried out on the engine at regular intervals is described in the maintenance schedule and is to be understood as a guide. The maintenance intervals are dependent on the mode of operation and load as well as on the quality of the fuel used.

Precautionary Measure For Maintenance Work

Prior to carrying out any maintenance work on the engine (especially on the running gear), the following precautions have to be taken.

Pull out the Vacuum Circuit Breaker of generator engine under maintenance to avoid accidental closing.

Installation of automatic control: Put automatic control switch to “OFF” position. Close stop valves of starting air receivers. Open all indicator cocks on the cylinder heads and leave in this position until

maintenance work is completed. Engage turning gear (gear pinion must bee in engage position) and lock the

lever. In case the engine had to be stopped due to overheated running gear or bearings, wait at least 10 minutes before opening the crankcase doors.

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Recommendations For Carrying Out The Work

Prior to turning the crankshaft with the turning gear, make sure that no loose parts, tools or devices can get jammed.

When carrying out maintenance works, use the tools and devices intended for the work.

Tools and devices should be ready prior to use and be in perfect conditions. Hydraulic tools are to be checked from time to time for tightens and perfect

functioning. All work must be done carefully, observing utmost cleanliness. Where openings appear after certain parts have been removed, pipelines, oil

holes, etc., they must be temporarily closed off in order to prevent entry of any dirt into the engine.

All parts overhauled during the course of servicing have to be checked for perfect functioning before reinstalling back into service.

Pipes that have been removed have to be checked for tightness after refitting. Clearances of moving parts must be checked periodically. Should the maximum

permissible values have been reached or exceeded, these parts must be replaced.

When tightening studs, nuts or bolts, the utmost care must be taken not to damage their threads and that they can be screwed in by hand until metal-to-metal contact is obtained. The specified lubricants are to be used.

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