“Industrial Training Report on Indian Oil Corporation Limited, Gujarat Refinery, Vadodara”

In Electrical Engineering Discipline

(6th June 2016 to 25th June 2016)

By

“Final Year Student of Bachelor of Engineering in Electrical Engineering Stream.”

Gujarat Technological University (GTU)

Prepared by

1. Najar Shah (K.J.I.T) 2. Mahendra Rajput (K.J.I.T)

3. Sapna Joshi (K.J.I.T) 4. Harshit Patel (I.T.M)

5. Mitesh Vaghela (K.J.I.T) 6. Manish Prajapati (K.J.I.T)

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CETIFICATE

This is certify that following student have successfully completed

their Industrial / vocational training in Indian Oil Corporation limited,

Gujarat Refinery, Vadodara Davison, during their summer vacation

from 6th June 2016 to 25th June 2016.

1. Najar Shah

2. Mahendra Rajput

3. Sapna Joshi

4. Harshit Patel

5. Mitesh Vaghela

6. Manish Prajapati

INDEX2

1. Cover page………………………………………………………1

2. Certificate……………………………………………………….2

3. Acknowledgement………………………………………………3

4. Gujarat Refinery (company profile)…………………………….5

5. Fire and Safety Training ………………………………………..8

6. Main function and Instrumentation department in IOCL……...10

7. Power plant operation (CGP-2)…………………………….…..13

8. Power plant operation (TPS)……………………………….…..27

9. Electrical Maintenance (SRU)………………………………….29

10. Electrical Maintenance (FCC)………………………………...29

11. Electrical Testing ………………………….………………….34

12. Electrical Workshop……………..……….…………….……..36

ACKNOWLEDGEMENT

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Before proceeding to our vocational training report, we are really thankful to GOD for making our vocational training successful.

We would like to thank Mr A. C. Shekhar for letting us enjoy this experience of getting trained at Gujarat Refinery (Baroda). It has helped us for grown up our practical knowledge about refinery.

Besides this, we would like to thank Gujarat Refinery, Indian Oil Corporation Ltd for providing us a good environment and facilities to complete our vocational training successfully.

We are also thankful to all the technicians and operators and other staff of training department who speared their valuable time and took effort explaining the working of various units and various equipment of the plants. We greatly thankful for their co-operation. The information provided by them has helped me a lot in our future. The tremendous effort put by them have motivated me and made me gain confidence in completing the vocational training.

Yours sincerely,

Najar Shah

Mahendra Rajput

Sapna Joshi

Harshit Patel

Mitesh Vaghela

Manish Prajapati

GUJARAT REFINARY

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The Gujarat Refinery at Koyali in Western India is Indian Oil’s second largest refinery. The refinery was commissioned in 1965-1966.

Its facilities include five atmospheric crude distillation units. The major units include CRU, FCCU and the first Hydrocracking unit of the country.

Gujarat Refinery, operating with an installed crude processing capacity of 13.7 million metric tonnes per annum, processes indigenous and imported, both low sulphur and high sulphur grades of crude oil. The product slate includes besides fuels, petrochemical products such as Linear Alkyl Benzene (LAB), Polypropylene Feed Stock, and Food & Polymer Grade Hexane.

Gujarat Refinery is implementing a mega project worth around Rs.7000 crore to comply with the road map for supplying eco-friendly Bharat Stage-III and IV compliant MS and HSD and to upgrade the bottom of the barrel to improve the gross margin of the Refinery.

History

Following the conclusion of the Indo-Soviet Treaty of Friendship and Cooperation in February 1961, a site for the establishment of a 2 million metric ton per annum (mmtpa) oil refinery was selected on 17 April 1961.[2] Soviet and Indian engineers signed a contract in October 1961 for the preparation of the project. Prime Minister Jawaharlal Nehru laid the foundation stone of the refinery on 10 May 1963.

The refinery was commissioned with Soviet assistance at a cost of Rs.26 crores began production in October 1965. The first crude distillation unit with a capacity of 1 mmtpa was commissioned for trial production on 11 October 1965 and achieved its rated capacity on 6 December 1965. Throughput reached 20% beyond its designed capacity in January 1966.

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President Sarvepalli Radhakrishnan dedicated the refinery to the nation with the commissioning of second crude distillation unit and catalytic reforming unit on 18 October 1966.

The third 1 mmtpa distillation unit was commissioned in September 1967 to process Ankleshwar and North Gujarat crudes. In December 1968, Udex plant was commissioned for production of benzene and toluene using feedstock from CRU. By 1974-75 with in-house modifications, the capacity of the refinery increased by 40% to a level of 4.2 mmtpa. To process imported crude the refinery was expanded during 1978-79 by adding another 3 mmtpa crude distillation unit along with downstream processing units including vacuum distillation, visbreaker and bitumen blowing units. By 1980-81 this unit started processing Bombay High crude in addition to imported crudes. It was the first time that Indian engineers independently handled a project of that scale.

To recover products from the residue, secondary processing facilities consisting of fluidized catalytic cracking unit of 1 mmtpa capacity along with a feed preparation unit of 1 mmtpa capacities, were commissioned in December 1982. The refinery set up pilot distillation facilities for the production of n-Heptane and light aluminium rolling oils. To enable absorption of increased indigenous crudes the refinery's capacity was further increased to 9.5 mmtpa.

In 1993-1994, Gujarat commissioned the country's first hydrocracker unit of 1.2 mmtpa along with feed preparation unit-2 and hydrogen generation unit-1 (GHC Complex), for conversion of heavier ends of crude oil to high value superior products.

India's first diesel hydrodesulphurisation unit to reduce sulfer content in diesel was commissioned in June 1999. A methyl tertiary butyl ether unit was commissioned in September 1999 to eliminate lead from motor fuels. The facility conceptualised and commissioned South Asia's largest centralised effluent treatment plant by dismantling the four old ETP's. In June 1999. By September 1999 with the commissioning of an atmospheric distillation unit, Gujarat

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Refinery further augmented its capacity to 13.7 mmtpa making it the largest public sector undertaking refinery of the country.

A project for production of linear alkyl benzene from kerosene streams was implemented in August 2004. It is the largest grassroots single train Kerosene-to-LAB unit in the world, with an installed capacity of 1.2 mmtpa. To meet future fuel quality requirements, MS.

quality improvement facilities were commissioned in 2006.The Residue Upgradation Project undertaken by the Gujarat Refinery was completed by 2011 which increased the high sulfer processing capacity of Gujarat refinery, improved the distillate yield as well produce BS III & IV quality of MS and HSD. The Residue upgradation project came in two parts namely, the south block which consisted of HGU-III, SRU-III, DHDT and ISOM units and the north block consisted of VGO-HDT and DCU units. To support the new units a new Co-Generation Plant (CGP) and Heat Recovery Steam Generation (HRSG) were also commissioned.

The refinery's facilities include five atmospheric crude distillation units. The major secondary units include Catalytic Reforming Unit (CRU), Fluidized Catalytic Cracking Unit (FCCU) and the first hydrocracking unit of the country. Through a pipeline to Ahmedabad and a pipeline connecting to the BKPL. Pipeline and also by rail and truck, the refinery primarily serves the demand for petroleum products in western and northern India.

When commissioned, the refinery had an installed capacity of 2 mmtpa and was designed to process crude from Ankleshwar, Kalol and Nawagam oilfields of ONGC in Gujarat. The refinery was modified to handle imported and Bombay High crude. The refinery also produces a wide range of specialty products such as benzene, toluene, MTO, food grade hexane, solvents and LABFS.

Fire and Safety Training

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Fire and safety refer to the precautions that are taken to prevent or reduce the likelihood of a fire that may result in death, injury or property damage, alert those in a structure to the presence of fire in the event one occurs, better enable those threatened by afire to survive, or to reduce the damage caused by a fire. Fire safety measures include those that are planned during the construction of a building or implemented in structures that are already standing. Threats to fire safety are referred to as fire hazard. A fire hazard may include a situation that increases the likelihood a fire may start or may impede escape in the event a fire occurs.

FIRE & SAFETY REGULATION

1) No smoking except at the prescribed smoking booths. 2) Mobile phones, litter, torch etc. are prohibited in battery area. 3) Spark arrester is compulsory for every vehicle. 4) Do not sit/eat/rest in inside unit. Particularly near running equipment. 5) In case of any fire dial 7333/6333. 6) For ambulance dial 7444/6444. 7) Fire call can be given through fire alarm. Fire alarm point provided along the road. 8) Know emergency siren code. 9) During emergency move to the closest assembly point. Total 13 assembly point is in the refinery. 10) Do not touch any running or open equipment. 11) No photography/videography allowed inside refinery. 12) Work permit

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Safety PPE (Personal protective equipment) is compulsory.

There are three mandatory PPE : shoes, helmet, goggles. Use of PPE such as safety belts, hearing aids, hand glove,

aprons, gas mask etc. also there.

For working in chemical industry a industry must have the following permit 1. Hot work permit. 2. Cold work permit. 3. Height work permit. 4. Confined space permit. 5. Excavation work permit. 6. Radiography.

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Main function and Instrumentation department in IOCL

Provide and maintain automatic control and monitoring processes in different plants of refinery.

Provide and maintain automatic safety systems to ensure safe plant operation/startup/shutdown.

Provide and maintain process and environment monitoring analyzers to ensure product quality, increase efficiency and meet environmental commitments.

Planning related activities. Engineering related services jobs including procurement. Preventive maintenance scheduling. QMS/EMS/OHSMS related activities. Process modification scheme implementation, engg assistance

foe new plants etc. Absorption of new technology. Skill up gradation of personnel. Interfacing with other departments for coordinated functioning

INSTRUMENTATION USED IN REFINERY:

1. TEMPERATURE MESUREMENT:

Bimetallic gauge:

A bimetallic temperature gauge employs a sensor bimetallic strip by name.

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A bimetallic strip is used to convert a temperature change into mechanical displacement. The strip consists of two strip of different metals which expand at different rates as they are heated usually steel and copper. The strip s are joined together throughout their length by riveting brazing or welding. The different expansion forces the flat strip to bend one way if heated and in the opposite direction if cooled below its initial temperature. The metal with the higher coefficient of thermal expansion is on the outer side of the curve when the strip is heated and on the inner side when cooled. It is connected to a pointer in order to detector the temperature.

This sensor is utilized to show the temperature locally.

RTD

Resistance temperature detectors (RTDs) are typically made of nickel, copper, or platinum. Temperature is determined by measuring

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resistance and then using the RTD‟s resistance vs. temperature characteristics to extrapolate temperature.

They’re the once to use when applications requires accuracy, long-term electrical (resistance) stability, element linearity, and repeatability. The device can work in a wide temperature range – some platinum sensors handle temperature from -328 to 1202.

PRINCIPLE OF OPERATION:

RTDs are manufactured from metals whose resistance increases with temperature. Within a limited temperature range, this resistivity increases linearly with temperature:

Rt = R0[1 + a(t – t0)] Where: Rt = resistivity at temperature t R0 = resistivity at a standard temperature t0 a = temperature coefficient of resistance ( ) IEC/DIN grade platinum: a = 0.00385// Reference grade platinum: a = 0.003926// (max.)

Thermistor

Normally NTC type of thermistor is used. Resistance of thermistor decreased with increase in temperature. It is non-linear type device so rarely used.

Thermocouple

In 1821, Thomas See beck discovered the operating principle of the thermocouple: If two dissimilar metals are joined at one end, a voltage (the See beck voltage) proportional to the temperature difference between the joined and open ends is generated.

Power plant operation (CGP-2)

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1. GAS turbine overview

1.1 Functional Description

Figure 1 Gas Turbine Side View1. Inlet Casing2. Thrusts and Journal Bearing3. Variable Inlet Guide Vanes4. Compressor Rotor Blades5. Reverse Flow Combustion Chamber6. Transition Piece7. Turbine Nozzle8. Buckets9. Exhaust Diffuser10. Compressor Forward Casin g11. Compressor Wheel12. Compressor After Casing13. Duel Fuel Nozzles14. Turbine Exhaust

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15. Axial Flow Compressor16. Combustion System17. Turbine Section

As described by the below figure a Gas turbine operates by

(i) Stage 1 Continuously drawing fresh air through inlet air filters.

(ii) Between stage 1 and 2 Compressing this air to higher pressure.

(iii) Between stage 2 and 3 Adding and burning fuel in the compressed air to increase its energy level.

(iv) Stage 3 Directing this high pressure, high temperature air to an expansion turbine that converts the gas energy to the mechanical energy of a rotating shaft.

(v) Stage 4 The resulting low pressure, low temperature gases are discharged to atmosphere / heat recovery steam generator (HRSG).

Figure 2 Gas Turbine Operating Principle

When the turbine starting system is actuated and the clutch is engaged, ambient air is drawn through the air inlet plenum assembly, filtered and compressed in the 17 stage axial flow compressor. For

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pulsation protection during startup, the 11th-stage extraction valves are kept open and the variable inlet guide vanes are in the closed position. When the turbine reaches 95 % speed, the variable inlet guide vanes are opened to the normal turbine operation position. Compressed air from the compressor flows into the annular space surrounding the ten combustion chambers, from which it flows into the space between the outer combustion casing and the combustion liners and enters the combustion zone through metering holes in each of the combustion liners.

Fuel from an off-base source is provided to ten equal flow lines, each terminating at fuel nozzle located at the individual combustion chamber. Prior to being distributed to the nozzles, the fuel is accurately controlled to provide an equal flow into the ten nozzle feed lines at a rate consistent with the speed and load requirements of the gas turbine. The nozzles introduce the fuel into the combustion chambers where it mixes with the combustion air and is ignited by one or both of the spark plugs. When fuel is ignited in one combustion chamber flame is propagated, through connection crossfire tubes, to all other combustion chambers. After the turbine reaches operating speed combustion chamber pressure causes the spark plugs to retract to remove their electrodes from the hot flame zone.

The hot gases from the combustion chambers expand into the ten separate transition pieces attached to the aft end of the combustion chamber liners and flow from there to the three-stage turbine section of the machine. Each stage consists of a row of fixed nozzles followed by a row of rotatable turbine buckets. In each following row of moving buckets, a portion of the kinetic energy of the jet is absorbed as useful work on the turbine rotor.

After passing through the third-stage buckets, the gases are directed into the exhaust hood and diffuser, which contains a series of turning vanes to turn the gases from an axial direction to a radial direction, thereby minimizing hood losses. The gases then pass into the exhaust plenum and are introduced to atmosphere through the exhaust stack.

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Resultant shaft rotation is used to turn the generator for electrical power generation.

1.2 Support System

Support system of Gas Turbine typically includes following:

1. The Lube Oil System for furnishing normal lubrication and absorbing the heat rejection of the gas turbine.

2. The Hydraulic Supply System which provides the necessary hydraulic flows and pressures for control devices on the turbine.

3. The Trip Oil System used in hydraulic trip oil system which acts as an interfacing medium between valves and hydraulic oil for the positive and fast operation.

4. The Cooling Water System which is used as a cooling agent for lube oil and DM water.

5. The Starting System including the starting device here Diesel Engine and the required logic sequence for starting the gas turbine and bringing it up to a speed such that GT is able to run on its own.

6. The Cooling And Sealing Air System which provides the necessary airflow from the turbine compressor to the other parts of the turbine rotor and stators to prevent excessive temperature build up and prevent bearing oil leakage.

7. The Fuel System which supplies and controls the flow and directs the fuel to the fuel nozzles in the gas turbine combustors according to the load demand. The fuel system includes NG, HSD and NAPHTHA. Duel fuel is also possible with one fuel being NG and other being HSD or NAPHTHA.

8. The Atomizing Air System provides sufficient pressure in the air to atomize the liquid fuel i.e. to break the thick and continuous fuel jet to fine droplets permitting ignition and combustion with increased efficiency.

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9. The Ventilating and Heating System provides the ventilation of hot air from compartments so that various devices in these compartments work in the allowable compartment temperatures.

10. The Fire Protection System is provided to extinguish fires in the compartments, in case any fire takes place. Separate fire protection system is provided for Gas Turbine and Generator.

11. The Inlet and Exhaust System provides atmosphere air to be brought into the compressors through inlet ducting and let exhaust gases to atmosphere or to heat recovery steam generators.

12. The Hazardous Gas Detection System is provides for detection of hazardous gas leakages here NG which is used as a fuel.

13. Compressor Water Wash System is provided to wash the compressor for any foreign material contamination on its blade and buckets. Washing can be done online or offline.

14. Water Injection System is provided for controlling of the NOx

gases formation caused by burning of Nitrogen and Oxygen at very high combustion temperature (exceeding 28000F).

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2. Constructional features

A Gas Turbine unit mainly consists of1. Air inlet system2. Accessory gear compartment3. Turbine compartment4. Load gear compartment5. Generator and exciter compartment6. Exhaust system

2.1 Air Inlet System

The air inlet system consists of an integrated, self-cleaning filter house and support structure, an inlet ducting system and an inlet plenum leading to the compressor section of the turbine. Inlet air enters the inlet compartment and flows through the ducting, with built-in acoustical silencers and trash screen, to the inlet plenum before entering the turbine compressor. The elevated intake arrangement provides a compact system and minimizes pickup of dust concentrated in the air near the ground. All external and internal surface areas of the inlet system are either coated with a corrosion preventive primer or galvanized for corrosion protection.

2.1.1 Inlet CompartmentThe inlet filtration compartment and its integrated support structure

sits on a separate Foundation just upstream of the control compartment. The filter house is a self-cleaning design consisting of a number of filtration modules which flow upward to a tapered clean air plenum.

Air filtersIt consists of a single stage air filter utilizing surface acting cellulose and/or synthetic base high efficiency paper media. These highly efficient filter elements are used to achieve Compressor inlet air flow requirements. During normal operation, a duct cake is gradually formed on the surface of the filter media, creating airflow restriction.

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The filter elements are re-generated to ensure an acceptable low level of Del-P across filters by injecting compressed air into a selected number of elements in reverse flow direction for cleaning the duct cake formed on filter surface. A programmable electrical control unit activates and modulates the self-sequencing system for filter cleaning initiated on either time basis or on pressure drop basis or on combination of both.

Filter pairs (cylindrical and conical) are arranged horizontally to improve cleaning during operation. In this way the dust particles which are pulsed off the filter elements are allowed to fall down out more freely and thus re-entry of fine dust particles are reduced by positive downdraft within the system.

Figure 3 Horizontal Filter Assembly

The clean air plenum has an aft outlet flange which connects to the inlet ducting. Each filtration module contains numerous single-stage, high efficiency, self-cleaning filter elements.

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In GT#4 and GT#5 no. of installed filters is as following-

No. of horizontal filter assembly lines 15

No. of vertical filter assembly lines 12

Total duplex filters 15X12 = 180

Air Processing Unit (APU)This compartment contains a self-cleaning filtration unit with high efficiency filter cartridges that are cleaned sequentially by pulses of pressurized air during turbine operation. Compressor discharge air from the gas turbine compressor 17th stage is supplied to the self-cleaning inlet filters for use as pulse air during the cleaning cycle. Air from the compressor discharge contains lots of moisture, which will not clean air filters effectively, if injected directly. So air dryer is used to treat 17th stage compressor discharge air, before using it for pulse cleaning. A brief description of APU is given below.

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Figure 4 Air Processing Unit (APU)

As shown in figure even after passing through the pre-filter (moisture separator), the compressed air still contains vapor moisture, which are subsequently removed by air dryer. Dryer contains activated alumina, which has a natural tendency to establish equilibrium with its surrounding by absorbing moisture from incoming wet air. The compressed air passes through towers by means of pneumatically operated control valves (CV1, CV2, CV3) which in turn are actuated by solenoid valves (SV1, SV2, SV3) with timer. Wet air enters from bottom and come out from top as dry air. When the timer is switched ‘ON’, the solenoid valve SV1 will actuate the 3-way valve CV1 for 5

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minutes, thereby directing the compressed air to tower-B. Simultaneously (after 5 sec), the 2-way valve CV2, which is connected to tower-A will open. This will de-pressurize tower-A and is placed for purging for 3 minutes. After 3 minutes, the valve CV2 will close and tower-A will then pressurize in next two minutes through needle valve. At the end of 5 minutes, tower changeover occurs, and compressed air from pre-filter now flows to tower-A, by means of 3-way control valve CV1. Simultaneously (after 5 sec), the 2-way valve CV3, which is connected to tower-B will now open and tower-B is placed on purging for 3 minutes. Subsequently CV3 will close and tower-B is pressurized in next 2 minutes. So, it is standard 10 minutes cycle for a tower i.e. 5 min drying-3 min purging-2 min pressurization, and after 5 minute tower changeover occurs.

2.1.2 Inlet Ducting and SilencingThe air inlet ductwork connecting the inlet compartment to the compressor inlet consists of an expansion joint, extension ducting, silencer, down elbow, a transition duct and the inlet plenum and plenum side extensions. The extension ducting and silencer runs horizontally above the control and turbine accessory compartments and is supported on its own steel support structure. The flow is then directed down and transitioned into the inlet plenum by the elbow and transition ducts. The inlet silencer consists of an acoustically lined duct containing silencing baffles constructed of a low-density insulating material which is encapsulated by perforated sheet steel. The acoustic lining in the walls of the silencer duct and the walls of the ducting downstream of the silencer have a similar construction. The vertical parallel baffle is specifically designed to eliminate the fundamental compressor tone as well as attenuating the noise at other frequencies. There is a stationary trash screen within the transition duct with can be accessed for cleaning and inspection through a removable access panel on the side of the elbow. The inlet ducting makes use of materials and coatings in their construction which are designed to make them maintenance free. The perforated sheet and internal stiffeners used in the silencers and lined ductwork are

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fabricated of galvanized steel. The carbon steel walls are painted with multiple coats of zinc-rich, corrosion inhibiting paint.

2.2 Accessory Gear Compartment

Most of the mechanical and electrical auxiliary equipments necessary for starting and operating the gas turbine are contained within the accessory compartment. Several major components of the accessory compartment includes-

2.2.1 Starting MeansGas turbine is fully independent machine when running on loaded condition, but to start-up a standstill gas turbine some external means are needed. This may be done by a motor or diesel engine. In this gas turbine diesel engine is used. Diesel engine alone is not sufficient to break away such huge mass. So torque converter and ratchet assemblies are used to achieve this. During the starting sequence, the gas turbine is driven through the accessory gear by the diesel engine, torque converter output gear and the starting clutch. The starting clutch assembly and the engagement cylinders are mounted on the accessory gear assembly. The accessory gear is permanently coupled to the turbine compressor shaft by a flexible coupling. The starting system provides power for both cranking and turning during gas turbine start up and shutdown cycles. In the starting cycle there are three primary functions provided by the starting system:

(i) Start the gas turbine rolling (breakaway from standstill);

(ii) Accelerate the gas turbine to a speed where it can be fired

(iii) After the turbine has fired, further-accelerate it to a self-sustaining speed (a speed at which gas turbine develops net positive power output).

Starting system components include:

Diesel Engine When operating, the diesel engine draws combustion air from

the accessory compartment through a filter into the turbocharger

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inlet. Air dampers, located downstream of the turbochargers are equipped with a manual emergency shutdown latch. Engine coolant exchanges its heat with the Gas Turbine cooling water system. The flow rate is controlled by thermostats on the engine. The engine operates on a completely self-contained lube oil system. Lube oil pressure can be read on a panel mounted pressure gauge and is monitored by pressure switch 63QD-1. A fuel tank for the diesel engine has been fabricated in the accessory compartment. The main fuel pump driven by the Diesel engine itself draws fuel from canister and pumps it through a filter and into the injector’s headers. Each fuel injector draws the required amount of fuel from the headers, while the excess fuel (used to cool the injectors) is returned to the canister and through the overflow drain back to the tank. There is a manual “priming” pump installed in parallel with the high lift pump. Engine starter 88DS-1 is a direct current motor that engages with the engine through a Benedix clutch. Engine speed is controlled by the positioning of a lever on the variable speed governor. The positioner is a hydraulic cylinder controlled by solenoid valves 20DA-1 and 20DA-2. A small engine driven pump, pressure limited by relief valve VR13-1, supplies a controlled flow rate of engine oil for cylinder operation. When 20DA-2 is energized, the governor lever is driven to and held at the maximum speed position. When 20DA-2 is de-energized, the lever is returned to the idle position. Energizing 20DA- 1 when the lever is anywhere between the end positions, stops the positioner travel and holds the lever at the existing position (governing at an intermediate speed). This system allows control of the gas turbine cranking speed. Except under certain emergency conditions, the engine is only stopped with the governor lever in the idle position. Following an emergency shutdown, the engine can be safely restarted regardless of governor lever position; but the operator has the option of manually resetting the lever before attempting a restart. The engine stop device is an "energize-to-stop" solenoid (20DV-1) connected to the governor that when energized activates the shutdown mechanism and stops the engine. Electronic, logic in the control panel provides automatic sequencing of 88DS-1,

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20DA-1, 20DA-2 and 20DV-1 for normal unit startup, for normal and emergency engine shutdown and for exercising and/or test of the engine.

To protect the system hardware, the logic also monitors the starting clutch position (33CS-1), the engine lube oil pressure (63QD-1) and the engine speed. Necessary ALARMS and / or TRIPS are built into the control system. The engine will operate at constant speed when the unit is between 2300 and 2700 rpm during the startup sequence this is the crank speed range of the turbine. Routinely checking the engine speed in this speed range will provide a good check on engine performance level in that a persistent speed decrease of more than about 35 rpm from the "normal" indicates a need to have the engine serviced by a qualified mechanic.

Diesel Engine Operation After the starting clutch is engaged, 88DS-1 is energized to start the engine. The engine idles through the warm-up cycle and then 20DA-2 is energized to accelerate the engine to maximum speed for unit breakaway (requires assistance of the hydraulic ratchet). Following breakaway, 20DA-2 is de-energized to decelerate the engine to approximately 1900 rpm at which point 20DA-1 is energized to hold constant engine speed until the gas turbine is sequenced through the end of warm-up. Then 20DA-1 is de-energized and 20DA-2 energized to accelerate the engine back to maximum speed (and power) for acceleration of the unit to self-sustaining speed. At a unit speed of about 3100 to 3200 rpm, the clutch automatically disengages and 20DA-2 is de-energized. The engine returns to idle speed, idles through a cool-down period, and stops when 20DV-1 is energized for several seconds.

Ratchet System Operation

With the pump in operation and solenoid valve 20CS-1 energized, oil from the turbine main lubrication system is ported to the starting clutch and the ratchet system. This causes the ratchet mechanism to operate continuously as the hydraulic self-sequencing control

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automatically shifts the oil flow between the forward and reset strokes of the ratchet mechanism. A forward stroke advances the starting clutch about 47 degrees during the 10 second duration. The reset stroke is of about 4.5 second duration. Operation for unit cool down is automatically sequenced by the control panel. Once every three minutes, the mechanism is operated, through one complete cycle. The cycle is terminated in the forward stroke position to lock the clutch in the engaged position.

Ratchet operation is normally required to achieve breakaway of the unit rotor system during the unit startup sequence. With the starting mean (here Diesel Engine) at maximum power, 88HR-1 and 20CS-1 are energized for continuous operation until breakaway is achieved. If breakaway is not achieved within three minutes, the ratchet system is de-energized. The ratchet system can also be manually operated by use of "Jog" switch 43HR-1 located in the accessory compartment. Actuation of the "Jog" switch interrupts and terminates operation in any automatic sequence. Switch actuation energizes 88HR-1 and 20CS-1 and maintains both in an energized state as long as switch contact is maintained. Release of the switch immediately de-energizes both 88HR-1 and 20CS-1 independent of the ratchet stroke position. Excessive continuous ratchet operation and/or jogging ("inching the rotor") by use of the "jog" switch can seriously affect the life of 88HR-1 and/or 20CS-1.

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Power plant operation (TPS-2)

A thermal power station is a power plant in which heat energy is converted to electric power. In most of the world the turbine is steam driven. Water is heated, turns into steam and spins a steam turbine which drives an electrical generator. After it passes through the turbine, the steam is condensed in a condenser and recycled to where it was heated; this is known as a Rankine cycle. The greatest variation in the design of thermal power stations is due to the different heat sources, fossil fuel dominates here, although nuclear heat energy and solar heat energy are also used. Some prefer to use the term energy centre because such facilities convert forms of heat energy into electrical energy.[1] Certain thermal power plants also are designed to produce heat energy for industrial purposes of district heating, or desalination of water, in addition to generating electrical power. Globally, fossil-fuel power stations produce a large part of man-made CO2 emissions to the atmosphere, and efforts to reduce these are varied and widespread.

Types of thermal energy sources

Almost all coal, nuclear, geothermal, solar thermal electric, and waste incineration plants, as well as many natural gas power plants are thermal. Natural gas is frequently combusted in gas turbines as well as boilers. The waste heat from a gas turbine, in the form of hot exhaust gas, can be used to raise steam, by passing this gas through a Heat Recovery Steam Generator (HRSG) the steam is then used to drive a steam turbine in a combined cycle plant that improves overall efficiency. Power plants burning coal, fuel oil, or natural gas are often called fossil-fuel power plants. Some biomass-fuelled thermal power plants have appeared also. Non-nuclear thermal power plants, particularly fossil-fuelled plants, which do not use co-generation, are sometimes referred to as conventional power plants.

Commercial electric utility power stations are usually constructed on a large scale and designed for continuous operation. Virtually all

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Electric power plants use three-phase electrical generators to produce alternating current (AC) electric power at a frequency of 50 Hz or 60 Hz. Large companies or institutions may have their own power plants to supply heating or electricity to their facilities, especially if steam is created anyway for other purposes. Steam-driven power plants have been used to drive most ships in most of the 20th century until recently. Steam power plants are now only used in large nuclear naval ships. Shipboard power plants usually directly couple the turbine to the ship's propellers through gearboxes. Power plants in such ships also provide steam to smaller turbines driving electric generators to supply electricity. Nuclear marine propulsion is, with few exceptions, used only in naval vessels. There have been many turbo-electric ships in which a steam-driven turbine drives an electric generator which powers an electric motor for propulsion.

Combined heat and power plants (CH&P plants), often called co-generation plants, produce both electric power and heat for process heat or space heating. Steam and hot water

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Electrical Maintenance

In electrical maintenance we had visited two plants i.e. FCC and SRU. In which we show a different component of indoor substation and study about their single line diagram, schematic diagram etc.

We also see different switches, contactor, vacuum circuit breaker, Induction motor etc.

Different components and their Name plate as follow:

1. Transformer:-

2. Induction motor:-29

3. Vacuum circuit breaker:-

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Electrical maintenance is the upkeep and preservation of equipment and systems that supply electricity to a residential, industrial or commercial building. It may be performed by the owner or manager of the site or by an outside contractor. The work is commonly performed on a schedule based on the age of the building, the complexity of the electrical system or on an as-needed basis.

The main areas of general electrical maintenance commonly include the power outlets and surge protectors, generators and lighting systems. These supply sources are checked for structural integrity as well as internal stability. The maintenance plan normally includes the regular replacement of burned out fluorescent and incandescent lights. Many building managers in recent years have refitted their lighting systems with energy saving bulbs and elements.

Preventive maintenance is also generally part of a building’s upkeep. This plan ordinarily includes the scheduled inspection of large systems and equipment by a professional electrician. The purpose of these periodic assessments is to fix small problems before they escalate into large ones. This is particularly important at plants, hospitals and factories that heavily rely on these systems for daily operations.

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Electrical Testing

Electrical testing is a vital procedure.  Electrical testing is an essential task and can be difficult so it's necessary to let a professional do it.  The electrical test report is displayed in a test certificate which is a legal document. The certificate is similar to a fault log report but it also contains a count of occurrences of each fault.   

Electrical testing over temperature is the industry standard for testing a component’s functional and parametric requirements at the recommended manufacturer’s or specific industry extreme operating temperatures. Electrical testing is an essential task and can be time consuming and inconvenient as the power has to be turned off for some tests. We can generally work around your limitations to losing power in the office, home, workplace.

Inspection provides the ideal opportunity for checking the general condition of the equipment and that all parts are in sound condition. Our skilled team provides a comprehensive testing and inspection service, ensuring that anything from a mobile home to a factory complex is running as safely and efficiently as possible.

A periodic inspection report will reveal if any circuits or electrical equipment are being overloaded, locate any potential electrical shock risks and fire hazards in an installation, identify any defective DIY electrical work, or highlight any lack of earthing or bonding.

In electrical testing there are different instruments are used for assurance of electrical equipments some of them are as follow

1. Megger

2. Oil tester kit

3. Multimeter

4. Clamp On meter

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5. CT and PT

6. Relay test kit

7. Earthing and Discharge rode

Besides these there is lots of protection system and methods are used for electrical testing.

All test are conducted as per procedure describe in manual.

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Electrical Workshop

The fortunes of the heavy electrical industry have been closely linked to the development of the power sector in India. The heavy electrical industry has under its purview power generation, transmission, distribution and utilisation equipments. These include turbo generators, boilers, turbines, transformers, switchgears and other allied items. These electrical equipments (transformers, switchgears, etc.) are used by almost all the sectors. Some of the major areas where these are used include power generation projects, petrochemical, refineries, chemical plants, integrated steel plants, non-ferrous metal units, etc. 

The design, engineering and construction of industrial plants involves a multi-disciplinary team effort. The goal is to design safe and dependable processing facilities in a cost effective manner. The fact is that there are very few formal training programs that focus on design and engineering of Electrical systems of such big plants. Therefore, most of the required skills are acquired while on the job, reducing productivity and efficiency.

The objective of this course is to provide the delegates the basic knowledge and skills in this discipline to facilitate faster learning curves while on the job.

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