AREPORT

ON

VOCATIONAL TRAININGIN

INDIAN OIL CORPORATION Ltd.GUJARAT REFINERY

BARODA

DURATION: - 18/06/09 TO 03/07/09

GU I DIED BY Mr. G. D. PARASHAR

PREPARED BYNEELKUMAR R. SOLANKI

PIET, LIMDA

1

GUJARAT UNIVERSITYBARODA

CERTIFICATE

THIS IS TO CERTIFY THAT

NEELKUMAR R. SOLANKI

IInd B. E. ELECTRICAL HAS SATISFACTORILY COMPLETED THE TRAINING & HAS SUBMITTED THE REPORT OF

“VOCATIONAL TRAINING”IN

INDIAN OIL CORPORATION LTD.“GUJARAT REFINERY”

BARODA

UNDER THE SUPERVISION & GUIDANCE OFSHREE G. D. PARASHAR

CPUM (GUJARAT REFINERY) &

SHREE A. S. PATELSMNMEL (GUJARAT REFINERY)

2

PARUL INSTITUTE OF ENGINEERING & TECHNOLOGY, LIMDAGUJARAT UNIVERSITY

BARODA, GUJARAT

SIGNATURE OF SIGNATURE OFHEAD OF ELECTRICAL DEPT. HEAD OF TRAINING DEPT.

ACKOWLEDGEMENTIt is a great opportunity for me to get training at Indian Oil Corporation Limited (Baroda), which has given touch entirely in terms of practical approach of industrial hygiene and safety. Also it helped to increase my caliber to practice for industrial hygiene and safety. This would not be possible without guidance of my guide, faculty members and colleagues.

I am extremely thankful to MR. B. ARUNKUMAR [DGM (HR)] for providing me opportunity to work with such a big organization.

I am thankful to MR.G. D. PARASHAR [ELECT P&U] who has acted as my advisor.

I express gratitude to MR.S. SAINI [DMEL], MR.P.J.SHAH [MNMEL], MR.D.B.THAKER [SELE], MR.K.S.RAMAROA [MNMEL], MR.P.V.RAMAKRISHNA [PUM] who guided me in difficult and confusing situations while working with such an excellent company.

I would like to pay my deep respect to MR.B.K. NAIK [SAFETY ENGGINEER (IPCL) ] for their guidance for preparing report.

I express my heartily gratitude to MR.YOGESH BHAVSAR [OM&S] & MR.YOGESH SHUKLA [OM&S] for guiding me continuously throughout my training period.

I take this opportunity to thank MR. SWETABH BAGE [P&U] & MS.MINAKSHI THAKUR [P&U] to help me to work at GRE & FCC UNIT.

3

I am thankful to MR.S.S.SHAH & MR.N.H.SHAH to guide me about the true responsibility of an Electrical Engineer at ELECTRICAL WORKSHOP.

Also I am thankful to MR.RAHUL SHARMA, MR.SANTOSH PANDEY & MR.MEHUL KUMAR [P&U] for giving the practical guidance about the POWER PLANT operation and maintenance at CGP AND SUB STATION.

I would like to render my special thanks to all members of technical library and training center.

I also thank my classmates MR.PARTH V SHAH & MS.ROOPA R KUDVA for their help and support throughout the period of my training.

I am grateful to my parents who are not less than God to me who have been a source of motivation and strength. I thank my friend HONEY ANTAPURKAR for his constant support and help for making report.

Lastly, I thank God, with whose grace I am here and have complete the training.

Thanking you,

INDEX

SR NO. CHAPTERS NAME

PAGE NO.

1 LIST OF TABLES 6

2 LIST OF FIGURES 7

3 LIST OF CHARTS 7

4 ABREVIATION 8

5 PROFILE OF GUJARAT REFINERY 9

TECHNOLOGY EXCELLENCE 9

GUJARAT REFINARY FROM 1961 ONWARDS 12

ENVIRONMENT STEWARDSHIP 13

FIRE & SAFETY 13

TRAINING 13

PUBLICITY 13

EMERGENCY PREPAREDNESS 13

4

EMERGENCY RESPONSE TEAM 13

COMMUNITY EMERGENCY SERVICES 14

ENVIRONMENT-CONSERVING NATURAL

RESOURCES 14

WATER POLLUTION; PREVENTION & CONTROL 14

WATER CONSERVATION 15

AIR POLLUTION; PREVENTION & CONTROL 15

SOLID WASTE MANAGEMENT 15

ENERGY CONSERVATION 16

GREEN BELT 16

6 HAZARDS OF ELECTRICITY 17

5

6

7 CO-GENERATION PLANT 22 INTRODUCTION 22 COMPONENTS OF CGP 23 66KV SWITH YARD 29 COMPARISION BETWEEN CGP & TPS 30 8 ELECTRICAL WORKSHOP 35 MOTOR MAINTAINANCE & TESTING 35

BREAKDOWN STRENGTH IMPROVEMENT OF TRANSFORMER

OIL 9 ELECTRICAL TESTING 37 MEASURMENT OF EARTH RESISTANCE 37 GREASING 37 MEGGER 38

TRANSFORMERR RESISTANCE MEASUREMENT

METER 38 HRC FUSES 38 TYPES OF TRIPPING 38 PRIMARY INJECTION 38 SECONDARY INJECTION 39 CONTACTOR 39 TERMINATION TEST 40 MOTOR STARTOR 40 BREAKER 40 BATTERY 41 BREAKDOWN VOLTAGE TEST 42

10 LAB SUB-STATION UNIT 43

11 SAFETY TALK ON ELECTRICAL SAFETY 45

12 SUGGESTION 46

13 CONCLUSION 47

14 REFRENCES 48

15 ANNEXERS 49

LIST OF TABLES

TABLE NO. TITLE PAGE NO.

1 PROCESS CONTROL 10

2 HAZARDS OF ELECTRICITY 17

3 STATIC ELETRICITY 20

4 GENERATORS & LOADS 25

5 GENERATORS & LOADS 25

6 TURBINES & TURBINE CONTROL

25

7 EXCITERS 26

8 COMPARISION BETWEEN CGP & TPS

31

9 LOAD SHEDDING 32

10 LAB UNIT 43

11 LAB UNIT 44

LIST OF FIGURES

7

FIGURE NO.

TOPIC PAGE NO.

1 HAZARDS OF ELECTRICITY

17

2 CO-GENERATION POWER PLANT

23

3 COMPONENTS OF CGP 24

4 CO-GENERATION POWER PLANT

33

5 CO-GENERATION POWER PLANT

33

6 CO-GENERATION POWER PLANT

34

7 ELECTRICAL TESTING 41

8 LAB UNIT 43

LIST OF CHARTSCHART

NO.TOPIC PAGE

NO.

1 CO-GENERATION POWER PLANT

29

2 TYPE OF MOTORS 36

ABBREVIATION:

AU: ATMOSPHERIC UNIT

FCCU:FLUIDIZED CATALYTIC CRACKING

FPU: FEED PREPARATION UNIT

8

PDF: PILOT DISTITATIONLARO: LIGHT ALUMINUM ROLLING OILS

DHDS:DIESEL HYDRODESULPHURIZATION UNIT

ETP: EFFLUENT TREATMENT PLANTF&S: FIRE AND SAFETYCGP: CO GENERATION PLANTTPS: THERMAL POWER SYSTEM

ESD:ENGINEERING SERVICES DEPARTMENT

GT: GAS TURBINE

HRSG:HEAT RECOVERING STEAM GENRATION

CPP: CAPATIVE POWER PLANTGEB: GUJARAT ELECTRICITY BOARDIFO: INTERNAL FUEL OILCNG: COMPRESSED NATURAL GARCO: RESIDUAL CRUDE OILRG: REFINERY GASLS: LOAD SHEDDINGP&U: POWER & UTILITYDET: DIGITAL EARTH TESTERBS: BURNING SETSG: SURGE GENARATORSVD: SEISMIC VIBRATION DETECTORCT: CURRENT TRANSFORMERPT: POTENTIAL TRANSFORMERBDV: BREAK DOWN VOLTAGE TEST

UPS:UN-INTRRUPTED POWER SUPPLY

LAB: LINEAR ALKYL BENZENEGR: GUJARAT REFINERY

PROFILE ON GUJARAT REFINERY

9

GUJARAT REFINERY a prestigious refinery of INDIAN OIL CORPORATION LIMITED began its operation in 1965. Since then, the refinery has grown to be the company’s largest and country’s second largest refinery. The refinery’s success is built upon business and community partnerships with the people of Vadodara, as well as production of quality products that are compatible with the community and the environment. At the heart of the Gujarat Refinery’s success, are its employees and their commitment to Indian Oil’s vision and mission. Gujarat refinery is situated at Jawaharnagar near Bajwa railway station on the broad gauge line between Bombay-Ahmedabad on western railway, north of Baroda. Also it is connected with the national highway no. 8, which is connecting both Bombay-Ahmedabad and Bombay-Delhi is at east of refinery township. The refinery is spread over about very much huge area including Asoj and Dumad terminal operations.

The refinery township is situated at distance of about 2-½ km from the plant which is comprising of quarters, shopping complex, bank and post office, two schools, stadium, open air theatre, outdoor sports stadium, two guest houses and an officer’s club. TECHNOLOGY EXCELLENCE:PROCESSING CRUDE

GUJARAT REFINERY is designed to processes indigenous as well as imported crude oil. On an average it processes approximately three lakes eight thousand metric tones crude per day. Out of the crude slot it receives, refinery processes around 45% imported crude. GUJARAT REFINERY’S manufacturing and storage facilities consist of 26 major process units, 28 product lines and crude storage tanks with capacity ranging from 300 to 65,000 kls. SOUTH GUJARAT CRUDE: 2.3 MMTPA; supply from ONGC SOUTH GUJARAT pipeline.NORTH GUJARAT: 3.5 MMTPA; supply from ONGC NORTH GUJARAT pipeline.Imported Low / High SULPHUR CRUDE & BOMBAY HIGH: 6.2 MMTPA supply from SALAYA - VIRAMGAM - KOYALI pipeline. TECHNOLOGY LEADER- First riser cracker FCCU in the country.- First hydro cracker in the country.- First diesel HYDRO DE-SULPHURISATION unit.- First spent caustic treatment plant in Refineries.- First automated rail loading gantry.- First LPG mounded bullets in Indian Refineries.- Operates Southeast Asia’s biggest centralized effluent treatment plant.

10

PROCESS CONTROL:

Using the latest electronic technology to monitor and control the plants, engineers run the process units around the clock, 7 days a week. From control rooms located in each operations area, technical personnel use a computer-driven process control system with console screens that display color interactive graphics of the plants and real-time (current) data on the status of the plants. The process control systems allow operators to “fine tune” the processes and respond immediately to process changes. With redundancy designed into the control system, safe operations are assured in the event of plant upset. YIELD PATTERN (2002-03)CRUDE PROCESSED = 12.4 MMT

TABLE-1

PRODUCT TMT

% ON CRUDE

LPG 375.2 3.02FGH 3.3 0.03BENZENE 9.9 0.08TOLUENE 7.3 0.06NAPHTHA

1318.2 10.6

MS 773.7 6.22SK / ATF

1341.2 10.79

LABFS 725.9 5.84

HSD 4384.

8 35.27LDO 269.6 2.17LSHS / FO

2508.7 20.18

BITUMEN 415.5 3.34SULPHUR 15.2 0.12

QUALITY CONTROL

For quality assurance to customers, laboratory correlation programs with major customers (apart from R&D & marketing laboratories) are being conducted on regular basis. Customers like IPCL, GSFC, GNFC, NIRMA, and TEC have been identified for the purpose.

11

PRODUCT MARKETING

A network of product pipelines, tank wagons and tank trucks carries finished products to regional distribution center. In turn, these centers supply products to consumers and industrial customers in GUJARAT, MAHARASHTRA, MADHYA PRADESH and RAJASTHAN. In addition to this GUJARAT REFINERY caters to the needs of NCR and KARNATAKA.

DISTILLATION

Modern distillation involves pumping oil through pipes in hot furnaces and separating light hydrocarbon molecules from heavy ones in downstream distillation towers. The refining process begins when crude oil is distilled in two large, two-stage crude units. The units are two-stage because they have two distillation columns, one that operates at near atmospheric pressure, and another that operates at less than atmospheric pressure, i.e., a vacuum. The lightest materials, Liquid Petroleum Gas like Propane and Butane, vaporize and rise to the top of the first atmospheric column. Medium weight materials, including Jet and Diesel fuels, condense in the middle. Heavy materials, called Gas Oils, condense in the lower portion of the atmospheric column. The heaviest tar-like material, called Residuum is referred to as the “bottom of the barrel” because it never really rises. This distillation process is repeated in many other plants as the oil is further refined to make various products. CONVERSION

Refinery converts middle distillates, GAS OIL and Residuum into MS, ATF and HSD, as well as other fuel oils, by using a series of processing plants. Most of the oil is treated with hydrogen to remove contaminants before the conversion process. Heat and catalysts are then used to convert the heavy oils to lighter products.Since the marketplace establishes product value, Refinery’s competitive edge depends on how efficiently it can convert middle distillate, GAS OIL and Residuum into the highest value products. Cracking is one of the conversion methods, because it literally “cracks” large, heavy hydrocarbon molecules into smaller, lighter ones. Gujarat refinery uses two cracking methods: fluid catalytic cracking and hydro cracking. The fluid catalytic cracker (FCC) uses high temperature and catalyst to crack heavy gas oil mostly into gasoline. Hydro cracking uses catalysts to react gas oil and hydrogen under high pressure and high temperature to make both ATF and MS. TREATING (REMOVING IMPURITIES)

The products from the crude distillation units and the feeds to conversion units contain some natural impurities, such as sulfur and nitrogen. The sulfur is

12

converted to hydrogen sulfide and sent to the sulfur recovery unit where it is converted into elemental sulfur and nitrogen is transformed into ammonia in nitrogen unit and than burnt through flare.

GUJARAT REFINERY: FROM 1961 ONWARDS

Following the conclusion of an Indo-Soviet agreement in 1961 February, a site for the establishment of a 2 million Tones Oil Refinery in Gujarat at Koyali near Vadodara was selected on the 17th April 1961.

➢ The soviet and Indian engineers signed a contract in October 1961 for the preparation of the project report jointly.

➢ On 10th may 1963, the then prime minister of India, pundit Jawaharlal Nehru laid the foundation stone of the refinery.

➢ The first million Tone crude distillation units were commissioned for trial production on 11th October 1965 and full production at the rated capacity was achieved on 6th December 1965. The throughput was further increased by 20% beyond the designed capacity in January 1966.

➢ Dr. S. Radhakrishnan, the then president of India dedicated the refinery to the nation with the commissioning of second crude distillation unit and catalytic reforming unit on 18th October, 1966.

➢ The third 1.0 MMTPA crude distillation units (au-3) was commissioned in September 1967 to process Ankleshwar & north Gujarat crudes thus raising the refining capacity to 3.0 MMTPA.

➢ In December 1968, UDEX plant was commissioned for production of benzene & toluene sing feedstock available from cru.

➢ By 1974-75 with in-house modifications, the capacity of the refinery was further 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 (au-4) along with downstream processing units like vacuum distillation, Visbreaker & Bitumen blowing unit. By 1980-81 this unit started processing Bombay high crude in addition to imported crudes. It was for the first time in Indian petroleum industry that Indian Engineers independently handled such a big project.

➢ To recover high value products from the residue, the secondary processing facilities consisting of fluidized catalytic cracking unit (FCCU) of 1.0 MMTPA capacity along with a feed preparation unit (fpu-1) of 1.7 MMTPA capacities, were commissioned in December 1982. Refinery also set up Pilot Distillation Facilities (PDF) for the production of n-Heptanes &

13

Light Aluminum Rolling Oils (LARO). Meanwhile, to enable absorption of increased indigenous crudes the crude processing capacity of the refinery further increased to 9.5 MMTPA.

➢ In 1993-94, Gujarat Refinery commissioned country’s first hydrocracker unit of 1.2 MMTPA for conversion of heavier ends of crude oil to high value superior products.

➢ Country’s first Diesel Hydrodesulphurization Unit (DHDS) to reduce Sulphur content in diesel was commissioned by Gujarat refinery in JUNE 1999. Also MTBE unit was commissioned in September 1999 to eliminate lead in MS.

➢ Conceptualized and commissioned Southeast Asia’s largest centralized effluent treatment plant by dismantling all the four old ETP’s in June 1999.

➢ By September 1999 with commissioning of Atmospheric Distillation Unit–5, Gujarat Refinery further augmented its capacity to 13.7 MMTPA making it the largest PSU refinery of the country.

ENVIRONMENT STEWARDSHIP:

GUJARAT REFINERY’s VALUES, business strategies and field operations reflect the highest possible environmental standards, which are built into its system since its inception. All efforts are intended to lead the refinery in operational excellence through safe, reliable, efficient and environmentally sound operations. Our safety policy not only stresses commitment to employee health, but also emphasizes promotion of activities that provide a safe and protected workplace for employees, contract workers, visitors and our neighbours. FIRE & SAFETY

GUJARAT REFINERY owns and operates one of the best safety & fire management system in Indian refining sector. Its exemplary safety record, boast of five fire free years with sixth year in running as on April 2003. It is also the first Indian refinery to achieve “international safety rating of level - 8. “

TRAINING

Refinery personnel receive extensive safety training in their specific duties before they begin their jobs and receive refresher trainings at regular intervals. F&S department conduct trainings for employees, contractor personnel, POL tanker drivers, CISF personnel, housewives and school children to enhance safety awareness. PUBLICITY

14

Display of safety posters at critical locations, announcements of safety messages at the time of shift changing, individual rewards like “PRATIBHA SAMMAN” to employees for rendering exemplary services in the field of safety drives down the message of safe operations. EMERGENCY PREPAREDNESS & RESPONSE

GUJARAT REFINERY personnel exercise forward thinking by constantly monitoring process units to identify what could go wrong, such as mechanical breakdowns, and what the impact might be. In addition, refinery maintains regular contact with neighbouring industries like Gujarat State Fertilizer CorporationIndian Petro Chemical Corporation under mutual aid scheme and has interactions for better understanding of other’s facilities and conduct mock drills/competitions. Direct hot lines are also available between these companies to respond without time delay. EMERGENCY RESPONSE TEAM

The Refinery’s on-site fire department is equipped with state-of-the-art response equipment and staffed by 54 full-time professional fire fighters. A strong fleet of eleven fire tenders is available round the clock for any emergency. The refinery maintains two fire stations and its main fire station is equipped with latest fire & safety systems, which are introduced for the first time in India by Gujarat Refinery. COMMUNITY EMERGENCY SERVICES

Refinery fire services had done excellent job during devastating Gujarat earthquake. It was one of the first rescue team to arrive at worst effected “bhachau” town. The GR fire fighters worked continuously for four days and saved several lives. During communal disturbances in the nearby villages, Gujarat Refinery fire service attended sixteen fire calls including six major fires. GUJARAT REFINERY recognizes that working environment can have direct effect on the health of workers. Therefore it believes in creating a healthy and productive work environment for all its employees. Health of a worker is influenced by occupational factors (heat, noise, humidity, dust etc) And non-occupational factors (food, clothing, water, housing, diet, smoking, alcohol etc). The refinery has a well-established occupational health centre, which harmoniously combines environmental protection and health promotion of the employee.

To maintain the healthy workforce, refinery’s OHC focuses on:

1. Regular check ups of employees handling hazardous material like Benzene, CO, CL2, H2S, SO2, LPG and employees working as welders, LOCO operator, drivers and radiographers.

2. Periodical check up of executives above 40 years of age

15

3. Audiometry of employees working in high noise areas (turbines, boilers, steam-air line, pump houses).

4. Titmus vision testing of all employees.5. Health education training to the employees.

ENVIRONMENT - CONSERVING NATURAL RESOURCES

In Gujarat Refinery, environment activities are not limited to air, water and land pollution control only but also includes improvement of Eco-System in and around the Refinery. WATER POLLUTION PREVENTION & CONTROL

In 1999, Refinery conceptualized state of the art centralize effluent treatment plant by dismantling previous four ETP’s. This CETP can take care of wastewater generated from existing facilities as well as future projects. Refinery’s treated effluents have been consistently meeting the minas (minimal national standards) stipulation. At present, most of the time, the treated effluent is reused in refinery operations as make up water to cooling towers & firewater network. However, treated effluent is also discharged into effluent channel project in case of emergency or excess effluent after reuse.

WATER CONSERVATION

Water conservation is one of the thrust areas at Gujarat Refinery. Modern tertiary treatment facilities have been incorporated in CETP to excel the water quality.To ease out pressure on fresh water resources, treated effluent is totally recycled in the refinery operations most of the time. Steps such as better monitoring by installing water meters in various water circuits and close watch on the consumption pattern of various consumption centers have resulted in 23 % reduction of fresh water consumption during the year 2001-2002 over the consumption in the year 2000-2001. The fresh water used in the refinery’s processes is supplied by Mahi River. The water is pumped from the river through pipelines to the treating facility where clarification, filtration, and ph adjustments are done. Treated water is transported by pipeline to the refinery and township areas. AIR POLLUTION PREVENTION & CONTROL

GUJARAT REFINERY controls air pollution at source only by:- Usage of fuels having low sulfur in unit furnaces and boilers,

16

- Exercising energy conservation measures like replacement of low efficiency furnaces, - Optimization of heat exchanger trains to contain stack emissions in spite of increase in refining capacity. - Tall stacks for better dispersion of emissions.- Refinery has set up amine treating unit for fuel gas for removing H2S from the fuel source itself and sulfur recovery unit which uses off-gas from the amine regenerator as feed to convert gaseous H2S in to solid elemental sulfur thereby reducing atmospheric emission. - SO2 monitors installed on all major stacks of the refinery for continuous monitoring of emission level.- Six continuous ambient air monitoring stations having instruments for measurement of SO2, NOX, SPM keep constant vigil on the quality of ambient air. A mobile ambient air monitoring van, equipped with analyzers for SO2, NOX, SPM & THC with weather monitors and data-logging system is also in operation for monitoring pollution level and pattern in and around Gujarat Refinery. - For minimization of fugitive emission, all the tanks of naphtha, motor gasoline, SK, ATF, slop and HSD are provided with floating roof to minimize the evaporation losses. SOLID WASTE MANAGEMENT

1. Spent caustic treatment plant with state-of-the-art technology converts, reactive sulfide into less harmful soluble sulfate by wet air oxidation. Oxidized spent caustic stream is mixed up with normal effluent for further treatment in CETP. This facility has eliminated chemical waste generation from Gujarat Refinery.2. To avoid land contamination and preserve the ground water quality, secured landfill facility has been constructed within the refinery premises for disposal of oily waste. A number of bore wells have been drilled around the sludge-dumping site to monitor the quality of ground water.3. The gas oil treatment method for tank bottom sludge using indigenous chemical surfactant reduces oil content in residual sludge by less than 10%.4. Excess bio-sludge is fed to the sludge thickener for reduction of volume and then to bio-sludge centrifuge for sludge de-watering and subsequently to sludge drying beds. Final dried sludge is used as manure in the green field and also used as fuel in brick kiln. ENERGY CONSERVATION

Energy conservation plays a vital role towards cost reduction as well as upkeep of the environment. It is directly related with the reduction in fuel consumption, thus the adverse effects of fuel burning on environment due to SO2, NOX, CO &CO2 emissions are contained. Gujarat refinery has put maximum efforts in the area of hydrocarbon loss reduction.

GREEN BELT:

17

Gujarat Refinery has utilized much area within its premises to develop green belt. It has about two Lacks grownup trees and innumerable flowering bushes as part of its plant and township landscape.

A beautiful ECO Park developed within battery area green belt with a pond, which adds aesthetic value to the refinery complex. A bridge built out of waste scrap iron transports visitors to an island in the middle of the pond. An open log hut constructed on the island provides the visitors panoramic view of the ECO Park. Rahu & Katla fishes inhabit the water and ducks roam at leisure on the banks. A nursery with rose saplings is also part of eco-park. Treated sewage is used for filling up the pond as well as for watering the trees of the eco-park.

HAZARDS OF ELECTRICITY

ELECTRIC SHOCK:

• Electric shock is a term that relates to the consequences of current flow through nerves, muscles and organs of the body. Owing to a heating effect of current, the body tissues can also be damaged by burns. A particular danger with ac is that it often causes the person concerned to

18

maintain an involuntary grip on the live conductor or metal and this prolongs the current flow.

• Death could occur when the rhythm of the heart is disturbed such as to affect the blood flow. This results in reduction of oxygen supply to the brain. This is known as ventricular fibrillation. Unless skilled attention is given immediately, by say, artificial respiration (oral resuscitation), ventricular fibrillation can be irreversible.

• The severity of an electric shock is the product of the current value and the time for which it flows through the body. 50mA current can flow for 4 sec through the body without any danger, whereas 500ma current flowing even for 500ms could be fatal. Personal sensitivity to electric shock varies from person to person. It depends also on age, sex and heart condition. For an average person; relationship between shock current and time for which body can tolerate without danger of life is given by;

Another term ‘let go current’ is also referred. It is the current which a man can let off an energized conductor or object on his own. The maximum safe let go current is about 10mA for male and 6ma for female.

FIG.1From the above discussion it is obvious that current passing through the body is very important factor in electrical hazard.When the current passes through human body, it affects various systems of the body. Following data shows the effect of ac on human (male) body:TABLE-2:

CURRENT (milli amp) EFFECTUPTO 1 NO SENSATION1 TO 8 SENSATION-NOT PAINFUL8 TO15 PAINFUL SHOCK, MUSCULAR

CONTROL NOT LOST15 TO 20 MUSCULAR CONTROL LOST,

STICKING20 TO 50 SEVERE MUSCULAR CONTRACTION50 TO 200 VENTRICULAR FABRICULAR

FABRILLATION & POSSIBLE DEATH200 & ABOVE SEVERE BURNS, SEVERE

VENTRICULAR FABRILLATION-DEATH

There are various factors on which current passing through the body depend.(A)CONDITION OF BODY:Dry skin offers 1, 00, 000 to 6, 00,000 ohms resistance to current, whereas wet skin offers only 1,000 ohms resistance. (Average body resistance of children and woman is only 60 to 66% of that of men).Thus, when body is wet, there is very great danger of electrical accident and even fatality. When skin is dry and a man is working with portable tool (220v system) maximum current which can pass through is:

19

I=v/r=2.2milli amp

But when his skin is wet,

I=v/r= 220milli amp

(B) AMBIENT TEMPERATURE & HUMIDITY:When ambient temperature is higher, there will be lot of perspiration, if humidly is also high; the body will remain wet which is dangerous.

(C) OXYGEN AND CARBON DIOXIDE CONTENT IN THE SURROUNDING AIR:When oxygen content is less in the air, resistance of the body gets reduced. Same is true for higher content of carbon dioxide. The electrical hazards for welders obviously increase for this reason.

(D) MATERIAL/FLOORING: If a man is standing on insulated flooring, he is well protected than a man standing on an ordinary floor. Wet floor offers only 100 ohms resistance.

(E) POSITION OF LEGS AND HANDS:When the current passes through the body, there are positions of legs and hands through which current can reach to earth. The most dangerous condition is the one in which current passes through the heart.

USE OF ELECTRICITY IN INDUSTRY AND FACTORS LEADING TO ACCIDENTS:

• Poor knowledge of equipments and systems.• Over confidence.• Taking a chance/risk/short cuts.• Hurry to complete the job & charge the equipment.• Money tricks.• Working without concentration.• Poor maintenance of equipments/systems.• Poor quality of tools.• Not using safety appliances.• Miscommunication.• Not following safety procedure.• Temporary repairs.• Earthing not connected properly / earthing absent.

WHILE USING PORTABLE TOOLS, ONE MUST BE CAREFUL FOR FOLLOWING POINTS:

• Check up broken plug/socket.• Do not use the tool when its casing is damaged /broken.• Cable (cord) should be sufficiently long to reach work place without tension.• Earthing should be connected at both ends.

20

• Never stand on a damp or wet surface.• Portable tool operation should be checked near the isolating point before

using at the required location.• Plug rating should match the tool rating.• Periodic checking/maintenance should be carried out regularity.

ELECTRICAL HAZARDS INVOLVED DURING CONSTRUCTION ACTIVITIES:

Portable equipments like grinders, drills, welding generators & transformers and hand lamps etc. are widely used.

Temporary overhead lines are in use.Main reasons for accidents on temporary OVER HEAD lines are:

• Broken live wires.• Damaged insulation.• During repairs/connections.• Poor quality of wires/equipments.

Welding operation: ground return cable should be connected directly to the equipment being welded. During conduction period, a welder has to work even in damp, poorly ventilated area. Also, the fumes generated during welding, reduce oxygen & increases carbon dioxide. This reduces his body resistance.

Poor maintenance of welding transformer can become reason of accident because any leakage between primary and second will raise secondary voltage to the same level as that of primary Crane movements.

EARTH LEAKAGE CIRCUIT BREAKER:

For getting protection against electric shock, it is essential to interrupt the main current, before the leakage current (passing through the body) reaches dangerous level.

STATIC ELETRICITY:

WHEN AND HOW?

21

When dissimilar materials come in contact and separate, i.e. They are in motion and maintain contact with each other, there is a transfer of electrons between them. This results in static electricity.If one of the materials is a non conductor or is a poor conductor, electrically insulated static electrical charges can accumulate upon it. The excess o electrons are called negative charge and deficiency of electron is called positive charge.Opposite charges attract each other. This attraction can be measured as a potential difference or voltage. Larger the voltage, greater the flow of electrons across the air gap. This is the cause of sparks.There are various types of surface in contact, as mentioned below:

TABLE-3:

SOLID-SOLID GRIT BLASTINGPNEUMATIC CONVEYING OF POWDERBELTS, PULLEYS

SOLID-LIQUID LIQUID IN PIPE LINESOLID-GAS HYDROCARBON GAS COMING OUT FROM NOZZLELIQUID-LIQUID WATER SETTLING IN OIL TANKGAS-LIQUID RELEASED GAS OR AIR BUBBLE RISING IN A LARGE TANK

CONDITIONS FOR ELECTROSTATIC HAZARD:• Rate of generation is more than the rate of dissipation.• Accumulation of charge is sufficient enough to ignite gas mixture.• The gas mixture around the spark is inflammable.• The electric field must cause a spark with intensity, sufficient to ignite the

gas mixture.

DETECTION/MEASUREMENT:Static electricity presence is usually demonstrated by shock, sparks or attraction/repulsion of light particles. Its measurement can be done by one of the meters mentioned here below:

• Electroscope• Neon glow tube• Electrostatic voltmeter• Vacuum tube electrometer•

Spark given off from accumulated charge can result in fire and/or explosion of vapors, gasses or dust. Severity of electric shock is not as that from electricity power supply, but involuntary movement may cause injury.In some industries like printing, rubber, paper, etc, where light weight non-conductive materials are handled, material stick together or stay apart.

Products that are better conductors are also better generators of static electricity. They also discharge rapidly. Their relaxation time is very short:Refined flammable liquids like petrol, kerosene, jet fuels, etc Become charged with static electricity.

22

Loading of a product having a high flash point after a load of product having low flash point (switch loading) the principle factor in about nine out of ten fires on loading rack trucks.Gasoline has low flash point. Jet fuels, benzene, toluene and special naphtha do not vaporize as quickly as gasoline. Kerosene, fuel oil, lubes oil and diesel fuel has high flash point.

CONTROL OF STATIC ELECTRICITY:

• Draining the accumulated charge by bonding and earthing• Avoid splashing• While designing the piping, relaxation time’ should be taken into

consideration• Maintaining high relative humidity in the atmosphere near materials• Providing ionized atmosphere• Controlling of flow/velocity

✔ For pipes up to 8” dia-7mt/sec✔ For pipes of higher dia-1.5mt/sec

COGENERATION POWER PLANT

INTRODUCTION:

23

Gujarat Refinery is equipped with two power plants - Co-Generation Power Plant (CGP) and Thermal Power Station (TPS). Complexity of power system is due to different Generation voltage levels, Grounding and Protection systems employed. Even a small lapse while designing for the expansion / modification of generation / distribution systems may lead to catastrophic consequences in the stability of power system.

Various equipment specification standards for selection of equipment are available in the refinery. Expertise for engineering and selection of equipment are also available. Need has been felt to consolidate all good design practices gained through experience, equipment selection specifications etc. to serve as a guideline to the electrical design engineers of the Refinery to achieve consistency in design on regular basis.

The role of an Electrical engineer in Engineering Services Department includes but not limited to study the Process scheme, evaluate the scope of electrical jobs involved, design a suitable electrical scheme to provide stable power supply and procurement of suitable materials required for the same etc. Accordingly, the Chapter on Design Basis is developed to provide an overview of Power Generation, Distribution, Protection, Metering, Earthing, Lighting, Cabling etc. It also gives the basis on which the equipment / system is to be designed. The Chapter on Codes and Standards includes the various Standards which are being followed such as IE Rules, NEC, IEC, OISD, NFPA, BIS etc. The Chapter on Substation Building Design provides the important design requirements to be taken care of, while designing a substation building. Chapter on Equipment Selection gives guidelines for fixing the basic design parameters of the equipment to be selected. Chapter on Earthing and Lightning Protection provides the guidelines for selection / calculation of the earthing grid sizes, lightning protection of structures etc.

Inside the Refinery Battery Area, various lighting design practices such as Centralized switching, Area Illumination using Motorized High Mast etc. are being followed for safety, ease in Operation and Maintenance. These practices including selection of suitable light fixtures are specified in the Chapter on Lighting. Standardization of Equipment Specifications was taken up by the Refinery to procure the best and latest equipment within the shortest period of time. This also contributes to minimizing the Project cost and time. These standardized specifications are included in the chapter on Equipment Specifications for ready reference... Chapter on Standard Drawings includes few commonly used drawings related to earthing, lighting and switchgear.

Frequently used Tables are also included in the manual.This manual is intended to standardize all Engineering practices and provide a ready reckoned to the electrical engineers in the Refinery.

NOTE – ONE MORE COGENERATION POWER PLANT CONTAINING TWO GENERATORS IS UNDER CONSTRUCTION.

CO-GENERATION PLANT is modern sophisticated power plant, with generation capacity of 60 mw. Major of the plant is automatically operated, but still there are few portions which are manual. The total installation is done by BHEL, India.In CGP, power is generated by Gas Turbine (GT). The cycle use is brighten cycle.In CGP, gas turbine works on principle of simple cycle or open cycle. But after the expansion of flue gases in the turbine the heat of flue gases is used for converting water into steam i.e. Steam generation (by diverting this flue gases

24

to the boiler) this is done in the heat recovering steam generation (HRSG). As there is cogeneration of power as well as steam so this plant is called Co-Generation Power Plant. This plant at the same time is also called as Captive Power Plant (CPP) - as the power generated through this plant is only for the company related uses and not for the commercial use.

The over view for CPG plant (of two generators only for convenience):

FIG-2

COMPONENT OF CGP

In GUJARAT REFINERY the main components of CGP plant is given below:1. GENERATORS2. TURBINES3. EXCITERS4. D.C. STARTER MOTOR

25

5. COMPRESSORS6. IGNITION CHAMBER7. HRSG

Flow chart of a simple Gas Turbine is shown below:

FIG-3:1. GENRATORS & LOAD GEARS:

Generators used in CGP are manufactured by BHEL. Capacity of each generator is 30 mw. There are three generators installed in CGP. The rated speed of the generator is 3000 rpm the speed at which turbine rotates is 5100 rpm but the rated speed of generator is 3000 rpm, so a load gear is used. This has a special gear arrangement due to which shaft speed is brought down to 3000rpm. The generator turbine e 1 & 2 has sophisticated control of mark iv system which is solid state electronic system and 3rd has mark v control system, which is even more advanced. Because of this total generator and turbine is controlled, in the Distribution Control System (DCS) fitted in control room. In the DCS system the complete flow of gases can be seen on the screen, with the help of the single line diagram even electrical fault location can be done with the help of the single line diagram. Even electrical fault location can be done with help of this system.

The details about the generators and load gear are given the tables to follow:TABLE-4

RATINGS OF THE GENERATORS OF CGP (BHEL)KW 3000 COOLENT AIR

26

POWER FACTOR 0.9 INSULATION F CLASS

KVA 375000 TYPE TARI 800 – 26 P

RPM 3000 SPECIFICATION IEC – 34, IS – 5422

FREQUENCY 50 Hz SERIAL NO. 1376

PHASE 3 DIVISION HYDERABAD

CONNECTION Y YEAR 1996-1999

STATOR ROTORVOLTS 11000 VOLTS 162

AMPERES 1968 AMPERES 56.6

TABLE-5

RATINGS OF THE LOAD GEAR OF CGP (BHEL)SIZE TRL 650

VSPEED 5113.6/300

0SERIAL No. LB

60079OIL VISCOSITY ISO VG 46

MANUFACTURED DATE 20/3/98 OIL FLOW 750 lit/min.

WEIGHT 12000 KGs.

RATING Std. API 613

OIL INLET PRESSURE 1.7 bar POWER 54000 KW

2. TURBINES AND TURBINE CONTROL

GENERAL DESIGN DATA:TABLE-6

GAS TURBINE MODEL SER.

MS 6000

GAS TURBINE APPLICATION

GENERATOR DRIVE

CYCLE SIMPLE & HRSG

SHAFT ROTATION COUNTER CLOCKWISE DIRECTION

TURBINE SHAFT SPEED 5100 RPM

CONTROL MARK IV SPEED TRONIC

BASIC PROTECTION OVERSPEED, OVER TEMP., VIBRATION AND FLAME DETECTION

BACKSTART CAPACITY START-UP PROVISIONS UPON LOSS OF STATION AUXILLARY AC.

27

Different kind of plants based on the turbine action:OPEN CYCLE PLANT:Here steam is used to drive the seam turbine, which in turn drives the generator rotor thus producing power. The exhaust steam is then released into the atmosphere. The efficiency of the open cycle plant is generally very low, approximately 30% only.

COGENERATION PLANT:Here the hot gases from the combustion chamber are used to drive the gas turbine, which drives the generator thereby producing electric power. The hot flue gases from the turbine outlet are use to heat the feed water of the boiler, thereby producing steam, before finally being released into the atmosphere. This steam is then supplied to the process plants. This is the reason why these kinds of plants are famous nowadays. In Gujarat Refinery also such kind of power generation is preferred.

COMBINED CYCLE PLANT:The power is first produced with the help of the gas turbine driven generator. Again the hot flue gases from the turbine outlet are used to heat the feed water in the boilers. This steam is then used to drive the steam turbine, which causes power gain. The efficiency of this plant is less than the co-generation plant and is about 75%.

3. EXCITERS

Exciter means it is a kind of a device which is used to give supply to a electrical assembly, i.e. It excites the given assembly. Exciter is one of the main devices connected on the shaft after the generator. Exciter works has a small generator. Exciter has a permanent magnet and a winding is there which generates the EMF.And this EMF is supplied to the rotor of the generator after rectifying it.

The details about the exciter ratings are as follows:TABLE-7

SERIAL No. 10527 EXCITATION WATTS 533YEAR 1998 EXCITATION VOLTS 46.2STD. No. IS 4722 EXCITATION AMPS. 11.5KW 111 KVA 8CONTINUOUS VOLTS 178 PM VOLTS 220CONTINUOUS AMPS. 622 PM AMPS. 26COTINUOUS RPM 3000 PM RPM 3000TYPE EPL 39/12-

30/0PM Hz. 150

PHASE 3 MADE BY: BHEL

28

4. DC STATER MOTORDC Motor Starter is a basic requirement of the CGP plant. If Diesel Generator (DG) set is run directly then we cannot obtain a high speed to which shaft is required to be. Hence, a dc starter motor is installed before the dg set. DC Motor helps in initializing the whole assembly of the power generation system which is on the single shaft. DC Motor works at 125 volts.

5. COMPRESSOR

There is 17 stage compressor and they have big filters attached to their inlet. This filter serves the purpose of filtering the inlet air, which enters into the compressor for compression. The compressors have the capacity of 450 tones per hour (t/hr). The inlet temperature and pressure is ambient i.e. 1 atmospheric pressure and 28 ˚c. But after the process of compression is over the temperature rises to 280˚c i.e. 10 times that of the inlet temperature, also now the pressure reaches the value of 11 kg (again this is also around 10 times that of the inlet pressure. Compressed is taken out of the compressor at various stages; this air is utilize for various kind of jobs. Air is taken out of the compressor once at 5th stage when pressure is 2 kg, it is removed again at 11th

stage when the pressure is about 4 kg and finally it is removed at the 17th stage when pressure is 8-9 kg. The theoretical value is 11 kg but this is not achieved because of losses.

6. IGNITION CHAMBER

From the compressor the high pressure air enters the combustion chamber. Combustion chamber or ignition chamber has mainly three divisions.

1. COMPRESSED AIR SECTION2. IGNITION SYSTEM3, IGNITER FUEL SYSTEM

The compressed air section receives the air from the compressor and gets it’s into chamber ignition system. Ignition system has a special arrangement for ignition of fuel. And finally the fuel system, it consists of 2 fuel inlets. There are 2 kinds of fuel used in this system.

1. NATURAL GAS2. INTERNAL FUEL OIL (IFO).

The natural gas is taken from gas authority of India Ltd. (GAIL), where the IFO has is readily available from Gujarat Refinery (GR) itself. Usually the preferred fuel is natural gas because it does not cause any choking, it is cheap, and moreover the life of the burner than the combustion chamber increases by its use. The temp in the ignition rises to about 1102˚c the high pressure gases now

29

enter the turbine which causes it to rotate. Such high temp cannot be measured directly so it is measured with the help of thermocouple.

7. HRSG

This is the special unit of the co-generation plant. The gases, which come out of the turbine, are still at a high temperature, still at 566˚c. If they are allowed to directly move out then lot of heat energy will be wasted. To save this energy we use HRSG unit.

The gases coming out of the turbine now have a connection going to the water tube boiler. There is a divider damper in-between the way. There is a chimney right at the first itself, in case the boiler is not to be operated or is in shut-down, this chimney is opened by the help of the divider damper and the gas is allowed to go out. The height of this chimney is not very high as the gases are at high temperature and so they can easily get lost in the atmosphere.

Now in case, the boilers are to be operated then the divider damper closes the direct chimney stack, so now the flue gases reach the HRSG. In this HRSG the heat of the gases is used to convert the water into steam. This steam is now given to the process plants, where it is actually required.

The actual capacity of the HRSG is 105tones/hr. There is a special system arranged over here for the supplementary firing. When only flue gases are used as fuel for the furnace the capacity of the HRSG becomes 80tones/hr. But when some additional fuel (gas/IFO) is brunt to raise the temperature of the furnace the capacity increases by 30-35tones/hr. This is how the capacity of 100-105tones/hr is achieved. The steam that comes out of the HRSG is at the temperature of290˚c & at the pressure of 13kg/cm2.

By the time the whole process is over the temperature of the flue gases now reduces to around 120˚C. These gases now cannot easily escape into the atmosphere, so the chimney, which is provided, is taller one (it is as per the government pollution norms). When IFO is used then at such low temperature of 120˚ it combines with sulphur and forms toxic and corroding substances like h2so4, so to avoid such happenings special care is taken and it is always tried that natural gas is used instead of IFO.

This is how the HRSG unit functions.

30

•Along with these all imp components of he CPG, there is one more very imp component of the unit and it is called as a cranking motor. It is a diesel engine (it is a started with the help of cranking dc shunt motor). This diesel engine is used to lift up the turbine, to give it a starting torque. This diesel engine starts the turbine & takes it up to the speed from which it is capable of rotating on its own, rather on the firing from the combustion chamber. The details are as given below:

AT 0 RPM THE ENGINE CAUSES THE TURBINE TO ROTATE AND THIS CONTINUES UPTO THE SPEED OF 1020 RPM. NOW, EVEN THE TURBINNE HAS ITS FIRING STARTED, SO BY THIS TIME THE FIRING AS WELL AS THE DIESEL ENGINE IS MOVING. AS SOON AS THE SPEED OF 3060 RPM IS ACHIEVED THE TURBINE GETS ITS SELF-CONTROL AND NOW THE DIESEL ENGINE DISENGASES FROM THE TURBINE AND ITS SHUT DOWN BEGINS. FROM NIW THE TURBINE ROTATES ON FIRING ONLY.

So, this is the important function that a cranking unit does.

GENERAL INFORMATION REGARDING CPG PLANT:

There are three units and each unit contains an assembly of above mentioned components. Each unit generates 30 MW powers. All the three units are synchronized in such a manner that total 90 MW power is generated. As result it is considered as a major power plant of Gujarat Refinery.Flow chart of CGP is shown below:

CHART NO.1Efficiency of a CGP is 80-85%. In CGP earthing is done by neutral grounding resistance. If plant is totally shut down then to start the plant again 20 min are required to run the whole plant to its stable condition.

66 KV SWICHYARD:

Gujarat refinery is also connected to the Gujarat state electricity board, normally referred to as GEB. There is a switchyard made both at the CGP as well as the TPS for this interconnection.

Although, the power compulsion from the GEB is not taken, the connection is isolated with a breaker. This is done, keeping in mind the worst circumstances in which GR may need to take from GEB in case of power failure. Power could have been taken from GEB instead of erecting there own power plant, but the supply from the GEB is not very reliable. It does not maintain the desired frequency always and moreover there is a possibility of the GEB drawing the power from GR instead at the time of reversal. Other problem is the cost at which GEB provides power & GR needs very much power in which GEB fails to supply. Thus, GR required exerting the power plant.

Bus-bars, which operate at a constant voltage, are insulated from earth and from each other and act as conducting bars to which nos. Of feeders are connected. The overhead line is expressed to lightning strokes. A high voltage surge due to

31

lighting can cause the breakdown of insulation of transformers, generators, circuit breakers, bus-bars support etc the lighting arrestors connected between conductor and earth divert the high voltage surges. Lightning arrestors are installed such that the high voltage surge meets the arrestor first, before meeting the equipment.

In high voltage installations, the capacitance between line and earth is significant. Though the line is disconnected by opening the circuit breaker and isolator, there is some voltage to which the capacitance is charred. This capacitive voltage to which the capacitance voltage is discharged to earth by closing switch is usually mounted on the frame of isolator. Isolator (also called as simply disconnect or disconnecting switch) is basically a no load switch design to operate basically under no-load condition. Therefore, the isolator operates only after the opening of the circuit breaker. While closing isolator closes first, and then the circuit breaker. Isolator is interlocked with the circuit breaker such that wrong operation is avoided. Potential transformers & current transformers are necessary for the purpose of protective relaying and measurements. Power transformers are installed between two bus-bars of different voltage levels.

DETAILS:

Two lines of three phase supply from GEB. The line is taken down is first connected to the lighting arrestor. After this a potential transformer (famous as pt) is connected, it measures the amount of current from GEB. It also checks for reverse flow of power from GR to GEB. The total system remains same for both the lines and all three phases. Then an isolator is connected between pt and a breaker. Isolator is connected so that in case the switchyard is to be required. It can be isolated from the grid.

From breakers is connected, which in turn is connected to isolator. This isolator is connected to pt breaker. The function of the isolator remains the same and breaker also serves as a protection device. Transformer breaker is in turn connected to pt, then to ct & then to lightning arrestor. The connection from the la then goes to the power transformer of 66/11kV

The same GEB line extends up to TPS & a very similar kind of a switchyard is also present over there. The internal import export of power from CGP to TPS and visa versa is done through this line. Transportation is done through high voltage lines because in that case the current is less, thus the heisting and the losses decreases up to and great extent in the cable. Very opposite is logic why low voltage is preferred in distribution, as the current required is high.

32

P.T.O……….

COMPARISION BETWEEN CGP & TPS

CGP TPSBY-PRODUCT STEAM STEAMPRODUCTION OF POWER

3 TURBINES- 30 MW. TOTAL 90 MW

2 TURBINES- 12 MW, 1 TURBINE- 12.5 TOTAL 36.5 MW

BASED ON CYCLE

CO-GENERATION CYCLE OPEN CYCLE

EFFICIENCY 80-85% 35%COST CHEAPER COSTLYVOTAGE LEVEL 11 KV 6.9 KVFUEL INTERNAL FUEL OIL

(IFO), COMPRESSED NATURAL GAS (CNG)

RESIDUAL CRUDE OIL (RCO), REFINERY GAS (RG)

CONTROL SYSTEM

HIGH-GRADE CONTROL MARK IV, V,VI

MANUALLY

SNYCHRONISATION

AUTOMATICALLY AS WELL AS MANUALLY

MANUALLY

REACTOR SERIOUS REACTOR ON BUS-BAR

SERIOUS REACTOR CONNECTED IN BETWEEN GENERATOR &FEEDER FOR DROP IN THE VOLTAGE LEVEL 6.9-6.6 KV.

NOTE: GUJARAT REFINREY HAS LOAD SHEDDING (L. S.)SYSTEM

All information regarding load shedding is given on next page:

33

Load shedding settings at GR after review by producing depts.: TABLE NO-9

34

35

Sr. No.

LOAD DESCRIPTION UNDER L. S. LOAD

PRESENT SETTINGS

LOAD SHED

TOTALL. S.

MW LEVEL

Hz T

1 OMS, LPG 1.4 I 49.5 O.5

3.30 MW

3.30 MW2 OLD ADM. BLDG. 0.53 NEW ADMN. A/C CW MOTORS &

AC0.5

4 33 KV DUMAND FEEDERS 0.55 MTBE+ BUTUNE+ PDF+ FGH+

FDRS FROM NEW CT0.4

6 AU-1 1.0 II 49.30

0.5 3.0 MW 6.30 MW7 AU-5 2.08 AU-3 1.3 III 49.2

00.5 1.3 MW 7.6 MW

9 DHDS 3.7 IV 49.10

0.5 3.7 MW 11.3.MW

10 GRE GROUP-1 (CDU) SELECTED FEEDERS+ BITT.

2.0 V 49.00

0.5 2.0 MW 13.30MW

11 GRE GROUP-2 (VDU+ GRE PRODUCTS) I/C OF A-03

2.2 VI 48.90

0.5 2.8 MW 16.10 MW

12 GRE CRUDE PUMPS 15-PM-101 A,B,C,D,E

0.6

13 FPU-II AT GHC 1.6 VII 48.80

0.5 1.6 MW 17.70 MW

14 FDU-I AT FCC 1.0 VIII 48.70

O.5

2.2 MW 19.9 MW15 830-KM-01B 1.216 AU-2 1.0 IX 48.6 0.5 1.3 MW 21.2 MW17 CBPS S/S-14 FDR-61 & 75 0.318 CRU 0.5 X 48.4

00.5 4.0 MW 25.2 MW

19 LAB PLANT FRONT END 3.520 MSQU (FFCC GASOLINE+

MEROX+ NHTU)4.4 XI 48.3

00.5 4.4 MW 29.6 MW

21 MSQU 2.2 XII 48.20

0.5 4.0 MW 33.60 MW22 ONE NET GAS COMPRESSOR 1.823 UDEX 0.6 XIII 48.1

00.5 1.8 MW 34.2 MW

24 FCU 1.8 XIV 48 0.5 1.8 MW 36 MW25 MSQU (G R) WITHOUT NET GAS

COMPRESSOR3.2

XV 47.90

0.5 7.56 MW

43.56 MW26 NEW C/TOWER, CT FANS 0.3027 HCU GROUP-1 (ONE MAKE UP

COMPRESSOR ONLY)4.06

28 HCU GROUP-2 (WITH ONE MAKE UP COMPRESSOR)

6.3 XVI 47.80

0.5 6.3 MW 49.86 MW

29 CETP (EXCLUDING MERCING PUMP)

1.5 XVII 47.75

0.5 1.5 MW 51.36 MW

30 NEW C/TOWER CW PUMPS 3.4 XVIII 47.70

0.5 3.4 MW 54.76 MW

31 CGP/HCU CT FANS 0.35 XIX 47.60

0.5 0.95 MW

55.71 MW32 SRU O.6TOTAL L. S.

55.71

The diagram of the generators in CPG with there power factor (pf ), mw & kV is as follow:FIG.4

The zone division of the CPG is shown in fig below:FIG.5

36

Exciter connected with the AVR is shown in the fig. Below:FIG.6

37

ELECTRICAL WORKSHOP

INDIAN OIL COPORATION has operated an electrical workshop which is governed by electrical maintenances department (P & U). As we know the nature each and everything needs maintenance for proper functioning for life.

The main aim of workshop is to repair and service motors, and to perform various test to confirm its efficiency, vibration, temperature; mainly induction motors.

MOTOR MAINTENANCE AND TESTING:

Now we know that IOCL is has operated a electrical workshop which is governed by electrical maintenance department (p & u). As we know the nature each and everything needs maintenance for proper functioning for life.

The main aim of workshop is to repair and service motors, and to perform various test to confirm its efficiency, vibration, temperature; mainly induction motors.Now we know that IOCL is

This is a petroleum industry, so, every plant constitutes different types of pumps, blowers, compressors, and fans of different ranges. For the operation of all these equipments, the motor is a very essential and primary necessity. So, the maintenance work for these kinds of motors is required. If there is any fault in any of the motors, then it is informed to the workshop people. If on the location, maintenance is possible then the technicians do so, otherwise the motor assembly is taken to the workshop. Now the work shop is having a no. of spare motors each with different ratings. Therefore, the maintenance is done accordingly. Here mainly the earthing contacts are tested first. Then other testing’s like, megger test and other winding tests are done. The motor needs proper insulation over the conductors throughout the length. So, the body and the stator winding are painted with red bectol. It improves the insulation strength. Then, bearing maintenance is another important job in the workshop. Here the bearings are tested and replaced for all the motors.

The balancing process is also done in the workshop. Here there are three types of balancing and vibrations in the motor:

- VERTICAL BALANCING- HORIZONTAL BALANCING- SHAFT BALANCING

As we saw in the workshop that, all the motors are squirrel cage induction motors, and generally wound rotor type induction motor is not preferred here. We also saw the difference between an ordinary motor and a flame proof motor as far as the industrial application is concerned. The work shop is having a storage facility for all the motor components like, ordinary terminal boxes, flame proof terminal boxes, casing and yokes, fan covers and bearings etc.

38

TYPES OF MOTORS:

CHART NO.2

BREAKDOWN STRENGTH IMPROVEMENT OF TRANSFORMER OIL:

Here, oil test for the transformer oil is also done. The transformer oil is kept in a proper quantity. In the work shop, there is an instrument for improving the breakdown strength of the transformer oil. In this instrument, first the oil is fed into its inlet. At the inlet, the oil is passed through a magnetic strainer. So that the impurities like, iron and aluminum scraps are removed from the oil. Then it is fed into the heater chamber with the help of an inlet pump. Thereafter, it is fed into the safety thermostat and then the oil is fed into the micro filter tank. Here the filtering process is done. Impurities are removed from the oil here. Then the oil is fed into the degassing chamber. Here the oil falls from the top, towards the bottom of the chamber and then a glowing bulb is connected. Then, at the other side a sight glass is fixed.

This oil is again circulated in the heater chamber with the use of an inlet pump for a number of times. During the whole process, the outlet valve is kept closed. Then after 1 or 2 hours the outlet valve is opened and the oil is taken out of the instrument chamber and its breakdown strength is measured (as a sample for

39

further testing). In this way the breakdown strength of the transformer oil is tested.

ELECTRICAL TESTING

MEASUREMENT OF EARTH RESISTANCE:

The earthing connection of all the machines, heavy bodies (IM) etc is linked to an underground network called as GRID. The value of resistance should be minimum (less than 5 ohms) for safety of workers and prevention of electric shocks.

This is done using “THE DIGITAL EARTH TESTER”. Two metallic rods act as electrodes; they are inserted into the ground and are connected to the tester. A third wire is connected to the body of the machine and is connected to the tester. The voltage drop is measured for the current which is passed through the electrodes.

Hence, the resistance can be found by this formula: R=V/L.

GREASING:

First of all, Greasing of machine bearings is done by isolating them from the power supply for safety reasons or wherever online greasing facility is not available. Greasing of some machines can also be done when the machines are working. Here the grease is injected trough a port which reaches the bearings.

If there is a breakdown in the insulation of a long under ground cable, very high voltage is set up by “THE BURNING SET” and “THE SURGE GENERATOR” which will burn the affected point completely i.e. it damages the insulation completely.To measure the distance “TELEFEX” is used. It sends the signals and receives the same after they are reflected from the affected point. Hence, by calculating the time duration between sending and receiving the signal, distance is determined. Then the location is pin pointed using the “SEISMIC VIBRATION DETECTOR.”

THE SECONDARY WINDING OF CURRENT TRANSFORMER IS SHORT CIRCIUTED WHEN NOT IN USE:

In a current transformer, when the current is transferred due to mutual induction from the primary to the secondary winding, the value of current decreases and voltage is transformed to higher value.Hence large voltage is obtained at the secondary. This may lead to an electric shock or any accident if the terminals are left open; therefore, the secondary winding is short circuited. Then current circulates in the loop safely.When the secondary winding is open, there is no control over the load i.e. no control over the current at the primary winding. Large amount of fixed flux is

40

produced which leads to core saturation and causes overheating and damage of the transformer.

MEGGER:

It is an instrument used to measure the insulating resistance of an “INDUCTION MOTOR”. Actually, the value of resistance should be very high (infinite), but comes to be in GIGA ohms, above some particular value. If there is any damage in the insulation, the value of its resistance decreases and hence this can be detected. Voltage is supplied by the instrument and resulting current flow is measured, giving the value of resistance.

R=V/I.

TRANSFORMER RESISTANCE MEASUREMENT METER:

This is an instrument, used to remove the resistance of the transformer coil. Here, the current is passed through the transformer coils by the instrument and then the voltages across the coils are measured. Consequently the resistance value is measured R=V/I. This is done at both input and output side of the transformer.

HRC FUSES:

In the industries everywhere HRC fuses are used i.e. HIGH RUPTURING CAPACITY fuses. This is because they don’t produce any spark or smoke, hence provide safety against fire.

TYPES OF TRIPPING:

a) Electrical Tripping: In case of circuit breakers, tripping is energized through the actuation of the trip current either trough the control or protection current.

b) Mechanical tripping: It occurs due to some mechanism, generally protection mechanism,

Releases are actuated which are mechanical in nature and are done by certain Inductive coils and through different mechanisms.

PRIMARY INJECTION:

Here particular valves of current are injected externally through the primary of a current transformer and the functioning of its relay is checked at the site itself.

To check the proper connection of CT after opening, for proper working of bus, CT etc, the supply is given to the primary winding of CT trough a loading coil,

41

current from the secondary of the CT then passes to a relay through a bus, and accordingly tripping takes place if any fault occurs. This test mainly checks the complete conductivity of circuit.

Supply provided by a VARIAC is just about 2 to 5 amperes. This is then passed through the loading coil which increases the supply given to primary. The AISCTORPRIMARY of this loading coil have high voltage and low current, while the secondary will have less turns, and will supply high current and will be at a lower voltage.

SECONDARY INJECTION:

Here in the case, current of a particular value corresponding to the secondary of the current transformer is passed through a relay at the testing lab to check the functioning of the relay. This is done on relays at testing center. It checks the proper working of a relay, mainly current and voltage relay.

CONTACTOR:

DEFINATION: A contactor is an electromagnetic operated switch which can be operated remotely (not by hand).

Switch gear is used to fulfill to the standard requirement of switching various loads under normal and abnormal conditions with various in built features for protection against various hazards. One such device is contactor.

Principle: When a definite voltage is applied across a coil, energizing an electromagnetic system comprising of a fixed and a moving part. The moving part gets attracted to the fix part, thus the electrical circuit is completed. When the magnet is demagnetized, it gets pushed back to its position and contactor becomes open thus breaking the electrical connections.Advantages:

High number of neck breaks operation.High making and breaking capacity.Remote on/off switchHigh mechanical and electrical life.No overvoltage protection.

Here in contactors, the sending pole lags flux. Air breaker contactor does not need any kind of lubrication as they are designed without lubrication.

TERMINATION TEST:

Proper termination of cables, bus-bar and crimping of cables can be tested by measuring mini-volt drop across them.

42

If the termination is not good, i.e. Loss or unclean or less contact area than the point resistance increases. The voltage drop across such point will be more compare to good joints.

EXAMPLE:

TERMINATION TO

TEST CURRENT AMP

MAX mV ALLOWED

GOOD mV

BUS-BAR/LINK 100 2.5 0.5 TO 1

MOTOR STATER:

Majority of industrial motors are induction motors. Among them percentage of squirrel cage motors are more than slip ring motors.

Different methods of starting squirrel cage induction motors are:DOL (DIRECT ON LINE) STARTSTAR-DELTA STARTAUTO TRANSFORMER STARTSOFT START.

DOL (DIRECT ON LINE) START:

This type of starter is very popular. It has low cost, it is used at places where high starting torque and rapid acceleration is required. Starting torque with DOL vary from 100 to 250% of full load torque. Starting current with DOL is 6 to 8 times the full load current.

DISADVATAGES:✔ Sudden voltage drop occurs in the supply leads results in flickering lights

nearby. Therefore only small motors with ratings up to 2.2 to 5.5 kW is started with DOL.

✔ Mechanical stresses are developed on the motor and its load by the increasing torque.

Therefore DOL starter is used only where the source is capable of supplying sufficient power or where dip will not affect the other equipments.

STAR-DELTA START:

The main supply is first fed to star connection which reduces the torque and current to 1/3 of the normal valued needed for a DOL starter.

WORKING:The motor runs in start mode in the 1st stage. Since it reduces the starting torque and starting current to 1/3 roughly, When the speed of the motor

43

becomes greater than or equal to 80% of the rated speed, then change is done. This change is done in two ways either manually or by using a timer. Changer over from star to delta in short time, which is in milli-second creates high current peak. This inrush current produces a sudden jerk.

BREAKER:

These are the following types of breakers available:AIR CIRCUIT BREAKERVACCUM CIRCUIT BREAKEROIL CIRCUIT BREAKERMINIMUM OIL CIRCUIT BREAKERSF6 CIRCUIT BREAKER.

DIAGRAM:

FIG.7WORKING: It consists of two rods, as shown in the fig. above. Upper rod is a moving rod and the lower one is fixed. When connections are done, the live wire is connected to the moving rod which is the incoming one and the outgoing wire is taken out from the bottom fixed rod.

During connection and normal working, the moving rod goes down and touches the fixed rod, thus completing the circuit.If any fault occurs, the relay gives command to the breaker. The spring recoils, thus pushing back the moving rod and breaking the connectivity. Thus the circuit is broken.

In general, when contacts break (between any two wires) a spark is produced. To absorb this spark the breaker tube is filled with, either oil or vaccum, etc. Air can also be used for the same in some cases.

BATTERY:

44

It provides the necessary DC supply when required even when the power supply is cut off. This dc current and dc voltage is required to operate the circuit breakers when there is no supply from the mains. To start various motors (especially Generators) during black out. After shut down the generators, the blades of the generator are stopped slowly otherwise there will be formation of slag. Therefore, the blades are rotated after every 3 minutes at 45˚ during shutdowns.

There are 3 types of battery chargers: I TRICKLE CHARGER: it gives the current to compensate the leakage

charger. Very small current is provided.II FLOAT CHARGER: It maintains the level supplied it the load.III BRUCE CHARGER: It is used when the battery is drained out. When all the

cells die or get used off completely, it chargers the cells again.

BREAL DOWN VOLTAGE TEST:

The BDV-BREAK DOWN VOLTAGE TEST is done to find out the break down of any liquid.

There is an instrument to measure the break down voltage of a liquid. The instrument consists of a box which is filled with necessary oil. Two electrodes are separated by a small gap of approx 25 mm. Voltage is supplied to both the ends of the electrodes. Slowly the voltage is increased, the moment a breakdown occurs, voltage is noted. This is the breakdown voltage of that particular liquid.

The break down voltage of transformer oil is generally 40V but filtration increases it to 60-65 volts.

45

LAB UNIT

In LAB substation two incomer of 11kV coming from CGP (co-generation plant) which will step down to 6.6 kV which are directly stepped down 0.4kV.

In this sub-station, vacuum CKT breakers are used. The rating of this CKT breaker is described in this table:TABLE NO-10

VOLTAGE 12 kVFREQUENCY 50 HzINSULATION LEVEL 28/75 kVNORMAL CURRENT 800 ASHORT CKT BREAKING CURRENT

26.3 A

DURATION OF SHORT CKT

3 Sec

SHORT CKT MAKING CURRENT

66 Ka

OPERATING SEQUENCE 0-0.35-CO-3 min-CO

CLOSING COIL 110 V DCOPENING COIL 110 V DCMOTOR 110 V DCMASS 100 kg

There were lightning transformers in LAB S/S. The rating of these lightning transformers is:

DRY TYPE TRANSFORMER & ITS VECTOR DIAGRAM:FIG.8:

46

Name plate of dry type transformer:TABLE NO-11:

BASIC INSULATION LEVEL

SWITCH POSITIO

N1

PRIMARY LEAD

CONNECTED

NOLOAD VOLTAGE

IMPULSE VOLTAGE kV

PEAK

PRI - 2-3 PRI SECSEC - 2 2-4 454.65

433P. F.

VOLTAGEPRI 3 3 2-5 443.83SEC 3 4 2-6 433.00

kV RMS 5 2-7 422.18411.35

RATING 250 k VA REF IS 11171NO LOADVOLTAGE

PRI 0.433 KV MAX AMB TEMP 47˚CSEC 0.433 KV MAX TEMP WDG 115˚C

CURRENT PRI 333.34 A IMPEDANCE V 4-20%SEC 333.34 A CORE & WINDING

kg880

PHASE 3 TOTAL WEIGHT 1135 kgFREQ 5O Hz PROTECTION

CLASSIP-45

COOLING ANAN YEAR OF MANUFACTURE

2003

INSULATION CLASS

‘H’ Sr. No. JND 9287

DIAGRAM OF CONNECTIONS No. 3DRY-RD-9287/1

47

SAFETY TALK ON ELECTRICAL SAFETY

INCIDENT EXPLOSION RISKS IN BATTERY ROOM

• IT IS COMMON PRACTICE TO HAVE “UPS” (UN-INTRRUPTED POWER SUPPLY) BACKED BY BATTERY IN THE MODERN TECHNOLOGY WORLD.

• HOWEVER, THE VENTILATION ISSUES ARE NOT ADEQUATELY UNDERSTOOD AND ADDRESSED WHILE DESIGNING “BATTERY” ROOM.

• A MAJOR EXPLOSION OCCURRED IN BATTERY ROOM DUE TO INADEQUATE VENTILATION.

• ACCIDENT IS A VERY GOOD EXAMPLE OF WHAT HAPPENED IN A BATTERY ROOM.

• THE EXPLOSION BLEW A 400 SQ FOOT HOLE IN THE ROOF AND COLLAPSED MANY WALLS AND CEILING THROUGHOUT THE BUILDING.

• HYDROGEN MONITORING SYSTEM WAS INTERLOCKED WITH VENTILATION AND RELAY TO FIRE DEPTT. SYSTEM NOT WORKED.

• BATTERIES WERE IN CHARGING FOR A LONG TIME WITH NO VENTILATION.

REASONS FOR EXPLOSION

✔ SEVERAL BATTERY ROOM EXPLOSION INCIDENTS SUPPORT THIS FACT.

48

✔ INADEQUATE VENTILATION, ABSENCE OF FLAME PROOF EQUIPEMENT.✔ HYDROGEN GAS GET GENERATED SLOWLY (1.3X 10-7 m/s PER amp cell)

DURING CHARGING PHASE OF BATTERY OPERATION.✔ RISK OF AN EXPLOSION INCREASES SUBSTANTIALLY, IF HYDROGEN-IN AIR

MIXTURE IS 4 % OR GREATER. ✔ ORDINARY TYPE EXHAUST FANS AND ELECTRICAL ACCESSORIES

ARE PROVIDED. ✔ ZERO AIR CHANGES, NO AIR CIRCULATED.

SUGGESTIONS

➢ CENTRAL LIGHTING SYSTEM:

Main reason is for protection purposes during war time, as we know today’s scenario of the world.

During this type of situation it is strongly required to keep the production on as it feeds the fuel for the whole country.

So it is necessary to switch of the lights of the whole battery area without disturbing the production and to keep the plant safe from the attack.

But system should be such that lighting system should be such that only exterior lights should be shut off

49

without disturbing production and also the interior lights for control rooms.

➢ CABLE PATH DIAGRAM:

Specific line diagram should be drawn with specifying the actual height of the cable on the towers and the depth in ground.

This will help in detection of fault and repairing it again with minimum labor work.

CONCLUSION

It has been very well observed that though the GUJARAT REFINERY is a chemical (PETROLEUM) industry, the matter related to power generation, power supply and all necessary electrical appliances, machines are implemented to prevent any kind of problems, to give first preference to safety along with progress.

The set up and role of all the sub stations is very impressive. It is the case with all the Units of the

50

refinery. It stands true to of great importance. All the latest of techniques and machines are its slogan:

Where growth is the essence of life”

REFRENCES:

➢ IN HOUSE JOURNEY OF GUJARAT REFINERY➢ PLANT MANUALS➢ SABARMATI (INTERNET)➢ ELECTRICAL TECHNOLOGY

-B. L. THERAJA

51