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A WINTER PROJECT REPORT ONVOCATIONAL TRAININGinTITAGARH GENERATING STATIONBY
SHRAYUS DESARKAR
ELECTRICAL ENGINEERING DEPARTMENTUNIVERSITY OF ENGINEERING & MANAGEMENT, JAIPURDURATION OF TRAINING : 04/01/2016 TO 16/01/2016
ACKNOWLEDGEMENTMy name is SHRAYUS DESARKAR. I am 3rd year EE student from University of Engineering & Management, Jaipur. I am really thankful to CESC Limited and my Institute for allowing me to attend this VT during the winter semester break at Titagarh Generating Station. Without their help it would have been an impossible task to complete this report and enrich me with all the information I gathered during the training.
I take this opportunity to express my sincere thanks to my project guide,Mr. Debanjan Basak, Station Manager & Mr. Hirak Das,Training Head for their invaluable guidance,advice, constant encouragement and enlightening discussions during the course of Vocational Training 2015-16 at Titagarh Generating Station without which it would not have been possible for me to give the progress report in this shape.
I owe a great many thanks to a great many people who helped me during my Training season at Titagarh Generating Station.
I would also thank my Institution and the HRD Department of CESCLimited without whom this project would have been a distant reality. I alsoextend my heartfelt thanks to my family and well-wishers.
Dated: 15/1/2016 (SHRAYUS DESARKAR) B.Tech 3rd year Undergraduate Electrical Engg. Dept. Uem, Jaipur.
ABOUT CESCThe Calcutta Electric Supply Corporation or CESC is the Kolkata-based flagship company of the RPG Group, under the chairmanship of businessman Sanjiv Goenka. It is an Indian electricity generation and the sole distribution company serving 567 square kilometres (219 sq mi) of area administered by the Kolkata municipal corporation, in the city of Kolkata, as well as parts of Howrah, Hooghly, 24 Parganas (North) and 24 Parganas (South) districts in the state of West Bengal. It serves 2.8 million consumers approximately, which includes domestic, industrial and commercial users. The first demonstration of electric light in Calcutta was conducted on July 24, 1879 by P W Fleury & Co. In 1881, 36 electric lights lit up a Cotton Mill of Mackinnon & Mackenzie. The Government of Bengal passed the Calcutta Electric Lighting Act in 1895. The first license covered an area of 5.64 square miles (14.6 km2). On 7 January 1897 Kilburn & Co. secured the Calcutta electric lighting license as agents of The Indian Electric Company Limited. The company soon changed its name to the Calcutta Electric Supply Corporation Limited and in 1897, The Calcutta Electric Supply Corporation Limited was registered in London.
A BRIEF OVERVIEW OF TITAGARH GENERATING STATIONShri Jyoti Basu, former Chief Minister of West Bengal commissioned theTitagarh Generating Station (TGS) in 1983. It marked the beginning of anew approach to solve the States power shortage. On January 1, 1987,the name of the company was changed to CESC Limited. TGS iscommitted to ensuring required power supply to the CESCs distributionnetwork in line with the varying level of electricity demand. In TGS thegenerating voltage 10.5 KV is stepped up by generating transformer to33KV. This 33 KV supply is again stepped up to 132 KV in the receivingstation & is sent to distribution station & stepped down to 11KV.Thereafter it is again stepped down to 6.6 KV, 415 V for distributing to consumers.
Some of the noteworthy information about the Titagarh GeneratingStation is given below:
Location: B.T ROAD, TITAGARH, 24 PARGANAS (N), KOL-700119.
Installed Capacity : 4 X 60 MW
Year of Commissioning: Unit 1 1983 Unit 2 1983 Unit 3 1984 Unit 4 1985
Type and Make of Boiler:Type - Single radiant furnace, Single drum and natural circulation, balanced draft furnace, front fired, hopper bottom, top supported, pulverized fuel fired boiler.Maker M/s ABL.
Type and make of Turbine:Type - Impulse reaction, condensing, non-reheat.Maker - NEI Parsons, UK.
Type and Make of generator:Type Air cooled, Synchronous.Maker -NEI Parsons.
Performance Parameters for 2011-12:PLF 81.38%PAF 96.15%Generation in MU 1715.6021 (Yearly)Auxiliary Power Consumption 8.35%Heat Rate 2740 kJ/kW-hr.
Others :ISO- 9001-2000 awarded in 1999.ISO-14000 awarded in February 2006.OHSAS certification done in October 2008.
DEPARTMENT: FUEL & ASHThe primary fuel for these units is Low grade bituminous coal supplied from coal mines. Mixing of different samples of coal is done there. Heat rate increases with the mixing of different grades of coal. The coal handling plant for 960 MTH coal of 300mm size received from the site.
Coal Yard
LDO, light diesel oil is used during light up of boilers. LDO is mixed with the supplied coal in the furnace to ignite. In Budge Budge Generating station coal is supplied from stock pile of the station itself or is received from wagon. Coal unloading from the wagon is done by two methods:
Track hopper Wagon tippler
Track hopper is used for box wagon where coal is discharged through the bottom of the wagon or by wagon tippler where coal containing BOB wagon is rotated by 1350 for unloading of coal. 10500 tons of coal is used each day. The coal extracted from the track hopper is conveyed through 101B and 101A conveyor belt and belts 1D and 1C are used to collect coal from wagon tippler.
Wagon Tippler
The coal is then crushed in 2 stages before it is fed into the boiler bunkers. The conveyor belt before conveying the coal to primary crusher passes through two electro magnets where the foreign particles from the mixture of coal is excluded and is fed to the primary crusher. In primary crusher, the coal is fed to rotary breaker through conveyor belt where the coal is crushed to (-) 100mm size. The rejected particles are separated by reject conveyors.
The 100mm sized coal is conveyed through 3A and 3B belts to the secondary crusher house and is passed through the double deck vib-screen to the crusher. The 100mm coal is crushed to (-) 20 mm size by secondary crusher which is then conveyed to the bunker units 1 and 2 respectively.
Conveyor Belt
From units 1 and 2 bunker the coal is conveyed to the coal mill through feeder. The 20mm coal is finally pulverized where the size is reduced to 50 microns. The pulverised coal is fed to the boiler through the primary air fan and primary pre-heater. Ash handling system is divided into removal of bottom ash from the boiler and fly ash from SILO. The bottom ash from each unit is crushed and conveyed from bottom ash hopper to dewatering ash tank where the water from ash is separated and the remaining ash is collected and supplied to the consumers from zero discharge system for further use. Fly ash is collected in ESP and is removed in two stages. In first stage the fly ash is collected in high compressed air to intermediate surge hoppers and is second stage the dry fly ash is further conveyed from ISH to fly ash and is exported to Bangladesh. High concentration slurry system has been incorporated at TGS to handle fly ash in form of thick slurry and transport the same to distant location forming a mount over which suitably identified plantation will take place creating an environmentally friendly area.
DEPARTMENT: E&I SWITCH YARD : It is a part of the power plant where generated voltage comes from generator transformer. Switch yard system transfer voltage from high to low. Switch yard contains current carrying conductors, grounding wires and switches, transformers, disconnects, double breakers, insulators, pentograph etc.
The switch yard is connected to generator via generating transformer in the generating bay. Here the voltage produced by the generator is stepped up and send for transmission. There are two types of isolator: double break isolator and pentographs. Isolators are required for connecting the main bus through which current will flow, current will flow through one bus at a time. Circuit breakers are there for protection purpose. There are bays in switch yard like MBCB- Main Bus Coupler Bay. It is used for interconnecting main buses. It comes under operation when one of the buses gets faulty. Then whole power is taken onto another bus using bus coupler, but under normal conditions the circuit remains open. During normal operation, a feeder bay is connected to the main buses directly to transmit the power to the various substations. Another bay called transfer bus bay is used when fault occur in generating bay circuit breaker or isolator, then the whole supply transfers to the main bus instead of transferring to the transfer bus directly to feeder circuit in feeder bay.
SWITCH YARD
BREAKER GALLERY There are three types of transformers used in the plant for transmitting power. They are (1) Station transformer, (2) Generating transformers and (3) Unit transformers.
From the LV side of station transformer 132KV is stepped down to 6.6KV which is supplied as incomer in station boards. There are boiler feed pumps, switch gear, water intake pump, boiler feed pump, etc. Boiler feed pump draws 8.8MW power and others draw 6.6KW power. Stationary auxiliary board takes 6.6KV from power station board. There is dry transformer in station auxiliary board which steps down 6.6KV to415V and supply it in each board over there. In unit board there are all types of boiler accessories mentioned earlier. Unit auxiliary board takes 6.6KV from unit board. They are tied up. In unit auxiliary board there is lightening transformer and dry transformer. Here 6.6KV is stepped down to 415V and this 415V is stepped down using lightening transformer to 230V and is supplied to various lights in the plant. All the MCCs are of 415V. DM plant board draws 6.6KV current which goes to the oil transformers of the DM plant and step it down to 415V. DMT1 and DMT2 are the transformers used. The motors are operated at 415V.
At TGS the generating voltage 10.5 KV is stepped up by generating transformer to 33KV. This 33 KV supply is again stepped up to 132 KV in the receiving station & is sent to distribution station & stepped down to 11KV.There after it is again stepped down to 6.6 KV, 415 V for distributing to consumers. In generator transformer it is stepped up to decrease the current rating by which the i2R loss or core loss will be reduced.
DEPARTMENT: OPERATIONThe main operation of the plant is to produce electricity or power and to transmit it to the distribution centres throughout the city. Now to complete this operation a method is followed by the station. At first water is taken from The Ganga river, then it is demineralised using various measures which will be discussed later. This demineralised water is send to the boiler through pipelines for producing superheated steam. Now to produce steam fuel is required, which comes in the form of coal imported from different parts of the country as well as abroad. A minimum of 2.45 million tonnes of coal is required per annum. Now this coal is refined into small particles of size 20mm using primary and secondary crushers respectively. Now this coal is used as a fuel to superheat water into steam at a pressure of 95kg/cm2 and main steam temperature of 515oC. This superheated steam is used to rotate the turbine at high speed which acts as the prime-mover of the alternator which in turn produces electricity in three separate units inside the plant.
The major equipment required for this operation are the boilers, turbine, generator, coal mills, fans, heaters and transformers. Following are the specifications:
BOILER:- Manufacturer: M/S ABB ABL Limited, Durgapur, W.B. (Unit#2,3&4), M/S BHEL (Unit#1)
Type: Single radiant furnace, Single drum and natural circulation,balance draft.
Furnace: front fired, hopper bottom, top supported, pulverized fuel fired boiler.
Furnace: Each 4 unit has width 17940mm and depth 17173mm Super heater: Primary/LTSH, Platen, Final No of safety valves: Each of 4 units:-(total 10 nos.) At drum-2, at MS Line-2, At CRH-4, At HRH-2 No of air heater:- Unit#1&2-2 nos. Unit#3&4-2 nos. No of F.D:- Fan/each of 4 units 2 No of I.D :- Fan/each of 4 units 2 No of P.A :-Fan/each of 4 units 2No of Coal Mills/unit 5Steaming Parameter at 100% BMCREvaporation of Boiler-805 Te/Hr R/H Max Working Pressure-50 Kg/cm2gMax. Working Pressure of Boiler-184 Kg/cm2g R/H Inlet Steam Pressure- 39.8Kg/Cm2gFinal S/H Outlet Steam Pressure-152-155 Kg/cm2g R/H Inlet Steam Temperature-353 CFinal S/H Outlet Steam Temp-515 C R/H Outlet Steam Pressure-37.8 Kg/cm2gFeed Water Temperature-247 C R/H Outlet Steam Temp-515 CR/H Steam Flow-700 Te/Hr each of the 4 units.
BOILER(TOP VIEW)
TURBINE:- No Of Cylinders:- HP - 1 Single Flow, IP - 1 Single Flow; LP - 1 Double Flow SV Pressure & Temp :- 146.0 Kg/Cm2 Abs & 537C Reheat Pressure & Temp :- 35.7 kg/Cm2 Abs & 535C Speed :- 3000 rpm. Number:- each of 4 units
HP: 1no - Impulse & 18 nos. -50% Reaction 25 nos. - Reaction IP: 16-50% Reaction,17- Reaction LP: 4-50% Reaction Per Flow, 3-Vanable Reaction 8- Reaction per flow
TG FLOOR WITH TURBINE
GENERATOR:- Each unit [x4] 1. Maximum Continuous Rating 60 MW 2. Rated Power Factor 0.85 3. Rated Terminal Voltage 10.5kV 4. Rated Current 10291A 5. Frequency 50Hz 6. Number Of Phases 3
RANKINE CYCLEThe Rankine Cycle is an ideal cycle for comparing the performance of the steam plants. It is a modified form of Carnot Cycle. In TGS modified Rankine cycle in used.
Fig. of rankine cycle
The Rankine cycle is the ideal cycle for power plants; it includes the following four reversible processes:-
1-2:Isentropic compressionWater enters the pump as state 1 as saturated liquid and is compressed isentropically to the operating pressure of the boiler. Dry steam is represented by point 2.
2-3:Constant P heat additionSaturated water enters the boiler and leaves it as superheated vapour at state 3. Since no heat is supplied or rejected during this process, therefore there is no change in entropy.
3-4:Isentropic expansionSuperheated vapour expands isentropically in turbine and produces work
.
4-1:Constant P heat rejectionHigh quality steam is condensed in the condenser
DEPARTMENT: MMD There are 3 main type of maintenance: - I) Preventive Type2) Predictive Type3) Breakdown Type
PREVENTIVE TYPE :-This type of maintenance is preventive type. This maintenance is done mainly to prevent any type of occurrence of breakdown or other faults of particular equipment. Preventive type maintenance is done as per schedule provided by the manufacturing company.
PREDICTIVE TYPE :-This type of maintenance is done at regular interval. Various parameters (e.g. temperature, vibration etc.) are measured using different equipment of a power plant. From the corresponding values of the parameters any chance of occurrence of fault is predicted and required steps are taken.
BREAKDOWN TYPE :-This type of maintenance is done when breakdown of particular equipment occurs. This maintenance is done only when a breakdown or fault occurs. This maintenance is done as soon as possible so that fault is cleared and generation is resumed.
The major divisions in this department include:
Maintenance of Boiler & its auxiliaries :- Boiler, ID Fan, FD Fan, PA Fan. Coal Mill, Various Pumps, etc.
Maintenance of Turbine & its auxiliaries :- Turbine, CEP, BFP, NASH pump, HP-LP bypass system, Condensate Transfer pump, Circulating cooling water (CW) pumps, service cooling water pumps, etc.
Maintenance of Fuel and Ash :- Conveyor System. Rotary Breakers. Crusher. Wagon Tipplers. Track Hoppers. Bottom & fly ash
Main equipment and systems which fall under the MMD department are briefly described below:-
PULVARIZED COAL MILLThe mill is a large ball slow speed, E-type machine with horizontally disposed grinding rings. The ring elements consist of top and bottom grinding rings having machine tracks in which run 10 Alloy Steel Hollow cast balls each of 830 mm. After certain running hours when the balls come down to a dia 760 mm a fill in ball (11th ball) of that dia is inserted in the grinding track. No further action will be then be necessary until all the 11 balls reach the dia of 720 mm. Then they require replacing. The bottom ring is mounted on the yoke, which sits on the gearbox output shaft flange, and this rotates at 33.41 rpm. The top ring is prevented from rotating by a spider which is keyed to it. The spider has four hard steel guide carried on a large diameter pins and these blocks are controlled to move in a
vertical direction only by guides attached to the mill housing and fitted with hard steel wear plates. A static type classifier is situated on the top of the mill housing and a centrally disposed coal chute ensured that raw coal is fit to the centre of the grinding elements. Centrifugal action forces the coal outwards between the balls and the grinding rings where it is pulverized. Two PA Fans supply the required primary air for 6 nos. mills (normally 4 nos. running). Hot PA bus and old PA bus runs over the E-nos. mills. Mill outlet temperature and PF flow are properly maintained by HAD and CAD operation of individual mill. It then passes through throat ring gap and air grid plates window. The resulting increase in velocity prevents panicles of coal from falling past the ring. The air string passed towards the classifier picks up finer particles. Larger particles separate out and fall back on to the grinding zone. The mixture of coal and air then passes through classifier where over size particles are returned further grinding and the fine product passes to the coal pipes and the burners. Rejects falling through the throat gap are carried around and fall into reject chamber, which is scraped out by scrapper plough and controlled through reject gate. When reject gate is being open then pyrite gate is closed. There is one Relief gate. The relief gate is protected from metal plate called metal apron plate against any damage by scrape iron or large stone piece. There is one scrapper plough under the bottom yoke, which scrap the reject and drops the materials into pyrite chamber. The classifier is mounted on the top of the mill and is fitted with individually adjustable for fineness control. At the bottom of the classifier a ring of hanging plates (skirt plate) is arranged so that over size coal can pass back into the grinding elements but primary air is prevented from short-circuiting the classifier vanes. Turing the vanes towards their radial position will decreases the fineness of the PF and turning them towards the closed position will increase fineness. There is a provision for sampling the P. F. from vertical portion of the coal pipe at the Burner Front.
Cooling tower
MILL GEAR BOX LUBRICATION SYSTEM :-The oil lubrication system is designed to lubricate the 10.9E Mill gearbox unit. The complete system is mounted as a substantial steel sob plate on a concrete foundation. It consists of pump motor, Fillers, cooler etc. The oil is drawn from the reservoir of the sump of the gearbox by the motor drives gear pump & is fed to the dual fiker. The oil is then passed through a water tube cooler & hence via the flow indicator to the gearbox. The interconnecting piping take the oil to the gear unit internal lubrication system. Four spring loaded relief valves are incorporated in the system. First two are after the pumps & act as a Safety valve for the pump increase of filter blockage. Third one acts as a cooler by pass & operated when the oil is cold at the time of starting. The forth one act as a pressure regulator is adjusted to maintain specific working pressure at the gear unit.
The system has one main pump & one stand by pump, duplex filter, one main cooler & one stand by cooler. So that in case of failure of any one of them. the stand by equipment can take over.
DEPARTMENT: DCSDistributed control systems (DCSs) are dedicated systems used to control manufacturing processes that are continuous or batch-oriented, such as oil refining, petrochemicals, central station power generation, fertilizers, pharmaceuticals, food and beverage manufacturing, cement production, steelmaking, and papermaking. DCSs are connected to sensors and actuators and use set point control to control the flow of material through the plant. The most common example is a set pointcontrol loopconsisting of a pressure sensor, controller, andcontrol valve. Pressure or flow measurements are transmitted to the controller, usually through the aid of a signal conditioning input/output (I/O) device. When the measured variable reaches a certain point, the controller instructs a valve or actuation device to open or close until the fluidic flow process reaches the desired set point. Large oil refineries have many thousands of I/O points and employ very large DCSs. Processes are not limited to fluidic flow through pipes, however, and can also include things likepaper machinesand their associated quality controls (seequality control system QCS),variable speed drivesandmotor control centers,cement kilns,mining operations,ore processingfacilities, andmany others.
Control room
A typical DCS consists of functionally and/or geographically distributed digital controllers capable of executing from 1 to 256 or more regulatory control loops in one control box. The input/output devices (I/O) can be integral with the controller or located remotely via a field network. Todays controllers have extensive computational capabilities and, in addition to proportional, integral, and derivative (PID) control, can generally perform logic and sequential control. Modern DCSs also supportneural networksandfuzzy application. Recent research focuses on the synthesis of optimal distributed controllers, which optimizes a certainH-infinityorH-2criterion.
DCSs are usually designed with redundant processors to enhance the reliability of the control system. Most systems come with displays and configuration software that enable the end-user to configure the control system without the need for performing low-level programming, allowing the user also to better focus on the application rather than the equipment. However, considerable system knowledge and skill is required to properly deploy the hardware, software, and applications. Many plants have dedicated personnel who focus on these tasks, augmented by vendor support that may include maintenance support contracts.
DCSs may employ one or more workstations and can be configured at the workstation or by an off-line personal computer. Local communication is handled by a control network with transmission over twisted -pair, coaxial, or fibre-optic cable. A server and/or applications processor may be included in the system for extra computational, data collection, and reporting capability.
DEPARTMENT: PLGIn a plant or an industrial sites planning and environmental department plays an important role. Planning is essential for maintaining the whole plant, and every plant there should have an environmental management. Planning helps for proper management of every section of a plant and environmental management helps that the plant is operating without violating the laws of pollution control board and maintaining cleanliness in the plant. In Budge Budge generating station all employees are being differentiate by their performance as they are being provided a target in every year. These plans and works for the development and growth of the plant. There is a target and floor that is given to the General Manager from the board of directors. The plant must achieve the targets however it should not go below the floor value.The objective of PLG is to break down the large target into smaller targets and give it to individuals departments. Each dept. must reach their targets. The large goal is broken down to smaller goals. When each department succeeds in their goal, the plant as a whole succeeds.
It also monitors the activities of all the employers working here. They are further given a basic target each year. If they succeed then their target is set higher next time. This measures the better performance of each employee. For example, each employee is encouraged to do something new known as kaizen. They must submit their reports to managers and manager forwards it to the plant dept. manager. If they create something new they are provided with monetary benefits and encouraged to do more of the same. Each officer level employee is sent out for monitoring the workers and must submit quite a number of reports each year.
Fig. shows the total cycle of power generation at TGS
Some IMAGES OF VARIOUS PARTS at TGS
TURBINE GENERATOR FLOOR
CONCLUSIONEach part of the plant is equally important for generating this huge amount of power. The maintenance of the plant is done very thoroughly after a set period of time in regular intervals. The machines are repaired and checked every now and then. A healthy and friendly environment is maintained throughout the plant where more than 400 workers work daily in different fields. For the benefit of the workers breakfast and lunch is provided at affordable cost for everyone. There are trees planted all around the area and small gardens are also maintained for a pollution free area. Surveying is done at the beginning of each year where replacements of old machines are done and checking is also done. In my two weeks of training I learnt a lot of things and also observed a lot of processes.
SHRAYUS DESARKARDEPT OF ELEC. ENGG. UEM, JAIPUR.
BIBLIOGRAPHYDocuments and information provided by different departments of the plant and also my interpretation of all the processes taking place as I observed during the training. And also I collected data from Google & Wikipedia.
CESC LIMITEDTITAGARH GENERATING STATION
DETAILS OF STUDENT:
NAME : SHRAYUS DESARKARBRANCH : ELECTRICAL ENGINEERINGINSTITUTE : UNIVERSITY OF ENGINEERING & MANAGEMENT, JAIPURDURATION OF TRAINING : 04/01/2016 to 16/01/2016SIGNATURE :
. . signature of training in-charge (SHRAYUS DESARKAR ) B.Tech 3rd year Undergraduate Electrical Engg. Dept UEM, JAIPUR.
