A

Report on

Study of Power House – 4 Drive System

Under the Guidance of

Mr. Nirbhay Kumar Gupta

(Maintenance Expert Group)

Submitted by

Ayushi Dhall (VT 0513148722 (2013))

Joyita Sarkar (VT 0513148725 (2013))

Kangan (VT 0513148728 (2013))

B.Tech 2nd year

Electronics and Electrical Engineering

KIIT University, Bhubaneswar

CERTIFICATE This is to certify that the project report entitled “STUDY OF POWER

HOUSE – 4 DRIVE SYSTEM”, being submitted by Ms. Ayushi Dhall, Ms. Joyita Sarkar, Ms. Kangan of Kalinga Institute of Industrial Technology,

Bhubaneswar to TATA Steel, as a part of summer training course of B.Tech curriculum is a bonafide record of work carried out by them

under my supervision and guidance. The sincerity and sense of dedication shown by them during the project is commendable.

Mr. Nirbhay Kumar Gupta Sr. Technologist Maintenance Expert Group TATA Steel Limited Jamshedpur Date:

CONTENTS

1. Acknowledgement 1 2. Action Plan 2 3. Introduction to TATA Steel 3-5 4. Steel making process 5-8 5. DRIVES

a. DC Drives 9-12 b. AC Drives 12-16 c. Comparison between AC and DC Drives. 16-17

6. POWER HOUSE-4. 18-19 7. Thermal Power Plant. 19-20 8. Drives installed in Power House-4.

a. SINAMICS G 120(SIEMENS) 21-22 b. ABB Standard drives 22-23 c. ABB’s ACS 600 23 d. Powerflex Drives 23

9. References 24

ACKNOWLEDGEMENT

With a great pleasure we would like to express our deep sense of gratitude to Mr. Ajit Kar, Chief, MEG; Mr. Arghay Deb, Head, MEG and to our guide and training co-ordinator Mr. Nirbhay Kumar Gupta, Sr. Technologist, MEG, TATA Steel Limited, for their valuable instructions, guidance and illuminating criticism throughout our project. Without their involvement and supervision we could not have been able to complete this project. We would like to express our sincere thanks to Mr. K. Paswan, Manager, PH-4; Mr. V.G. Rao, Consultant, MEG; Mr. O.P. Gupta, MEG and so many other countless people of TATA Steel Limited, Jamshedpur for helping us in our project during our entire internship. We would also like to thank Dr. Saranjit Singh, Dean, Training and Placement Department, KIIT University, Bhubaneswar for providing us with the opportunity of undertaking our training at TATA Steel Limited, Jamshedpur. We also wish to thank Mr. Parveen Kumar Dhall, Chief, C.B., TATA Steel Limited, West Bokaro Division for making all the arrangements for our training and for his useful guidance. We would also thank Ankit Dhall for his useful assistance during our project. Last but not the least we would like to thank all of our friends and the employees of Maintenance Expert Group for their sincere co-operation and help throughout our training. Thanks to everybody and to almighty for giving us this opportunity in our lifetime. Maintenance and Experts Group Ayushi Dhall,Joyita Sarkar,Kangan TATA Steel Limited VT 2013 Jamshedpur B.Tech 2nd Year KIIT University, Bhubaneswar

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ACTION PLAN

WEEKS

WORK PLAN

WEEK 1

Study of documents on TATA Steel and steel making process. Visit of Electrical Repair Shop.

WEEK 2

Study of documents on drives. Visit of Power House-4 plant.

WEEK 3

Visit of Electronics Repair Lab, LDC. Study of documents.

WEEK 4

Project Work.

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INTRODUCTION TO TATA STEEL

Tata Steel Limited

Type Public

Traded as NSE: TATASTEEL,BSE: 500470 (BSE SENSEX Constituent)

Industry Steel

Founded 1907

Founder(s) Dorabji Tata

Headquarters Mumbai, Maharashtra, India[1]

Area served Worldwide

Key people Cyrus Pallonji Mistry (Chairman) Hemant M. Nerulkar (Managing Director)

Products Steel, flat steel products, long steel products, wire products, plates

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Tata Iron and Steel Company was established by Dorabji Tata on August 26, 1907, as part of his father Jamshedji's Tata Group. By 1939 it operated the largest steel plant in the British Empire. The company launched a major modernization and expansion program in 1951. Later, the program was upgraded to 2 MTPA project. In 1990, it started expansion plan and established its subsidiary Tata Inc. in New York. The company changed its name from TISCO to TATA Steel in 2005.

Tata Steel Limited (NSE: TATASTEEL, BSE: 500470) (formerly Tata Iron and Steel Company Limited (TISCO)) is an Indian multinational steel-making company headquartered in Mumbai, Maharashtra, India, and a subsidiary of the Tata Group. It is the 12th-largest steel producing company in the world, with an annual crude steel capacity of 23.8 million tons, and the largest private-sector steel company in India measured by domestic production.

Tata Steel has manufacturing operations in 26 countries, including Australia, China, India, the Netherlands, Singapore, Thailand and the United Kingdom, and employs around 81,600 people. Its largest plant is located in Jamshedpur, Jharkhand. In 2007 Tata Steel acquired the UK-based steel maker Corus in what was the largest international acquisition by an Indian company to date.

Tata Steel is listed on the Bombay Stock Exchange, where it is a constituent of the BSE SENSEX index, and the National Stock Exchange of India. It is ranked 401st in the 2012 Fortune Global 500 ranking of the world's biggest corporations. It is the eighth most-valuable Indian brand according to an annual survey conducted by Brand Finance and The Economic Times in 2010.

In August 2004, Tata Steel agreed to acquire the steelmaking operations of the Singapore-based NatSteel for S$486.4 million in cash. The acquisition was completed in February 2005.

In 2005, Tata Steel acquired a 40% stake in the Thailand-based steelmaker Millennium Steel for $130 million from Siam Cement.

On 20 October 2006, Tata Steel signed a deal with Anglo-Dutch Company, Corus. On 19 November 2006, the Brazilian steel company Companhia Siderúrgica Nacional (CSN) launched a counter offer for Corus at 475 pence per share, valuing it at £4.5 billion. On 11 December 2006, Tata preemptively upped its offer to 500 pence per share, which was within hours trumped by CSN's offer of 515 pence per share, valuing the deal at £4.9 billion. The Corus board promptly recommended both the revised offers to its shareholders. On 31 January 2007 Tata Steel won their bid for Corus after offering 608 pence per share, valuing Corus at £6.7 billion.

In 2007 Tata Steel through its wholly owned Singapore subsidiary, NatSteel Asia Pte Ltd acquired controlling stake in two rolling mills: SSE Steel Ltd, Vinausteel Ltd located in Vietnam.

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The Tata Group of Companies has business operations (114 companies and subsidiaries) in seven defined sectors – Materials, Engineering, Information Technology and Communications, Energy, Services, Consumer Products and Chemicals. Tata Steel with its acquisition of Corus has secured a place among the top ten steel manufacturers in the world and it is the Tata Group’s flagship Company. Other Group Companies in the different sectors are – Tata Motors, Tata Consultancy Services (TCS), Tata Communications, Tata Power, Indian Hotels, Tata Global Beverages and Tata Chemicals.

Tata Motors is India’s largest automobile company by revenue and is among the top five commercial vehicle manufacturers in the world. Jaguar and Landrover are now part of Tata Motor’s portfolio.

Tata Consultancy Services (TCS) is an integrated software solutions provider with delivery centres in more than 18 countries. It ranked fifth overall, and topped the list for IT services, in Bloomberg Business week's 12th annual 'Tech 100', a ranking of the world's best performing tech companies.

Tata Power has pioneered hydro-power generation in India and is the largest power generator (production capacity of 2300 MW) in India in the private sector.

Indian Hotels Company (Taj Hotels, resorts and palaces) happens to be the leading chain of hotels in India and one of the largest hospitality groups in Asia. It has a presence in 12 countries in 5 continents.

Tata Global Beverages (formerly Tata Tea), with its major acquisitions like Tetley and Good Earth is at present the second largest global branded tea operation.

Tata Steel is headquartered in Mumbai, Maharashtra, India and has its marketing headquarters at the Tata Centre in Kolkata, West Bengal. It has a presence in around 50 countries with manufacturing operations in 26 countries including: India, Malaysia, Vietnam, Thailand, Dubai, Daggaron, Ivory Coast, Mozambique, South Africa, Australia, United Kingdom, The Netherlands, France and Canada.

Tata Steel primarily serves customers in the automotive, construction, consumer goods, engineering, packaging, lifting and excavating, energy and power, aerospace, shipbuilding, rail and defense and security sectors.

Tata Steel has set a target of achieving an annual production capacity of 100 million tons by 2015; it is planning for capacity expansion to be balanced roughly 50:50 between greenfield developments and acquisitions. Overseas acquisitions have already added an additional 21.4 million tons of capacity, including Corus (18.2 million tons), NatSteel (2 million tons) and Millennium Steel (1.2 million tons). Tata plans to add another 29 million tons of capacity through acquisitions.

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Major greenfield steel plant expansion projects planned by Tata Steel include

• A 6 million ton per annum capacity plant in Kalinganagar, Odisha, India • An expansion of the capacity of its plant in Jharkhand, India from 6.8 to 10 million tons per

annum • A 5 million ton per annum capacity plant in Chhattisgarh, India (Tata Steel signed a

memorandum of understanding with the Chhattisgarh government in 2005; the plant is facing strong protest from tribal people)

• A 3 million ton per annum capacity plant in Iran; • A 2.4 million ton per annum capacity plant in Bangladesh; • A 10.5 million ton per annum capacity plant in Vietnam (feasibility studies are underway); • A 6 million ton per annum capacity plant in Haveri, Karnataka.

STEEL MAKING PROCESS

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Iron ore fines are not suitable for use in the Blast Furnace. Hence, the iron ore fines are agglomerated into larger porous lumps, which is suitable for use in the Blast Furnace. A green mix of carefully proportioned iron ore fines, fluxes and coke breeze is prepared in granular form in Mixers. Heat generated through combustion within the mass itself produces large lumps of hot Sinter. This Sinter is cooled, sized and stored for use in the blast furnace. Iron ore fines are recycled to make sinter, to help produce hot metal of predictable and standard quality in the Blast Furnace. Naturally found coal contains Fixed Carbon (FC), Volatile matter (VM), Ash, Moisture and other impurities. Its poor crushing strength and the volatile matter content makes it unsuitable for use in Blast Furnace. Hence, naturally found coal is converted into coke in the coke oven for use in Blast Furnaces. Heating coal in the absence of air carbonizing it to form a hard porous mass, devoid of volatile matter produces coke. Coal after carbonization, which gives blast furnace quality coke, is called metallurgical coal. Coal is graded as prime, medium and blendable, based on its coking properties. Blending of different grades of coal is necessary in order to conserve metallurgical

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coal, yet ensure uniform coking properties. Currently, there are 6 batteries of coke oven supplying coke to the blast furnaces. The coke plant blends coal from different sources, converts coal to coke and cuts to the correct size for use in the blast furnace. The Blast Furnace is a ceramic refractory lined tall reactor, used for the production of liquid iron called Hot Metal. Iron oxide, present in the iron bearing raw materials, is reduced inside the reactor by coke and carbon monoxide. Coke is used for combustion to attain the high temperatures required for reduction. Coke on combustion generates carbon monoxide, which acts as the reducing agent and converts the iron oxides into molten iron. Fluxes are used to make low melting slag and control the quality of Hot Metal. Hot Metal and Slag are collected in the hearth and tapped periodically. Blast Furnaces A, B, C, D, E and F together produce 2.8 million tons of hot metal, annually. G-Blast Furnace produces 1.30 million tons of hot metal annually. Blast Furnace F has been rebuilt in 2002 to enlarge its capacity to 1 million tons. Blast Furnaces are used for producing Hot Metal. Hot Liquid Iron (commonly called Hot Metal in Tata Steel) is converted to Steel in the Steel Melting Shops. Hot Metal from the Blast Furnace is stored in Mixers in LD#1 shop. The Hot Metal is converted to Steel in the LD converters by removing its carbon, silicon, sulphur and phosphorous contents. The liquid steel from the converter is converted to billets using Continuous Casting machine. A small portion of steel is teemed into ingots through Bogie Bottom Poring process using cast iron moulds. The liquid steel is treated in On Line purging, Ladle Refining Furnace or Argon Rinsing station before continuous casting. Special grades of steel, which are cast as ingots, are processed in On-line purging, followed by the Vacuum Arc degassing & refining unit. The Steel Melting Shop requires an Oxygen Plant to cater to the requirement of oxygen for steel making. The Lime Calcining Plant and the Tar Dolo Plant are auxiliary units required for the manufacture of Steel. Hot metal is converted to Steel and cast into Billets. The LD#2 Shop has three Converters of 140 tons capacity each, producing 2.6 million tons of crude steel per annum. Hot Metal is brought from A, D, E, F and G Blast Furnaces in Torpedo ladles. The metal from the Torpedo ladle is taken into the Hot Metal for Desulphurization. It is then charged into the vessel. Primary refining of steel is done in the Ladle Furnace (LF) and RH Degasser (RH) to make cleaner steel of different value added grades. LD 2 makes superior & cleaner grades of steel required to process Flat products of world-class standards.

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DRIVES

DC DRIVES

DC DRIVE CONTROL SYSTEM: A basic DC drive control system generally contains a drive controller and DC motor as shown in the figure given below:

The controls allow the operator to start, stop, and change direction and speed of the motor by turning potentiometers or other operator devices. These controls may be an integral part of the controller or may be remotely mounted.

The drive controller converts a 3-phase AC voltage to an adjustable DC voltage, which is then applied to a DC motor armature.

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The DC motor converts power from the adjustable DC voltage source to rotating mechanical force. Motor shaft rotation and direction are proportional to the magnitude and polarity of the DC voltage applied to the motor

The tachometer (feedback device) shown in Figure converts actual speed to an electrical signal that is summed with the desired reference signal. The output of the summing junction provides an error signal to the controller and a speed correction is made.

FEATURES: • Field orientation via mechanical commutator.

• Controlling variables are Armature Current and Field Current, measured DIRECTLY from the motor.

• Torque control is direct.

OPERATION: The magnetic field is created by the current through the field winding in the stator. This field is always at right angles to the field created by the armature winding. This condition, known as field orientation, is needed to generate maximum torque. The commutator-brush assembly ensures this condition is maintained regardless of the rotor position.

Once field orientation is achieved, the DC motor’s torque is easily controlled by varying the armature current and by keeping the magnetizing current constant. Torque is the inner control loop and speed is the outer control loop.

TYPES OF DC DRIVES:

Armature and Field Controlled DC Drives The motor is armature voltage controlled for constant torque-variable HP operation up to base speed. Above base speed the motor is transferred to field current control for constant HP reduced torque operation up to maximum speed.

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APPLICATIONS: DC drives were used for VARIABLE SPEED CONTROL DRIVES because they could easily achieve a good torque and speed response with high accuracy.

Variable Speed Control Drive: Basic function of a variable speed drive (VSD) is to control the flow of energy from the mains to the process. Energy is supplied to the process through the motor shaft. Two physical quantities describe the state of the shaft: torque and speed. To control the flow of energy we must therefore, ultimately, control these quantities. In practice, either one of them is controlled and we speak of “torque control” or “speed control”. When the VSD operates in torque control mode, the speed is determined by the load. Likewise, when operated in speed control, the torque is determined by the load.

ADVANTAGES:

• Accurate and fast torque control • High dynamic speed response • Simple to control

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DRAWBACKS:

• Reduced motor reliability: the fact that brushes and commutators wear down and needs regular servicing. • Regular maintenance • Motor costly to purchase •Needs encoder for feedback.

AC DRIVES

AC drives provide a very efficient and direct method of controlling the speed of the most rugged and reliable of prime movers, the squirrel cage motor. AC drives provide many economic and performance advantages in a wide variety of adjustable speed drive applications.

The following are some of the benefits provided:

1. High efficiency and low operating cost. 2. Minimal motor maintenance. 3. Controlled linear acceleration and deceleration provide soft. 4. Starting and stopping and smooth speed changes. 5. Multiple motor operations are easily accomplished. 6. Current limit provides for quick and accurate torque control. 7. Adjustable speed operation can be accomplished with existing AC motors. 8. Improved speed regulation can be accomplished by slip compensation. 9. AC motors are available in a wide variety of mechanical configurations. 10. Flexibility of machine design due to the light weight and compact size of AC motors. 11. IR compensation provides high starting torque easily and economically. 12. AC motors are available in enclosures suitable for hazardous or corrosive environments. 13. Fewer spare motors are required since the same motor can be used for both adjustable

speed and constant speed operations. 14. Cutler-Hammer rugged and reliable designs ensure minimum downtime expense. 15. High speed operation can be economically accomplished using extended frequency

operation. 16. Reverse operation is accomplished electronically without the need for a reversing

starter.

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ADJUSTABLE FREQUENCY AC DRIVE SYSTEM

INTRODUCTION An adjustable frequency AC drive system consists of an ordinary three-phase induction motor, an adjustable frequency drive to control the speed of the motor and an operator's control station.

The most common motor used with an AF drive system is a standard NEMA design B squirrel cage induction motor, rated for 230 or 460 volt, 3-phase, 60 Hz operation. The adjustable frequency controller is a solid-state power conversion unit. It receives 240 or 480 volt, 3-phase, 60 Hz power and converts it to a variable frequency supply which can be steplessly adjusted between 0 and 60 Hz. The controller also adjusts the output voltage in proportion to the frequency to provide a nominally constant ratio of voltage to frequency as required by the characteristics of the motor. The operator's station provides the operator with the necessary controls for starting and stopping the motor and varying the motor speed. These functions can also be performed by a wide variety of automatic control systems. There are several classifications of adjustable frequency AC drives. Some common types of drives are Variable Voltage Input (VVI) sometimes called Six Step drives, current source input (CSI), pulse width modulated (PWM) drives, Sensorless Vector drives, Field Oriented drives and Closed Loop Vector drives.

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PRINCIPLES OF ADJUSTABLE FREQUENCY MOTOR OPERATION The operating speed of an AC induction motor can be determined by the frequency of the applied power and the number of poles created by the stator windings. Synchronous speed is the speed of the magnetic field created in the stator windings. It is given by:

N = 120f /P

Where:

n = speed in RPM

f = operating frequency

P = number of poles

When the frequency is changed, the voltage must also be changed, based on the formula for reactance and Ohm’s Law.

XL = 2πfL

Where L = inductance

XL = reactance

V = voltage

Im = magnetizing current

Im = V/XL

Combining the above equations yields:

Im = (V/f).(1/2πfL)

For steady-state operation, a constant volts per hertz ratio must be maintained. This is equal to the motor rated voltage divided by the rated frequency. For the magnetizing current to remain constant, the V/f ratio, or the volts per hertz ratio, must remain constant. Therefore, the voltage must increase and decrease as the frequency increases and decreases.

INDUCTION MOTOR SPEED CONTROL Standard induction motors (NEMA design B) have approximately 3% slip at full load. If the drive only controls the output frequency, the motor speed will deviate from the set speed due to slip. For many fan and pump applications, precise speed control is not needed.

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Vector controlled drives need speed feedback of the rotor. For Sensorless Vector, the rotor speed is calculated based on a model of the motor stored in the drive. For Closed Loop Vector, a digital encoder is added to the motor to provide actual rotor speed.

VOLTS PER HERTZ REGULATION In order to operate the motor with the desired speed/torque curve, we must apply the proper voltage to the motor at each frequency. As we have already seen, it is necessary to regulate motor voltage in proportion to the frequency at a constant ratio. In reality, this requirement for constant volts/hertz does not apply to the motor terminals, but to a hypothetical point inside the motor. The voltage at this point is called the air gap voltage. The difference between air gap voltage and motor terminal voltage is the IR voltage drop.

AC DRIVE APPLICATIONS MATCHING THE AC DRIVE TO THE MOTOR PWM and Vector AC Drives are designed for use with any standard squirrel cage motor. Sizing the drive is a simple matter of matching the drive output voltage, frequency and current ratings to the motor ratings.

OUTPUT VOLTAGE AND FREQUENCY Most modern AC Drives are designed for use with various voltages and frequencies. By adjusting the V/Hz properly, almost any 3-phase motor can be used.

OUTPUT CURRENT AC drive full load currents are matched to typical full load motor current ratings. Usually an AC drive can be matched to an AC motor by their hp ratings; however, actual motor current required under operating conditions is the determining factor. If the motor will be run at full load, the drive current rating must be at least as high as the motor current rating. If the drive is to be used with multiple motors, the sum of all the full load current ratings must be used, and adding up the hp ratings of the motors will usually not provide an accurate estimate of the drive needed.

MOTOR PROTECTION Motor overload protection must be provided as required by the applicable codes. Motor protection is not automatically provided as part of all AC drives. It may be provided as a standard feature on one model or it may be an optional feature on another. The best means of motor protection is a direct winding over temperature protection such as an over temperature switch imbedded in the motor windings. Direct over temperature protection is preferred

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because overheating can occur at normal operating currents at low speeds. Most AC drives are equipped with electronic overcurrent protection, such as I2t protection, similar to a convention overload. In multiple motor applications, individual motor overload protection must be provided even where electronic protection is provided by the drive. In some cases, short circuit protection may be required.

MOTOR WINDING DAMAGE The voltage output of AC drives contains voltage steps. In modern PWM drives, the dV/dt of a motor causes can cause very large voltage spikes. Voltage spikes of 1500 volts or more are typical for a 460 volt motor. This can cause the end windings of a Non-Inverter Duty or standard induction motor to fail. This problem gets worse as the cable length from the drive to the motor gets longer. Corrective action is normally required for cables longer than 150 feet. Load side reactors, installed at the drive output terminals, will reduce the voltage spikes at the motor terminals. Most drive manufacturers have load side reactors available as an option.

COMPARISON BETWEEN AC DRIVES AND DC DRIVES

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1. The Dc motor is complicated and requires a lot of maintenance, which makes it expensive to run; it also has a lower degree of protection. The AC motor, on the other hand, is simple and sturdy, does not need much maintenance, is therefore less expensive, and possesses a higher degree of protection into the bargain.

2. In contrast to the AC standard motor with fixed basic speeds (synchronous speeds of 3000/ 1500/1000/... rpm at 50 Hz), the DC motor's basic speed can be designed from approx. 300 rpm to about 4000 rpm for each working point. 3. Power limitation is caused by the breakdown torque of AC motor decreasing as the square of speed (1/n2). Power limitation is caused by the commutation of DC motor.

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POWER HOUSE – 4 (TATA Steel, Jamshedpur)

At TATA Steel Limited, Jamshedpur, there are three captive power plants namely Power House-3, Power House-4 and Power House-5. Power House-3 and Power House-4 have 4 boilers and Power House-5 has 3 boilers.

Power House Boilers Turbo Generators(TG)

PH-3 5 6 7 8 30 MW 30 MW

PH-4 1 2 3 4 12.5 MW 20 MW 25 MW

PH-5 A B C 30 MW

Total Capacity of PH-4 = 136 tons X 4 = 544 tons

In PH- 4 AC Drives have been used with ID Fan, FD Fan and Coal Feeder ID Fan – ABB ACS 600 FD Fan – SIEMENS SINAMICS G 120 Coal Feeder – ABB ACS 550 (Boiler - 1,2,3) - Powerflex Drive (Boiler – 4)

Chimney

Coal Feeder

Fuel Gas

(FD Fan-Forced Draught Fan ID Fan-Induced Draught Fan)

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BOILER

136 Ton ID Fan

FD Fan (air)

Here, drives have been used to reduce the auxiliary power and for smooth running of the process.

INLET

OUTLET

Inlet and outlet are kept open completely and the speed (rpm) of the motor is controlled to reduce the auxiliary power. In order to operate the motor with the desired speed, proper voltage is applied to the motor at each frequency. For steady state operation, a constant volts per hertz ratio (V/f) is maintained.

THERMAL POWER PLANT Coal is conveyed from an external stack and ground to a very fine powder by large metal spheres in the pulverized fuel mill. There it is mixed with preheated air driven by the forced draught fan. The hot air–fuel mixture is forced at high pressure into the boiler where it rapidly ignites. Water of a high purity flows vertically up the tube-lined walls of the boiler, where it turns into steam, and is passed to the boiler drum, where the steam is separated from any remaining water. The steam passes through any manifold in the roof of the drum into the pendant superheater where its temperature and pressure increase rapidly to around 200 bar and 570°C, sufficient to make the tube walls glow a dull red. The steam is piped to the high pressure turbine, the first of a three-stage turbine process. A steam governor valve allows for both manual control of the turbine and automatic set-point following. The steam is exhausted from the high pressure turbine, and reduced in both pressure and temperature, is returned to the boiler reheater. The reheated steam is then passed to the intermediate pressure turbine, and from there passed directly to the low pressure turbine set. The exiting steam, now a little above its boiling point, is brought into thermal contact with cold water in the condenser, where it condenses rapidly back into water, creating near vacuum-like conditions inside the condenser chest. The condensed water is then passed by a feed pump through a deaerator. The cooling water from the condenser is sprayed inside a cooling tower, creating a highly visible plume of water vapor, before being pumped back to the condenser in cooling water cycle.

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MOTOR FAN

The three turbine sets are sometimes coupled on the same shaft as the three phase electrical generator which generates an intermediate level voltage. This is stepped up by the unit transformer to a voltage more suitable for transmission and is sent out onto the three phase transmission system. Exhaust gas from the boiler is drawn by the induced draught fan through an electrostatic precipitator and is then vented through the chimney stack.

Jamadoba

West Bokaro

COAL

Through conveyer BUNKERS Fine Particles Primary Air FAN Ignition FD Fan Chimney

ID ASH FAN SLURY HP pump (Coal+water) o/p Bara Series Steam Generator Pump 3-4 kms away Turbine 33 KV

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1 2 3 4

MILL

BOILER Fumes are passed through the ESP

12.5 MW

20 MW

25 MW

DRIVES INSTALLED IN POWER HOUSE- 4

SINAMICS G-120 (SIEMENS) - These types of AC drives have been used with Forced Draught Fans in Power House-4.

The modular single drive for low to medium outputs. Some of its features are-

1. Vector control with or without encoder. 2. With square low load torque (T ̴n2). 3. Constant load characteristics. 4. Modular design. 5. Easy to operate. 6. Built-in break chopper. 7. Regenerative feedback to the mains possible. 8. Quiet and compact.

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1-Axis Applications of this drive are-

1. Ready to operate in block size format 2. The versatile drive for low pressure applications. 3. Industrial and commercial fields. 4. Vector controlled.

Its specifications are as follows- IP 120 3-AC, 380-480 Volts, 370-90 KW 7.5 - 37 KW In contrast to the existing inverter range SIMOVERT MASTER DRIVES and MICRO MASTER with SINAMICS G120 the power mobile and the control unit can be separately unmounted as individual components. Scope of supply- Power module and control unit are ordered separately as individual components. Like- Basic Operator Panel (BOP) , Breaking Resistors ,Line Reactors , Filters , Output Reactor. Start Up- 1. Either by using the BOP. 2. With the Starter tool.

ABB standard drives ABB standard drives are simple to buy, install, configure and use, saving considerable time. They are widely available through ABB channel partners, hence the use of the term standard. The drives have common user and process interfaces with fieldbuses, common software tools for sizing, commissioning, maintenance and common spare parts.

APPLICATIONS ABB standard drives can be used in a wide range of industries. Typical applications include pump, fan and constant torque use, such as conveyors. ABB standard drives are ideal in those situations where there is a need for simplicity to install, commission and use and where customizing or special product engineering is not required.

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HIGHLIGHTS − FlashDrop tool − Intuitive use with assistant control panel − Swinging choke for superior harmonic reduction − Vector control − Coated boards for harsh environments − Built-in category C2 EMC filter (1st environment) as standard − Flexible fieldbus system with built-in Modbus and numerous internally mountable fieldbus adapters − UL, CUL, CE, C-Tick and GOST R approved − RoHS complian

ABB’s ACS 600 ABB introduced the ACS 600 single drive series with its unique Direct Torque Control (DTC) in 1995. The ACS 600 calculates the state of a motor 40,000 times per second, making the drive trip less. The ACS 600 is ideal for powering AC motors in general purpose production applications such as pumps, fans, and factory automation systems. The drive provides direct speed and torque control without an encoder or tachometer. ABB’s ACS 600 drive has been used with ID Fans in PH-4.

POWERFLEX DRIVES Powerflex AC Drives provide OEM’s, machine builders and end users with performance enhancing motor control in an easy-to-use package. These drives feature sensorless vector control to meet low speed torque demands. With flexible enclosure options, and simple programming, they can be installed and configured quickly.

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REFERENCES

1. www.tatasteel.com 2. www.wikipedia.com 3. Documents on AC and DC Drives. 4. Guide book on SIEMENS.

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