POWER PLANT FAMILIARISATION TRAINING

CARRIED OUT AT:

NTPC Ltd,

RAMAGUNDAM SUPER THERMAL POWER STATION

Under the guidance of

SRI A.BIXAPATHI

DY.MANAGER (OPERATION)

NTPC – RAMAGUNDAM

DURATION: 16-01-2015 TO 31-01-2015

POWER PLANT FAMILIARISATION REPORT

BACHELOR OF TECHNOLOGY

IN

MECHANICAL ENGINEERING

BY

KURAPATI RAHUL (13H65A0336)

JADI KISHORE (13H65A0333)

ROWTHU GOPI (12H61A0344)

ANURAG GROUP OF INSTITUTIONS (FORMERLY CVSR COLLEGE OF ENGINEERING)

Under the guidance of

SRI A.BIXAPATHI

DY.MANAGER (OPERATION)

NTPC RAMAGUNDAM

ACKNOWLEDGEMENT

The successful completion of our project is indeed practically incomplete without mentioning of all those encouraging people who genuinely supported and encouraged us throughout the project

We would like to express our heartfelt thanks to SRI P.SURESH AGM(operation) for giving this wonderful opportunity to do Inplant training(PROJECT) at NTPC RAMAGUNDAM

With deep sense of gratitude we record our thanks to SRI M.MUTHAREDDY, Principal & SRI CHALAPATHI SRINIVAS RAO, Head of the Department (ME) of ANURAG GROUP OF INSTITUTIONS VENKATAPUR(V),GHATKESAR(M),R.R.DIST.,T.S for the help and support during training period.

We express our profound gratitude to SRI A. BIXAPATHI, DY.MANAGER (Operation), for the Consistent support and exceptional resourcefulness throughout our training period.

We would like to thank…

Sri P.M.G.V-SRINIVAS HR(EDC),

Sri M.V.R.SHARMA Asst.MANAGER HR(EDC),

SrI C.KESHAVULU Staff Asst (EDC) for their valuable advices and guidance to the project work.

Finally, we thank one and all who have given their assistance directly or indirectly.

RAMAGUNDAM SUPER THERMAL POWER STATION

RAMAGUNDAM, TELANGANA STATE

CERTIFICATE

This is to certify that an inplant training report on ”POWER PLANT

FAMILIARISATION” at NTPC Ramagundam, has been successfully carried out

by ,K.RAHUL, J.KISHORE and R.GOPI students of Bachelor of Technology in Mechanical

Engineering from ANURAG GROUP OF INSTITUTIONS(CVSR) HYDERABAD under our

guidance and supervision at NTPC Ltd., Ramagundam from 16-01-2015 to 31-01-2015.

PROJECT GUIDE PROJECT CO-ORDINATOR

Sri. A.BIXAPATHI Sri .P.SURESH

DY. MANAGER (OPERATION) AGM (OPERATION)

NTPC Ltd., RAMAGUNDAM NTPC Ltd., RAMAGUNDAM

CONTENTS

1. Introduction to NTPC ……………………………… 5

2. Power plant Familiarization ………………………………….. 12

Energy conversion

3. Power plant equipments …………………………………… 16

Fuel Handling

Coal bunkers, coal feeders and mills

Primary air fan and Seal air fan

Forced draft fan, Scanner air fan and ID fan

Air Pre Heaters

Electrostatic precipitator

Boilers and its auxillaries

4.Turbine ..…………………………………… 21

Condenser and condensate extraction pump

Low pressure heater

Deareater

Boiler feed pump

High Pressure Heater

Generator

Cooling Tower

Operational cycles

5. Study on Boiler feed pump suction flow control loop ………….. 27

Feed water system .

6.Conclusion …………………………………………………………….. 30

1. INTRODUCTION TO NTPC

Power is an important infrastructure in developing countries. Power development in INDIA

received a big boost with the dawn of National Thermal PowerCorporation Limited(NTPC)

NTPC is established on 7th of November 1975 to construct, operate and maintain large

capacity power developing stations. With the vision “To be one of the world’s largest and best power utilities, powering India’s growth” this corporation is on the run is maintaining its impeccable record by consistently generating quality and reliable power

Leader in power sector :

NTPC with an installed capacity of 43,128 MW is generating 26.5% of the countries entire power requirement. So it is recognized as the India’s largest power utility.

Along side with its core values BECOMMITTED

Business Ethics

Environmentally & Economically sustainable

Customer focus

Organizational & Professional pride

Mutual respect and Trust

Motivating Self & Others

Innovation & Speed

Total Quality for Excellence

Transparent & Respected Organisation

Enterprising

Devoted

Profile of Ramagundam Super Thermal Power Station:

Availability of power in the southern region at certain duration was not as per the demand. As there was an imbalance in the power developed from that being generated. The annual reports were made during 1984-1985 to 1988-1989. Which made evident that an installation of large capacity power station was must to meet the growing requirements. As the basic inputs availability’s like coal, land and water were in abundant a mammoth thermal station was setup to fulfill the requirements at Ramagundam named Ramagundam Super Thermal Power Station(RSTPS).

Foundation :

Ramagundam Super Thermal Power Station is third in the series of super thermal power stations set up by NTPC. Late Shri.Morarji Desai, the former Prime Minister of India, laid foundation stone for this project on 14th November 1978. This station consists of 3x200MW units referred as stage-1 and 3x500MW units referred as stage-2 and 1x500MW units , as stage-3, making a total capacity of 2600MW

Plant location and Lay out :

While planning for the future the total area presently is about 10,231 acres based on unit composition of 3x200MW+3x500MW+1x500MW . The area is covered between longitudes 79deg-52min and 79deg-30min. With in the latitudes 18deg-35min and 18deg-52min with a lot remaining for setting up of additional units as per the future demands

Fuel requirements :

The entire requirement of coal for the plant was proposed to be met from the nearby Singareni Collieries Mines which are about 13km away from the plant. The mines were possening about 1800million tones of coal at the time of installation. A dedicated MGR system having a length of 53km has been developed to haul the coal from nearby open cast mines.

Water Requirements:

At the time of making feasible report several alternatives were considered for meeting the water requirements of cooling water . A detailed study indicated that it would not be possible to meet it through direct circulation so a dam was proposed. The Pochampad dam was built on river Godavari. Measures were taken to ensure that station is not required to be closed under closure of irrigation canal or during draughts. Water requirement of the plant during such conditions can be met for 9-10 weeks without any replacement from the distributory canal.

Ash Disposal:

Large area of land is required for the disposal of the waste like coal ash. Ash being generated from the plant is pumped in a slurry from through pipelines to the ash pod at Kundanpalli, which are 5km away from the power station. The ash disposed is utilized in various forms.

Environmental Control :

Station is equipped with highly efficient ESP system and with tall chimney of about 225m height. Effluent treatment plant was also installed for reuse of decants ash water from ash pad

Evacuation of Power :

The power generated from the station is evacuated through seven no’s 400kv / four no’s 200kv /two no’s 132kv over head transmission lines.

Distribution Of Electricity:

Total Capacity of Ramagundam NTPC is 2600 MW of stage 1 , 2 & 3 ( i.e. 1,2,3, & 4,5, 6 ,&7 unit’s ) distributing electricity to following states in MEGA WATT.

STATE MW % AGE

ANDHRA PRADESH 610 MW 29 %

TAMIL NADU 470 MW 22 %

KARNATAKA 345 MW 16 %

KERALA 245 MW 12 %

GOA 100 MW 5 %

PONDICHERY 50 MW 2 %

Remaining 250 MW is used to any state, now it is used for A.P.

Total capacity of stage – III (unit – VII) is 500 MW – distributing electricity to

following states in MW:-

STATE MW % AGE

ANDHRA PRADESH 145.86 MW 29 %

TAMIL NADU 118.20 MW 23 %

KARNATAKA 86.76 MW 17 %

KERALA 1.61 MW 12 %

PONDICHERY 12.57 MW 2.5 %

2. POWER PLANT FAMILIARISATION

It is known for ages that when coal is burnt it release heat energy. The same phenomenon when

chemically represented.

C + O2 -- C02 + heat energy ( 395 KJ/ mole)

In the boiler, chemical energy is converted into thermal energy by heating water and converting into steam. The steam produced in the boiler expands in the turbine. In the turbine the thermal energy of the steam is converted into the kinetic energy. This motion of the turbine rotor is transmitted to generator in which mechanical energy is converted into the electrical energy which is transmitted to various load centre’s through the transmission lines.

The energy conversion diagram can be shown as follows:

CHEMICAL THERMAL KINETIC ELECTRICAL

BOILER TURBINE GENERATOR

ENERGY ENERGY ENERGY ENERGY

Energy conversion:

The generation of electricity from coal can be classified into the following stages:

Coal to Steam Steam to Mechanical Energy Mechanical Energy to Electrical Energy

COAL TO STEAM CONVERSION:

This conversion takes place in boiler

CoalMills

PAPH

SAPH

Burners

ID Fan

Chimney

SH SteamHRH

CRHWater

PA Fan

FD Fan

Primary Air

The energy produced in boiler has

1) Energy contained in the flame.

2) Energy contained in the hot combustion products called flue gas.

The coal to be fired is fed to mills through the feeders. The mills pulverize the coal so that it can be fully burnt. As coal is a heavy item, air with high velocity is used to carry the coal. This is called primary air. To remove the moisture in the coal primary air is heated before it is sent to mills. It is done in primary air pre heaters. The primary air is supplied by primary air fans.

The oxygen required for combustion is contained in atmospheric air. Air required for combustion is called secondary air. This is supplied by FD (Forced Draft) fans. The air from FD fans is heated to improve combustion efficiency. This is done in secondary air pre heaters.

The combustion products namely flue gas is drawn from the furnace to chimney by ID fans. The FD fans & ID fans together maintain furnace under slight vacuum so that flame & flue gas will not come out. This is to ensure safety.

The boiler consists of a larger number of tubes extending the full height of the structure and the heat produced raises the temperature of the water circulating in them to create stream, which passes to the steam drum at very high pressure. The steam is then heated further in the super heater and fed through the outlet valve to the high-pressure cylinder of the steam turbine

STEAM TO MECHANICAL ENERGY:

SH COILS

MSHPT

IPT

CONDENSOR

LPT

CRH

WATER

CW

HRH

RH

A steam pipe conveys steam to the turbine through a stop valve (which can be used to shut off steam in an emergency) and through control valves that automatically regulate the supply of steam to the turbine.

Steam from the control valves enters the high-pressure cylinder of the turbine , where it passes through a ring of stationary blades fixed to the cylinder wall. These act as nozzles and direct steam into a second ring of moving blades mounted on disc secured to the turbine shaft. This second ring turns the shaft as a result of the force of the steam. The stationary and moving blades together constitute a ‘stage’ of the turbine and in practice many stages are necessary, so that the cylinder contains a number of rings of stationary blades with rings of moving blades arranged between them. The steam passes through each stage in turn until it reaches the end of the high-pressure cylinder and in its passage some of its heat energy is changed into mechanical energy.

The steam leaving the high-pressure cylinder goes back to the boiler for reheating and returns by a further pipe to the intermediate pressure cylinder. Here it passes through another series of stationary and moving blades

Finally, the steam is taken to the low pressure cylinders, each of which it enters at the center flowing outwards in opposite directions through the rows of turbine blades an arrangement known as double flow to the extremities of the cylinder. As the steam gives up its heat energy to drive the the turbine, its temperature and pressure

Fall and it expands. Because of this expansion the blades are much larger and longer towards the low-pressure ends of the turbine.

The turbine shaft usually rotates at 3,000 revolutions per minute. This speed is determined by the frequency of the electrical system used in this country and is the speed at which a 2-pole generator must be driven to generate alternating current at a frequency of 50 cycles per second.

MECHANICAL TO ELECTRICAL ENERGY:

The mechanical energy is converted in to the electrical energy in the generator of the power plant. This conversion takes place through the principle of dynamically induced EMF and in accordance with the Maxwell’s laws of Electromagnetic Induction. The principle of these generators is exactly the opposite of the motors in which electrical energy is converted into mechanical energy

3.POWER PLANT EQUIPMENTS:

Fuel handling:

Fuel (coal) from the storage is fed to the Boiler through the fuel feeding plant commonly known as “coal handling plant”

Selection of proper method of local supply from the coalmines to the power stations depends upon the system capacity in tones per hour, location of available outside storage and overhead coalbunkers. The transfer of coal takes place by “merry go round” system, in which loading and unloading will take place within 12-20 minutes.

Preparation of coal before feeding to the combustion chamber becomes necessary only if unsigned coal is brought to the site and sizing (coal to be 20 mm. Size) is desirable for purpose of storage. The coal (from coal handling plant) is transferred to the indoor storage(bunkers) through conveyer belts via tuning points.

Coal bunkers:

These are in process storage silos used for storing crushed coal from the coal handling system. Generally , these are made up of welded steel plates and the storage capacity of a bunker in terms of time is

24 hours. Normally, there are six such bunkers supplying coal to the corresponding mills and two bunkers to ensure redundancy. These are located on top of the mill so as to aid in the gravity feeding of coal.

Coal feeders:

Each mill is provided with a gravimetric feeder to transport raw coal from the bunker to the inlet chute, leading to mill at a desired rate. This involves control mechanism for flow of coal from bunkers to coal mill. Based upon the flow control mechanism feeders are classified into two tyoes.

1. Gravimetric feeder2. Volumetric feeder

In these most commonly used is gravity feeder which controls the flow of coal by measuring weight of coal using load cells and speed of the conveyer belt.

Coal mills:

Coal mill is a machine in which the 20mm size of coal from the coal feeder is grounded into fine powder. This finely powdered coal is lifted up to the furnace level against gravity force, for this purpose primary air fan (PAF) is used. Coal mill contains four pipes surrounding a center one. Through the center pipe coal enters the mill and fine coal powder is taken to the furnace through surrounding pipes. Ungrounded particles of coal come out through the Bottom Reject Gate(BRG). The BOWL MILL is one of the most advanced designs of coal mill presently manufactured. The advantages of this mill are:

Lower power consumption. Reliability Minimum maintenance Wide capacity.

Primary air fan(PAF):

Primary air fan sucks air from atmosphere pressurizes it and sends it to coal mill through primary air pre heater which heats up this pressurized air.

Seal air fan(saf):

As coal mill is of heavy mass ball bearings are not used but slew bearings are used. To prevent the damage of slew bearing of coal mill seal air fan is used. SAF blows air with pressure more than the pressure of coal in the coal mill thus dealing is done.

Furnace:

Area below the boiler in which combustion of fuel takes place and from which heat passes into the boiler proper is known as furnace. It takes coal, oil, and air from coal mills, oil guns, and FD fans respectively and gives fire. The furnace has four walls. The wind boxes which allow air into the furnace, coal inlets, and oil guns are all arranged at the four corners of the walls of the furnace. They are arranged in levels(they are eight in number for each corner). There are igniters at the corners to ignite the oil and air mixture. The fires from the four corners are made tangential to the fireball. It provides a chamber in which atw combustion reaction can be isolated and confined so that the reaction remains a controlled force. In addition it provides support or enclosure for the firing equipment. The furnace has to provide

Proper installation, operation and maintenance of fuel burning equipment. Sufficient volume for combustion requirements Adequate refractory and insulation. Accessibility to the boiler for maintenance and repair work thwt must be handled from inside the

furnace chamber.

Forced draft fan:

The air supplied by the PAF is not sufficient for combustion process the additional air required is supplied using FD fans (2 per unit – 50% capacity each). This FD fan sucks air from atmosphere pressurizes it and sends it into the furnace. Prior to sending pressurized air is heated in secondary air pre heater (SAPH). The source of heating in SAPH is the hot steam from low pressure turbine.

Scanner Air Fan :

The furnace consists of scanners to sense the flame . Air required for cooling the scanner is supplied by a scanner air fan, which are two in number.

Air Pre-Heaters :

Air pre-heater transfers heat from flue gases to cold primary and/or secondary air by means of rotating heating surface elements. Beneath this regenerative type air pre-heater, there exists a steam coil air pre-heater. These are located in secondary pass of the furnace at a height of around ‘16’ M level. Each 500 MW unit is provided with two such air pre-heaters namely Primary Air Pre-Heater(PAPH) and Secondary Air Pre-Heater(SAPH).

BOILER AND ITS AUXILLARIES:

Boiler or the steam generator is the main part in the power generation process. Boiler acts as a medium in which water is converted into steam by using the heat released in the process of combustion of coal in the presence of oxygen. The steam generator is a natural circulation. Single drum type, front fired, double pass and balanced draft unit designed for various conditions

There are many mountings to the boilers, which are compulsory for the safe run of the boilers. Also there axe accessories, which increase the efficiency of boiler.

Boiler Contains Mainly 4 Parts:

1) Economizer2) Boiler drum3) Super heater4) Reheater

Economizer:

The economizer consists of the feed water through which the heat recovery takes place in the furnace. The steam and water produced in the economizer are feed in to the boiler drum.

Electrostatic Precipitator (ESP):

This consists of alternative plates and windings that carry positive and negative charges respectively. The positive plates are grounded. The potential that exist between the windings is 40kv to 50 kv. With these potential; the ash gets separated from the flue gases. The ash that accumulated on the windings is blow or is hammered by the high forced air so that they fall down and get collected in the hopper at the bottom of the furnace. This ash thus obtained is then removed and sent to the ash pond.

Boiler Drum:

Boiler drum is the important part of the boiler. In this; steam and water are separated. Water having more density than steam it remains in the bottom part of the drum. The steam thus produced is of low pressure and temperature.

Super Heater :

The steams from the boiler drum of low pressure and temperature is sent into the super heater before sending it to the turbine. Here, the steam is heated to a temperature of 545 deg.cel. and a pressure of 170 Kg/sq.cm. This is sent to high pressure turbine.

Reheater:

The steam sent into the high pressure turbine loses its temperature and pressure while it rotates. So, this depleted is then again heated to the required temperature of 535deg cel and a pressure begin constant at 40 Kg/sq.cm, which was obtained at the low pressure turbine. This steam is sent to the intermediate turbine.

4.TURBINE

The turbine is a device consisting of blades mounted on a cylindrical metal object which is kept on a shaft itself is coupled to the generator. Turbine is divided into three categories. They are

High Pressure Turbine :

The steam from the boiler drum, first is sent on to the HPT, where it rotates the turbine. Here, the steam is at a temperature of 540 deg.cal and a pressure of 170 kg/sq.cm and most of the temperature and pressure of the steam is used by the HPT itself.

Intermediate Pressure Turbine:

The steam from the reheater is sent to the IPT, where it is used to rotate the turbine. Which is having temperature of 540 Deg. Cel. And pressure of 4.5 kg per Sq. cm.

Low Pressure Turbine:

The expanded steam from the IPT is sent to the LPT. But the pressure decreases to a negative value of -0.86 kg/sq. cm.

Condenser:

The steam after expansion from the turbine goes to the condenser. The use of turbine increases the efficiency of the plant by decreasing the exhaust power of the steam below atmosphere. Another advantage of condenser is that the condensed steam can be recovered and that provides a source of good and pure water to the boiler and non-condensable gases can also be removed from the steam by passing it through the condenser.

Condensate Extraction Pump (CEP):

Steam after doing work in turbine is condensed in condenser so that it becomes water. This water is stored in Hot well. CEP’s are used to pump this water from Hot well to Desecrator from where it is pump to Drum.

Low pressure heater (LPH):

It is a three stage heater where the temperature of the water is raised to 130deg.cel. the pressurized water from the CEP passes through the coils present in the LPH. The steam tapped from the LPT, is used to heat water.

Deaerator:

As the pressure of the steam is negative in the condenser there is a chance of mixing atmospheric air in the steam that may react with the metal and corrode them. Deaerator is used to separate the air from the steam or more aptly water in it. Thus pure and gas less feed water is obtained.

Boiler Feed Pump (BFP):

The boiler feed pump takes the water from the desorator and pressurizes it to a high pressure of 190 kg/sq.cm and feeds it to the boiler through the high – pressure heater.

High Pressure Heater :

It is a two-stage pressure heater, in which the tapped steam from turbine is used to heat he feed water in HPH, feed water flows in a coil in which steam is sent in opposite direction of feed water such that heat exchange takes place. Feed water regulating system (FRS) regulator the quality of feed water to be fed into the boiler.

Generator:

The generator is one of the important blocks in the power production plant. Generator is coupled with the turbine, which rotates due to the steam. The generator consists of two important parts namely the stator & the rotor. The stator consists of windings to generate electric flux with the help of an excitation unit provided. The rotor is the rotating part, which is coupled to the shaft with hearings.

The rotor is a conductor and as a conductor is cutting the flux an E.M.F. is induced which is tapped as power supply. Thus the steam energy is converted into electric supply. This supply is 22KV voltage is increased to 400 KV for transmission purpose by using a step up transformer.

Cooling tower:

The cooling tower rejects watste heat from the steam cycle to atmosphere. A cooling tower is a specialized heat exchanger in which two fluids air & water) are brought into direct contact with each other to affect the transfer of heat. In a “spray-filled” tower, this is accomplished by spraying a flowing mass of water into a rain-like pattern, through which an upward moving mass flow of coal air induced by the action of a fan or by natural draft.

STEAM AND CONDENSATE CYCLE:-

In the power plant the medium used for conversion of one form of energy into other is water or steam. To prevent scaling inside boiler tubes DM (demineralized ) water is used. It being costly, the water is recirculated after it expands in the turbine and gives out its energy. For this purpose the steam after LP turbine is sent to condenser, where its heat is removed by Circulating Water (CW). The water thus obtained is called condensate. The condensate is pumped through condensate extraction pumps (CEP). Then it is passed through low-pressure heaters (LPH) and reaches deaerator. From turbine tapping is given to heaters for heating the water. These are called extractions. This heating will improve the efficiency. In the deaerator, air from the condensate is removed by sprinkling it and the deaerated condensate water is called Feed water.

FEED WATER CYCLE:

The deaerated water from DA is pumped by high pressure pumps called boiler feed pump (BFP0. the pressurized feed water is passed through high pressure heaters (HPH). The feed water is heated in the HPHs by extractions from turbine.

The outlet from HPHs is passed through FW regulating station. This station controls the FW flow to the boiler. The feed water upon entering the boiler is passed through.

Economizer. In this flue gas energy is used to heat the feed water further, then it is sent to boiler drum and FW cycle is shown in Fig. 3

STEAM CYCTLE:

From drum feed water is sent through down comers and it is sent through riser tubes located in firing zone. In the riser tubes the water is converted into steam. The steam thus generated again reaches the Drum.

The density difference between water and steam will help the water circulation from drum to drum again. The steam entering the drum from riser tubes is separated from water in drum by cyclone separators. The steam is sent to there. The super heater outlet temp is controlled by addition of spray water taken from FW line. The superheated steam from boiler is sent to turbine. This is called Main Steam. Its pressure is 170 Kg/ cm2 where as MS temp. is 535 deg. C. To increase the net output from the turbine, the steam at the outlet of HP turbine is sent back to boiler from heating. This is called re-heating.

The CW receives the net output from LP turbine exhaust steam and this represents a loss in the total cycle

5. STUDY ON BOILER FEED PUMP SUCTION FLOW CONTROL LOOP

Feed Water System:

Introduction:

This system plays an important role in the supply of feed water to the boiler at requisite pressure and steam/water ratio. This is something like preheating the water i.e., condensate and cycling it to boiler.

Drum

Down Comers

FurnaceRiser

Tubes

Heat

Boiler Feed Pumps:

This pump is horizontal and of barrel design driven by an Electric motor through a hydraulic coupling. All the bearings of pump and motor are forced lubricated by a suitable oil lubricating system with adequate protection to trip the pump if the lubrication oil pressure falls below a present value.

The feed pump consists of pump barrel, into which is mounted the inside stator together with rotor. The hydraulic part is enclosed by the high pressure cover along with the balancing device. The suction side of the barrel and the space in the high pressure cover behind the balancing device are enclosed by the low pressure covers along with the stuffing box casings. The brackets of the radial bearing of the suction side and radial and thrust bearing of the discharge side are fixed to the low pressure covers. The entire pumps are mounted on a foundation frame. The hydraulic coupling and two claws coupling with coupling guards are also delivered along with the pump.

BFPs are of two types:

Turbine driven Motor driven

Mechanical Seal:

The use of mechanical seal reduces the loses of feed water in the stuffing box to a minimum and working ability of the feed pump increases.

Balancing Device :

A small portion of the feed water of about 10% which is not calculated to the guaranteed delivery capacity is taken off from the space behind the last impeller for the operation of the automatic balancing device to balance the hydraulic axial thrust of the pump rotor. That means the pressure difference created at the ends is brought down by this small portion

Lubricating System :

All the bearing of boiler feed pump, pump motor and hydraulic coupling are force lubricated. The feed pump consists of two radial sleeve bearings and one thrust bearing.

Booster Pump :

This is one of the intermediate stages of increasing pressure of the condensate being sent to BFP. One of the major damages which may occur to a B.F. pump is form cavitations or vapor bounding at the pump suction due to suction failure. Cavitations will occur when the suction pressure of the pump at the pump at the pump suction is equal or very near to the vapor pressure of the liquid to be pumped at a particular feed water temperature.

Advantage: By the use of a booster pump in the main pump suction line, always there will be positive suction pressure which will remove the possibility of cavitation. Therefore all the feed pumps are provided with a main shaft driven booster pump in its suction line for obtaining a definite positive suction pressure.

FEED WATER CONTROL VALVE DIFFERNTIAL PRESSURE CONTROL

The differential pressure across the feed water control valves is maintained at a preset value by varying the BFP speeds.

The differential pressure across the feed water control valves is measured by a DP transmitter and compared to the DP set point on the BFP speed master. The rate effect of steam flow is also added. The resultant error is fed to a PI controller, the output of which represents the BFP speed demand i.e., the set point for BFP scoop tube position.

In order to have a uniform dynamic response the Gain is automatically changed depending on the number of pumps, which are in auto.

The output of the BFP speed master acts as scoop position set point f or the individual boiler feed pumps. It is compared with the actual scoop position and the error is fed to the individual PI controller for Each BFP. The output of this controller positions the respective scoop tube so as to have the desired BFP

speed. There is a provision for individual biasing of the BFPs.

It is ensured that the scoop tube will be at, the minimum Position before pump start.

In case none of the BFP controllers are in auto then BFP master will remain in manual and will track the maximum of the scoop positions of all the three BFPs. This ensures bumples transfer of BFP Master to Auto.

6. CONCLUSION:

Power is an important infrastructure in developing countries. Power development in India received a big boost with the dawn of National Thermal Power Corporation Limited.

Ramagundam Super Thermal Power Station is a plant with switching station for

southern grid, distributing 400 KV, generating 2600 MW, having mines, and Rail transport facility. Plant generating power in three stages. Stage one with three units of 200 MW capacities, stage two with three units of 500 MW capacities and stage three with 500 MW capacity.

Boiler feed pump control loop in RSTPS is manufactured by SIEMENS

which involves the measurement and maintenance of water level in the BFP through pumps, controller, make-up valve, level transmitter and converters. Whose main aim is to maintain the water level in the condenser so as to use the pressure and heat of the water effectively to increase the efficiency of the system.

The plant is effectively and efficiently managed by various departments. NTPC Ramagundam has

been producing a qualitative power minimizing the hazardous disposals.

References

o www.ntpc.co.in

o www.wikepedia.org

o www.google.co.in s

Bibliography

Training manual of Control and Instrumentation given to us by

SRI .A.BIXAPATHI and staff of (O) , NTPC/RSTPS.

Schematic Diary of Stage 1 and Stage 2. SEIMENS Manuals.