Gazal File

7/29/2019 Gazal File

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Institute Of Science and Technology Klawad (2012-2013)

CHAPTER - 1

1.1 INRODUCTION TO HPGCL

Haryana Power Generation Corporation Limited (HPGCL) was incorporated as a company

under Companies Act 1956 on 17th March 1997 and certificate for commencement of business

was granted on 5th August 1997. The business of generation of power of erstwhile Haryana

Stated Electricity Board was transferred to Haryana Power Generation Corporation Limited on

14th August 1998 pursuant to the implementation of power reforms in the state of Haryana.

The main objective of HPGCL is to generate power in the state of Haryana from the existing

generating station in most efficient manner on commercial lines and sell whole of the power

generated exclusively to Haryana Vidyut Parsaran Nigam Limited and to set up new power

projects in the state sector.

The main objectives of HPGCL are as under:

1. To generate power from its exiting Generating Stations in the most efficient manner on

commercial line and to sell the same to distribution companies.

2. To set up new power generation projects.

3. From June 2005 HPGCL is also responsible for the work of power trading i.e.

Procurement of power on long term and short-term basis signing of power purchase

agreements with power producers/traders

1.2 DCRTPP YAMUNA NAGAR

DEENBANDHU CHHOTU RAM THERMAL POWER STATION YANUNANAGAR is an

undertaking of Haryana Power Generation Corporation Panchkula (HPGCL), This a coal based

thermal power plant, which produced electricity by using heat energy coal. It was established in

2003.

It is established near PANSARA village on YNR-SAHARAPUR Road, 7k.m.s. from EAST of

Yamunanagar the station required area is 1200 acre. The inputs of the plant are mainly Water

and Coal. The water is cleaned and demineralised and then sent to the boiler for the production

of steam.

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The output of the plant is electric power. The present capacity of the plant is 600 MW with a

total investment. The capacities of Two units are 300 MW each, is operating by HPGCL. This

is coal based thermal power plant, which produced electricity by using heat energy coal.

1.3 UNIT OVERVIEW

Figure 1.1 Unit Overview2


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1.3.1 TURBINE:-

There are three types of turbines HP, IP, LP operated at 3000 rpm with initial parameters 13

kg/cm2. the superheated steam enters the HP turbine and strikes its blade hence heat energy ofsteam is converted into mechanical energy. The steam from HP turbine is reheated in re-heaters

and reheated steam is sent to IP turbine through hot steam lines after working here the steam

sent to LP turbine where it is ejected by vacuum ejectors and condensed. The direction of

revolution of turbine is clock wise when looking at turbine from front bearings pedestal

Figure 1.2 Turbines

1.3.2 BOILERS:

The boiler is also termed as, is also termed as steam generator steam generator is is a

container in which water can be fed and by the a container in which water can be fed and by the

application of heat evaporated continuously into application of heat evaporated continuouslyinto steam. The heat source is obtained by burning steam. The heat source is obtained by

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burning the fuel, which is coal. Water circulates in the water walls the heat energy is applied to

the water walls the heat energy is applied to the water walls and water converted into steam,

this water walls and water converted into steam, this steam is fed into upper heaters to remove

water steam is fed into upper heaters to remove water particles to obtained superheated steam is

fed particles to obtained superheated steam is fed into super heater where water particles is into

super heater where water particles is completely removed & finally fed to turbine. Completely

removed & finally fed to turbine.

1.3.3 AIRPRE HEATER:

Air preheater is a heat exchange in which is a heat exchanger in which air temp. raised by

transferring heat from air temp. raised by transferring heat from other flue gases. Since air

heater cab be successfully employed to heater cab be successfully employed to reclaim heat

from flue gas at lower temp reclaim heat from flue gas at lower temp. level, thus heat ejected to

chimney is level, thus ejected to chimney is reduced, hence boiler efficiency is reduced, hence

boiler efficiency isincreased.

Figure1.3Air Pre heater

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1.3.4 CRUS HERHOUSE PLANT:

A steel hopper has been provided in crusher house to receive coal & distribute crusher house

to-receive coal & distribute it through manually operated rack & pinion it through manually

operated rack & pinion gate to three vibrated screens of gate to three vibrating screens of 675

t/hr 675t/hr capacity each coal above 200mm size passes granular & discharged on to crushed

conveyor belt. After that the coal crushed in bowl mill & convert into fine powder.

1.3.5 ASH HANDLING PLANT:

The ash handing ash handing system provide for system provide for continuous collection ofbottom ash from continuous collection of bottom ash from furnace hearth & its intermittent

removal furnace hearth & its intermittent removal by hydro ejectors to a common slurry sump.

Each boiler is provided with ash precipitator for collecting the fly ash from flue gases.

1.4 ANGULARVIEW OF THERMAL POWER PLANT

Figure 1.4 Angular View Of TPP

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1.5 BRIEF DESCRIPTION OF PLANT LAYOUT:-

A thermal power station is a power plant in which the prime mover is steam driven. Water is

hearted; it turns into steam and spins a steam turbine, which drives an electrical generator.After it passes through the turbine, the steam is condensed, this is known as a Rankin cycle.

The greatest variation in the design of thermal power is due to the different fuel sources. Some

prefer to use term energy center because such facilities convert forms of heat energy into

electrical energy.

The basic energy into involved in the plant is as follows:

Chemical Energy

(Coal)

Heat Energy

Mechanical Energy

Electrical Energy

1.5.1 GENERATION UNIT

Table 1.1

Yamunanagar Thermal Power Station

S.No Stage No Unit No. Capacity

1. Stage-1 Unit-1 300MW

2. Stage-2 Unit-2 300MW

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1.6 ESSENTIAL FEATURE OF THE LOCATION OF A THERMAL

POWER PLANT:-

There are various whose consideration is essential while deciding the location of any thermal

power plant. The two essential inputs i.e. WATER & COAL must be easily available. The raw

water should be available near the site. For getting the supply the plant should be connected by

rail or road.

1.7SELECTION OF SITE FOR A THERMAL STATION DEPENDS

UPON THE FOLLOWING POINTS:-

2. Nearness to load center

3. Supply of water

4. Availability of coal

5. Land requirement

6. Type of load

7. Transportation facilities

8. Labor supplies

9. Ash disposal

10. Distance from populated area

1.7.1 Steam turbine

Table 1.2

MW 300 Main Steam temperature 535o C

MVA 353

RPM 3000

Steam Pressure 150kg/cm2

Reheat Temperature 535o C

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1.7.2 Exciter

Table 1.3

Brushless Exciter

KW 1650 VoltDC 475

Exciting VoltDC 16 AmpereDC 3474

Insulation Class B Duty S1

Weight 24500kg

RECT 26LO-40 Current 400A

1.7.3 Turbo Generator

Table 1.4

RPM 3000 KVA 294100

Winding KW 2.5 lakhs

Power Factor 0.85

Lagging

Type THR/108/44-F

Frequency 50 Hz Phase 3

Connection ** Cooling Hydrogan& CO2H2 Gas Pressure 0.31Mpa-G Insulation Class F

1.7.4 Stator

Table 1.5

Voltage 20000V Current 10189 A

Wt. stator 210000kg Rotor 53000kg

1.7.5 Rotor

Table 1.6

Voltage 302 V Current 2510 A

1.7 COAL HANDING:-

Raw Material

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The coal is the major source of energy in the D.C.R.T.P.P. The raw coal is found in Bihar,

Orissa in India. The raw coal for D.C.R.T.P.P. is bought from the Bihar Mines. In this stage,

the coal is in the form of big stones, it has many impurities.

Coal Transportation

The raw coal may be delivered by rail or road. In the D.C.R.T.P.P. This raw coal is delivered

mainly through Railways; provide better and reliable transportation services. The transportation

coat much reduced as road transportation.

Coal Unloading

The coal reached the plant in the Railway wagon. The coal is unloaded from the rail wagon

mechanically by tiling the wagon by tippler. The coal is sent to storage yard through the

conveyor belts

Preparation

The coal before sending to the coal mill it is brought to the site and crushed to desired size. The

pulverization plant may include:

1. Crusher

2. Roller Screen

3. Magnetic Separation

4. Wagon Tippler

5. Stacker cum Reclaimer

6. Vibro Feeders

Coal Conveyor belt:The conveyor belt is the best way to transfer the coal in plant. The coal at unloaded plant is

transferred to the storage by specific conveyer belts. The coal from storage further transported

to the feeding bunker belt. The conveyor belts are continuous run type belt. It runs on the roller

and at both end points electric motors are used to operate the belt

Coal Mill:-

The proper sized coal is red to manual mill where it is pulverized to the powder from. In this

unit the ball tube type mill is used For crushing the coal high carbon steel balls are used. Thedia of this ball is 40 to 50 mm and 200.in number: The liner is provided for protection the mill

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shill. This liner is replaced when it worn out. The pulverized coal is fed to the furnace through

nozzle by the hot primary air supplied by PA fan. The air takes away the coal dust passes

upward into the classifier. In the classifier the moisture and coarse particles are removed. Finer

coal dust along with primary air leaves the classifier onto the coal transport piping from where

it goes to nozzle.

The number of coal mills employed in the unit is six among them four are running mill and two

are standby.

1.9 COMBUSTION:-

1.9.1 FURNACE :

The furnace which is employed in the D.C.R.T.P.P. is tangential fired. The furnace consists of

coal nozzles, oil guns, igniter provided at each corner of the furnace.

To start up the furnace the heavy furnace oil is sprayed by oil guns and it is fired by the spark

provided by igniter. When the desires temperature for burning of coal is pulverized coal is used

instead of the heavy furnace oil to provide the safety of igniter from the high temp of furnace

cold air is supplied.

1.9.2 FD FAN :

The FD Fan is called forced Draft Fan. The FD Fan moves the air / gas continuously against the

moderate pressure. They feed the hot air in the boiler FD fans are used in boiler for different

applications, such as supplying air for combustion, removal of combustible products and air for

cooling equipments working at hot zone. It seeks air from atmosphere. The FD fan used in this

unit is multistage pump which is made in Germany. These are powered by using motors.

1.9.3 PA FAN :

PA Fan is called primary Fan. The purpose of primary air fan is to provide air at desired

pressure for carrying the coal from the coal mills to the furnaces. The air from the primary air

fan passes through the primary air preheater before entering the coal mill is to remove moisture

from coal particle and to provide required temp for proper burning of pulverized coal. PA fan

are used in this unit is also of axial type and it sucks the air from the atmosphere. The No. of

PA fans used in this unit are two for proper supply of primary air.

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1.9.4 AIR HEATER:

There are two types of air heater in use; the first one is primary air pre heater and the other one

is secondary air heater. The air from FD fans passes through the secondary air heaters. A & B

and air from PA fans passes through primary air pre heater. The purpose of using air heater is

to heat air supplied to the furnace up to the required temperature for proper burning of fuel. The

flue gases come out from the furnace is used in air pre heater to heat the air. The air rotary type

b/w economizer and electrostatic precipitator.

1.10 ASH HANDING SYSTEM:-The ash produced in the boiler is transported to ash dump area by means of sluicing type

hydraulic ash handing system. Which consists of bottom ash system, ash water system, flu ash

system, ash slurry system which is explained as follows:

Bottom Ash System

In the bottom ash system. The ash slag discharge from the furnace bottom is collected into

water impounded scraper though its stalled bellows water ash system. The ash is continuouslytransported by means of scrapper chain conveyor on the respective clinker grinders which

reduce the temp. Sizes to the required fineness. The crushed ash from clinker grinders falls into

the ash sluice trench provided below the bottom ash hoper from where the ash slurry further

transported to ash slurry sump added by ash sluice channel.

The water with high pressure coming out from the tip of the nozzle push the ash slurry along it

towards the sump. From the tip sump this ash slurry disposed form the plant though the no. of

ash disposal pump. By creating the great vacuum by them.

Fly Ash System :

The flushing hoppers are provided under EP hoppers (40 Nos.) Economizer Hopper (4 Nos.) air

preheater (4 Nos.) and stack hoppers (2 Nos.) The fly ash collected in these hoppers drop

continuously to flushing apparatus where fly ash get mixed with flushing water and the

resultant slurry drops into the ash sluice channel. Low- pressure water is applied through the

nozzle directing tangentially to the section of pipe, to create turbulence and proper mixing of

ash, with water. For the maintenance of flushing apparatus and connection chute.

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Ash Water System

High pressure water required for B.A. Hoppers quenching nozzles, windows spraying, clinker

grinder sealing scrapper bars, cleaning nozzles, B.A. Hoppers seal through flushing,

economizer hoppers flushing nozzles is tapped from the high pressure water ring main

provided in the plant area. According to the direction of steam flow Axial turbine in which

steam flows in a direction parallels to the axis of the turbine. Radial turbine in which steam

flows in a direction perpendicular to the axis of the turbine, one or more low pressure stages in

such turbines are made axial. Here we use axial turbine.

According to the number of cylinders:

1. Single cylinder

2. Multi Cylinder.

According to the steam condition at inlet to turbine:

1. Low pressure turbine using at 1.2 to 2 afa pressure.

2. Medum pressure turbine using steam at 40 afa.

1.11 WATER TREATMENT:-

The objective of the water treatment is to produce boiler teea water so that there shall be no

scale formation causing resistance to passage of heat and burning of tube, no corrosion, no

priming and foaming problems. This will ensure that steam generated shall be clean and the

boiler plant will provide turbine free uninterrupted service.

Water treatment plant used in thermal power plant are designed to process the raw water very

low in dissolved solid known as demineralised water.

The types of demineralization process chosen for power station depend on three main factors:

1. The quality of raw water.

2. The degree of deionization i.e. treated water quality.

3. Selectivity of resins.

The water treatment process is generally made up of two sections.

1. Pretreatment Section

2. Demineralization Section.

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1.11.1 I.P. TURBINE

This consists of 4-4 wheels in each flow that is 4-4 stages. It consists of double flow. It also has

double casing for the sake of same reason as for HP & I.P. casing.

1.11.2 BEARINGS

A bearing is machine part whose function is to support a moving element and to guide or

confine its motion, while preventing motion in the direction of applied load. Since there is a

relative motion b/w the bearing and the moving element, there will be a power loss or energy

loss due to friction and if their surface actually touch each other.

Wear may alsoTakes place. Hence a bearing should perform its function with a minimum loss

of energy from and at the same time should control the rate of wear. These are achieved to

large extem by inter posing a layer of lubrication b/w the contact surface of the bearing and a

moving element. In many applications the bearing are located b/w the shoft frame of a m/c.

they are also located b/w the contact member and the frame or b/w contact member and linkage

member.

1.12 STEAM GENERATION

1.12.1 BOILER :-

Boiler is a mechanical device used for producing steam under pressure. These are mainly two

types:

a) Fire Tube Boiler.

b) Water Tube Boiler.

In the fire tube boiler, the hot air passes through the pipes and the water flows around the pipes

and get heated Boiler used in this unit is water tube boiler. In the boiler the heat energy transfer

takes place through the tube walls. It is provided with water drum to maintain construction head

of feeding water.

The steam generated in the boiler is firstly fed to super heater where the steam is heated to

super saturate state by the heat of flue gases. Boiler is provided with several mountings like

pressure relief Valve pressure gauge, water level indicator, temperature measuring devices etc.

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1.12.2 SUPER HEATER

Super heater are meant to raise the steam temperature above the saturation temperature by

absorbing heat from the flue gases. It is placed just after the drum. By increasing the temp of

stem, efficiency of cycle is increased, Super heater desuperheater are provided in b/w the

LTSH>Section and played super heater for controlling super heater temperature.

The hot gases of the furnace come in contact with water tubes of the boiler. The heat transfer

takes place through the tube wall. Thus the water in the tube get heated by the flue gases water

converted into wet steam. This steam goes to the super heater, where the temperature and

pressure of the is increased by heat of flue gases. This super saturated steam fed to the HP

turbine.

Figure 1.5 Super Heater

1.12.3 REHEATER:-

Reheater is placed between the HP turbine and IM turbine after the expansion in HP turbine the

steam goes to the preheater, in the reheater the temp and pulverized fuel burners. The

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pulverized coal to burners at 4 corners, of the furnace. All the nozzle of the burners are

interlined and can be titled as a single unit from + 30 0 to -300.

1.12.4 IGNITER:-

There are twelve sides eddy plate oil igniter per boiler and capacity of each igniter is 50 kg/hr.

The igniters are located at AB, CD, EF. Four igniter at a time. The igniter air fans are also

provided in ignitor air system one working and other standby. The design capacity of each fan

is 1030 m3/hr and temp. and pressure 500C and 200mmwe respectively.

THE FURNACE MAY PROVIDE THE FOLLOWING

a. Proper installation operation and maintenance of fuel burning equipment.

b. Sufficient volume of combustion requirement.

c. Adequate refractory and insulation.

CHAPTER-2

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2.1 ELECTRICITY GENERATON

2.1.1 STEAM TURBINE :-

A prime mover in which inertly the energy of the steam is transformed in Kinetic energy bymeans of nozzle. Then the K.E. of the impacting jet is converted into force doing works on the

rings of blades mounted on a rotating part is known as steam turbine.

In steam turbine there is direct conversion of heat energy into mechanical energy & this energy

is directly available at the rotating shaft.

Classification of steam turbine.

1. Impulse and Reaction Turbine

a) A turbine in which the steam expands in nozzle and renditions at constant

pressure which passing over the blades is known as impulse turbine.

b) A turbine in which the steam pressure decreases gradually while expanding

thought he moving blades as well as its passage through the fixed blades

(nozzle) is known as reaction turbine

Figure 1.6 Steam Turbine

2.1.2 ELECTROSTATIC PRECIPITATOR :-

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It is an electric device which removes the ash particle from the smoke through furnace of

boiler. It helps in the prevention of air pollution. It woks the principles that a charge particles is

attracted towards opposite charge. Two plates of opposite polarity are fixed and smoke is

passed b/w them. When the dry ash come b/w the plates it gets charged and is attracted towards

the plate and collected by discharging the particles.

2.1.3 ID FAN :-

It is called induced draft fan, there are three different fans in even thermal plant. Its main

function is to remove the combustible products flue gases to the atmosphere. These ID fans are

placed at chimney base to draw out gases from the chimney to the atmosphere by creating a

draft.

2.1.4 CHIMNEY:-

These are tall RCC structure with multiple flues. The height of these chimney very depending

on the location consideration anywhere between 150m to 220m.

2.2 POWER TRANSFORMERS:-

General

a. Type:

Step-up transformer for use with main units should be of the oil immersed type for outdoor

operation, with a cooling system suited to the location.

b. Three-phase transformers:

in the majority of application, three-phase transformer should be used for generator step-up

(GSU) application for the following reasons:-

Higher efficiency than three single-0phase units of equivalent capacity.

Smaller space requirements.

Lower installed cost.

Lower probability of failure when properly pro-tested by surge arresters, thermal

devices, and oil preservation systems. Lower total weight.

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Reduction in weights and dimensions making larger capacity available within practical

weight and size limitations.

c. Transformer construction:

There are two types of construction used for GSU transformers.

These are the 1) Core form type and 2) the shell form type.

Core form transformers:- generally are supplied by manufacturers for lower voltage

and lower MVA rating. The core form unit is adaptable to a wide range ofdesign

parameters, is economical to manufacture, but generally has a low kVA- to weight ratio.

Typical HV ranges are 230 kV and less and 75 MVA and less.

Shell form transformers:- have a high kVA-to-weight ration and find favor on EHV

and high MVA applications. They have better short-circuit strength characteristics, are

less immune to transit damage, but have a more labor-intensive manufacturing process.

Both forms of construction are permitted by Corps transformer guide specification.

2. Rating:-

The full load kVA rating of the step-up transformer should be at least equal to the maximum

kVA rating of the generator or generator with which they are associated.

Where transformer with auxiliary cooling facilities have dual or triple kVA rating, the

maximum transformer rating should match the maximum generator rating.

3. Cooling:

a. Genera: transformers, when located at the powerhouse, should be sited so unrestricted

ambient air circulation is allowed. The transformer rating is based on full use of the transformer

cooling equipment.

b. Forced Cooling:- The use of forced-air cooling will increase the continuous self-cooled

rating of the transformer. High-velocity fans on the largest size groups will increase the self-

cooled rating 66-2/3 percent Forced-oil cooled transformers, whenever energized, must be

operated with the circulating oil pumps operating. Forced-oil transformers with air coolers do

not have a self-cooled rating without the air-cooling equipment in operation unless they are

special units with a triple rating

4. Accessories:

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a. Oil preservation systems. Three different oil preservation systems are available, as

described below. The first two systems are preferred for generator step-up transformers.

1) Inert gas pressure systems- Positive nitrogen gas pressure is maintained in the space

between the top of the oil and the tank cover from a cylinder or group of cylinders through a

pressure reducing valve.

2) Air-cell constant-pressure, reservoir tank systems. A system of one or more oil

reservoirs, each containing an air cell arranged to prevent direct contact between the oil and the

air.

3) Sealed tank. Gas is admitted to the space above the oil and the tank is sealed. Expansion

tanks for the gas are provided on some sizes. Sealed tank construction is employed for 2,500

kVA and smaller sizes.

b. Oil flow alarm:- Transformers that depend upon pumped circulation of the oil for cooling

should be equipped with devices that can be connected to should and alarm, to prevent closing

of the energizing power circuit, or to de-energize the transformer with loss of oil flow. In

forced-oil-cooled units hot spot detectors should be provided which can be connected to unload

the transformer if the temperature exceeds that at which the second oil pump is expected to cut

in. FOA transformers should employ control schemes to ensure pump operation prior to

energizing the transformer.

d. Fans and pumps:- The axial-flow fans provided for supplementary cooling on Class OA/FA

transformers are equipped with special motors standardized for 115-V and 230-V single-phase

or 208-V three-phase operation. Likewise, oil circulating pumps for FOA of Engineers practice

is to supply 480-V, three-phase power to the transformer and have the transformer

manufacturer provide necessary conversion equipment.

c. Surge arresters: Surge arresters are located near the transformer terminals to provide

protection of the high-voltage windings. Normal practice is to provide brackets on the

transformer case (230-kV HV and below) for mounting the selected surge arrester.

e. On-line dissolved gas monitoring system: The detection of certain gases, generated in an

oil-filled transformer in service, is frequently the first available indication of possible

malfunction that may eventually lead to the transformer failure if not corrected. The monitoring

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system can provide gas analysis of certain gases from gas spaces of a transformer. The system

output contacts can be connected for an alarm or unload the transformer if the gas levels exceed

a set point.

f. Temperature detectors: A dial-type temperature indicating device with adjustable alarm

contacts should be provided for oil temperature indication. Winding RTDs should be provided,

and monitored by the plant control system or a stand-alone temperature recorder, if one is

provided for the generator and turbine RTDs. At least two RTDs in each winding should be

provided.

g. Lifting devices: If powerhouse cranes are to be used for transformer handing, the

manufacturers deign of the lifting equipment should be carefully coordinated with the crane

clearance and with the dimensions of the crane hooks. The lifting equipment should safely clear

bushing when handing the completely assembled transformer, and should be properly designed

to compensate for eccentric weight dispositions of the complete transformer with bushings.

h. On-line monitoring systems: In addition to the on-line dissolved gas monitoring system

other on-line systems are available to monitor abnormal transformer conditions. These include:

1) Partial discharge analysis.

2) Acoustical monitoring.

3) Fiber-optic winding temperature monitoring.

4) Bearing wear sensor (forced-oil-cooled units).

5) Load tap changer monitor (if load tap changers are used).

Dialtype indicating devices: Dial-type indicating devices should be provided for:

1) Liquid level indication.

2) Liquid temperature indicator.

3) Oil flow indicators.

These are in addition to the dial-type indicators that are part of the winding temperature

systems.

1. Oil Containment Systems: If any oil-filled transformers are used in the power plant,

provisions are made to contain any oil leakage or spillage resulting

2. Ruptured tank or a broken drain valve. The volume of the containment should be

sufficient to retain all of the oil in the transformer to prevent

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Spillage into waterways or contamination of soil around the transformer foundations. Special

provisions (oil-water separators, oil traps, etc.) must be made to allow for separation of spillage

versus normal! Water runoff form storms, etc.

1. Routine tests

1.1 Measurement of winding resistance

1.2 Measurement of voltage ratio and testing of voltage vector relationship.

1.3 Measurement of impedance voltage, short-circuit impedance and load loss

1.4 Measurement of no-load loss and current.

1.5 Dielectric tests:

1.5.1 Separate source voltage withstand test

1.5.2 Induced over voltage withstand test

Witness type/special tests can be carried out on request.

2. Type tests

2.1 Temperature rise test


2.2.1 Lightning impulse test

3. Special tests


3.1.1 PD test

3.1.2 Chopped wave test

3.2 Measurement of zero-sequence impedance on three phase transformers

3.3 Short circuit test

3.4 Measurement of sound level

3.5 Measurement of harmonics in the on load current

3.6 Tests of auxiliary equipment and wiring

3.7 Tests on load tap-changer

3.8 Leakage test for transformer tank

2.3RANGE OF POWER T/F

Rated Power 370 MVA

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Made By AREVA

Rated Voltage 20/230KV

Rated Current (HV/LV) 929.9 / 10693.6

Number Of Taps 17 OLTS

% Impedance 14%

Oil Quality 70000 KG

Temp 50C

Insulation Class A

Average Winding 55C

Core Oil Mass 17000KG

2.4 UNIT Auxiliary Transformer:-

In recent years, Large units of a usually Designed on a unit system basis in which the required

devices, including the boiler, the turbine generator unit, and its power (step up) and unit

(auxiliary) transformer are solidly connected as one unit.

In addition to the above items, the unit auxiliary type system will incorporate a common or

startup arrangement which will consist of a startup and standby auxiliary transformer

connected to the switchgear and motor control center arrangement similar to that described

above for the unit auxiliary system.

The common bus system may have a similar arrangement for the standby transformer.

1) This common system has three principal functions:

(a) To provide a source off normal power for power plant equipment and services which

are common to all units; e.g., water treating system, coal and ash handing equipment,

air compressors, lighting, shops and similar items.

(b) To provide backup to each auxiliary power system segment if the transformer

supplying that segment fails or is being maintained

(c) In the case of the unit system, to provide startup power to each unit auxiliary power

system until the generator is up to speed and voltage and is synchronized with the

distribution system.

2) The startup and standby transformer and switchgear will be sized to accomplish the

above three functions and, in addition, to allow for possible future addition to the

plant. Interconnections will be provided between the common and unit switchgear.

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Appropriate interlocks will be included so that no more than one auxiliary

transformer can feed any switchgear bus at one time.

2.5 CIRCUIT BREAKER:

A circuit breaker is an automatically-operated electrical switch designed to protect an electrical

circuit from damage caused by overload or short circuit. Unlike a fuse, which operates once

and then has to be replaced, a circuit breaker can reset (either manually or automatically) to

resume normal operation. Circuit breakers are made in varying sizes, from small devices that

protect an individual household appliance up to large switchgear designed to protect high

voltage circuit feeding an entire city.

2.5.1 SHORT CIRCUIT CURRENT

Circuit breakers are rated both by the normal current that are expected to carry, and the

maximum short-circuit current that they can safely interrupt.

Under short-circuit conditions, a current many times greater than normal can exist (See

maximum prospective short circuit current). When electrical contacts open to interrupt a large

current, there is a tendency for an arc to from between the opened contacts, which would allow

the current to continue. Therefore, circuit breakers must incorporate various features to divide

and extinguish the arc.

The maximum short-circuit current that a breaker can interrupt is determined by testing.

Application of a breaker in a circuit with a prospective short-circuit current higher than the

breakers interrupting capacity rating may result in failure of the breakers interrupting capacity

rating may result in failure of the breaker to safely

Interrupt a fault. In a worst-case scenario the breaker may successfully interrupt The fault, only

to explode when reset, injuring the technician.

Miniature circuit breakers used to project control circuit or small appliances may not have

sufficient interrupting capacity breakers are called supplemental circuit protectors to

distinguish them from distinguish-type circuit breakers.

2.5.2 HIGH VOLTAGE CIRCUIT BREAKER

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Figure 1.7 High Voltage Circuit Breakers

A 1200 A 3-pole 115,000 V breaker at a generating station

High-voltage breakers are broadly classified by the medium used to extinguish the etc.

o Oil-filled (dead tank and live tank)

o Oil-filled, minimum oil volume

o Air blast

o SF6

o Vacuum circuit breaker (manufacturing in ABB, AREVA, Cutler-Hammer (Eaton),

Siemens, Toshiba)

High voltage breakers are routinely available up to 765 kV AC.

Live tank circuit breakers are where the enclosure that contains the breaking mechanism is at

line potential, that is, Live. Dead tank circuit breaker enclosures are at earth potential.

(Interrupting principles for high-voltage circuit-breakers

Current interruption in a high-voltage circuit-breaker is obtained by separating two contacts in

a medium, such as SF6, having excellent dielectric and arc quenching properties. After contact

separation, current is carried through an arc and is interrupted when this arc is cooled by a gas

blast of sufficient intensity.

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microseconds, so that it is able to withstand the transientrecovery voltage that is applied across

the contacts after current interruption Sulphur hexafluoride is generally used in present high-

voltage circuit-breakers (of rated voltage higher than 52 kV

2.6 LIGHTINING ARRESTOR:-

Figure 1.8 Lighting Arrestor

Charged electrical energy called a Pilot Leader) positive lightning bolts actually move

upwards from vertical features in the earth such as the edges of buildings, chimneys or trees,

electric towers reaching towards along an ionized path in the air towards the downwards-

moving negative energy. [its interesting that UL says the energy moves in discrete 150 steps.

A lightning protection system does not prevent lightning from striking it provides a means for

controlling it and preventing damage by providing a low resistance path for discharge of

lightning energy.

Lightning arrestors directly connected at one end to the transmission system (transmission line,

transformer, switch yard) at the time of lightning it could be ground through LA.

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2.7 TRANSIMISSION TOWER:-

Figure 1.9 Transmission Towers

Aluminum Conductor Steel Reinforced

Aluminum Conductor Steel Reinforced (or ACSR) cable is a specific type of high-capacity,

high-strength stranded cable used in overhead power lies.

The outer strands are aluminum, chosen for its excellent, chosen for its excellent conductivity,

low weight, and low cost.

The center strand is of steel, providing extra strength. Serendipitously, however, the lower

electrical conductivity of the steel core has only a minimal effect on the overall

Current is carried by the outer, aluminum portion of the cable, so the higher resistance of the

inner, steel strand is largely immaterial.

2.8 HIGH DIFFERENTIAL EXPANSIONSE

When the rotor expands more than the casin. The diff. expansion goes on positive side and

when they rotor expansion is less then the expansion of the casing, the diff. expansion moves

on negative side.

Causes for high Diff. Expansion are:

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During cold start, the speed raising and rate of loading is too fast without allowing the

cylinder and flange to heat up to decide limits. This will cause an increase in the

positive side.

During the hot start, the speed raising and rate of loading is too slow which result incontraction of the rotor leading increase in the negative side.

Steam Condenser

A steam condenser is a device in which steam condenses and heat relased by steam is

absorbed by water. It serves the following purpose:

Figure 1.10 Condensers

Classification of Condenser

Mainly, condenser is of two type:

(1) Jet conderiser:

In it the exhaust steam and water come in direct contact with each other and temp of the

condenser is same as that of cooling water leaving water the condensing.

(2) Surface Condenser:

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The exhaust steam and water do not come in direct contact. The steam passes over the outer

surface of tubes through which a supply of cooling water is maintained.

Due to the fact the steam flows in a direction right angle to the direction of flow of water, it is

also called cross surface condenser.

Specification of Condenser Used

Type Surface Type

Cooling Area 3380 m2

No. of tubes 6800

Tube ticknes 1mm

Material Admirality Brass

Length 7500 mm

Cooling water Rate 7700 m3/liter

Fould Condencer Tube

Condenser tube results in drop in vacuum over along periods because of less heart transfer

between water and steam. It is necessary to clean the condenser tubes during overhauls.

Pugging of more than 10% of the total no of tubes would tower the condenser vacuum.

Pumps

The hydraulic machine which converts the mechanical work into hydraulic energy I called

pumps. The hydraulic energy is in the form of pressure energy by means of centrifugal force

acting on the fluid, the hydraulic is called centrifugal pump. If the mech energy is converted

into press energy by means of reciprocating piston on the fluid the hydraulic m/c is called

reciprocating pump.

The centrifugal pump acts as a reversed of an inward radial flow reaction turbine. This means

that the flow in centrifugal pump is in the radial outward direction. The centrifugal pump works

on the principle of forced vortex flow, which means that when a certain mass of liquid is

rotated by an external torque, the rise in press head of rotating liquid takes place.

Deaerator

It is a system in it self. Its function is to remove AIR or another Gases which is mixed inthe water from condenser. Mainly it consist of arrangement of plates as shown in fig.

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That is why it is known as tray type. In this system two ways for steam is side. Now as

water comes down it strikes with trayes and get separated from air or other gases, this gases get

mixed with steam vent out from top most portion of the deaerator. Now condensate without air

enters into feed water tank. This system is situated at 44 m height.

Figure 1.11 Dearreater

CHAPTER-3

3.1 PROGRAMMABLE LOGIC CONTROL:-

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Figure 1.12 PLC

A Programmable logic controller (PLC) or programmable controller is a digital computer used

for automation of industrial processes , such as control of machinery on factory assembly lines.

Unlike general-purpose computers, the plc is designed for multiple inputs and output

arrangement, extended temperature ranges, immunity to electrical noise, and resistance to

vibration and impact. Programs to control machine operation are typically

stored in battery-backed or non volatile memory. A plc is an example of real time system since

output results must be produced in response to input conditions within a bounded time ,

otherwise unintended operations will result.

3.1.1 FEATURES:

The unit consist of separate elements, from left to right; power supply , controller , relay units

for in and output. The main difference from other computers is that plcs are armoured for

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severe conditions (dust, moisture, heat, cold, etc) and have the facility for extensive

input/ouyput arrangements. These connect the plc to sensors and actuators. Plc read limit

switches, analog process variables (such as temperature and pressure), and the positions of

complex positioning systems. Some even use machine vision. On the actuator side, plcs

operate electric motors , pneumatic or hydralic cylinders , magnetic relays or solenoids , or

analog output . The i/o arrangements may be built into a simple plc, or the plc may have

external i/o modules attachedto a computer network that plugs into the plc

Figure 1.13 Features

Plcs were invented as replacements for automated systems that would use hundreds or

thousands of relays , cam timers , and drum sequencers . often , a single plc can be

programmed to replace thousands of relays . programmable controllers were initially adopted

by automative manufacturing industry , where software revision replaced the re-wiring of hard-

wired control panels when production models changed.

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Many of the earliest plcs expressed all decision making logic in simple ladder logic which

appeared smilar to the electrical schematic diagrams. The electicians were quite able to trace

out circuit problems with schematic diagrams using ladder logic . this problem notation was

choosen to reduce training demands for the existing technicals . other early plcsused a form of

instruction list programming , based on a stack-based logic solver.

The functionility of the plcs has evolved over the years to include sequential relay control ,

motion control , process control , distributed control system (DCS) and networking . the data

handling , storage , processing power and communication capapabilities of some modern plc

are equaling to desktop computer . plc like programming combined with remote i/o hardware ,

allow a general purpose desktop computer toi overlap some plc in certain application.

Under the IEC 61131-3 standard , plc can be programmed using standard based

programming language. A graphical programming notation called sequential function charts is

available on certain programmable controllers.

3.2 PLC COMPARED WITH OTHER CONTROL SYSTEM:-

Plc are well adapted to a range of automation task they are typically industrial processes in

manufacturing where the cost of developing and maintaining the automation system is high

relative to the total cost of the automation , and where changes to the system would be expected

during its operational life . plc contain input and output devices compatible with industrial pilot

devices and controls ; little electrical design is required ,

The design problem centres on expressing the desired sequence of operation in ladder logic

notation. Plc is low compared to the cost of a specific custom built controller design. on the

other hand in the case of mass produced goods customized control system are economic

due to lower cost of the components which can be opticallychosen instead of a generic solution

and where the non recuring engerring charges are spread over thousand of places

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For high volume or very simplefixed automation task different technique are usd foe example

a consumer dishwasher would be controlled by an electromechanical cam timer costing only a

few dollar in production quantitiess.

A michrocontroller based design would be appropriate wherehundred or thousands of units will

be produced and so the development cost can be spread over many sales and where the end

users would not need to alter the control . automative applications are an example;millions of

units are built each year, and very few end users alter the programming of these controllers.

However some special vehicle such as transit buses economically use plc instead of custom

designed controls because the volume are low and the development cost would be uneconomic.

Very complex process control, such as used in chemical industry , may require algorithm and

the performance beyond the capability of even high performance plc very high speed or

precision controls may also require customised solutions; for example aircraft flight controls.

Plc may include logic for simple variable feedback analog control loop a proportional integral

derivative or pid controller . a pid loop could be used to control the temperature of a

manufacturing process . historically plc were usually configeredwith only a few control analog

loops ; where process required hundred or thousand of loops a distributed control system (DCS)

Would instead used. However as ploc have become more powerfull the boundry between dcs

and plc applications has become less clear cut.

Plc have similar functionility as remote terminal units (RTU). An RTU however usually does

not support control algorithm or control loops . as hardware rapidly becomes more powerfull

and cheaper RTU, PLCand DCS are incrasignlybeginning to overlap in responsibilities , and

many vendors sell RTU with plc like features and vice versa. The industry has standardized on

the iec61131-3 functional block language for creating programs to run on rtu and plc although

nearly all vendors also offer proprietary alternatives and associates development environments.

3.2 DIGITAL AND ANALOG SIGNALS:-

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Digital and analog signals behave as binary switches, yielding simply an on or off signal (1 or

0, true or false, respectively). Push buttons, limit switches, and photoelectric sensors are

examples of devices providing a discrete signal. Discrete signal are sent using voltage or

current, where a

Specific range is designed as on and another as off. For example, a PLC might use 24V DC

Representing on, values below 2V DC representing off, and intermediate val undefined.

Initially, PLC had only discrete I/O.

Analog Signals are like volume controls, with a range of values between zero and full-scale.

These are typically interpreted as integer values (counts) by the PLC, with various ranges of

accuracy depending on the device and the number of bits avaible to store the data. As PLC

typically use 16-bit signed binary processors, the integer values are limited between -32768 to

+32767. Pressure, temperature, flow, and weight are often represented by analog signals.

Analog signals can be use voltage or current with a magnitude proportional to the value of the

process signal. For example, an analog 4-20Ma OR 0-10V input would be converted into an

integer of value 0-32767.

Current inputs are less sensitive to electrical noise (i.e. from welders or electric motor start)

than voltage inputs.

3.3.1 EXAMPLE

As an example, say a facility needs to store water in a tank. The water is drawn is drawn from

the tank by another system, as needed, and our example system must manage the water level in

the tank.

Using only digital signals, the PLC has two digital inputs from float switches (tank empty and

tank full). The PLC uses a digital output to open and close the inlet valve into the tank.

When the water level drops enough so that the tank empty float switch is off the plc will open

the valve to let more water in. Once the water level raises enough so that the tank full switches

is on (up), the PLC will shut the inlet to stop the water from overflowing.

An analog system might use a water pressure sensor on a load cell, and an adjustable

(throttling) dripping out of the tank ,the valve adjusts to slowly drip water back into the tank.

In this system to avoid flutter adjustments that can wear out the valve, many PLC incorporate

hystresis which essentially creates a deadband of activity. A technician adjusts thisdeadband so

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the valve moves only for a significant change in rate this will in turn minimize the motion of

the valve and reduce its wear.

A real system might combine both approaches using float switches and simple valves to

prevent spills, and a rate sensor and rate valve to optimize refill rates and prevent water

hammer. Backup and maintenance methods can make a real system very complicated.

3.3.2 SYSTEM SCALE:

Asmall PLC will have a fixed numbers of connections built in for inputs and outputs. Typically

expansions are available if the base model does not have enough I/O.

Modulor PLC have a chassis (also called a rack) into which is placed modules with different

functions. The processor and selection of I/O modules is customised for the particular

application. Several racks can be administered by a single processor and may have thousands of

inputs and outputs. A special high speed serial I/O link is used so that racks can be distributed

away from the processor, reducing the wiring costs for large plants.

PLC used in larger I/O systems may have peer-to-peer (P2P) communication between

processors. This allows separate parts of a complex process to have individual control while

allowing the subsystems to co-ordinate over the communications link. These communication

links are also often used for HMI (Human-Machine Interface) devices such as keypads or PC-

type workstations. Some of today PLC can communicate over a wide range of media including

RS-485. Coaxial and evenEthernet for I/O control at network speeds up to 100 Mbits/s.

3.3.3 USER INTERFACE:

PLC may need to interact with people for the purpose of configuration, alarm reporting or

everyday control.

A Human-Machine Interface (HMI) is employed for this purpose. HMI are also reffered to as

MMI (Man Machine Interface) and GUI (Graphical User Interface).

A simple system may use buttons and lights to interact with the user. Text displays are

available as well as graphical touch screens. More complex systems use a programming and

monitoring software installed on a computer, with the PLC connected via a communication

interface.

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3.3.4 COMMUNICATIONS:

PLC have built in communications ports, usually 9-pin RS-232, but optionally EIA-485 or

Ethernet. Modbus, BACnet or DF1 is usually included as one of the communications protocols.

Other options include various fieldbuses suchas DeviceNet or Profibus. Other communications

protocols that may be used are listed in the list of automation protocols.

Most modern PLC can communicate over a network to some other system, such as a computer

running a SCADA (Supervisory Control And Data Acquisition) system or web browser.

PLC used in larger I/O systems may have peer-to-peer (P2P) communication

Between processors. This allows separate parts of a complex process to have individual control

while allowing the subsystems to co-ordinate over the communication link. These

communication links are also often used for HMI devices such as keypads or PC-type

workstations.

3.4 SCADA :

3.5 INTRODUCTION:

SCADA stands for supervisory control and data acquistion. It generally refers to an industrialcontrol system: a computer system monitoring and controlling a process. The process can be

industrial, infrastucture or facility-based as described below:

Industrial processes include those of manufacturing, production, power generation, fabrication,

and refining and may run in continous, batch, repititive, or discrete modes.

Infrastructure processes may be public or private, and include water treatment and distribution,

wastewater collection and treatment, oil and gas pipelines, electrical power transmission and

distribution, windfarms, civil defense siren systems, and large communication systems.

Facility processes occur both in public facilities and private ones, including buildings, airports,

ships, and space stations. They monitor and control HVAC, access, and energy consuption.

A SCADA System usually consists of the following subsystems:

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A Human-Machine Interface or HMI is the apparatus which presents process data to a human

operator, and through this, the human operator monitors and controls the process.

A Supervisory (computer) system gathering (acquiring) data on the process and sending

commands (control) to the process.

Remote Terminal Units (RTU) connecting to sensors in the process, converting sensor signals

to digital data and sending digital data to the supervisory system

Programmable Logic Controller (PLC) used as field devices because they are more economical,

versatile, flexible, and configurable than special-purpose RTU.

Communication infrastructure connecting the supervisory system to the Remote Terminal

Units.

Elements of a distributed control system may directly connect to physical equiptment such as

switches, pumps and vaves or may work through an intermediate system such as a SCADA

system.

3.6 APPLICATION:

Distributed Control Systems (DCS) are dedicated systems used to control manufacturing that

are continuous or batch oriented, such as oil refining, petrochemicals, central station power

generation, pharmaceuticals, food and beverage manufacturing, cement production,

steelmaking, papermaking. DCS 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

point control loop consisting of a pressure sensor, controller, and control 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 untill the fluidic flow process

reaches the desired set point. Large oil refineries have many thousands of I/O points andemploy very large DCS. Processes are not limited to fluidic flow through pipes, however, and

can also include things like paper machines and their associated variable speed drives and

motor control centres, cement kilns, mining operations, ore processing facilities, and many

others

A typical DCS consists of functionally and/or geographically distributed digital controllers

capable of executing from 1 to 256 or more reegulatory.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. Today controller has extensive computational capabilities and, in addition to

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proportion, integral, and derivative (PID) control, can generally perform logic and sequential

control.

DCS may employ one or several 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 fiber optic cable. A server and/or applications

processor may be included in the system for extra computational, data collection, and reporting

capability.

3.7 Supervision vs. Control:

There is, in several industries, considerable confusion over the differences between SCADA

systems and distributed control systems (DCS). Generally speaking, a SCADA system usually

refers to a system that coordinates, but does not control processes in real time. The discussion

on real-time control is muddied somewhat by newer telecommunications technology, enabling

reliable, low latency, high speed communications over wide areas. Most differences between

SCADA and DCS are culturally determined and can usually be ignored. As communication

infrastructures with higher capacity become avaible, the difference betweem SCADA and DCS

will fade.

3.8 Cooling Tower

In power plants, the hot water from the condenser is cooled in the cooling tower, so that is can

be reused in condenser for condensing of the steam. In a cooling tower water is made to tickle

down drop by drop so that it comes in contact with the air moving in the opposite direction. As

a result of this some water is evaporated and is taken away with air.

In evaporation the heat is taken away from the bulk of work, which is thus cooled.

(a) Temp of air.

(b) Humidity of air

(c) Temp of hot air

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(d) Size and height of tower

(e) Velocity of air entering the tower

(f) Arrangement of air in tower.

In this station we make use of concrete cooling tower, natural draught type cooling

tower.

3.8.1 WORKING

The construction of cooling tower is as shown in fig. In it hot water from condenser is make to

fall from 6 m height. Air naturally blows in upward direction. This cool air comes in contact

with hot failling water and makes the hot water cool by evaporating some amount of hot water.

Now vapors strikes with plates and get

Figure 1.14 Factor Effecting Cooling of Water in Cooling Tower

CHAPTER-4

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4.1 SWITCHYARD CHARGING PROCEDURE

Equipment to be charged:

Jorian#1 & 2 Bays (Bay 12 and Bay 13 respectively); Transfer bus isolators of jorian 1 & 2

bays will be half charged.Main Bus 1 (end-to-end, including Bus LA and Bus PT)

All 14 Isolators connected to Main Bus 1 will be half charged.

Assumptions:- it is assumed that Jorian#1 & 2 Lines are ready in all respects, including their

controlling bays at the remote end. The procedure will be modified, if only one Jorian Line is

made available

4.2 STATION TRANSFORMER

Station transformer is used to provide supply to the power station at the shut down or tripping

time. It is mainly step down type transformer. In DCRTPP it is of 220/6.9k.V rating value. It is

live at every time from other power station.Station transformer is used to provide.

Supply to the power station at the shut down or tripping time. It is mainly step down type

transformer. In DCRTPP it is of 220/6.9k.V rating value. It is live at every time from other

power station.

Figure 1.15 Station T/F

4.3 EMISSION IN THERMAL POWER PLANT

Emissions from Thermal Power Plants

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The main emissions from coal combustion at thermal power plants are carbon dioxide (CO 2),

nitrogen osides (NOx), sulfur oxides (SOx), chlorofluorocarbons (CFCs), and air borne

inorganic particles such as fly ash, soot, and other trace gas species. Carbon dioxide, methane,

and chlorofluorocarbons are greenhouse gases. These emissions are considered to be

responsible for heating up the atmosphere, producing a harmful global environment. Oxides of

initrogen and sulfur play an important role in atmospheric chemistry and are largely responsible

for atmospheric acidity. Particulates and black carbon (soot) are of concern, in addition to

possible lung tissue irritation resulting from inhalation of soot particles and various organic

chemicals that are known carcinogens. CO2, SO2, NO, and soot emissions from each of the

power plants have been computed. Emissions from combustion of the supplementary fuels such

as high-speed diesel (HSD) and furnace oil used in small quantities (>1%) are not counted in

the present calculations.

Carbonaceous Material and Blank Carbon (SOOT)

Incomplete and/or inefficient combustion processes of fossil fuel generate soot. A

recently conducted Indian Ocean Experiment (INDOEX) suggests that the presence of soot

carbon in the atmosphere over the Nothern Indian Ocean hinders its natural heating processes

by about 15%. Enhancement of boundary.

CONCLUSION

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Thermal power plants are industrial goods that produce electricity. Moreover, these plants are

important to customers and are presumed to have a service life of greater than twenty years.

Accordingly, the reliability of a power plant is considered most important, followed by after-

sales service and then economic efficiency. As demand for electrical power increases

throughout the world, Fuji electric intends to continue to strive to supply power plants that

provides reliability, high performance and low price in accordance with the needs of customers.

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