project report 1 bits pilani

NTPC, Faridabad

BIRLA INSTITUTE OF TECHNOLOGY AND SCIENCE PILANI

Practice School 1 || Project Report 1

Gurdeep Singh

2010B1A3672G

Birla Institute Of Technology And Science Pilani

June 16, 2012

2 Project Report 1|Practice School 1

Project Report 1 on

The Gas Fired Power Plant Project at NTPC Faridabad

Practice School Station: National Thermal Power

Corporation (NTPC), Faridabad

Prepared for: The partial fulfillment of the course

Practice School 1

Submitted to: Dr. Amit Kumar Singh, Instructor, BITS

Pilani

Submitted by: Gurdeep Singh, 2010B1A3672G


June 16, 2012


ACKNOLEGDEMENTS

I would like to thank the munificent employees of NTPC Faridabad for their assistance in providing valuable inputs for the report. My particular thanks to Mr. Niranjan (Manger, HR Division), Mr. Kuldeep Singh (Teaching Assistant, HR Division), Mr. Anil Garg (Manager, Switchyard), Ms. Yogita (HR Division) and Mr. Anil Khanna (DGM, NTPC) for their liberal assistance to my project.

I am very grateful to Mr. Imaad (Sr. Engineer, Control Room) for taking the pain of elucidating me about the basic modules of a power plant cycle. I would also like to express my deep gratitude to our instructor Dr. Amit Kumar Singh for his constant support, guidance and motivation that helped me immensely in completing this project report. The Practice School 1 provided me with an opportunity to new career aspects. It gave me vivid exposure to the Industrial World. I shall always remain indebted to the PS Division for this.


June 16, 2012


ABSTRACT

NTPC Limited (National Thermal Power Corporation) is the largest

Indian state-owned electric utilities company based in New Delhi,

India. The current generating capability of NTPC is 36,014 MW. It

was founded on November 7, 1975.

NTPC's core business is engineering, construction and operation of

power generating plants and providing consultancy to power utilities

in India and abroad.

The total installed capacity of the company is 36,014 MW with 15

coal based and 7 gas based stations, located across the country. The

power generation portfolio is expected to have a diversified fuel mix

with coal based capacity of around 27,535 MW, 3,955 MW through

gas, 1,328 MW through Hydro generation, about 1400 MW from

nuclear sources and around 1000 MW from Renewable Energy

Sources (RES).

This project report gives a detailed insight of different departments

at NTPC Faridabad and how they work mutually. It provides synopsis

of the functioning of various modules of the combined cycle at a gas

fired power plant. It also gives the pitch plan about my project work

at NTPC, Faridabad.

http://en.wikipedia.org/wiki/Electric_utilities

http://en.wikipedia.org/wiki/New_Delhi


June 16, 2012


NTPC, Faridabad – At a Glance

Est. 1997 this state of the art plant has production

capacity of up to 430 MW of which the utmost

beneficiary is the Haryana State.

It is an environment friendly gas fired power

generation station.

The Faridabad station is an 11,650 Cr. Project.

It runs on Natural gas as the source which is being

supplied through the HBJ Pipeline.

The Gurgaon canal acts as the source for water.

The plant has installed 2 Gas Turbines and 1

Steam Turbine.

The ST is coupled to the GT thereby its production

dependents on GT.

The plant supplies its production to the Palla and

Samaypur which further distributes it to the

different parts of Haryana state.


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Layout Plan of NTPC, Faridabad


June 16, 2012


PART B

Combined Cycle

PART C

Project seeking at

NTPC

PART A

Department Visits

Project Report 1


June 16, 2012


Table of Contents Part A 9

1. Water treatment Division 10

2. Switchyard 11

3. Fuel Storage Department 12

4. Control Room 12

5. Combined Cycle Equipments 13

6. Safety Department 14

Part B 15

1. About Combined Cycle 16

2. Compressor 17

3. Fuel 18

4. Combustion Chamber 18

5. Gas turbine 19

6. Heat Recovery Steam Generator 20

7. Steam Turbine 21

8. Steam Surfaced Condenser 22

9. Cooling Tower 23

10. De-aerator 24

Part C 25

1. Project Study plan 26

2. What is Power System stability 28

3. Components involved in Protection 29

4. Types of Protection 34

5. Protective Device Coordination 37


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PART A

DEPARTMENT VISITS


June 16, 2012


1. Water Treatment Division

This division deals in the cleansing of water coming from

canal.

Here the water is treated with Chlorine Gas to it purify

from salts and other impurities which may become a

cause of corrosion.

This type of water is called as De-Mineralized water.

Apart from this, also Gravitational and Sedimentation

methods are procured to cleanse the water coming from

canal.

It is to be realized that Chlorine leakage is Hazardous

(dealt in Safety Dept.)

Water Treatment Cell


June 16, 2012


2. Switchyard

It deals in the safe transmission of generated electrical

energy and maintenance of equipments which do the

same.

There are two Main Bus Lines to transmit the 220 KV

generated electricity to the Palla and Samaypur District

of Haryana.

Different equipments used at switchyard are CT (current

Transformer), VT (Voltage Transformer), CVT

(Capacitive Voltage transformer), Circuit Breakers

and Relays.

In case of fault, the relay sent a trip command to the

circuit breaker which in turn isolates the faulty area by

breaking the power to it.

A separate Transfer Bus is provided which is utilized in

case of maintenance work in main bus lines.

It also has a Wave trap which acts as a high pass filter for

frequency.


June 16, 2012


3. Fuel Storage Division

There are three types of fuel; Natural gas, High

Speed Diesel (HSD) and Naphtha.

The prominent use of Methane (Natural gas) is

because of low gas emissions compared to the diesel.

Also amongst all the hydrocarbons, methane is used

because of its high hydrogen to the carbon ratio

which makes it the fuel which high specific heat

capacity.

However the low use of naphtha is because of its

high cost. However during high demand even

naphtha is used.

4. Control Room (Operations Dept.)

It is the centre heart of the plant. It controls the

turbines, compressor and generators etc.

It uses software developed by Siemens which

monitors the temperature, pressure etc. of

equipments.

It reports directly to the Switchyard and Mechanical

Dept. in case of any damage.


June 16, 2012


5. Combined Cycle Equipments

It consist of two Gas Turbines (143 MW each), a Steam

Turbine (144 MW), a combustor, a compressor,

HRSG/boiler and Cooling towers.

The atmospheric air is compressed to increase its pressure as well as temperature. This air is fed into the combustor where fuel is burned

and the gas hence released rotates the GT. Whereas the hot exhaust gas released is used to heat

the water -> water vapour (in boiler/HRSG) used to rotate the ST. Generators are attached to both GT and ST. Condensers are used to condense down the vapour to

water for reuse.


June 16, 2012


6. Safety Department

This dept. is spread across the plant. It ensures the

basic safety measures need to be taken to safeguard

the plant and its employees.

The basic requirements for safety are Rubber Shoes,

Safety helmet and Safety belt.

At different places in the plant flags are positioned

which indicate the direction of air. This helps in

realising the flow of air in case of Chlorine leakage.

In such an event wearing of masks is an essential.

EPB (Emergency Push Buttons) are provided to

stop the machinery in case of an accident.

Water Pumps are installed at different parts of plant

which act on the differential pressure principle.

Foam being more reactive is used in place of water.


June 16, 2012


PART B

CORE ELEMENTS OF A COMBINED

CYCLE


June 16, 2012


About the Combined Cycle

A gas-fired combined cycle, power plant also known

as a Combined Cycle Gas Turbine.

Power Plant, combines the strengths of two thermal

processes in ideal fashion electricity production

using a

Gas turbine together with a

Steam turbine

The acronym normally used to describe this system

is CCGT.

The waste hot gases of GT act as a source for the ST.


June 16, 2012


1. Compressor

It intakes the atmospheric air via a filter. This air is

further compressed so as to increase its pressure as well

as temperature.

This is done with help of Rotors and Stators.

Stators or Stationary Blades are stationed. They are

made of special air foil shape which helps in passage air

from one stator to another.

Rotors or Rotating Blades increment the Kinetic Energy

of passing air so that its pressure energy increases.

The compressor has inlet guide vanes which control the

amount of air entering.


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2. Fuel

There are three types of fuel: Natural gas, High

Speed Diesel and Naphtha.

The Natural gas being less gas effluent than HSD is

prominently used.

Also it is the fuel with highest specific heat

capacity.

Also it is quite cheaper than Naphtha.

3. Combustion Chamber

The pressurized air is fed to the combustion

chamber, where along with the fuel is ignited.

The combustion products are Hot exhaust gases.

These gases are fed in to the Gas turbine.


June 16, 2012


4. Gas Turbine

The gas turbine at NTPC is manufactured by

Ansaldo and runs on the license provided by

Siemens.

It weighs about 300 tons and generates power of

about 143 MW.

The gas is allowed to expand through the turbine

thus the pressure energy of gas acts as a source of

mechanical rotation of the turbine.

This rotation powers not only generator but the

compressor as well. The compressor consumes

nearly 60 % of the total output.

These turbines account for 2/3 of the total output

of the plant.


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5. Heat Recovery Steam Generator (Boiler)

The hot gases ejected from the turbine are left with

no more of pressure energy.

They can either be ejected out through stacks or

can be harnessed to produce another source for

mechanical rotation.

The only good thing left with these gases is heat i.e.

it is at a high temperature.

Thus this is fed into the HRSG, which is a reservoir

of water. This water is heated by these gases which

in turn produces steam.

This boiler is divided in three segments of

pressure so that maximum energy can be

obtained from it.

Thus the steam is further fed into the ST.


June 16, 2012


6. Steam Turbine

The gases released from HRSG are fed into the ST.

The STs at NTPC are manufactured by Ansaldo

under license by BBC.

The ST has a production capacity of 144 MW.

The steam expands through the turbine. The

turbine thus rotates and generates power through

generator.

The ST is a multi shaft turbine so that maximum

power can be harnessed.

ST contributes the 1/3 of total power

production.


June 16, 2012


7. Steam Surfaced Condenser

The steam released from the ST has no more

pressure energy. The only possible task is to

condense it back to water so that it can be reused in

HRSG to give steam.

Cold water can be sent through the tubes. These

absorb the heat from steam, thus condensing it t form

a condensate.

This condensate is also called “Hot” well. This is so

because the steam is heated to a temperature just

below steam temperature. so that water condensed is

hot. This water is sent back to HRSG which heats it to

steam. Thus by this comparatively less hot gases are

required to heat it.

The hot water ejecting from condenser is sent to

cooling tower to cool it down..


June 16, 2012


8. Cooling Tower

It is used to remove waste heat to the atmosphere.

It is of two types:


June 16, 2012


9. De-aerator

There may be a leakage in pipeline due to which

gases like oxygen and carbon dioxide might leak in.

These gases are cause for corrosion of pipes. Also

they are non condensable.

Removal of such gases is essential. Thus, the de-

aerator achieves this task.

A pure steam is at its saturation temperature is fed

from bottom. By the Henry’s law, the solubility of

gas decreases as the temperature of solution

increases. Thus the impure steam is fed from top and

except steam other gases in dissolve and is release

to the atmosphere.

Finally we obtain a pure steam which is fed into the

condenser.

Non De-aerated Steam

Non Condensable gases

Pure Steam

De-aerated water


June 16, 2012


PART C

PROJECT SEEKING AT NTPC FARIDABAD

PROJECT TITLE

GENERATION AND TRANSMISSION

PROTECTION SYSTEMS

AT NTPC, FARIDABAD


June 16, 2012


Project Study Plan:

Studying the types of Generation and

Transmission Instabilities (tripping)

Collecting data corresponding to power

system instabilities

Analyzing data Collected and studying the

cause for instabilities

Methods to eliminate the power system

instabilities


June 16, 2012


The Generator and Transmission Protection System

shall be my topic for Project Report 2. The study plan

for the same is mentioned above. The project would

involve the collection of data and understanding

about the types of instabilities at any power station

and how to eradicate such futile technical snags. This

would require collection of data from control room

and switchyard, thus further analyzing them.

Following sections elucidate the study work

completed till now.


June 16, 2012


1. What is a Power System Stability

When a power system operating under a steady load condition

is perturbed, causing the readjustment of the voltage angles of

the synchronous machines. If such an occurrence creates an

unbalance between the system generation and load, it results in

the establishment of a new steady-state operating condition,

with the subsequent adjustment of the voltage angles.

The perturbation could be a major disturbance such as the loss

of a generator, a fault or the loss of a line, or a combination of

such events. It could also be a small load or random load

changes occurring under normal operating conditions.

Adjustment to the new operating condition is called the

transient period. The system behavior during this time is called

the dynamic system performance, which is of concern in

defining system stability.

Power system protection deals with the protection of electrical

power systems from faults through the isolation of faulted parts

from the rest of the electrical network. The intent of a protection

scheme is to keep the power system stable by isolating only the

components that are under fault, whilst leaving as much of the

network as possible still in operation.

http://en.wikipedia.org/wiki/Fault_(power_engineering)

http://en.wikipedia.org/wiki/Grid_(electricity)


June 16, 2012


2. Components Involved In Protection

Current and Voltage Transformers

A transformer transfers electrical Energy from one circuit

to another through inductively coupled conductors. A

varying magnetic field in primary windings introduces

varying voltage or current in the secondary windings.

These transformers thus step up/down the

voltage/current to a stipulated level which can be dealt by

a protective relay.


June 16, 2012


Protective Relays

It is an electromechanical device which is designed to

calculate operating conditions on an electric circuit and trip

the circuit breakers in case of any fault.

Types:

a) Over current Relay- It operates when the current

surpasses a preset value. On initiation, it energizes one

or more contacts to trip the circuit breaker.

b) Distance Relay- This is used for protection of high

voltage transmission systems is distance relay

protection. Power lines have set impedance per km and

using this value and comparing voltage and current the

distance to a fault can be determined.

c) Current Differential- Another common form of

protection for apparatus such as transformers,

generators, busses and power lines is current

differential. This type of protection works on the basic


June 16, 2012


theory of Kirchhoff's current law which states that the

sum of the currents entering and exiting a node will

equal zero. It is important to note the direction of the

currents as well as the magnitude, as they are vectors. It

requires a set of current transformers (smaller

transformers that transform currents down to a level

which can be measured) at each end of the power line,

or each side of the transformer. The current protection

relay then compares the currents and calculates the

difference between the two.

Circuit Breakers

Its basic function is to detect a fault condition and,

by interrupting continuity, to immediately

discontinue electrical flow. Unlike a fuse, which

operates once and then must be replaced, a circuit

breaker can be reset (either manually or

automatically) to resume normal operation.

http://en.wikipedia.org/wiki/Fuse_(electrical)


June 16, 2012


Types:

a) Low Voltage Circuit Breaker- Includes Miniature

Circuit Breaker, which adhere to read current of more

than 100 Amps.

b) Magnetic Circuit Breaker- The circuit breaker

contacts are held closed by a latch. As the current in

the solenoid increases beyond the rating of the circuit

breaker, the solenoid's pull releases the latch, which

lets the contacts open by spring action.


June 16, 2012


c) Thermal Magnetic Circuit Breaker- They

incorporate both techniques with the electromagnet

responding instantaneously to large surges in current

(short circuits) and the bimetallic strip responding to

less extreme but longer-term over-current conditions.

d) Medium Voltage Circuit Breaker- Rated between 1

and 72 kV may be assembled into metal-enclosed

switchgear line ups for indoor use, or may be

individual components installed outdoors in

a substation.

e) High Voltage Circuit Breaker- High-voltage

breakers are nearly always solenoid-operated, with

current sensing protective relays operated through

current transformers.

Batteries

They provide power to power system in case of power

disconnection due to trips.

Communication Channel

It consists of a power line carrier or pilot wire to provide

a high data transfer reliably. These days a fiber optic pair

available for exclusive use by the relays provides optimal

performance for digital communications.

http://en.wikipedia.org/wiki/Electrical_substation

http://en.wikipedia.org/wiki/Solenoid

http://en.wikipedia.org/wiki/Protective_relay

http://en.wikipedia.org/wiki/Current_transformer


June 16, 2012


3. Types of protection

Generator sets – In a power plant, the protective relays

are intended to prevent damage to alternators or to

the transformers in case of abnormal conditions of

operation. Such failures are unusual, so the protective

relays have to operate very rarely. If a protective relay fails

to detect a fault, the resulting damage to the alternator or

to the transformer might require costly equipment repairs

or replacement, as well as income loss from the inability to

produce and sell energy.

High voltage transmission network – Protection

on the transmission and distribution serves two functions:

Protection of plant and protection of the public (including

employees). At a basic level, protection looks to

disconnect equipment which experiences an overload or a

short to earth. Some items in substations such as

transformers might require additional protection based on

temperature or gas pressure, among others.

Overload & Back-up for Distance (Over current) – Overload protection requires a current

transformer which simply measures the current in a

circuit. There are two types of overload protection:

instantaneous over current and time over current (TOC).

Instantaneous over current requires that the current

exceeds a pre-determined level for the circuit breaker to

operate. TOC protection operates based on a current vs.

http://en.wikipedia.org/wiki/Alternator

http://en.wikipedia.org/wiki/Transformer


June 16, 2012


time curve. Based on this curve if the measured current

exceeds a given level for the preset amount of time, the

circuit breaker or fuse will operate.

Earth fault – Earth fault protection again requires

current transformers and senses an imbalance in a three-

phase circuit. Normally the three phase currents are in

balance, i.e. roughly equal in magnitude. If one or two

phases become connected to earth via a low impedance

path, their magnitudes will increase dramatically, as will

current imbalance. If this imbalance exceeds a pre-

determined value, a circuit breaker should operate.

Distance (Impedance Relay) – Distance protection

detects both voltage and current. A fault on a circuit will

generally create a sag in the voltage level. If the ratio of

voltage to current measured at the relay terminals, which

equates to impedance, lands within a pre-determined level

the circuit breaker will operate. This is useful for

reasonable length lines, lines longer than 10 miles,

because its operating characteristics are based on the line

characteristics. This means that when a fault appears on

the line the impedance setting in the relay is compared to

the apparent impedance of the line from the relay

terminals to the fault. If the relay setting is determined to

be below the apparent impedance it is determined that

the fault is within the zone of protection. When the

transmission line length is too short, less than 10 miles,

distance protection becomes more difficult to coordinate.


June 16, 2012


In these instances the best choice of protection is current

differential protection.

Back-up – The objective of protection is to remove only

the affected portion of plant and nothing else. A circuit

breaker or protection relay may fail to operate. In

important systems, a failure of primary protection will

usually result in the operation of back-up protection.

Remote back-up protection will generally remove both the

affected and unaffected items of plant to clear the fault.

Local back-up protection will remove the affected items of

the plant to clear the fault.

Low-voltage networks – The low voltage network

generally relies upon fuses or low-voltage circuit breakers

to remove both overload and earth faults.


June 16, 2012


4. Protective Device Coordination

Where there are two or more series protective

devices between the fault point and the power

supply, these devices must be coordinated to

ensure that the device nearest the fault point will

operate first. The other upstream devices must be

designed to operate in sequence to provide back-up

protection, if any device fails to respond. This is

called selective coordination. To meet this

requirement, protective devices must be rated or

set to operate on minimum over current, in

minimum time, and still be selective with other

devices on the system. When the above objectives

are fulfilled, maximum protection to equipment,

production, and personnel will be accomplished.

The End


June 16, 2012


Thank You

project report 1 bits pilani

Documents

amit kumar

main bus lines

high speed

power system

power lines

combined cycle

total output

generates