This document is an industrial training report submitted by Harsh Kumar Gautam to the Department of Electrical and Electronics Engineering at KIET Group of Institutions. The report provides an overview of Harsh Kumar Gautam's 6-week training at Bharat Electronics Limited (BEL) in Ghaziabad, India. It includes details about BEL such as its history, units, mission, policies, awards, and research and development activities. It also describes some of the electrical equipment observed and learned about during the training, including radars, power systems, transformers, generators, and circuit breakers.

1. 1
(SESSION 2017-2018)
DEPARTMENT OF ELECTRICAL & ELECTRONICS
ENGINEERING
INDUSTRIAL TRAINING REPORT
SUBMITTED IN PARTIAL FULFILLMENT OF THE REQUIREMENT
FOR THE DEGREE OF BACHELOR OF TECHNOLOGY (DEPARTMENT
OF ELECTRICAL & ELECTRONICS ENGINEERING)
KIET GROUP OF INSTITUTIONS
Department of Electrical and Electronics Engineering
Submitted To:
Prof. Rahat Ullah Khan
Submitted by:
Harsh Kumar Gautam
1402921073

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TABLE OF CONTENT
1. Company profile of BEL 5
1.1. The Industry 5
1.2. Various Units 6
1.3. Corporate Motto 6
1.3.1. Corporate Objective 7
1.3.2. Quality Policy 8
1.3.2. Quality Objectives 8
2. Awards won by BEL 10
3. BEL Ghaziabad 11
4. RADAR 12
4.1. Application of RADAR 12
4.2. Working of simple RADAR 12
5. Central Services (Electrical) 14
6. Protection schemes of Power System 15
6.1.Components 15
6.2.Protective devices 15
6.3.Types of protection 16
6.4. Coordination 17
6.5. Disturbance monitoring equipment 17
6.6. Performance measures 18
7. Ring Main System 20
8. Transformer 21
8.1. Step-up Transformer 21
8.2. Step-Down Transformer 22
8.3. Protection (Buchholz Relay) 22
9. Generator 24
9.1. Diesel Generator 24
10. Circuit Breaker 25
10.1. Vacuum circuit breaker 25
10.2. AIR circuit breaker 28
11. Magnetics Department 31
12. Conclusion 33

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LIST OF FIGURES
8.1 Transformation Operation 23
8.2 Step Up transformer 24
8.3 Step Down transformer 25
9.1 Electric Generator 28
9.2 Diesel Generator 28
10.1 Circuit Breaker 29
10.2 Vacuum Circuit Breaker Operation Diagram 31
10.3 Vacuum Circuit Breaker 31
10.4 Construction of Air Blast Circuit Breaker 32
10.5 Air Circuit Breaker 32

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ACKNOWLEDGEMENT
I am highly grateful to Bharat Electronics Limited Ghaziabad, one of the leading defense
organization of the nation, for providing me an opportunity to undertake six weeks training at their
manufacturing premises at Ghaziabad. It was a great learning experience as I was introduced to
various aspects of the working of the organization, the latest state of the art technologies &
machines used in the manufacturing processes. It was wonderful to see the company striving hard
to keep the national security at par with the rest of the world. I would like to express my sincerest
gratitude towards Mr. Mohan Lal (Deputy Manager, Central Services) for his regular support and
guidance that helped me in successful completion of my six weeks training. At the end I would
like to thank all the staff members of BEL, Ghaziabad who made this training a rich learning
experience.
Harsh Kumar Gautam
UPT NO.: 231/B.TECH

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CERTIFICATE
This is to certify that MR. HARSH KUMAR GAUTAM, student of B.TECH (Electrical
Engineering), KRISHNA INSTITUTE of ENGINEERING and TECHNOLOGY,
Ghaziabad successfully completed her training in BHARAT ELECTRONICS LIMITED,
GHAZIABAD from 19th June 2017 to 05th Aug 2017.
Project “THE STUDY OF POWER SYSTEM OF BHARAT
ELECTRONICS LIMITED, GHAZIABAD” was assigned to her. In this period she worked
hard and made valuable contribution in developing the project. All her work is genuine and original
and was timely completed.
Deputy Manager (Central Services)
Mr. Mohan Lal

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CHAPTER 1
COMPANY PROFILE OF BHARAT ELECTRONICS LIMITED.
1.1 THE INDUSTRY
BEL was established in 1954 as a Public-Sector Enterprise under the administrative control of
Ministry of Defense as the fountainhead to manufacture and supply electronics components and
equipment. BEL, with a noteworthy history of pioneering achievements, has met the requirement
of the state of— art professional electronic equipment for defense , broadcasting, civil defense
and telecommunication as well as the component requirement of entertainment and chemical X-
ray industry. Over the years BEL has grown to a multi-product, multi-unit and technology driven
company with track record of profit earning PSU.
BEL was born to meet the growing needs of Indian Defense Services for electronic
systems. Employing the best engineering talent available in the country. BEL as progressed
manufacturing state-of-the-art products in the field of Defense Electronics like communications
involving encryptions, Radars and strategic components.
Over the years, BEL has diversified to meet the needs of civilian customers as well and
has provided products and network solutions on turnkey basis to consumers in India and abroad.
With the Research and Development efforts, its engineers have fructified it into a world
class organization. The company has a unique position in India of having dealt with all the
generations of electronic component and equipment. Having started with the HF receiver and
collaboration with T-CSF of France, the company’s equipment designs have had a long voyage
through the hybrid, solid-state discrete component to the state-of-art integrated circuit technology.
In the component arena also the company established its own electronic valve manufacturing
facility. It moved on to semiconductors with the manufacture of germanium and silicon devices
and then to manufacture the Integrated circuits. To keep in pace with the component and equipment
technology, its manufacturing and product assurance facilities have also undergone a sea change.
The design group has Cad’s facilities, the manufacturing has CNC machines and a Mass
Manufacture Facilities and QC checks are performed with multi-dimensional profile measurement
machines. Automatic testing machines, environmental labs to check the weather and other

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operational conditions there. All these facilities have been established to meet the stringent
requirements of MIL grade systems.
Today BEL’s infrastructure is spread over nine locations with 29 production
systems having ISO-900119002 accreditation. Product mix of the company are spread over the
entire electromagnetic (EM) spectrum ranging from tiny audio frequency semiconductor to a huge
RADAR systems and X-ray tubes on the upper edge of the spectrum. Its manufacturing units have
special focus towards the product ranges like defense communications, radars, optical and opto-
electronics, telecommunications, sound and vision broadcasting, electronic components, etc.
Besides the manufacturing and supply of a wide variety of products, BEL offers a
variety of services like Telecom and Radar Systems Consultancy, Contact Manufacturing,
Calibration of test and measuring instruments, etc. At the moment the company is installing MSSR
radar at important airports under the modernization of airports plan of National Airport Authority
(NAA).
BEL has nurtured and build a strong in-house R&D base by absorbing technologies
from more than 50 leading companies worldwide and DRDO labs for a wide range of products. A
team of more than 800 engineers is working in R&D. Each unit has its own R&D division to bring
out new products to the production lines. Central Research Laboratory (CRL) at Bangalore and
Ghaziabad works as independent agency to undertake contemporary design works on the state-of-
art futuristic technologies. About 70% of BEL’s products are of in-house design.
BEL was amongst the first Indian companies to manufacture computer parts and
peripherals under arrangement with International Computers India Limited (ICIL)in 1970’s. BEL
assembled a limited number of 1901 systems under the arrangement of ICIL. However, following
government’s decision to restrict the computer manufacture to ECIL, BEL could not progress in
its computer manufacturing plans.
1.2 VARIOUS UNITS
Its corporate office is at Bangalore. Bangalore complex is the BEL’s first and largest unit and it
accounts for two-thirds of both the companies turnover and manpower. This unit’s the product
range covers over 300 Defense and Civilian products.

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Ghaziabad is the second largest unit of BEL and it specializes in RADARS, COMMUNICATION
EQUIPMENTS AND MICROWAVE COMPONENTS.
In total BEL has 9 units. These are distributed all over the India as:
1. BANGALORE (Corporate office)
2. GHAZIABAD
3. PANCHKULA
4. MACHILIPATNAM
5. PUNE
6. HYDERABAD
7. CHENNAI
8. KOTDWARA
9. TALOJA
The passionate pursuit of excellence at BEL is reflected in are pulsion with its customers that can
be described in its motto, mission and objectives:
1.3 CORPORATE MOTTO
“Quality, Technology and Innovation”
CORPORATE MISSION
To be the market leader in Defense Electronics and in other chosen fields and products.
1.3.1 CORPORATE OBJECTIVES
• To become a customer driven company supplying quality products at a competitive price
at expected time and providing excellent customer support.
• To achieve growth in the operations commensurate with the growth of professional
electronics industry in the country.
• To internal resources of financing the investments required for modernization, expansion
and growth for ensuring a fair return to the investor.
• In order to meet the Nation’s strategic needs, to strive for self-reliance by indigenization
of materials and components.
• To retain the technological leadership of the company in Defense and other chosen fields
of electronics through in house in research development as well as through

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collaboration/co-operation with Defense /National Research Laboratories, International
Companies, Universities and Academic institutions.
• To create an organizational culture, which encourages members of the organization to
realize their full potential through continuous learning on the job and through other HRD
initiatives?
1.3.2 QUALITY POLICY
BEL is committed to consistently deliver enhanced value to our customers, through continual
improvement of our products and processes.
1.3.3 QUALITY OBJECTIVES
1. Effective and efficient design and development process, considering the present and future needs
of customers.
2. Enhanced customers satisfaction by on time delivery of defect fee products and effective life
cycle support.
3. Continual upgradation and utilization of infrastructure and human resources.
4. Mutually beneficial alliances with suppliers.
5. Continual improvement of processes through innovation, technology and knowledge
management.
The management of BEL is convinced of the need of quality enhancement, on a continuous basis,
in the company. The need was felt to impart Education I Training to all the officers on the basis of
facts of quality management. Accordingly, an institute called Bharat Electronics Quality Institute
(BEQI) was established in 1999.
Regular training programs are conducted for all employees working in different units of the
company. Business. Excellence models being followed by different organizations are studied and
efforts are made to implement the best possible in the functioning of the organization.
Bharat Electronics Ltd. (BEL), a premier Professional Electronics Company of India, has
established and nurtured a strong-in-house R&D base over the years to emerge and remain as a
market leader in the chosen areas of business in professional electronics. Each of the nine
manufacturing units of BEL is having its own house R&D Division to develop new products in its
field of operations. Besides, there are two Central Research Laboratories (CRL) located at
Bangalore and Ghaziabad, to address futuristic technologies of interest of BEL.
Main areas of R&D activities of BEL include development of military radars, naval systems,
military communication products, electronic warfare systems, telecommunication products, sound
and vision broadcasting equipment and systems, opto-electronic products, and electronic
components. CRLperforms the dual role carrying out blue sky research for the development of

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future technologies and supporting the D&E Divisions of BEL’s nine units of state of the art core
technology solutions in areas like Embedded computers and applications, Radar Signal Processing,
VLSI designs, RE and microwave communication technologies, software modules etc.
BEL’s R&D Units have state of art R&D infrastructure, facilities, and manpower with relevant
technical expertise for product development. There are about 1000 engineers working in BEL on
various D&E projects. BEL spends around 5% of company turnover for the year on R&D every
year. HRD divisions of BEL take adequate initiatives for the all round development and expertise
up gradation of R&D human resources. State of the art infrastructure, test equipments, computers
and work stations, software packages etc. are augmented every year for the R&D Divisions. BEL
R&D units are recognized by the department of scientific and industrial research under the ministry
of science and technology. Government of India.
R&D Units of BEL have close interactions with other National Design Agencies like DRDO,
CSIR, C-DOT and a no. of technical institutes. BEL jointly works with them to tap suitable
indigenous designs for commercialization. Technological collaborations with some of the
Multinational companies and subsequent absorption of these technologies also have enhanced the
technological base of BEL. On an average, about 67% of BEL’S turnover is from indigenous
design, and 33% of it is through foreign technology transfers.
List of world class companies with whom BEL has technological collaborations for different state
of the art products are as given below:

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CHAPTER 2
AWARDS WON BY BEL
R&D Division of BEL have been receiving number of National R&D awards. A list of showing
various R&D awards received by BEL since 1990 is as given below:
1. FICCI award for Research in Science and Technology1990 (for the corporate initiative of
R&D).
2. DSIR National R&D award 1992.
(for successful commercialization of Public Funded R&D).
(for D&E project handled at BEL-GAD).
3. DSIR National R&D award 1993.
(for in house R&D efforts under Electronics and Electrical Industries sector).
(for D&E projects handled at BEL-Bangalore, Machilipatnam& Ghaziabad).
4. DSIR National R&D award 1995.
(for in house R&D efforts under Electronics Industries Sector).
(for D&E projects handled at BEL-Bangalore & Ghaziabad).
5. DSIR National R&D Award 1998.
(for successful commercialization of Public Funded R&D).
(for D&E projects handled at BEL-Bangalore and Panchkula).
6. Defense Technology Absorption Award ’98 1999-2000’
(sponsored by DRDO).
(for D&E projects handled at BEL-Hyderabad).
7. Award for excellence in R&D for the year 1998, 2000, 2001.
(sponsored by Ministry of Information Technology, Gol)
(for BEL Ghaziabad’s developments of various 1FF systems).
8. Award for Excellence in Professional Electronics 2000-2001, for the year 1998.
(sponsored by Ministry of Information Technology, Gd).
(for BEL-KOT’s excellent performance in Production, R&D and its commitment to Quality and
Service).
9. Award for contribution in areas of Defense and R&D 2001-2002 To Col. Retd.)
H.S. Shankar, Director (R&D) for the year 2001-2002
(sponsored by Society of Defense Technologists—SODET).

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CHAPTER 3
BEL GHAZIABAD
The second largest Unit at Ghaziabad was set up in 1974 to manufacture special types of Radars
for the Air Defense Ground Environment Systems (Plan ADGES). The Unit provides
Communication Systems to the defense forces and Microwave Communication Links to the
various departments of the State and central govt. and other users. The Unit’s products range
included Static and Mobile Radars, troposcatter equipment, professional grade Antennae and
Microwave components.

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CHAPTER 4
RADAR
RADAR is an abbreviation of word RADIO DETECTING AND RANGING. It is an
electromagnetic system for detection and location of object. It operates by transmitting a particular
type of waveform.
An elementary form of radar consists of a transmitting antenna emitting electromagnetic radiation
generated by an oscillator, receiving antenna, and an energy detecting device or receiver. A
position of the transmitted signal is intercepted by a reflecting object (target) and is reradiated in
all the directions. The receiving antenna connects the returned energy and delivers it to the
receiver, where it is processed. The distance to the target is determined by measuring the time
taken by the radar signal to travel and come back. The direction or angular position of the target
may be determined from the detection of arrival of the reflected wavefront.
4.1 APPLICATION OF RADAR . RADAR has been employed on the ground, in air, on
the sea and in space. Some important areas of applications are:
• Air traffic control (ATC)
• Aircraft navigation
• Ship safety
• Space
• Remote Sensing
• Military
4.2. WORKING OF A SIMPLE RADAR
A simple RADAR system, as found on many merchant ships, has three main parts. They are:
1. Antenna unit or the scanner
2. the transmitter/receiver or transceiver and the visual display unit.
The antenna is about 2 or 3 meters wide and focuses the pulses of every high frequency radio
energy into a narrow vertical beam. The frequency of the radio waves is usually about 10,000
MHz. The antenna is rotated at the speed of 10 to 25 revolutions per minute so that the radar beam
sweeps through 300 degrees all around the ship out to a range of about 90 kilometers.
In all the radars it is vital that the transmitting and receiving in the transceiver are in close harmony.
Everything depends on accurate measurement of time which passes between the transmission of
the pulse and return of the ECHO about 1000 pulses per second are transmitted. Though it is varied
to suit requirement. Short pulses are best for short range work, longer pulses are better for longer
range.
An important part of the transceiver is the modulator circuit. This keys the transmitter so that it
can oscillate, or pulses, for exactly the right length of time. The pulses so generated are video
pulses. These pulses are short range pulses and hence cannot serve out long distance

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communication. In order to modify these pulses into radio frequency pulses, we need to generate
power. The transmitted power is generated in device called magnetron, which can handle these
very short pulses and very high oscillations.
Between each pulse, the transmitter is switched off and isolated. The weak echoes from the target
are picked up by the antenna and fed into the receiver. To avoid overlapping of these echoes with
the next transmitted pulse, another device called duplexer is used. Thus by means of duplexer,
undisturbed, two-way communication is established. The RF echoes emerging from the duplexer
are now fed into the mixer when they are mixed with pulses of RF energy. These pulses are
generated by means of a local oscillator. Once the two are mixed, a signal is produced in the output
which is of intermediate frequency range. The 1F signals is received by a receiver where it is
demodulated to video frequency range, amplified, and then passed to the displayed unit.
The display unit usually carried all the controls necessary for the operation of the whole radar. It
has a cathode ray tube, which consists of an electron gun in its neck. The gun shoots a beam of
electron at a phosphorescent screen at the far end. The phosphorescent screen glows when hit by
the electrons, the resulting spot of light can be seen through a glass surface. The screen is circular
and is calibrated in degrees around its edge. The electron beam travels out from the center to the
edge. This random motion of the electron beam, known as the trace, is matched with the rotation
of the antenna. So when the trace is at zero degrees on the tube calibration, the antenna is pointing
dead ahead. The beginning of each trace corresponds exactly at the moment at which the radar
energy is transmitted.
When an echo is received it brightens up the trace for a moment. This is a blip, and its distance
from the center of the tube corresponds exactly with the same time taken for the radar pulse to
travel to the target and return. So that blip of the screen gives the range and bearing of the target.
As the trace rotates, a complete picture is build up from the coating of the tube. This type of display
is called PPI (plane position indicator) and is the most common form of presenting radar
information.

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CHAPTER 5
CENTRAL SERVICES(ELECTRICAL)
The main task of this department is to supply power to all the production units, administrative
block and other parts of the factories. This department is arranged into one main station and five
substations located in the company. The power is received by the Uttar Pradesh Vidyut Board
through 33KV power line at the main station.
At the main station the power is stepped down to 11KV using 33/11KV step down transformer.
The main switch is provided with the gang operated switch, air circuit breakers (ACB), oil circuit
breaker (OCB). The air circuit breaker being used is of rating 11000V 800A. The gang operated
switch is to be operated always OFF-load. This is operated when there is some fault in the incoming
power line. In case we operate the operated switch ON-load, large amount of sparks will be
produced. There are two transformers at the main station. Out of these two only one is used at the
time and second one is standby transformer i.e. it is operated in case when first transformer does
not work properly. Current transformers are used at the main station for the measurement of the
power consumption. Lightening arrestors are used at the main station to protect the station and all
the electrical equipments from being damaged. For extra security, two different set of lightening
arrestors are used one above the other so that the station is not damaged at any cost and the excess
charge gets grounded.
There are five substations at BEL which receive the power from main station at 11KV and stepped
down to 433V for the use of various machines in the factory. The transformers being used at
various sub stations are of rating 1600 KVA. These sub stations provide power to different
divisions of the factory. Like the main station these stations are also provided with lighting
arrestors. ACB’s, OCB’s, and gang operated switches.
In case of power failure these are two generators, which can provide to production divisions only,
and some other important section . These generators are imported from Czechoslovakia and are of
ascorda make. These generators are air starting type and need a pressure of 1000 pound for starting.
These can develop a power of 325 bhp. And consume 400 Litres/Hr. of diesel each. Each generator
is having 6 cylinders. These have a firing order of 15-36-24 to operate the cylinders in the same
order. These are of capacity 860 KV and each generator generates 400V at 50 Hz.This voltage is
stepped up by a transformer to11KV and supplied to the sub stations.

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CHAPTER 6
PROTECTION SCHEME OF POWER SYSTEM
Power-system protection is a branch of electrical power engineering that deals with the protection
of electrical power systems from faults through the isolation of faulted parts from the rest of
the electrical network. The objective 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. Thus, protection schemes must apply with very pragmatic and
pessimistic approach to clearing system faults. The devices that are used to protect the power
systems from faults are called protection devices.
6.1 COMPONENTS
Protection systems usually comprise five components:
• Current and voltage transformers to step down the high voltages and currents of the
electrical power system to convenient levels for the relays to deal with.
• Protective relays to sense the fault and initiate a trip, or disconnection, order;
• Circuit breakers to open/close the system based on relay and auto recloser commands;
• Batteries to provide power in case of power disconnection in the system.
Communication channels to allow analysis of current and voltage at remote terminals of a line and
to allow remote tripping of equipment.
For parts of a distribution system, fuses are capable of both sensing and disconnecting faults.
Failures may occur in each part, such as insulation failure, fallen or broken transmission lines,
incorrect operation of circuit breakers, short circuits and open circuits. Protection devices are
installed with the aims of protection of assets, and ensure continued supply of energy.
Switchgear is a combination of electrical disconnect switches, fuses or circuit breakers used to
control, protect and isolate electrical equipment. Switches are safe to open under normal load
current, while protective devices are safe to open under fault current.
6.2. PROTECTIVE DEVICE
• Protective relays control the tripping of the circuit breakers surrounding the faulted
part of the network

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• Automatic operation, such as auto-re-closing or system restart
• Monitoring equipment which collects data on the system for post event analysis
While the operating quality of these devices, and especially of protective relays, is always
critical, different strategies are considered for protecting the different parts of the system.
Very important equipment may have completely redundant and independent protective
systems, while a minor branch distribution line may have very simple low-cost protection.
There are three parts of protective devices:
• Instrument transformer: current or potential (CT or VT)
• Relay
• Circuit breaker
Advantages of protected devices with these three basic components include safety,
economy, and accuracy.
• Safety: Instrument transformers create electrical isolation from the power system,
and thus establishing a safer environment for personnel working with the relays.
• Economy: Relays are able to be simpler, smaller, and cheaper given lower-level
relay inputs.
• Accuracy: Power system voltages and currents are accurately reproduced by
instrument transformers over large operating ranges.
6.3. 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, due to
internal failures, as well as insulating failures or regulation malfunctions. 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

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employees). At a basic level, protection looks to disconnect equipment which experience
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 and back-up for distance (overcurrent) – Overload protection requires a
current transformer which simply measures the current in a circuit. There are two types of
overload protection: instantaneous overcurrent and time overcurrent (TOC).
Instantaneous overcurrent requires that the current exceeds a predetermined level for the
circuit breaker to operate. TOC protection operates based on a current v/s 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 ("ground fault" in the United States) – 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. Restricted earth fault protection is a
type of earth fault protection which looks for earth fault between two sets current
transformers (hence restricted to that zone).
• 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 an impedance, lands within a
predetermined 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. In these instances the best choice of protection is current
differential protection.

19. 19
• 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.
6.4 COORDINATION
Protective device coordination is the process of determining the "best fit" timing of current
interruption when abnormal electrical conditions occur. The goal is to minimize an outage to the
greatest extent possible. Historically, protective device coordination was done on translucent log–
log paper. Modern methods normally include detailed computer based analysis and
reporting.Protection coordination is also handled through dividing the power system into
protective zones. If a fault were to occur in a given zone, necessary actions will be executed to
isolate that zone from the entire system. Zone definitions account for generators, buses,
transformers, transmission and distribution lines, and motors. Additionally, zones possess the
following features: zones overlap, overlap regions denote circuit breakers, and all circuit breakers
in a given zone with a fault will open in order to isolate the fault. Overlapped regions are created
by two sets of instrument transformers and relays for each circuit breaker. They are designed for
redundancy to eliminate unprotected areas; however, overlapped regions are devised to remain as
small as possible such that when a fault occurs in an overlap region and the two zones which
encompass the fault are isolated, the sector of the power system which is lost from service is still
small despite two zones being isolated.
6.5. DISTURBANCE MONITORING EQUIPMENT
Disturbance-monitoring equipment (DME) monitors and records system data pertaining to a fault.
DME accomplish three main purposes:
• model validation,
• disturbance investigation, and
• assessment of system protection performance.
DME devices include:
• Sequence of event recorders, which record equipment response to the event.
• Fault recorders, which record actual waveform data of the system primary voltages and
currents.

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• Dynamic disturbance recorders (DDRs), which record incidents that portray power system
behavior during dynamic events such as low frequency (0.1 Hz – 3 Hz) oscillations and
abnormal frequency or voltage excursions.
6.6. PERFORMANCE MEASURES
Protection engineers define dependability as the tendency of the protection system to operate
correctly for in-zone faults. They define security as the tendency not to operate for out-of-zone
faults. Both dependability and security are reliability issues. Fault tree analysis is one tool with
which a protection engineer can compare the relative reliability of proposed protection schemes.
Quantifying protection reliability is important for making the best decisions on improving a
protection system, managing dependability versus security tradeoffs, and getting the best results
for the least money. A quantitative understanding is essential in the competitive utility industry.
Performance and design criteria for system-protection devices include reliability, selectivity,
speed, cost, and simplicity.
Reliability: Devices must function consistently when fault conditions occur, regardless of possibly
being idle for months or years. Without this reliability, systems may result in high costly damages.
Selectivity: Devices must avoid unwarranted, false trips.
Speed: Devices must function quickly to reduce equipment damage and fault duration, with only
very precise intentional time delays.
Economy: Devices must provide maximum protection at minimum cost.
Simplicity: Devices must minimize protection circuitry and equipment.

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CHAPTER 7
RING MAIN SYSTEM
In electricity supply, a ring final circuit or ring circuit (often incorrectly called a ring main or
informally a ring) is an electrical wiring technique developed and primarily used in the United
Kingdom. This design enables the use of smaller-diameter wire than would be used in a radial
circuit of equivalent total current. Flexible cords connected between appliance and plugs intended
for use with sockets on a ring circuit are individually protected by a fuse in the plug.
Ideally, the ring circuit acts like two radial circuits proceeding in opposite directions around the
ring, the dividing point between them dependent on the distribution of load in the ring. If the load
is evenly split across the two directions, the current in each direction is half of the total, allowing
the use of wire with half the current-carrying capacity. In practice, the load does not always split
evenly, so thicker wire is used.

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CHAPTER 8
TRANSFORMERS
A transformer is an electrical device that transfers electrical energy between two or more circuits
through electromagnetic induction. Electromagnetic induction produces an electromotive force
within a conductor which is exposed to time varying magnetic fields. Transformers are used to
increase or decrease the alternating voltages in electric power applications. A varying current in
the transformer's primary winding creates a varying magnetic flux in the transformer core and a
varying field impinging on the transformer's secondary winding. This varying magnetic field at
the secondary winding induces a varying electromotive force (EMF) or voltage in the secondary
winding due to electromagnetic induction. Making use of Faraday's Law (discovered in 1831) in
conjunction with high magnetic permeability core properties, transformers can be designed to
efficiently change AC voltages from one voltage level to another within power networks.
Fig. 8.1. Transformer Operation
8.1 STEP-UP TRANSFORMER
A step-up transformer is the direct opposite of a step-down transformer. There are many turns on
the secondary winding than in the primary winding in the step-up transformers. Thus, the voltage
supplied in the secondary transformer is greater than the one supplied across the primary winding.
Because of the principle of conservation of energy, the transformer converts low voltage, high-
current to high voltage-low current. In other words, the voltage has been stepped up. We can find
step-up transformers located near power plants that are designed to operate megawatts of power.
Apart from the power plants, step-up transformers can also be used for local and smaller

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applications such as x-ray machine which requires about 50,000 volts to work. Even a micro-wave
oven requires a small step-up transformer to operate. The type of metal winding used is one of the
considerations used in determining the efficiency of transformers. Copper coils are more efficient
than many other coil metal choices such as aluminum. However, copper windings tend to cost
more, but you can expect to save the initial cost over time as the efficiency of the material will
save on electrical cost.
Fig. 8.2. Step-up Transformer
8.2. STEP-DOWN TRANSFORMER
There are two types of transformers, namely: Step down and Step up transformers. Generally, the
difference between them is the amount of voltage produced, depending on the number of secondary
coils. In a step-down transformer is one who secondary windings are fewer than the primary
windings. In other words, the transformer’s secondary voltage is less than the primary voltage. So,
the transformer is designed to convert high-voltage, low-current power into a low-voltage, high
current power and it is mainly used in domestic consumption. A common case of step-down
application is in the case of door bells. Normally, door bells use 16 volts, but most household
power circuits carry 110-120 volts. Therefore, the doorbell’s step-down transformer receives the
110 volts and reduces it to lower voltage before supplying it to the doorbell. Step-down
transformers are mostly used to convert the 220 volts electricity to the 110 volts required in most
domestic equipment.
Fig. 8.3. Step-Down Trandformer

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8.3. PROTECTION (BUCHHOLZ RELAY)
In the field of electric power distribution and transmission, a Buchholz relay is a safety device
mounted on some oil-filled power transformers and reactors, equipped with an external overhead
oil reservoir called a "conservator". The Buchholz relay is used as a protective device sensitive to
the effects of dielectric failure inside the equipment.
APPLICATION: Buchholz relays have been applied to large power transformers at least
since the 1940s, and are connected between the conservator and oil tank of a transformer.
OPERATION: Depending on the model, the relay has multiple methods to detect a failing
transformer. On a slow accumulation of gas, due perhaps to slight overload, gas produced by
decomposition of insulating oil accumulates in the top of the relay and forces the oil level
down. A float switch in the relay is used to initiate an alarm signal. Depending on design, a
second float may also serve to detect slow oil leaks. If an electrical arc forms, gas
accumulation is rapid, and oil flows rapidly into the conservator. This flow of oil operates a
switch attached to a vane located in the path of the moving oil. This switch normally will
operate a circuit breaker to isolate the apparatus before the fault causes additional damage.
Buchholz relays have a test port to allow the accumulated gas to be withdrawn for testing.
Flammable gas found in the relay indicates some internal fault such as overheating or arcing,
whereas air found in the relay may only indicate low oil level or a leak.

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CHAPTER 9
GENERATOR
A generator is a device that converts mechanical energy to electrical energy for use in an external
circuit. The source of mechanical energy may vary widely from a hand crank to an internal
combustion engine. Generators provide nearly all the power for electric power grids. The reverse
conversion of electrical energy into mechanical energy is done by an electric motor, and motors
and generators have many similarities. Many motors can be mechanically driven to generate
electricity and frequently make acceptable generators.
Fig. 9.1. Electric Generator
9.1 DIESEL GENERATOR
A diesel generator is the combination of a diesel engine with an electric generator (often an
alternator) to generate electrical energy. This is a specific case of engine-generator. A diesel
compression-ignition engine often is designed to run on fuel oil, but some types are adapted for
other liquid fuels or natural gas. Diesel generating sets are used in places without connection to a
power grid, or as emergency power-supply if the grid fails, as well as for more complex
applications such as peak-lopping, grid support and export to the power grid. Sizing of diesel
generators is critical to avoid low-load or a shortage of power and is complicated by modern
electronics, specifically non-linear loads. In size ranges around 50 MW and above, an open cycle
gas turbine is more efficient at full load than an array of diesel engines, and far more compact,
with comparable capital costs; but for regular part-loading, even at these power levels, diesel arrays
are sometimes preferred to open cycle gas turbines, due to their superior efficiencies.

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Fig. 9.2 Diesel Generator

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CHAPTER 10
CIRCUIT BREAKER
A circuit breaker is an automatically operated electrical switch designed to protect an electrical
circuit from damage caused by overcurrent or overload or short circuit. Its basic function is to
interrupt current flow after protective relays detect a fault. 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. 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 circuits
feeding an entire city. The generic function of a circuit breaker, RCD or a fuse, as an automatic
means of removing power from a faulty system is often abbreviated to ADS (Automatic
Disconnection of Supply).
Fig. 10.1. Circuit Breaker
10.1 VACUUM CIRCUIT BREAKERS
The Vacuum Circuit Breakers (VCB) are particularly advantageous for use in the voltage range 3
kV to 38 kV. In the Vacuum Circuit Breaker the arc interruption takes place in vacuum in the
interrupter. The pressure inside the vacuum interrupter is maintained below 10-4 torr. At this low
pressure very few molecules are available inside the interrupter chamber. This is one desired
characteristic of the interrupting medium for more efficient arc quenching.

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OPERATION: For opening the circuit breaker, the operating mechanism separates the moving
contact from the fixed contact inside the interrupter. Just at the point of contact separation, a very
small amount of metal vaporizes from contact tip and arc is drawn between the contacts. Current
flows between the contacts through this arc. Due to the sinusoidal nature of the AC current, the
current after reaching the maximum value decreases so reducing the vapour emission. Near zero
value of the sinusoidal current wave the arc is extinguished. The metal vapour is deposited on the
condensing shield (see Fig-A). The space inside the interrupter being high vacuum, very little ions
are available between the electrodes/contacts. So after arc extinction the space between the
contacts regains dielectric strength very rapidly which is the most desired characteristics of the arc
quenching medium. Due to the rapid regaining of dielectric strength of vacuum inside the
interrupter the re-striking does not takes place. In the figure below is shown the main constructional
features of a Vacuum Circuit Breaker (VCB). The vacuum condensing shield is used so that the
metallic vapour does not condenses on the enclosure glass. In the absence of the shield the metallic
vapour condenses on the glass and gradually the glass becomes conducting, so that the insulation
between the moving and fixed contacts is lost in the open condition of the breaker. The metallic
bellow makes it possible to maintain vacuum inside the interrupter chamber while allowing the
movement of moving contact for separation from the fixed contact. One side of the bellows is
welded to the moving contact stem as shown while the other side is welded to the interrupter end
plate. The contact surface is so designed that the arc between the contacts diffuse. The arc spread
to the sides of the contact surfaces. Diffusion of arc reduces its strength hence the arc quenching
is facilitated. The main requirements of the contact material is, very high electrical and thermal
conductivity, low contact resistance and high melting point.
ADVANTAGES:
• The vacuum interrupters have long life.
• Unlike oil CB (OCB) or air blast CB (ABCB), the explosion of VCB is avoided. This
enhances the safety of the operating personnel.
• No fire hazard.
• The vacuum CB is fast in operation so ideal for fault clearing. VCB is suitable for repeated
operation.
• Vacuum circuit breakers are almost maintenance free.

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• Due to the rapid gain of dielectric strength of vacuum interrupter, the separation required
between the moving contact from fixed contact is of the order of few millimetre. This
makes the VCB compact.
• VCB is light weight.
• No exhaust of gas to the atmosphere.
• Quiet operation.
DISADVANTAGES:
• The main disadvantage of VCB is that it is uneconomical for use of VCB at voltages
exceeding 38 kV. The cost of the breaker becomes prohibitive at higher voltages. This is
due to the fact that at high voltages (above 38 kV) more than two numbers of interrupters
are required to be connected in series.
• Advance technology is used for production of vacuum interrupters.
(a) (b)
Fig. 10.2. Vacuum Circuit Breaker operational diagram (a), Vacuum Circuit Breaker (b)
10.2 AIR CIRCUIT BREAKER
Air Circuit Breaker is a device used to provide Overcurrent and Short Circuit Protection for circuits
ranging from 800 Amps to 10000 Amps. One should not be confused between Air Circuit Breaker
and Air Blast Circuit Breaker. Air Circuit Breakers are usually used in low voltage applications
below 450 volts. We can today find these in Distribution Panels (below 450 volts). Air Blast Circuit
Breakers are high capacity breakers and can be seen in old substations mainly above 132 kV. The
working principle of these two circuit breakers are quite different. Here we will only discuss the
working of Air Circuit Breaker (ACB).

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OPERATION: Air Circuit breakers normally have two pairs of contacts. The main pair of
contacts carries the current at normal load and these contacts are made of copper. The additional
pair is the arcing contact and is made of carbon. When circuit breaker is being opened, the main
contacts open first and during opening of main contacts the arcing contacts are still in touch with
each other. As the current gets. a parallel low resistive path through the arcing contact during
opening of main contacts. there will not be any arcing in the main contact. The arcing is only
initiated when finally the arcing contacts are separated. The each of the arc contacts is fitted with
an arc runner which helps. the arc discharge to move upward due to both thermal and
electromagnetic effects as shown in the figure. As the arc is driven upward it enters in the arc
chute, consisting of splatters. The arc in chute will become colder, lengthen and split hence arc
voltage becomes much larger than system voltage at the time of operation of air circuit breaker,
and therefore the arc is quenched finally during the current zero. Air Circuit breakers (ACBs) are
available which can be Electrically Operated or Manually Operated. This means electrically
operated Air Circuit Breaker Can be Opened (switched OFF) and Closed (Switched ON) using
external power supply. The Electrically operated motor is used to operate spring charging
mechanism for closing and opening the Circuit Breaker. The power supply could be single phase
230V AC Supply or low voltage 24V-110V DC supply for operation during no availability of
power. Air Circuit breakers (ACBs) are also available as Fixed Type and Withdrawable (Drawout)
Type formats.
Fig. 10.3 construction of air blast circuit

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Fig. 10.4 Air Circuit Breaker

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CHAPTER 11
MAGNETICS DEPARTMENT
This department is making all types of transformers and coils that are used in various equipment’s.
This department basically consists of four sections:
1. Planning section
2. Mechanical assembly section
3. Moldings sections
4. Inspection
The D&E department gives the following description- numbers of layers, numbers of turns/layers,
types of winding, gapes in core, insulation between layers, ac/dc impedance, dielectric strength,
electrical parameters and earthing.
The various types of transformers being made are:
1. Open type transformer
2. oil cooling types transformers
3. molding type of transformer
4. PCB molding type transformers
Transformers are mechanically assembled, leads are taken out and checking of specification is
done.
Winding machines of are of three types:
1. Heavier one- DNR for 0.1 to 0.4 mm diameter.
2. LC control machines.
3. Torroidal machines having 32 operations from winding to mechanical assembly.
The various types of windings used are:-
1. Hand-winding
2. Torroidal winding
3. Sector winding
4. Pitch winding
5. Variable winding
6. Wave winding

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Two types of cores used are:
1. E-type for 3-phase
2. C-type for single phase.
Various procedures involved in the manufacture of transformers are:
1. Formers of glass- expoxy.
2. Winding.
3. Core Winding.
4. Varnishing.
5. Impregnation various varnished coils are heated, then cooled, reheated and put into
vacuum. Then air is blown to remove the humidity.
6. Molding-araldite mixed with black dye is used to increase mechanical as well as electrical
strength. Molding is done at 120 degrees centigrade for twelve hours.
7. A RDB compound is used for leakage production, oil is boiled at 70 to 80 degrees under
vacuum conditions to remove air bubbles after this the cols are dipped in vamish and core
is attached.
8. Painting
9. Mechanical assembly
10. Termination
11. Testing: dielectric testing is done at 50KV voltage applied for a minimum of one minute.
During inspection, the following characteristics are checked:-
(a) turn ratio
(b) DC resistance for each coil.
(c) Inductance
(d) No load voltage
(e) leakage

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CONCLUSION
The practical training aims at familiarizing the students with the working condition in a
professional firm as well as to apply their theoretical knowledge acquired in the institute into
practice.
This training was helpful to me in various direct and indirect ways, like understanding of machines
as well as procedure followed on a manufacturing a product. A good insight into inspection and
quality check of products.
This training has added a whole new dimension to my observation and practical approach as well
as introducing me to Organizational Hierarchy.