AKNOWLEDGEMENT
I firmly believe that a work of significant proportions cannot be attributed to a single person
or a single effort, its overall success depends upon all those individuals who contributed in
their unique way to the accomplishment of its broader objectives.
I express my deepest and most sincere thanks to Mr. R. K. Kajla, Deputy G.M.-HR for giving
me an opportunity to work on this project and extending support to me during my stint with
HAVELLS INDIA LTD.
I acknowledge my indebtness to Mr S. K. Yadav, for giving me inspiring support, guidance,
valuable suggestions and encouragement throughout this project.
Above all I wish to thank my family for being my constant support and
source of encouragement during the project.
APROVAL FROM GUIDE
This is to certify that Mr. Sumit Bansal student of NATIONAL INSTITUTE OF
TECHNOLOGY, KURUKSHETRA has completed project work on “STUDY ON
ELECTRICAL POWER SYSTEM” under my guidance and supervision.
I certify that this is an original work and has not been copied from any source.
DATE: Signature of Guide
Name of Project Guide
Mr. S. K. Yadav
DECLARATION
I hereby declare that this Project Report entitled “STUDY OF ELECTRICAL POWER
SYSTEM” in HAVELLS INDIA LTD. submitted in the partial fulfillment of the requirement
of B.TECH. of SEEDLING ACADEMY OF DESIGN TECHNOLOGY AND
MANAGEMENT, Jaipur is based on primary & secondary data found by me in various
departments, books, and websites & Collected by me in under guidance of Mr. S. K. Yadav.
DATE: SUMIT BANSAL
B.TECH
MECHANICAL ENGINEERING
N.I.T.K.
CONTENTS
1. Electrical Industry
2. Company’s Profile And History
3. Electric Motor
3.1 History Of A.C. Motor
3.2 Principle
3.3 A.C. Motor
3.4 D.C. Motor
3.5 Universal Motor
4. Electric Generator Or Dynamo
4.1 Historic Development
4.2 Principle
4.3 Jedlik’s Dynamo
4.4 Faraday’s Disk
5. Transformer
5.1 Power Transformer
5.2 Auto-Transformer
5.3 Polyphase Transformer
5.4 Oil Cooled Transformer
5.5 Pulse Transformer
5.6 Audio Transformer
6. Substation(S.L.D.)
Bibliography
ABOUT ELECTRICAL INDUSTRY
The electrical industry contributed and helped reshape the modern technology, powering the
tools and appliances used in daily life.
It all started with Allessandro Volta's development of the battery in 1800 and Joseph Henry's
work on electromagnets, Michael faraday’s invention of the generator in 1830 marked an era
of modern technologies followed with the first commercial application of electricity, the
Telegraph by Samuel F.B. Morse.
The production of arc light with the help of direct current (DC) generator invented by Charles
Brush in 1876 illuminated the 19th century
Thomas Edison, recognizing the desire for electric lighting similar to existing gas lights,
invented in 1879 an Incandescent Lamp that produced light when current passed through a
high resistance filament in a vacuum.
In 1882, Nikola Tesla invented the rotating magnetic field, and pioneered the use of a rotary
field of force to operate machines. He exploited the principle to design a unique two-phase
induction motor in 1883. In 1885, Galileo Ferraris independently researched the concept. In
1888, Ferraris published his research in a paper to the Royal Academy of Sciences in Turin.
Tesla had suggested that the commutators from a machine could be removed and the device
could operate on a rotary field of force. Professor Poeschel, his teacher, stated that would be
akin to building a perpetual motion machine.[11] Tesla would later attain U.S. Patent
0,416,194, Electric Motor (December 1889), which resembles the motor seen in many of
Tesla's photos. This classic alternating current electro-magnetic motor was an induction
motor.
Michail Osipovich Dolivo-Dobrovolsky later invented a three-phase "cage-rotor" in 1890.
By 1890, Edison general electric, the Westinghouse electric and manufacturing company
founded by George Westinghouse, and the Thomson Houston electric company were the key
players. Westinghouse aggressively promoted the use of alternating current (AC), while
Thomson Houston assisted fledgling utilities to fund power stations. AC, which could serve
more customers over a wider area, soon became the industry standard. After Edison GE and
Thomson Houston merged in 1892 to form the general electric company, the new firm
dominated in finance, incandescent lamp manufacture, and the manufacture of steam turbines
to power generators. In 1896, the first hydroelectric power station, at Niagara Falls delivered
abundant electricity to industries demonstrating AC's full potential.
After greatly expanding generating capacity, the electrical industry in the 1920s campaigned
to increase domestic consumption. Many households in this decade acquired electric stoves,
washing machines, irons, radios, and vacuum cleaners.
Seeking lower costs, electrical utilities adopted nuclear reactor technology, predictions were
that electricity would soon be “too cheap to meter” went unfulfilled, however. Nuclear‐power
plants proved not only expensive to build but difficult to manage and prone to dangerous
accidents.
Yet consumer demand for electricity increased as they grew more dependent on reliable
electric power to heat and cool buildings, control machinery, operate appliances and
computers, and supply indoor and outdoor illumination, governments established programs to
promote wind, water, and solar power.
AFTER BEING in the doldrums towards the end of the 1990s, the Indian electrical
equipment industry is seeing a revival in the last couple of years with the growth rate
averaging 7 per cent per annum. The worldwide electric power industry provides a vital
service essential to modern life. It provides the nation with the most prevalent energy form
known in history “electricity”. It advances the nation’s economic growth and productivity;
promotes business development
and expansion; and provides solid employment opportunities to workers globally in general
and India
in particular. It is a robust industry that contributes to the progress and prosperity of our
nation. Today the electric power industry operates in a hybrid model of competition and
regulation. The worldwide electrical and electronics industry is growing at a fast pace which
consist of manufacturers, suppliers, dealers, retailers, electricians, electronic equipment
manufacturers
Power industry restructuring, around the world, has a strong impact on Asian power industry
as well. Indian power industry restructuring with a limited level of competition, since 1991,
has already been introduced at generation level by allowing participation of independent
power producers (IPPs). The new Electricity Act 2003 provides the provision of competition
in several sectors. It is felt that the prevailing conditions in the country are good only for
wholesale competition and not for the retail competition at this moment.
As per the recent surveys, the global electrical & electronics market is worth $1,038.8 billion,
which is forecasted to grow to $ 1,216.8 billion at the end of the year 2008. If we talk of
electrical & electronics production statistics, the industry accounted for $1,025.8 billion in
2006, which is forecasted to reach $ 1,051.5 billion in future.
OUTLOOK OF THE WORLD'S ELECTRICAL &
ELECTRONICS MARKET
Classification 2007 2008
Home Use 116,221 119,201
Industrial Use 730,928 119,201
Information Device 330,834 345,131
Communication Device 248,424 258,307
Office Devices 11,735 258,307
Others 139,935 258,307
Electronics Parts 321,439 338,308
Total 1,168,588 1,216,895
SIZE OF THE ELECTRICAL INDUSTRY
Top three electrical and electronic goods manufacturing countries in the world are: United
States of America, Japan and Korea respectively. The United States of America being the
largest producer of electronic products worldwide contributes the total share of around 21%.
Furthermore, USA is at the forefront to have the largest market share with around 29% in the
Global market.
The World's electrical market size was $1038.8 billion in 2006, since last year an increase of
10.6% is forecasted to grow even more. The industrial electrical goods industry size was
$651.3 billion, contributing around 62.7% of the total. With regard to electronics parts and
components sector, the total market share was around $282.7 billion i.e. 27.2% while home
electronics was $ 104.7 billion. This figure is supposed to increase in this decade.
MAJOR PRODUCTION AND EXPORT CENTERS
As electrical manufacturing industry is growing with a fast pace, Western Europe is
developing gradually to contribute this industry. Western Europe comprising of 16 countries
is contributing around 22% of the global market share. Simultaneously, Eastern Europe is
forecasted to grow about $ 24 billion in 2013 from $ 9 billion in 2006.
If we talk of Asia Pacific region, China, Japan, North & South Korea, Singapore and India
are the top manufacturer of electrical and electronic products. Among these Asian countries,
China is becoming the manufacturing region of electronic products on the globe.
One of the issues often raised is the fear of flood of imports from China. According to Mr.
Krishnakumar, President of the Indian Electrical and Electronics Manufacturers Association
(IEEMA). Chinese electrical products certainly are lower in cost, but their quality is suspect.
For example, Chinese compact fluorescent lamps proved to be a failure in India. The Indian
industry is not afraid of Chinese competition, so long as the products from there are
conforming to quality standards. The Quality Control Order of February 2003, promulgated
by the Govt. of India, has specified that unless a product conforms to the Bureau of Indian
Standards criteria, it cannot be marketed in India. This should go a long way in preventing the
flood of low quality, low price products coming from China.
At persent, Asia is growing with more speed in comparision to Americas and Europe. In
2002, Asia occupied 41% of total electronics market share, which grew upto 56% in 2007.
Those days are not far away when Asia will become the market leader globally.
FUTURE OUTLOOK OF ELECTRICAL INDUSTRY
Today, the electrical industry is experiencing phenomenal and remarkable changes
worldwide. The worldwide electrical industry is distinguished by fast technological advances
and has grown rapidly than most other industries over the past 30 years. Products are heading
towards new destination where cost is less than other place with higher costs involved. These
places offer the most long term potential for market growth. Companies indulged in
manufacturing electrical products are investing a lot on research and development for the best
products to meet the demand of the market. They are manufacturing the product with best
quality at reduced cost due to many competitors.
The domestic market in India is itself large, and one must firstly satisfy this market with
products that meet international quality standards. With increasing globalization, every
international player is now operating in India, providing goods and services complying with
international quality. Once we deliver high quality products and services within the domestic
market, accessing the international market for exports should not pose a serious challenge.
The Electrical/Electronics Industry in India is growing to its full potential in the coming years
and no doubt that India will soon come to be recognized for quality products and services
which in turn, will bring this industry to a position of true leadership.
FACTORS GOVERNING THE GROWTH OF
ELECTRICAL INDUSTRY
Every industry thrives on some supporting factors. In this connection, there are few factors
governing the growth of electrical and electronics industry:
Research & development played an important role to the increased productivity and
higher-value added electrical and electronics products.
Foreign investments accelerated growth in production and export as well. To expand
their business, foreign companies have done huge investment which lead developing
countries in establishing production units.
Global industries like Medical, Telecommunications, Industrial & Automotive
industries have been cordially supported by electrical & electronics industry.
Increase in income changed living standards of the common mass. As a result, it
increased the demand of electronics especially consumer electronics products
globally.
Electric & Electrical industry is highly fragmented which comprises of many small
and medium size enterprises resulting into a huge industry.
Asia Pacific region is emerging as the most spinning place for the consumer
electronics industry, as the markets remain still unbroached.
Innovation has played importantly in this industry. It led to a consistent demand for
newer and faster products and applications
ABOUT HAVELLS
Company History - Havells India
YEAR
1983 - The Company was originally incorporated as Havell's India Private Limited
on 8th August, under the Companies Act, 1956 and subsequently the name was
changed to Havell's India Limited vide Certificate dated 31st March, 1992.
The Company was promoted by S/Shri Qimat Rai Gupta and Surjit Kumar Gupta.
It has facilities for manufacture of switchgear items viz.
Miniature Circuit Breakers (MCB), MCB Distribution Boards (DB) and HRC fuses at
Samepur Badli, Delhi.
The Company also entered into a Technical Collaboration with M/s Christian Geyer
GmbH & Co., Germany for the manufacture of Miniature Circuit Breakers in India.
1989 - The company undertook addition to its tool room facilities by going in for
manufacturing of sheet metal and molding tools in-house.
1991 - The company amalgamated with itself Elymer Havbell's Pvt. Ltd. which had
facilities for manufacture of HRC fuses with an installed capacity of 2,50,000 pcs.
1992 - For the manufacture of ELCBs, the Company signed another Technical
Collaboration with M/s Schiele Industrieworke, Germany.
1994 - The company successfully launched the latest IEC design contractors, relays, and
motor starters for the first time in India which have been well received in the market.
The company has finalized tie-ups in UAE, Oman, Kuwait and Egypt for marketing
its vast range of products in these countries.
1995 - The Company has introduced Product Managers and Industrial Teams to emphasize
the product mix and to strengthen its presence in all market segments.
1996 - Schiele industriwerke, Germany, who have been our collaborators for ELCBs, have
entered into a new technical collaboration with the company for quality up gradation
for its products in the control gear division.
The company decided to enter into the manufacture of Three Phase Energy Meters for
industrial applications.
Keeping in view business synergy's with the Cable Industry, the Company has entered
into the manufacture of low tension power cables.
Havell's group signed a Joint Venture Agreement with Hanson Electrical, a group
company of the UK Pound 11 Billion Anglo-American conglomerate, Hanson Plc.,
one of the top ten Companies of UK.
1997 - One of the biggest achievements during the year is that the JV partners have tested the
MCBs and have entered into an agreement with the Company to exclusively market
the MCBs in the worldwide markets.
Havell's Dorman Smith Pvt. Ltd., U.K. JV company, wherein Havell's India Ltd is a
25% shareholder, with Electrium Ltd. UK with the introduction of state-of-the-art
‘DORMAN SMITH’ brand Moulded Case Circuit Breakers in India.
Havell's group, has signed a new JV agreement with Ampy Automation Digilog Ltd.,
UK.
1998 - Cable division at Alwar is now ISO-9001 certified.
Havell's group has signed a new JV agreement with the Deutsche Zahiergesellschaft
(DZG), Germany.
The 50:50 JV company Havell's Dorman Smith Ltd. in which Havell's India Ltd. is a
25% shareholder had launched Moulded Case Circuit Breakers last year in the Indian
market.
The Company also launched Crabtree brand modular plate switches which is being
perceived as the best available product in the market.
1999 - Electrical switchgear makers Havell's India has entered into a strategic partnership
with Cambridge Technology Partners
India for implementing ERP on a fast-track.
The company has a 50:50 joint venture with DZG of Germany for manufacture of
high-end electromechanical and electronic energy meters.
2000 - Havell's entered into a technical collaboration with Geyer in 1998 to manufacture
miniature circuit-breakers.
For MCBs, the company has a technical collaboration with Geyer AG of Germany,
with Schiele Industriewerke of Germany for RCCBs and with Peterriens Schaltechik
Gmbh for changeover switches.
The Company has entered into a joint venture agreement with Standard Electricals
Ltd., an unlisted company wherein the company hold 60% shareholding.
Havell's India Ltd has acquired a 60 per cent stake in Hyderabad-based Duke Arnics
Electronics Ltd.
2001 - The Company has been awarded the highest revenue payer award for the year 2000 in
the organised sector category. Havell`s India Ltd has informed BSE that the company
had earlier acquired 60% shareholding of Standard Electricals Ltd., Jalandhar, an
unlisted company.
The company has acquired the entire 100% shareholding of Standard Electricals
Ltd.,
by purchasing balance 40% shareholding of the company. The Standard Electricals
Ltd., has thus become a 100% subsidiary of company w.e.f. December 31,2001.
2004 - Forays into the luxury bathroom fittings and accessories segment under the Crabtree
Frattini brand name
Havells India Limited has sold out its entire shareholding of Standard Electricals
Limited, an un-listed public limited company which was a 100% subsidiary of the
Company. Consequently, with effect from such transfer, Standard Electricals Limited
is no longer a subsidiary of the Company.
2006 - Havells India Ltd has informed that Ms Sabina Geyer has resigned from the
Directorship of the Company with immediate effect.
2007 - Havells India Limited has appointed Mr.N Balasubramanian as additional director of
the Company who shall hold office up to the date of next Annual General Meeting.
Havell's India is under the QRG group and was set up in 1958, with its corporate office in
Noida. Havell's India is a company worth US$ 1 billion and is one of the leading companies
in India's equipment-power distribution industry. Havell's India Ltd. produces and supplies
low-voltage electrical equipments in India.
Havell's India Company has 3 divisions – consumer electrical durables, wires and cables, and
switchgears. It has entered into alliances with electrical companies like DZG, Electrium, and
Geyer AG and this has helped the company improve their technical expertise in the segment
of electrical products. A lot many international certifications such as KEMA, ASTA,
SEMKO, and CSA have been acquired by Havell's India.
All the manufacturing plants of Havell's India are highly technologically developed and as a
result, all the products are of the best quality. The turnover of the Havell's India Ltd.
amounted to Rs. 29308.25 lakh in 2003, Rs. 41922.40 lakh in 2004, and Rs. 66538.46 lakh in
2005.
The various products manufactured by the Havell's India are:
Cables
Fans
Switches
Capacitor
Bath accessories and fittings
Lightning solutions
Havell's India Ltd. had established its cables plant in Alwar in 1996. It is a unit which has
been certified with ISO: 9001-2000 for its standards in manufacturing cables and wires from
the best quality of raw materials. Its latest automatic laser controlled machines are also of
international standards. This has ensured that the wires and cables manufactured by Havell's
India are of the best quality. The company entered the fan business in 2003 and offers great
variety in order to satisfy client requirements.
Havell's India Company designs and produces capacitors by using S3 technology. The bath
accessories and fittings manufactured by the company are of the best quality and are available
in a wide variety. Havell's India has become the top-most company in India on the basis of its
quality of products which are of the world class standards and its pricing which is accessible
by the common man.
Havell’s exports its products to approximately 55 countries across the globe and has
marketing offices in the EU, the Middle East and the USA.The company is listed on the
Bombay Stock Exchange and the National Stock Exchange. Its consolidated revenues
amounted to EUR 207 million in 2005.Europe is critical to the company’s business,
contributing approximately 40 per cent to its total revenues, generated by exports in 2005.
FUTURE PLANS
As a part of its growth strategy, Havell’s is taking initiatives to tap potential markets in the
EU.The company has developed a strong brand presence through alliances with and the
acquisition of leading electrical equipment manufacturers in the region. It has also initiated
various segment-wise growth plans to drive growth in its overall operations. The company
has identified the housing and power sectors as future growth drivers and plans to tap these
spheres. Havell’s has plans to diversify its product portfolio by venturing into the electrical
motors and power capacitors space. It also aims to leverage its established brand presence in
these segments. The company expects to increase its exports by approximately 100 per cent
from 2005-07. Havell’s also plans to increase its capacity to ward off cost pressures and
reduce development costs.The company has plans to increase its brand presence and reach in
the EU through strong acquisitions. It has plans to expand its operations in the EU in-
organically and enhance its international presence.
FACTORS FOR SUCCESS
STRATEGIC ALLIANCES
The company has formed strategic alliances and partnerships with many leading players
operating in the end-to-end solutions in the power distribution equipment industry. Havell’s
has entered manufacturing alliances with several leading electrical companies such as
Electrium, Geyer AG, DZG, etc., which has assisted the company to leverage the technical
expertise and developing quality products in the electrical products segment. Havell’s has
efficiently leveraged alliances to gain an entry into global markets, developing a strong
product portfolio to capture them.The company has developed efficient partnerships to
increase its market penetration in the EU.
LEADING THE WAY THROUGH INNOVATION
Havell’s has focussed on research and development to produce novel products, at the same
time, reducing cost and upgrading the quality of its products.The company has a skilled
workforce that works on its R&D projects. It has also entered into alliances with several
companies, thereby facilitating sharing of technology. It has developed a good brand name by
introducing innovative products in the market, which has enabled it to penetrate the market
ELECTRIC MOTOR
An electric motor is a device using electrical energy to produce mechanical energy, nearly
always by the interaction of magnetic fields and current-carrying conductors. Traction motors
used on vehicles often perform both tasks.
Electric motors are found in myriad uses such as industrial fans, blowers and pumps, machine
tools, household appliances, power tools, and computer disk drives, among many other
applications. The smallest motors may be found in electric wristwatches. Electric motors may
be classified by the source of electric power, by their internal construction, and by
application.
The physical principle of production of mechanical force by the interaction of an electric
current and a magnetic field was known as early as 1821. Electric motors of increasing
efficiency were constructed throughout the 19th century, but commercial exploitation of
electric motors on a large scale required efficient electrical generators and electrical
distribution networks.
Principle
The principle of conversion of electrical energy into mechanical energy by electromagnetic
means was demonstrated by the British scientist Michael Faraday in 1821 and consisted of a
free-hanging wire dipping into a pool of mercury. A permanent magnet was placed in the
middle of the pool of mercury. When a current was passed through the wire, the wire rotated
around the magnet, showing that the current gave rise to a circular magnetic field around the
wire.
Categorization Of Electric Motors
The classic division of electric motors is:-
1). Alternating Current (AC) types,
2). Direct Current (DC) types.
3). Universal Motor ( DC motors that runs on AC power).
1. AC Motors
In 1882, Nikola Tesla invented the rotating magnetic field, and pioneered the use of a rotary
field of force to operate machines. He exploited the principle to design a unique two-phase
induction motor in 1883. In 1885, Galileo Ferraris independently researched the concept. In
1888, Ferraris published his research in a paper to the Royal Academy of Sciences in Turin.
Tesla had suggested that the commutators from a machine could be removed and the device
could operate on a rotary field of force. Professor Poeschel, his teacher, stated that would be
akin to building a perpetual motion machine. Tesla would later attain U.S. Patent 0,416,194,
Electric Motor (December 1889), which resembles the motor seen in many of Tesla's photos.
This classic alternating current electro-magnetic motor was an induction motor.
Michail Osipovich Dolivo-Dobrovolsky later invented a three-phase "cage-rotor" in 1890.
This type of motor is now used for the vast majority of commercial applications.
A typical AC motor consists of two parts:
An outside stationary stator having coils supplied with AC current to produce a rotating
magnetic field, and;
An inside rotor attached to the output shaft that is given a torque by the rotating field.
2. DC Motors
A DC motor is designed to run on DC electric power. Two examples of pure DC designs are
Michael Faraday's homopolar motor (which is uncommon), and the ball bearing motor, which
is (so far) a novelty. By far the most common DC motor types are the brushed and brushless
types, which use internal and external commutation respectively to create an oscillating AC
current from the DC source—so they are not purely DC machines in a strict sense.There are
four types of DC motor:
DC series motor
DC shunt motor
Permanent Magnet DC Motor
DC compound motor
DC compound motor - there are also two types:
o Cumulative compound
o Differentially compounded
3. Universal Motors
A variant of the wound field DC motor is the universal motor. The name derives from the fact
that it may use AC or DC supply current, although in practice they are nearly always used
with AC supplies. The principle is that in a wound field DC motor the current in both the
field and the armature (and hence the resultant magnetic fields) will alternate (reverse
polarity) at the same time, and hence the mechanical force generated is always in the same
direction. In practice, the motor must be specially designed to cope with the AC (impedance
must be taken into account, as must the pulsating force), and the resultant motor is generally
less efficient than an equivalent pure DC motor.
The advantage of the universal motor is that AC supplies may be used on motors which have
the typical characteristics of DC motors, specifically high starting torque and very compact
design if high running speeds are used. The negative aspect is the maintenance and short life
problems caused by the commutator. As a result such motors are usually used in AC devices
such as food mixers and power tools which are used only intermittently. Continuous speed
control of a universal motor running on AC is easily obtained by use of a thyristor circuit,
while stepped speed control can be accomplished using multiple taps on the field coil.
Household blenders that advertise many speeds frequently combine a field coil with several
taps and a diode that can be inserted in series with the motor (causing the motor to run on
half-wave rectified AC).
Uses
Electric motors are used in many, if not most, modern machines. Obvious uses would be in
rotating machines such as fans, turbines, drills, the wheels on electric cars, and conveyor
belts. Also, in many vibrating or oscillsting machines, an electric motor spins an irregular
figure with more area on one side of the axle than the other, causing it to appear to be moving
up and down.
Electric motors are also popular in robotics. They are used to turn the wheels of vehicular
robots, and servo motors are used to turn arms and legs in humanoid robots. In flying robots,
along with helicopters, a motor causes a propellor or wide, flat blades to spin and create drag
force, allowing vertical motion.
In industrial and manufacturing businesses, electric motors are used to turn saws and blades
in cutting and slicing processes, and to spin gears and mixers (the latter very common in food
manufacturing). Linear motors are often used to push products into containers horizontally.
Many kitchen appliances also use electric motors to accomlish various jobs. Food processors
and grinders spin blades to chop and break up foods. Blenders use electric motors to mix
liquids, and microwave ovens use motors to turn the tray food sits on. Toaster ovens also use
electric motors to turn a conveyor in order to move food over heating elements.
ELECTRICAL GENERATOR
In electricity generation, an electrical generator is a device that converts mechanical energy to
electrical energy, generally using electromagnetic induction. The reverse conversion of
electrical energy into mechanical energy is done by a motor; motors and generators have
many similarities. A generator forces electric charges to move through an external electrical
circuit, but it does not create electricity or charge, which is already present in the wire of its
windings. It is somewhat analogous to a water pump, which creates a flow of water but does
not create the water inside. The source of mechanical energy may be a reciprocating or
turbine steam engine, water falling through a turbine or waterwheel, an internal combustion
engine, a wind turbine, a hand crank, compressed air or any other source of mechanical
energy.
Historic Developments
Before the connection between magnetism and electricity was discovered, electrostatic
generators were invented that used electrostatic principles. These generated very high
voltages and low currents. They operated by using moving electrically charged belts, plates
and disks to carry charge to a high potential electrode. The charge was generated using either
of two mechanisms:
Electrostatic induction
The turboelectric effect, where the contact between two insulators leaves them
charged.
Because of their inefficiency and the difficulty of insulating machines producing very high
voltages, electrostatic generators had low power ratings and were never used for generation
of commercially-significant quantities of electric power. The Wimshurst machine and Van de
Graaff generator are examples of these machines that have survived.
Jedlik's Dynamo
In 1827, Hungarian Anyos Jedlik started experimenting with electromagnetic rotating devices
which he called electromagnetic self-rotors. In the prototype of the single-pole electric starter
(finished between 1852 and 1854) both the stationary and the revolving parts were
electromagnetic. He formulated the concept of the dynamo at least 6 years before Siemens
and Wheatstone but didn't patent it as he thought he wasn't the first to realize this. In essence
the concept is that instead of permanent magnets, two electromagnets opposite to each other
induce the magnetic field around the rotor. Jedlik's invention was decades ahead of its time.
Faraday Disk
In 1831-1832 Michael Faraday discovered the operating principle of electromagnetic
generators. The principle, later called Faraday's law, is that a potential difference is generated
between the ends of an electrical conductor that moves perpendicular to a magnetic field. He
also built the first electromagnetic generator, called the 'Faraday disc', using a copper disc
rotating between the poles of a horseshoe magnet. It produced a small DC voltage, and large
amounts of current.
This design was inefficient due to self-cancelling counter flows of current in regions not
under the influence of the magnetic field. While current flow was induced directly underneath
the magnet, the current would circulate backwards in regions outside the influence of the
magnetic field. This counter flow limits the power output to the pickup wires, and induces
waste heating of the copper disc. Another disadvantage was that the output voltage was very
low, due to the single current path through the magnetic flux. Experimenters found that using
multiple turns of wire in a coil could produce higher more useful voltages. Since the output
voltage is proportional to the number of turns, generators could be easily designed to produce
any desired voltage by varying the number of turns. Wire windings became a basic feature of
all subsequent generator designs.
The first Turbo generator Designed by the Hungarian engineer Ottó Bláthy in 1903
The Dynamo was the first electrical generator capable of delivering power for industry. The
dynamo uses electromagnetic principles to convert mechanical rotation into a pulsing direct
electric current through the use of a commutator. The first dynamo was built by Hippolyte
Pixii in 1832.
Through a series of accidental discoveries, the dynamo became the source of many later
inventions, including the DC electric motor, the AC alternator, the AC synchronous motor,
and the rotary converter.
A dynamo machine consists of a stationary structure, which provides a constant magnetic
field, and a set of rotating windings which turn within that field. On small machines the
constant magnetic field may be provided by one or more permanent magnets; larger machines
have the constant magnetic field provided by one or more electromagnets, which are usually
called field coils.
Large power generation dynamos are now rarely seen due to the now nearly universal use of
alternating current for power distribution and solid state electronic AC to DC power
conversion. But before the principles of AC were discovered, very large direct-current
dynamos were the only means of power generation and distribution. Now power generation
dynamos are mostly a curiosity.
Terminology
The two main parts of a generator or motor can be described in either mechanical or electrical
terms.
Mechanical:
Rotor: The rotating part of an alternator, generator, dynamo or motor.
Stator: The stationary part of an alternator, generator, dynamo or motor.
Electrical:
Armature: The power-producing component of an alternator, generator, dynamo or
motor. In a generator, alternator, or dynamo the armature windings generate the
electrical current. The armature can be on either the rotor or the stator.
Field: The magnetic field component of an alternator, generator, dynamo or motor.
The magnetic field of the dynamo or alternator can be provided by either
electromagnets or permanent magnets mounted on either the rotor or the stator. (For a
more technical discussion, refer to the Field coil article.)
Because power transferred into the field circuit is much less than in the armature circuit, AC
generators nearly always have the field winding on the rotor and the stator as the armature
winding. Only a small amount of field current must be transferred to the moving rotor, using
slip rings. Direct current machines necessarily have the commutator on the rotating shaft, so
the armature winding is on the rotor of the machine.
TRANSFORMER
A variety of types of electrical transformer are made for different purposes. Despite their
design differences, the various types employ the same basic principle as discovered in 1831
by Michael Faraday, and share several key functional parts.
Power Transformers
This is the most common type of transformer, widely used in appliances to convert mains
voltage to low voltage to power electronics
Widely available in power ratings ranging from mW to MW
Insulated laminations minimize eddy current losses
Small appliance and electronic transformers may use a split bobbin, giving a high
level of insulation between the windings
Rectangular core
Core laminate stampings are usually in EI shape pairs. Other shape pairs are
sometimes used.
Mumetal shields can be fitted to reduce EMI (electromagnetic interference)
A screen winding is occasionally used between the 2 power windings
Small appliance and electronics transformers may have a thermal cut out built in
Occasionally seen in low profile format for use in restricted spaces
laminated core made with silicon steel with high permeability
Auto-Transformer
An autotransformer has only a single winding, which is tapped at some point along the
winding. AC or pulsed voltage is applied across a portion of the winding, and a higher (or
lower) voltage is produced across another portion of the same winding. The higher voltage
will be connected to the ends of the winding, and the lower voltage from one end to a tap. For
example, a transformer with a tap at the center of the winding can be used with 230 volts
across the entire winding, and 115 volts between one end and the tap. It can be connected to a
230-volt supply to drive 115-volt equipment, or reversed to drive 230-volt equipment from
115 volts. Since the current in the windings is lower, the transformer is smaller, lighter
cheaper and more efficient. For voltage ratios not exceeding about 3:1, an autotransformer is
cheaper, lighter, smaller and more efficient than an isolating (two-winding) transformer of the
same rating. Large three-phase autotransformers are used in electric power distribution
systems, for example, to interconnect 33 kV and 66 kV sub-transmission networks.
In practice, transformer losses mean that autotransformers are not perfectly reversible; one
designed for stepping down a voltage will deliver slightly less voltage than required if used to
step up. The difference is usually slight enough to allow reversal where the actual voltage
level is not critical. This is true of isolated winding transformers too.
Polyphase Transformers
For three-phase power, three separate single-phase transformers can be used, or all three
phases can be connected to a single polyphase transformer. The three primary windings are
connected together and the three secondary windings are connected together. The most
common connections are Y-Delta, Delta-Y, Delta-Delta and Y-Y. A vector group indicates
the configuration of the windings and the phase angle difference between them. If a winding
is connected to earth (grounded), the earth connection point is usually the center point of a Y
winding. If the secondary is a Delta winding, the ground may be connected to a center tap on
one winding (high leg delta) or one phase may be grounded (corner grounded delta). A
special purpose polyphase transformer is the zigzag transformer. There are many possible
configurations that may involve more or fewer than six windings and various tap connections.
Oil Cooled Transformer
For large transformers used in power distribution or electrical substations, the core and coils
of the transformer are immersed in oil which cools and insulates. Oil circulates through ducts
in the coil and around the coil and core assembly, moved by convection. The oil is cooled by
the outside of the tank in small ratings, and in larger ratings an air-cooled radiator is used.
Where a higher rating is required, or where the transformer is used in a building or
underground, oil pumps are used to circulate the oil and an oil-to-water heat exchanger may
also be used.[1] Formerly, indoor transformers required to be fire-resistant used PCB liquids;
since these are now banned, substitute fire-resistant liquids such as silicone oils are instead
used.
Pulse Transformers
A pulse transformer is a transformer that is optimised for transmitting rectangular electrical
pulses (that is, pulses with fast rise and fall times and a relatively constant amplitude). Small
versions called signal types are used in digital logic and telecommunications circuits, often
for matching logic drivers to transmission lines. Medium-sized power versions are used in
power-control circuits such as camera flash controllers. Larger power versions are used in the
electrical power distribution industry to interface low-voltage control circuitry to the high-
voltage gates of power semiconductors. Special high voltage pulse transformers are also used
to generate high power pulses for radar, particle accelerators, or other high energy pulsed
power applications.
To minimise distortion of the pulse shape, a pulse transformer needs to have low values of
leakage inductance and distributed capacitance, and a high open-circuit inductance. In power-
type pulse transformers, a low coupling capacitance (between the primary and secondary) is
important to protect the circuitry on the primary side from high-powered transients created by
the load. For the same reason, high insulation resistance and high breakdown voltage are
required. A good transient response is necessary to maintain the rectangular pulse shape at
the secondary, because a pulse with slow edges would create switching losses in the power
semiconductors.
The product of the peak pulse voltage and the duration of the pulse (or more accurately, the
voltage-time integral) is often used to characterise pulse transformers. Generally speaking,
the larger this product, the larger and more expensive the transformer.
Pulse transformers by definition have a duty cycle of less than 1, whatever energy stored in
the coil during the pulse must be "dumped" out before the pulse is fired again.
Audio Transformers
Transformers in a tube amplifier. Output transformers are on the left. The power supply
toroidal transformer is on right.
Audio transformers are usually the factor which limit sound quality when used; electronic
circuits with wide frequency response and low distortion are relatively simple to design.
Transformers are also used in DI boxes to convert high-impedance instrument signals (e.g.
bass guitar) to low impedance signals to enable them to be connected to a microphone input
on the mixing console.
A particularly critical component is the output transformer of an audio power amplifier.
Valve circuits for quality reproduction have long been produced with no other (inter-stage)
audio transformers, but an output transformer is needed to couple the relatively high
impedance (up to a few hundred ohms depending upon configuration) of the output valve(s)
to the low impedance of a loudspeaker. (The valves can deliver a low current at a high
voltage; the speakers require high current at low voltage.) Most solid-state power amplifiers
need no output transformer at all.
For good low-frequency response a relatively large iron core is required; high power handling
increases the required core size. Good high-frequency response requires carefully designed
and implemented windings without excessive leakage inductance or stray capacitance. All
this makes for an expensive component.
Early transistor audio power amplifiers often had output transformers, but they were
eliminated as designers discovered how to design amplifiers without them.
SINGLE LINE DIAGRAM
HT SIDE
33 KV Supply (R.S.E.B.)
Drop Out Fuse (33KV)
Lightning Arrester (33KV)
Gang Operated Switch (G.O) With Earthing
M.O.C.B or V.C.B (33KV)
Current Transformer (5 A )
Potential Transformer (33KV / 110 V)
Three Phase Step Down Transformer (Delta - Star)2000 KVA,
L.V. Side - At No Load (433 V / 2666.7 A)
The first device encountered in a substation is typically a disconnect switch.
The most commonly used switch in small to medium substations is a GANG-OPERATED
SWITCH. "Gang-operated" because the three separate switches for each phase are operated
as a group from a single control.
The purpose of this switch is to disconnect the substation from the incoming line, not to
disconnect the transformer from the load. It is like a large safety switch with no load breaking
capability. It can only break, or "interrupt" the relatively small "magnetizing current" of the
substation transformer. (This is the small amount of current needed to set up the magnetic
field in the transformer core.) A substation must first be disconnected from its secondary or
load side before the primary or high voltage side can be disconnected using the disconnect
switch.
The next device encountered in a substation is the HIGH VOLTAGE POWER FUSES /
DROP OUT FUSE. Depending on the line voltage, they may be up to six feet long. These
fuses stop the flow of current in the event of an internal fault or short-circuit in the
transformer. Overloads due to faults or short circuits on the distribution side of the substation
are prevented by low voltage protective equipment. Drop out fuse are complete with fuse
carrier of fiber glass tube with both end heavily tinned non ferrous metal parts. The brush
type phosphor bronze contacts provide positive high pressure multilane connection and
wiping and cleaning action on closing. The pressure exerted by the contacts initiates the
opening movement of the fuse carrier copper & copper alloys high pressure heavily tinned
metal contacts for fix top contacts assembly and bottom contact assembly. The D.O. Fuse
units are manufactured up to and including 33kv system.
The next device encountered in a substation is LIGHTNING ARRESTER A lightning
arrester is a device used on electrical power systems to protect the insulation on the system
from the damaging effect of lightning. Metal oxide varistors (movs) have been used for
power system protection since the mid 1970s. The typical lightning arrester also known as
surge arrester has a high voltage terminal and a ground terminal. When a lightning surge or
switching surge travels down the power system to the arrester, the current from the surge is
diverted around the protected insulation in most cases to earth.
The next device encountered in a substation is TRANSMISSION LEVEL CIRCUIT
BREAKERS OR CIRCUIT SWITCHERS / MINIMUM OIL CIRCUIT BREAKER are
some of the last devices found in a substation. They are utilized when there is a need to
remotely switch the incoming or outgoing transmission circuits in a substation. They also
may be used in place of high voltage power fuses.
The Circuit Breakers are automatic Switches which can interrupt fault currents. The part of
the Circuit Breakers connected in one phase is called the pole. A Circuit Breaker suitable for
three phase system is called a ‘triple-pole Circuit Breaker. Each pole of the Circuit Breaker
comprises one or more interrupter or arc-extinguishing chambers. The interrupters are
mounted on support insulators. The interrupter encloses a set of fixed and moving contact's
The moving contacts can be drawn apart by means of the operating links of the operating
mechanism. The operating mechanism of the Circuit Breaker gives the necessary energy for
opening and closing of contacts of the Circuit Breakers.
The arc produced by the separation of current carrying contacts is interrupted by a suitable
medium and by adopting suitable techniques for arc extinction. The Circuit Breaker can be
classified on the basis of the arc extinction medium.
The Fault Clearing Process
During the normal operating condition the Circuit Breaker can be opened or closed by a
station operator for the purpose of Switching and maintenance. During the abnormal or faulty
conditions the relays sense the fault and close the trip circuit of the Circuit Breaker.
Thereafter the Circuit Breaker opens. The Circuit Breaker has two working positions, open
and closed. These correspond to open Circuit Breaker contacts and closed Circuit Breaker
contacts respectively. The operation of automatic opening and closing the contacts is
achieved by means of the operating mechanism of the Circuit Breaker. As the relay contacts
close, the trip circuit is closed and the operating mechanism of the Circuit Breaker starts the
opening operation. The contacts of the Circuit Breaker open and an arc is draw between
them. The arc is extinguished at some natural current zero of A.C. wave. The process of
current interruption is completed when the arc is extinguished and the current reaches final
zero value. The fault is said to be cleared. The process of fault clearing has the following
sequence:
1- Fault Occurs. As the fault occurs, the fault impedance being low, the currents increase and
the relay gets actuated. The moving part of the relay move because of the increase in the
operating torque. The relay takes some time to close its contacts.
2 - Relay contacts close the trip circuit of the Circuit Breaker closes and trip coil is energized.
3 - The operating mechanism starts operating for the opening operation.
The Circuit Breaker contacts separate.
4 - Arc is drawn between the breaker contacts. The arc is extinguished
in the Circuit Breaker by suitable techniques. The current reaches final zero
as the arc is extinguished and does not restrict again.
The type of the Circuit Breaker is usually identified according to the medium of arc
extinction. The classification of the Circuit Breakers based on the medium of arc extinction is
as follows:
(1) Air break' Circuit Breaker. (Miniature Circuit Breaker).
(2) Oil Circuit Breaker (tank type of bulk oil)
(3) Minimum oil Circuit Breaker.
(4) Air blast Circuit Breaker.
(5) Vacuum Circuit Breaker.
(6) Sulphur hexafluoride Circuit Breaker. (Single pressure or Double Pressure).
Type Medium Voltage, Breaking Capacity
1 – Air break Circuit
Breaker
Air at atmospheric
pressure
(430 – 600) V– (5-15)MVA
(3.6-12) KV - 500 MVA
2 – Miniature CB. Air at atmospheric
pressure
(430-600 ) V
3 – Tank Type oil CB. Dielectric oil (3.6 – 12) KV
4 – Minimum Oil CB. Dielectric oil (3.6 - 145 )KV
5 – Air Blast CB. Compressed Air
(20 – 40 ) bar
245 KV, 35000 MVA
up to 1100 KV, 50000 MVA
6 – SF6 CB. SF6 Gas 12 KV, 1000 MVA
36 KV , 2000 MVA
145 KV, 7500 MVA
245 KV , 10000 MVA
7 – Vacuum CB. Vacuum 36 KV, 750 MVA
8 – H.V.DC CB. Vacuum , SF6 Gas 500 KV DC
The next device encountered in a substation is INSTRUMENT TRANSFORMERS
i.e. Current Transformer & Potential Transformer
In electrical engineering, a current transformer (CT) is used for measurement of electric
currents. Current transformers are also known as instrument transformers. When current in a
circuit is too high to directly apply to measuring instruments, a current transformer produces
a reduced current accurately proportional to the current in the circuit, which can be
conveniently connected to measuring and recording instruments. A current transformer also
isolates the measuring instruments from what may be very high voltage in the primary circuit.
Current transformers are commonly used in metering and protective relays in the electrical
power industry.
Design
Like any other transformer, a current transformer has a primary winding, a magnetic core,
and a secondary winding. The alternating current flowing in the primary produces a magnetic
field in the core, which then induces current flow in the secondary winding circuit. A primary
objective of current transformer design is to ensure that the primary and secondary circuits
are efficiently coupled, so that the secondary current bears an accurate relationship to the
primary current.
The most common design of CT consists of a length of wire wrapped many times around a
silicon steel ring passed over the circuit being measured. The CT's primary circuit therefore
consists of a single 'turn' of conductor, with a secondary of many hundreds of turns. The
primary winding may be a permanent part of the current transformer, with a heavy copper bar
to carry current through the magnetic core. Window-type current transformers are also
common, which can have circuit cables run through the middle of an opening in the core to
provide a single-turn primary winding. When conductors passing through a CT are not
centered in the circular (or oval) opening, slight inaccuracies may occur.
Current transformers used in metering equipment for three-phase 400 ampere electricity
supply
Usage
Current transformers are used extensively for measuring current and monitoring the operation
of the power grid. Along with voltage leads, revenue-grade CTs drive the electrical utility's
watt-hour meter on virtually every building with three-phase service, and every residence
with greater than 200 amp service.
The CT is typically described by its current ratio from primary to secondary. Often, multiple
CTs are installed as a "stack" for various uses (for example, protection devices and revenue
metering may use separate CTs). Similarly potential transformers are used for measuring
voltage and monitoring the operation of the power grid.
Safety Precautions
Care must be taken that the secondary of a current transformer is not disconnected from its
load while current is flowing in the primary, as the transformer secondary will attempt to
continue driving current across the effectively infinite impedance. This will produce a high
voltage across the open secondary (into the range of several kilovolts in some cases), which
may cause arcing. The high voltage produced will compromise operator and equipment safety
and permanently affect the accuracy of the transformer.
Accuracy
The accuracy of a CT is directly related to a number of factors including:
Burden
Burden class/saturation class
Rating factor
Load
External electromagnetic fields
Temperature and
Physical configuration.
The selected tap, for multi-ratio CT's
Voltage Transformers
Voltage transformers (VTs) or potential transformers (PTs) are another type of instrument
transformer, used for metering and protection in high-voltage circuits. They are designed to
present negligible load to the supply being measured and to have a precise voltage ratio to
accurately step down high voltages so that metering and protective relay equipment can be
operated at a lower potential. Typically the secondary of a voltage transformer is rated for 69
or 120 Volts at rated primary voltage, to match the input ratings of protection relays.
The transformer winding high-voltage connection points are typically labelled as H1, H2
(sometimes H0 if it is internally grounded) and X1, X2, and sometimes an X3 tap may be
present. Sometimes a second isolated winding (Y1, Y2, Y3) may also be available on the
same voltage transformer. The high side (primary) may be connected phase to ground or
phase to phase. The low side (secondary) is usually phase to ground.
The terminal identifications (H1, X1, Y1, etc.) are often referred to as polarity. This applies
to current transformers as well. At any instant terminals with the same suffix numeral have
the same polarity and phase. Correct identification of terminals and wiring is essential for
proper operation of metering and protection relays.
While VTs were formerly used for all voltages greater than 240V primary, modern meters
eliminate the need VTs for most secondary service voltages. VTs are typically used in
circuits where the system voltage level is above 600 V. Modern meters eliminate the need of
VT's since the voltage remains constant and it is measured in the incoming supply.
Potential Transformer is designed for monitoring single phase and three phase power line
voltages in power metering applications
The primary terminal can be connected either in line to line or in line to neutral configuration.
Fused Transformer models are designated by a suffix of “F” for one fuse or “FF” for two
fuses.
A Potential Transformer is a special type of transformer that allows meters to take readings
from electrical service connections with higher voltage (potential) than the meter is normally
capable of handling without at Potential Transformer.
Three-Phase Transformer Circuits
Since Three-Phase is used so often for power distribution systems, it makes sense that we
would need Three-Phase transformers to be able to step voltages up or down. This is only
partially true, as regular single-phase transformers can be ganged together to transform power
between two three-Phase systems in a variety of configurations, eliminating the requirement
for a special Three-Phase transformer. However, special Three-Phase transformers are built
for those tasks, and are able to perform with less material requirement, less size, and less
weight than their modular counterparts.
A Three-Phase Transformer is made of three sets of primary and secondary windings, each
set wound around one leg of an iron core assembly. Essentially it looks like three single
Phase transformers sharing a joined core as in Figure below.
Three-Phase Transformer core has three set of windings..
Those sets of primary and secondary windings will be connected in either Δ or Y
configurations to form a complete unit. The various combinations of ways that these
windings can be connected together in will be the focus of this section.
Whether the winding sets share a common core assembly or each winding pair is a separate
Transformer, the winding connection options are the same:
Primary - Secondary
Y - Y
Y - Δ
Δ - Y
Δ - Δ
The reasons for choosing a Y or Δ configuration for Transformer winding connections are the
same as for any other Three-Phase application: Y connections provide the opportunity for
multiple voltages, while Δ connections enjoy a higher level of reliability (if one winding fails
open, the other two can still maintain full line voltages to the load).
Probably the most important aspect of connecting three sets of primary and secondary
windings together to form a Three-Phase Transformer bank is paying attention to proper
winding phasing (the dots used to denote “polarity” of windings). Remember the proper
phase relationships between the phase windings of Δ and Y: (Figure below)
(Y) The center point of the “Y” must tie either all the “-” or all the “+” winding points
together. (Δ) The winding polarities must stack together in a complementary manner ( + to
-).
Getting this phasing correct when the windings aren't shown in regular Y or Δ configuration
can be tricky. Let me illustrate, starting with Figure below.
Inputs A1, A2, A3 may be wired either “Δ” or “Y”, as may outputs B1, B2, B3.
Three individual transformers are to be connected together to transform power from one
Three Phase system to another. First, I'll show the wiring connections for a Δ -Y
configuration: Figure below.
Phase wiring for “Δ-Y”Transformer.
Such a configuration (Figure above) would allow for the provision of multiple voltages (line-
to-line or line-to-neutral) in the second power system, from a source power system having no
neutral.