Vidyut Sanchaar Electrical Magazine NIT Arunachal Pradesh

5/21/2018 Vidyut Sanchaar Electrical Magazine NIT Arunachal Pradesh

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About National Institute of

Technology Arunachal Pradesh

The National Institute of TechnologyArunachal Pradesh was inaugurated on 18thAug 2010 as a member of a group of tennew NITs. These new NITs were establishedas centers of excellence in technicaleducation to combat the growing need oftechnological professionals in India as well as in the World. The institute has been

through many trials since its establishment in 2010, but ultimately has triumphedover all challenges and is thriving today with more than 350 students on roll and

many distinguished members of faculty as well as a good many numbers ofcompetent administrative staff.

About Electrical & Electronics Engineering:

Electrical & Electronics Engineering is afield of engineering that generally deals

with the study and applicationof electricity, electronics andelectromagnetism. The field first becamean identifiable occupation in the latenineteenth century aftercommercialization of the electrictelegraph and electrical power supply. Itnow covers a range of subtopics including power, electronics, control systems,

signal processing and telecommunications. The Department of Electrical &

Electronics Engineering was established right from inception of the institute in2010. The department offers a four year degree program in Electrical & ElectronicsEngineering with an annual intake of 30 students.


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Wireless Power Transmission for Space Based Solar Power

1Krishna Kumar,

2Vivek Hanumante,

1Santosh Shukla

1Department of Electrical & Electronics Engineering

2Department of Electronics & Communication Engineering

National Institute of Technology, Arunachal Pradesh

Wireless Power Transmission has been the major breakthrough in the field ofelectricity in recent years of technological advancements. The significance ofgreenhouse effect resulting from burning fossil fuels and escalating prices of fossilfuels have again brought to the publics attention the possibility of utilizingrenewable energy sources. As the level of energy consumption is mounting

throughout the world, the chances for the generation of uninterrupted renewablepower is becoming more likely with the implementation of solar power systems.

The concept of wireless power transmission for Space based Solar Power (SPS)was first proposed by Peter Glaser in 1986. This article presents the wide

possibility of generating electricity using the Solar Power in space by using solarcells in earth orbit and utilizing wireless power transmission. Since earth suffersfrom the lack of availability of solar power as is it is available only during daytime. The solar panel can be mounted on the satellite which can revolve in earthsorbit. In a geo-synchronous system, SPS can be illuminated for over 99% of thetime. Figure 1 presents the comparison of solar energy.

Figure 1: Comparison of Space and Ground solar energy.

In space, a solar energy collected and converted into DC electricity. The powergenerated in space can be transmitted wirelessly to earth in three ways using:

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Microwave signal: Collected DC energy is converted into Microwave usinga DC-to-microwave converter, and a large array to beam down the microwave

power; over the ground, a large Rectenna (rectifying antenna) to convert themicrowave power back to DC power. The main advantage of using Microwavesignal is its haze (atmosphere) penetrating property, and high travelling speedequals to the speed of light, which in turns results into the high range of


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transmission of wireless power. Due to this it is remote sensing and can beadvantageous in transmitting power in hard locations.

But it suffers from major disadvantage of requirement of large antenna size.2. LASER: LASER helps in overcoming the disadvantage of wireless power

transmission usingmicrowave signal. LASER

being highly directive and

having narrow beamwidthrequires less antennaaperture.

But LASER suffers fromthe disadvantages like powerlosses due to atmosphere,rain attenuation in

stratosphere.3. Hybrid LASER-

Microwave: This method isemployed to overcome the major disadvantages of previous two methods. In thismethod power is beamed using LASER from satellite to photovoltaic array on the

platform present in stratosphere at the height of 20km from the ground. Then

received power at stratosphere is again converted into microwave and istransmitted to the ground.In this hybrid method LASER is used to transmit power from satellite to platform

since it is highly directive and does not suffer from atmospheric losses tillstratosphere. Further power is transmitted using microwave to eliminate the lossesby LASER. Conversion and retransmission of power reduces the systemefficiency, but the combination of LASER and microwave reduces the size ofRectenna, which in turns also reduces the total cost of the system.

Apart from utilizing the benefit of Wireless Power Transmission, one of thesophisticated applications of SPS system is in Thunderstorm Solar Power Satellite(TSPS). In the TSPS concept this beam is concentrated and directed into the coldrain region of a thunderstorm. Directing this beam of intense energy into the coldrain downdraft of a mesocyclone will heat the raindrops. This is expected to

disrupt the tornado formation process if the heating is applied to the right place todestabilize the convective shears. This can be helpful in saving many lives and

properties.Wireless Power Transmission is one of the prevailing fields in Power and

Energy. This includes a wide range of future scope and technologicaladvancement.


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Coreless Motor

Motors are those devices which convert electrical energy into motion. It is one ofthe most beautiful applications of the theory- "current carrying conductor

experience force when placed in magnetic field for certain orientation".First device which response to electrical signal by producing circular motion wasdemonstrated by Michael Faraday in 1821.He dipped a bar magnet in a cup filledwith mercury and a free-hanging wire above it so that its one end is dipped in poolof mercury. When current flows from wire, it will rotate around magnet. Later on,

practical motor are developed with armature placed in magnetic field and can beused to get motion.Conventional motors are consisting of

coil winded on a soft iron core whichtogether called armature. Armature is

placed between two opposite poles ofmagnet and when current flows fromthe coil, torque experience byarmature causes rotatory motion.Coreless motor was invented by

Nobuteru Maekawa. He published hispaper and made patent in his name in 1978.Since then, many innovations and

development were introduce to make it more efficient.Coreless motors are those motors in which rotor is used which is analog to iron

core armature in conventional motor. But rotor shape and structure is totallydifferent from that of armature. Armature resemble solid cylindrical structure with

rotating stuff at its axis whereas rotor is hollow cylindrical in structure. Othercomponents like commutator, brushes are used but main thing which createdifference is winding of coils in rotor, rotor structure and structure of magnet. Ithas a cylindrical magnet present at the center around which cup-shaped hollowrotor is free to rotate. Cylindrical magnet has as hole through the axis in whichstuff of rotor is placed to provide support to rotating rotor. The rotor is hollowcylindrical with one end open and other is provided with a flat circular supportingDisc. This disc is non-conducting with attached commutator comprising a plurality

of segments vertically erected around central axis of the disk-shaped plate. Rotorcomprising a radially thin cylindrical coil formed of progressive uniform andsmoothly continuous convolutions of insulated wire. Main innovation in this motoris the winding pattern which resembles rhombus structure. This rhombus shapedcoil is actually on the surface of cylindrical rotor.

Outside of the rotor is stator which is made up of magnetic material for encasingrotor. Since stator is made up of magnetic material, so it concentrate magnetic field

Fig: A section of Coreless Motor


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lines maximum to pass through rotor and produce maximum torque. It also protectrotating rotor from outer disturbance. There is a narrow space present betweencylindrical magnet and stator in which rotor is free to rotate.In coreless motor, rotor consists entirely of coil and no heavy component like iron,so it has low inertia and attains maximum speed in very less interval of time. Someof advantages of coreless motor over conventional motors are:

1. Smooth cog-free operation

2. Due to absence of iron core, rotor has low moment of inertia hence fastacceleration (150,000 rad/sec2).

3.Negligible iron loss and hence higher efficiency.4.

Zero detent and low ripple torque (


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Latest Trends in Power Systems

Germany is considering an aggressive plan that would push high-voltage direct

current, or HVDC, from its conventional position on the periphery of AC grids to a

central role .The primary reason is simple: For the first time, HVDC seems cheaperthan patching up the AC grid .But Germanys transmission planners also have

another motivation .They want to provide as much performance and reliability as

they can to an AC grid thats already stained by excess wind power. For that they

are considering implementing power electronics that are capable of doing

something thats never before done on a commercial line: stop DC current in

milliseconds flat.

The Smartest Greenest Grid.

One Factor that has made HVDC particularly attractive is improvements to

electronic convertors-the units at either end of the line that transform AC current


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into DC current, and vice versa. Classic HVDC lines use convertors built from

thyristors, which are efficient but limited in their capabilities.

In the late 1990s Swedish engineering giant ABB commercialized more

sophisticated and compact convertors, built from high-frequency silicon insulated-gate bipolar transistors(IGBTs). These Voltage source convertors (VSCs)

control their own voltage and can thus help stabilize the AC grid around them. In

an HVDC line using these advanced convertors, hundreds of IGBTs connected in

series fire synchronously to channel power from AC line and rectify it into steady

current for DC line. The convertor at the downstream end of the line powers a

similar process to convert the current back into AC .At the same time these IGBT-

based convertors can watch for and correct voltage dips or surges on the AC lines.

That has made them popular in applications such as linking offshore wind farms

where shifting power levels require dynamic regulation of voltage at the AC

connection point.

Stationary and Mobile Energy Storage Systems: According to a recent U.S.Department of Energy (DOE) Report, a future smart grid should accommodate all

generation and storage options. Pumped hydro, compressed air, superconductingmagnetic storage units, batteries, super capacitors, and flywheels are among themain stationary storage options envisioned for smart grids. Magnetic storage

options, e.g., superconducting magnetic energy storage (SMES) systems, are fast-acting and suitable for load leveling, voltage and frequency stability, andimproving Power quality. Electrochemical energy storage options have beenwidely adopted due to their desirable characteristics, such as rapid responses,cycling capability, and relatively low cost. Lithium-ion (Li-ion) batteries are thefastest-growing battery technology in utility-scale applications and will make upmore than a quarter of the US$4.1 billion stationary energy Storage market by2018. Sodium-sulfur (NaS) batteries are another viable large-scale storage option,given their high energy density, high efficiency of charge and discharge, long cyclelife, and low material cost. Their high operating temperature (300350 C) and the

highly corrosive nature of their sodium polysulfide des make them more suitablefor stationary applications. Recent advancements of the technology include solidsodium metals linked to a sulphur Compound by a paper-thin ceramic membrane.Such batteries can operate at a lower temperature range (less than 90 C) and storeup to 40 MWh. It is expected that NaS will Become the major energy storagetechnology for smart grid developments: Japan has installed more than 200 MW of


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NaS storage. The largest utility-scale NaS battery in the United States (4 MW),nicknamed big old battery, is installed in Presidio, Texas.

Mobile energy storage systems, such as plug-in hybrid electric vehicles (PHEVs),are viable storage options for future smart grids. Successful commercialization ofPHEVs as mobile storage options will correlate with onboard storage technologydevelopment. Li-ion batteries are a viable option; their energy density is projected

to reach the practical Limit of 250 Wh/kg by 2025, and their cost should decreaseto US$250300/kWh by 2030. Lithium sulfur batteries are another high-densityenergy option (350 Wh/kg). Their cycle life is expected to rise to 1,000 cycles by2020. Lithium air batteries, with very high energy densities of up to 1,000 Wh/kg,are expected to be commercially available by 2020. Hybrid ultra-capacitor/ batterystorage systems can benefit from ultra-capacitor characteristics such as long cyclelife, high charge and discharge efficiency, and wide range of operating

temperature. At a 2008 Los Angeles auto show, AFS Trinity demonstrated a PHEVwith an ultra-capacitor/battery storage unit that it said is six times as durable as Li-ion batterybased PHEV storage units.

(Source: - IEEE Spectrum May 2013 and IEEE Power and Energy Magazine2012)

Ankur Katiyar

4

th

year EEE


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THE NEXT GENERATION POWER TRANSMISSION

Japan wants to power up three million houses with wireless energy from space.They have serious plans to send a solar-panel-equipped satellite into space that

could wirelessly beam a gig watt-strong stream of power down to earth.

Japans wireless, power-generating, solar satellite system

Space Satellite System

The concept of wireless power transmission has been an area of research that theU.S. Department of Energy (D.O.E.) and the National Aeronautical SpaceAdministration (NASA) have been working to develop. NASA has been looking

into research to develop a collection of satellites with the capability to collect solarenergy and transmit the power to earth. The current design for project by NASAand DOE is to use microwaves to transfer power to rectifying antennas on earths.

William C. Brown, the pioneer in wireless power transmission technology, hasdesigned, developed a unit and demonstrated to show how power can betransferred through free space by microwaves. In the transmission side, themicrowave power source generates microwave power and the output power iscontrolled by electronic control circuits. The wave guide ferrite circulator which

protects the microwave source from reflected power is connected with the

microwave power source through the Coax Wave guide Adaptor. The tunermatches the impedance between the transmitting antenna and the microwavesource. The attenuated signals will separated which is based on the direction of

signal propagation by Directional Coupler. The transmitting antenna radiates thepower uniformly through free space to the rectenna. In the receiving side, arectenna receives the transmitted power and converts the microwave power intoDC power. The impedance matching circuit and filter is provided to setting theoutput impedance of a signal source equal to the rectifying circuit. The rectifyingcircuit consists of Schottky barrier diodes converts the received microwave powerinto DC power.


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Nikolai Tesla

Nikolai Tesla was the first to develop the designs for wireless power transmission.Tesla was famed for his work in the research and worked with alternating current.

His wireless research began with his original transformer design and though aseries of experiments that separated the primary and the secondary coils of atransformer. Tesla performed many wireless power transmission experiments nearColorado Springs. Tesla in his experiment was able to light a filament with only asingle connection to earth. Teslas findings lead him to design the Wardenclyffe

plant as a giant mushroom shaped wireless power transmitter. He was unable tocomplete construction of this project.

Wardenclyffe tower also known as teslas tower (187 foot) at long Island, New York.

Components of WPT System

The Primary components of Wireless Power Transmission are MicrowaveGenerator, Transmitting antenna and Receiving antenna (Rectenna).

Microwave Generator:- The microwave transmitting devices are classified asMicrowave Vacuum Tubes (magnetron, klystron, Travelling Wave Tube (TWT),and Microwave Power Module (MPM)) and Semiconductor Microwavetransmitters (GaAs MESFET, GaN pHEMT, SiC MESFET, AlGaN/GaN HFET,


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and InGaAS). Magnetron is widely used for experimentation of WPT. Themicrowave transmission often uses 2.45GHz or 5.8GHz of ISM band. The otherchoices of frequencies are 8.5 GHz, 10 GHz and 35 GHz. The highest efficiencyover 90% is achieved at 2.45 GHz among all the frequencies.

Transmitting Antenna:- The slotted wave guide antenna, micro strip patchantenna, and parabolic dish antenna are the most popular type of transmittingantenna. The slotted waveguide antenna is ideal for power transmission because ofits high efficiency (> 95%) and high power handling capability.

Rectenna:- The concept, the name Rectenna was conceived by W.C. Brown ofRaytheon Company in the early of 1960s. The Rectenna is a passive elementconsists of antenna, rectifying circuit with a low pass filter between the antennasand rectifying diode. The antenna used in rectenna may be dipole, Yagi Uda,

micro-strip or parabolic dish antenna. The patch dipole antenna achieved thehighest efficiency among all. Schottky barrier diodes (GaAs-W, Si, and GaAs) areusually used in the rectifying circuit due to the faster reverse recovery time andmuch lower forward voltage drop and good RF characteristics.

Ankit Kumar Garg

IIIrd Year, EEE


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How does solar power plant work

Solar power works by converting sunlight directly into electricity, which we can beuse to supply in our homes and cities. But this amazing feat does not happen by

magic. It takes a careful mix of chemistry, physics, engineering, manufacturing,electrical work and some good old-fashioned labor.

sun has almost everything to do with solar energy; it is only sun who manages to

provide 1000 watts of power per square meter. That is enormous amount of energy

to take, if we have enough solar cells array to place on open land to capture energy.

Proper solar panels are very common these days, these solar panels can take up the

entire electricity load of a home, although this is not very common but definitely

on the way to be very useful and adoptable in near future, Where all of our homeswill be using solar power.

Solar power plants can produce energy in two ways:

1. Solar thermalpower plants - In this type, solar energy heats a transfer fluid, which isused to heat water. That water creates steam to spin a turbine that can then produceelectricity.
http://solar.calfinder.com/library/thermalhttp://solar.calfinder.com/library/thermalhttp://solar.calfinder.com/library/thermal


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2. Solar photovoltaic (PV) plants - PV plants utilize solar power panels to convert solarradiation directly into electricity.

Solar-Thermal plants:

In these plants, commonly known as concentrated solar power (CSP) plants,several rows of trough-shaped, parabolic mirrors are strategically designed tocapture and concentrate the sun rays onto a focal point; Just like a child might usea magnifying glass to burn ants. That point is a black pipe running the length of therow of mirrors. Inside this pipe is a transfer fluid, which heats up to very hottemperatures, often upwards of 300 degrees Fahrenheit, which then heats water tocreate steam. The steam is piped to an onsite turbine-generator to produceelectricity, Subsequently transmitted over power lines. On cloudy days, the planthas a supplementary natural gas boiler. The plant can burn natural gas to heat the

water, creating steam to generate electricity.

A CSP power plant allows delivery of sustainable energy to the local ruralpopulations of developing countrieseven in the remotest areas. The only thingthat is needed is sunlight, a large area of flat land and water. These inputs are allavailable in Namibia and in Mozambique, where there is shortages of electricity.Such shortages regularly cause shutdowns of the electricity network of several

provinces. By providing electricity generation, the CSP power plant has thepotential to enormously improve the quality of life and living for people in theseareas.

Solar Photovoltaic Plants

Photovoltaic plants are very straightforward. Several solar power panels areinstalled to form an array. Typically, a handful of panels will be "strung" togetherin series on a single mounting system. Each set of panels collects solar energy,

converts it directly into electricity, and sends that electricity through wiring to theelectric grid. PV power plants are relatively rare because solar thermal power iscurrently much more efficient at producing electricity on a large scale.

The process begins with the solar cell. This scientific creation is the base fromwhich the solar panel is built. Solar cells contain one or more semiconductormaterials that are able through their makeup and positioning to convert sunlightinto electricity. These solar panels are shipped to our home, where they aremounted byqualified installers onto ourrooftop or some other mounting system.
http://solar.calfinder.com/library/solar-electricity/photovoltaic-cell/http://solar.calfinder.com/library/solar-electricity/photovoltaic-cell/http://solar.calfinder.com/library/solar-electricity/solar-panels/http://solar.calfinder.com/library/solar-electricity/solar-panels/http://solar.calfinder.com/blog/solar-information/semiconductors-the-science-behind-solar/http://solar.calfinder.com/blog/solar-information/semiconductors-the-science-behind-solar/http://solar.calfinder.com/blog/solar-information/semiconductors-the-science-behind-solar/http://solar.calfinder.com/http://solar.calfinder.com/blog/solar-information/what-are-the-different-types-of-home-solar-power-systems/http://solar.calfinder.com/blog/solar-information/what-are-the-different-types-of-home-solar-power-systems/http://solar.calfinder.com/http://solar.calfinder.com/blog/solar-information/semiconductors-the-science-behind-solar/http://solar.calfinder.com/blog/solar-information/semiconductors-the-science-behind-solar/http://solar.calfinder.com/library/solar-electricity/solar-panels/http://solar.calfinder.com/library/solar-electricity/photovoltaic-cell/


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Once installed, those panels are wired together in series to form a solar array. Theelectrical current running through these wires must pass through an inverter, wherethe direct-current (DC) electricity created by the solar panels is converted toalternating-current (AC) that is usable in the home. Most of the solar systems aregrid-tied,meaning that excess solar electricity is funneled back into the grid. Theremay be some additional steps which can be installed by different companies toenhance and improve the maintenance and overall performance of solar panels.

These steps may include, electric meter, weather station device, DC switchdisconnection module, Transformer, AC switch disconnection module, dataacquisition module, electricity distribution panel module

The efficiency of solar power, or more specifically a solar panel,depends on thematerials used to make each solar cell. A solar cell is that portion of a solar panelin which sunlight is collected and converted to solar electricity. The materialswithin each cell that perform this valuable duty are semiconductors.The efficiencyof a solar cell - and of solar power - is measured as the percentage of the totalsunlight striking the cell that is converted into electricity by the cell.
http://solar.calfinder.com/blog/solar-information/whats-the-difference-between-off-grid-and-grid-tie-home-solar-systems/http://solar.calfinder.com/blog/solar-information/whats-the-difference-between-off-grid-and-grid-tie-home-solar-systems/http://solar.calfinder.com/blog/solar-electric/how-do-solar-panels-work/http://solar.calfinder.com/blog/solar-information/semiconductors-the-science-behind-solar/http://solar.calfinder.com/blog/solar-information/what-are-the-different-types-of-home-solar-power-systems/http://solar.calfinder.com/blog/solar-information/what-are-the-different-types-of-home-solar-power-systems/http://solar.calfinder.com/blog/solar-information/semiconductors-the-science-behind-solar/http://solar.calfinder.com/blog/solar-electric/how-do-solar-panels-work/http://solar.calfinder.com/blog/solar-information/whats-the-difference-between-off-grid-and-grid-tie-home-solar-systems/


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In conventional solar panels, crystalline silicon is the semiconductor of choice.Silicon solar panels hold the highest consistent conversion efficiencies of solar

panels in use today. They convert on and average between 15 and 20 percent of thelight that hits them.

Thin-film solar panels are considered the wave of the future. They cost much lessto manufacture than crystalline silicon panels, but as of yet cannot equal silicon inconversion efficiency. Cadmium telluride (CdTe) and cadmium-indium-gallium-selenide (CIGS) solar panels are the current champions of thin-film solartechnologies, averaging around 11 percent efficiency. Most of the thin-film solarcells reside in the 4-10 percent range.

Solar power is sti ll a relati vely young technology. Scienti sts and researchers

bel ieve they can create solar cel ls that wi ll reach 30-40 percent eff iciency and

beyond in the not-too-distant future.
http://solar.calfinder.com/blog/solar-information/solar-cell-conversion-efficiency-how-three-generations-stack-up/http://solar.calfinder.com/blog/solar-information/solar-cell-conversion-efficiency-how-three-generations-stack-up/


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LIGHTING, VOLTAGE SURGES AND LIGHTING

ARRESTOR

Lighting is a very important factor that is to be considering in the power system.

This can create voltage surges in several ways. Lighting can score a direct hit onour house or can strike the overhead power lines which enters our house, or themain power line that is blocks away from our home. Lighting can strike branchcircuitry wiring in the walls of our house or an object near our home such as a treeor the ground itself and cause a surge.Voltage surges can also be created by cloud to cloud lighting near your home. A

highly charged cloud which passes over our home can also induce a voltage surge.Voltage surges can also be caused by standard on and off switching activities oflarge motors or pieces of equipment. These surges can be created by a neighbor or

by a business or manufacturing facility some distance from our house. Thesesurges are insidious and for the most part are silent. They can occur with little orno warning.

Method to suppress lighting and voltage surges:

When a voltage surge is created, it wants to equalize itself and it wants to do it asquickly as possible. These things seem to have very little patience. The surges willdo whatever it takes to equalize or neutralize them, even if it means short circuiting

all of our electronic equipment. Frequently it looks for the microchips in ourelectronic devices. They are an easy target. They offer a path of least resistanceThe method of providing maximum protection for equipment is quite simple. Bycreating a pathway for the voltage surge (electricity) to get to and into the groundoutside our house as quickly as possible. This is not, in most cases, a difficult task.The first step is simple. We have to create an excellent grounding system for yourhousehold electrical system. We can achieve this by driving numerous groundingrods into virgin soil around our house, connected by a continuous heavy solidcopper wire which is welded to each grounding rod. This solid copper wire beginson the grounding bar inside of our electrical panel and terminates at the last

grounding rod.Step two in household surge protection is to install a lightning arrester inside of ourelectric service panel. These devices can be extremely effective in interceptinglarge voltage surges which travel in the electric power lines. These devices capturethe voltage surges and bleed them off to the grounding wire which.

The final step in the protection plan is to install point of use surge suppression

devices. Often these are called transient voltage surge suppressors. They are


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capable of only stopping the leftover voltage surge which got past the groundingsystem and the lightning arrester. They cannot protect our electronic devices bythemselves. They must be used in conjunction with the grounding system and thelightning arresters.Some devices can also protect phone equipment at the same time. This is veryimportant for those individuals who have computer modems. Massive voltagesurges can come across phone lines as well. These surges can enter our computer

through the telephone line. We have to be sure the telephone ground wire is tied tothe upgraded electrical grounding system

What is a surge arrester?Surge arresters are devices that help prevent damage to apparatus due to high

voltages. The arrester provides a low-impedance path to ground for the currentfrom a lightning strike or transient voltage and then restores to a normal operating

conditions. When a high voltage (greater than the normal line voltage) exists on theline, the arrester immediately furnishes a path to ground and thus limits and drainsoff the excess voltage. The arrester must provide this relief and then prevent anyfurther flow of current to ground. The arrester has two functions; it must provide a

point in the circuit at which an over-voltage pulse can pass to ground and second,to prevent any follow-up current from flowing to ground.

Working Principle of LA:The earth screen and ground wires can well protect the electrical system against

direct lightning strokes but they fail to provide protection against traveling waves,which may reach the terminal apparatus. The lightning arresters or surge diverters

provide protection against such surges. A lightning arrester or a surge diverted is aprotective device, which conducts the high voltage surges on the power system tothe ground.It consists of a spark gap in series with a non-linear resistor. One end of the

diverter is connected to the terminal of the equipment to be protected and the otherend is effectively grounded. The length of the gap is so set that normal voltage is

not enough to cause an arc but a dangerously high voltage will break down the airinsulation and form an arc. The property of the non-linear resistance is that itsresistance decreases as the voltage (or current) increases and vice-versa.

The action of the lightning arrester or surge diverter is as under:

(i) Under normal operation, the lightning arrester is off the line i.e. it conducts nocurrent to earth or the gap is non-conducting


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(ii) On the occurrence of over voltage, the air insulation across the gap breaksdown and an arc is formed providing a low resistance path for the surge to theground. In this way, the excess charge on the line due to the surge is harmlesslyconducted through the arrester to the ground instead of being sent back over theline.(iii) It is worthwhile to mention the function of non-linear resistor in the operationof arrester. As the gap sparks over due to over voltage, the arc would be a short-

circuit on the power system and may cause power-follow current in the arrester.Since the characteristic of the resistor is to offer low resistance to high voltage (orcurrent), it gives the effect of short-circuit. After the surge is over, the resistoroffers high resistance to make the gap non-conducting.

Type of LA for Outdoor Applications:There are several types of lightning arresters in general use. They differ only in

constructional details but operate on the same principle, providing low resistancepath for the surges to the round.

1. Rod arrester 2. Horn gap arrester 3. Multi gap arrester 4. Expulsion type lightning arrester 5. Valve type lightning arrester

Installation of LA: The arrester should be connected to ground to a low resistance for

effective discharge of the surge current. The arrester should be mounted close to the equipment to be protected

& connected with shortest possible lead on both the line & groundside to reduce the inductive effects of the leads while discharginglarge surge current.

Maintenance of LA: Cleaning the outside of the arrester housing. The line should be de-energized before handling the arrester. The earth connection should be checked periodically.

To record the readings of the surge counter. The line lead is securely fastened to the line conductor and arrester The ground lead is securely fastened to the arrester terminal and

ground.

Santosh Shukla4thYear EEE


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Inrush Current of Transformers

A problem related to the voltage level in the transformer is the problem of currentinrush at starting. Suppose voltage is:

() ( )Is applied at the moment the transformer is first connected to the power line. Themaximum flux height reached on the first half cycle of the applied voltage dependson the phase of the voltage at the time the voltage is applied. If the initial voltage is

() ( ) ()And if the initial flux in the core is zero, then the maximum flux during the first

half cycle will just equal the maximum flux at steady state:

The flux level is just the steady-state flux, so ot causes no special problems. But ifapplied voltage happens to be

() The maximum flux during the first half cycle is given by

() ()

()

This maximum flux is twice as high as the normal steady state flux. The doublymaximum flux in the core results in an enormous magnetization current. For thistime transformer looks like short circuit and very large current flows. For any other

phase angle the applied voltage between 90, which is no problem and 0, which is

the worst case, there is some excess current flow. The applied phase angle of thevoltage is not normally controlled on starting, so there can be huge inrush currentsduring the first cycles after the transformer is connected to the line. Thetransformer and the power system which it is connected must be able to withstand

these currents.

Bikash SahFourth Year, EEE

(Courtesy @ Electrical Machinery Fundamentals, S. J Chapman)


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ANTENNA

Antenna is basically a transducer which is used to receive or transmit theelectromagnetic waves . It is also called aerial. Television antenna is designedto receive the broadcasting TV signals. Antenna Galaxies was established likethe name of the two colliding galaxies are NGC 4038 and NGC 4039.When a question arises in our mind of designing an antenna, then the firstthing we need to know is the basics or fundamentals of antenna. And these

basics includes the required questions- what is the desired frequency, gain,bandwidth, impedance, polarization? These parameters are explained below-

Frequency

Frequency is the oscillating speed of the electromagnetic waves which

governs how the wave propagates and how it reflects?

Frequency Bands

Frequency bands which is the range over which an antenna can properlyradiate or receive energy.

Radiation Pattern

It is the graphical depiction of the relative field strength transmitted from or

received by an antenna .

Directivity

It is a measure of how directional an antennas radiation pattern is.

Efficiency and Antenna Gain

An antennas efficiency is a measure of how much power is radiated by

the antenna relative to antenna input power. And antenna gain is the realpower radiated in a particular direction.

BEAMWIDTHS AND SIDELOBES

An antennas radiation pattern in the far field is often characterized by its

beam width and side lobe levels.


33

IMPEDANCE

Antenna impedance is presented as the ratio of voltage to current at theantennas terminals. Low and high frequency models are presented for

transmission lines.

BANDWIDTH

The bandwidth of an antenna is the frequency range over which the antennaradiates.

POLARIZATION OF WAVES

All electromagnetic plane waves have an associated polarization. The antennaconcepts of linear, circular and elliptical polarization are presented.

POLARIZATION OF ANTENNAS

This is the fundamental concept that antennas are also classified by their

polarization defining that type of plane wave polarization to which theantennas are most sensitive.

EFFECTIVE APERTURE

Effective aperture is a basic antenna concept that is a measure of the powercaptured by an antenna from a plane wave. Effective aperture can beexpressed as a function of the antenna gain and the wavelength ofinterest.

FRIIS TRANSMISSION EQUATION

Friis Transmission Formula is the most fundamental equation of antenna theory.This equation relates transmit power, antenna gain, distance and wavelengthto received power.

ANTENNA TEMPERATURE


34

Antenna Temperature is a property of an antenna and the environment itoperates in .It is the measure of the noise received by the antenna due tothermal effects.Some of the fundamental antenna types are also introduced in it-

WIRE ANTENNAS -Short Diploma Antenna -Diploma Antenna

-Half-Wave Antenna -Broadband Diplomas -Monopole Antenna -Loop Antenna

TRAVELLING WAVE ANTENNAS

-Helical Antennas -Spiral Antennas

MICROSTRIP ANTENNAS -Rectangular microstrip (patch) antennas -Planar Inverted F- Antennas (PIFA)

REFLECTOR ANTENNAS

-Corner Reflector -Parabolic Reflector APERTURE ANTENNAS -Slot Antenna -Cavity - Backed Slot Antenna

-Inverted F-Antenna -Horn Antenna

-Vivaldi Antenna -Telescopes

LOG - PERIODIC ANTENNA

-Bow Tie Antennas -Log- Periodic Antennas

OTHER ANTENNAS-

NFC Antennas

Now after knowing the basics, we can think of designing an antenna. So, to

design a simple antenna, we have to follow the below given steps At first, we have to determine the desired frequency. This is needed as

because of determining the antennas length


35

Then, Get a good conductor. For the example we can use a copper wire anda piece of copper plating. Also we will need a co-axial cable (75 ohm is

better than 50 ohm, for Wi-Fi 50 ohm is better than 75 ohm). Work out the length we need the wire to be . This is done by using the

frequency value from step 1 to find the wavelength of the signal. To do thiswe simply need to divide the speed of light (c = 299 792 458 m/s) by thefrequency (f). In the case of 2.45GHz the wavelength is 12.236cm. Usually

monopole antennas are half-wavelength structures, so the length of the wireshould be 12.236/2 = 6.118cm.

Cut the wire a little bigger than we need, about 6 .5cm or so. This way wecan pare it back based on performance.

Form a "Ground-Plane. This is basically used to form a theoretical mirrorimage of the antenna. Simply we can use the copper plate that we picked upearlier. It should be at least half a wavelength square.

Drill a hole in the center of the plate just big enough for the co-axial cable tofit through.

Pare the Co-ax cable to reveal its ground [outer conductor], which can bepulled back to reveal the inside insulator.

Push the cable through so that the start of outer insulation is flush with thehole . The ground conductor is now above the ground-plane. Fold the ground

conductor back and solder it to the copper ground plane. Pare the inside insulation back to reveal the signal conductor. Solder the copper wire to the signal conductor of the co-ax.

We should be sure about that the antenna is kept perpendicular to thesource of the radio signals as because the radiation pattern is null at the tipof the wire. Wire should be also kept perpendicular to the ground plane. So, ifa question is asked that how is the antenna designed? We can answer it as;

it starts with a firm understanding. Then if we know about many of thefundamentals begin to figure out which might work for the application. Anantenna design can range from virtually impossible to very situations andconstraints. Hence, there is no general formula or order to reliably design anantenna.

-By Bhawna KumariIInd Year, EEE


36

FAQS about CORONA EFFECT

Many of us have seen

this beautiful picture.

This is corona glow,

now we try to know,

what is corona (i.e.

corona effect), how it

occur and many more

about it.

In Electric-power

transmission

practically there is a

bulk transfer of

electrical energy,

from generating

stations situated many kilometers away from the main consumption centers or the

cities. For this reason the long distance transmission cables are of utmost necessityfor effective power transfer, which in-evidently results in huge losses across the

system. Minimizing those has been a major challenge for power engineers of late

and to do that one should have a clear understanding of the type and nature of

losses. One of them being the corona effect in power system, which has a

predominant role in reducing the efficiency of EHV (extra high voltage lines)

which we are going to concentrate on, in this article.

What is corona effect?

Electric transmission lines can generate a small amount of sound energy as a result

of corona. Corona is a phenomenon associated with all transmission lines. Under

certain conditions, the localized electric field near energized components and

conductors can produce a tiny electric discharge or corona that causes the


37

surrounding air molecules to ionize, or undergo a slight localized change of electric

charge.

Utility companies try to reduce the amount of corona because in addition to the

low levels of noise that result, corona is a power loss, and in extreme cases, it candamage system components over time. Corona occurs on all types of transmission

lines, but it becomes more noticeable at higher voltages (345 kV and higher).

Under fair weather conditions, the audible noise from corona is minor and rarely

noticed.

During wet and humid conditions, water drops collect on the conductors and

increase corona activity. Under these conditions, a crackling or humming sound

may be heard in the immediate vicinity of the line. Corona results in a power loss.

Power losses like corona result in operating inefficiencies and increase the cost ofservice for all ratepayers; a major concern in transmission line design is the

reduction of losses.

Why it occurs?

When an alternating current is made to flow across two conductors of the

transmission line whose spacing is large compared to their diameters, then air

surrounding the conductors (composed of ions) is subjected to di-electric stress.

At low values of supply end voltage, nothing really occurs as the stress is too less

to ionize the air outside. But when the potential difference is made to increase

beyond some threshold value of around 30 kV known as the critical disruptive

voltage, then the field strength increases and then the air surrounding it experiences

stress high enough to be dissociated into ions making the atmosphere conducting.

This results in electric discharge around the conductors due to the flow of these

ions, giving rise to a faint luminescent glow, along with the hissing sound

accompanied by the liberation of ozone, which is readily identified due to itscharacteristic odor. This phenomen of electrical discharge occurring in

transmission line for high values of voltage is known as the corona effect in power

system.

If the voltage across the lines is still increased the glow becomes more and more

intense along with hissing noise, inducing very high power loss into the system


38

which must be accounted for. Corona discharge usually forms at highly curved

regions on electrodes, such as sharp corners, projecting points, edges of metal

surfaces, or small diameter wires. The high curvature causes a high potential

gradient at these locations, so that the air breaks down and forms plasma there first.

In order to suppress corona formation, terminals on high voltage equipment arefrequently designed with smooth large diameter rounded shapes like balls or

toruses, and corona rings are often added to insulators of high voltage transmission

lines.

How Corona Effect Occur:

In a power system transmission lines are used to carry the power. These

transmission lines are separated by certain spacing which is large in comparison to

their diameters.

In Extra High Voltage system (EHV system ) when potential difference is applied

across the power conductors in transmission lines then air medium present between

the phases of the power conductors acts as insulator medium however the air

surrounding the conductor subjects to electro static stresses. When the potential

increases still further then the atoms present around the conductor starts ionize.

Then the ions produced in this process repel with each other and attracts towards

the conductor at high velocity which intern produces other ions by collision.

The ionized air surrounding the conductor acts as a virtual conductor and increases

the effective diameter of the power conductor. Further increase in the potential

difference in the transmission lines then a faint luminous glow of violet color

appears together along with hissing noise. This phenomenon is called virtual

corona and followed by production of ozone gas which can be detected by the

odor.

Still further increase in the potential between the power conductors makes the

insulating medium present between the power conductors to start conducting and

reaches a voltage (Critical Breakdown Voltage) where the insulating air medium

acts as conducting medium results in breakdown of the insulating medium and

flash over is observed. All this above said phenomenon constitutes CORONA

EFFECT in electrical Transmission lines.


39

Factors Affecting Corona Effect:

Corona Effect occurs because of ionization if the atmospheric air surrounding the

voltage conductors, so it is affected by the physical state of the atmosphere as well

as by the condition of the lines.

Conductor:

Corona Effect is considerably affected by the shape, size and surface conditions of

the conductor. It decreases with increases in the size (diameter) of the conductor,

this effect is less for the conductors having round conductors compared to flat

conductors and Corona Discharge Effect is concentrated on that places more where

the conductor surface is not smooth.

Line Voltage:

It is not present when the applied line voltages are less. When the Voltage of the

system increases (In EHV system) corona Effect will be more.

Atmosphere:

Breakdown voltage directly proportional to the density of the atmosphere present

in between the power conductors. In a stormy weather the ions present around the

conductor is higher than normal weather condition. So Corona Breakdown voltageoccurs at low voltages in the stormy weather condition compared to normal

conditions.

Spacing between the Conductors:

Electro static stresses are reduced with increase in the spacing between the

conductors. Corona Discharge Effect takes place at much higher voltage when the

distance between the power conductors increases.

Manish Kumar3

rd Year, EEE


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KNOW MORE ABOUT

SOLDERING

Soldering is the process of joining two

metals together by the use of a solder alloyto form a reliable electrical path. This

technique was first developed in ancient

Egypt. Soldering skills are needed to

assemble any electronic circuit. Faulty

solder joints may cause failure of major

equipment. It is therefore necessary to have high standards of workmanship in

soldering.

Soldering iron: A soldering iron consists of three main blocks: a resistance heating

unit, a heater block that acts as a heat reservoir and a soldering tip (also known as a

bit).Soldering iron comes in variety of shapes and wattage. The wattage varies

from 15w to 100w. The advantage of using a high wattage iron is that heat can

flow quickly into a joint and soldering can be done rapidly. The temperature of the

soldering bit depends upon the mains input voltage. Some important points to be

remember while using a soldering iron:

Clean the bit by wiping it with a wet sponge. The surface of the bit should be constantly tinned to ensure proper heat

transfer and to prevent impurities from entering the soldering joints.

When the iron is not in use, keep it in a holder, with the bit clean and coated

with solder

Bit: Soldering iron bits are available in different diameters and shapes. These can

be changed depending on the types of work. Often bits are either brighter plate or

made from unplanted copper to prolong their life. The bit should be clean

periodically to prevent a layer of oxide from accumulating between the bit and theheating element. A bright tin surface must be maintained at the working surface of

the bit. Proper uses and care of the soldering iron bit prolong the life of the bit and

prevent soldier joint failure as well.


41

Solder: Solder is an alloy of tin and lead in different proportion. It is usually

available in the form of wires of different sizes and grades. The grades of solder

refer to the percentage of tin to lead as 60/40, 50/50 and 40/60. The commonly

used solder for hand soldering in electronic circuit assembly is 60/40 with non-

corrosive flux-cores.

Flux: Perfect solder joints can be accomplished only with properly cleaned

soldering surfaces. The flux present in multicore solders is the chemical used for

removing the oxide films deposited on the surface to be joined. The corrosive

action of flux at melting temperatures removes metal oxides very fast, which

prevents reformation of new oxides and allows the solder to form a rigid bond.

Flux helps molten solder flow more easily over the joint. Flux melts at a

temperature lower than the solder temperature. A variety of flux is available for

many purposes and applications. The most common types specified by rosin

content are no clean, rosin mildly activated, rosin activated and water soluble.

Key to good soldering: Cleaning of the surface, soldering at the right temperature

and for the right duration, and adequate solder coverage are the key factors

affecting the quality of solder joints. It is absolutely necessary to ensure that the

leads of components are free from grease, oxidation and other contamination. The

oxide layer repels molten solder. It is very difficult to solder old components or

tracks on the PCB because of the layer of oxidation that builds up on the surface ofthe component leads. Even surfaces that look clean may have a thin, invisible film

of oxide on them. So for appropriate solder bonding, surfaces must be cleaned by

using flux.

It is important that the surfaces to be soldered together are brought to the same

temperature. When both are heated at a high temperature, solder flows evenly to

make a good mechanical and electrical joint.

The parts to be joined should be heated with a soldering bit for the right timelength. Excessive heating may damage the components or the printed circuit track.The heating period depends on the size of the joint and the temperature of thesoldering bit. Semiconductor components such as diodes, transistors and ICs aresensitive to heat and should not be overheated.


42

Soldering process: When the soldering iron bit is adequately hot, apply a littlesolder on the flattened tip and wipe it off with a piece of damp cloth or sponge.The solder will form a thin layer on the bit. This process is known as tinning the

bit. Heat up the joint with the bit and continue heating while applying solder. Themolten solder flows quickly from the bit onto both parts to be joined. It isimportant to use the right amount of solder. Remove the iron and allow the joint tocool. During the cooling period, if the joint is disturbed, it may become dry and

create serious problems in the working of the circuit. Sometimes it becomes verydifficult to trace out this defect.

After the soldering process is complete, remove the residual flux from the PCB.Clean it by dissolving it in a solvent and wiping the area dry with a tissue paper.The complete assembly should be totally free from flux and residual cleaningagents. The cleaning method and solvent solution used should not have any

adverse effect on the components and the connection.

Re-Soldering and De-soldering: Try to prevent re-soldering of joints as much aspossible. A dry or disturbed solder joint usually requires reheating and reflow ofsolder by applying a suitable quantity of flux. De-soldering is required whencomponents in the circuit need to be removed or replaced. To remove a damagedor defective component, either a de-soldering pump or a de-solder braid can beused.

(Courtesy- Electronics for you)


43

Earthing-Terms and Methods

Earthing should be a top priority of safety for both the engineer designing it andthe consumers using it. The main reason of this is to prevent or minimize the riskof shock to human beings and livestock. Earthing provides a low resistance pathfor earth leakage currents lack of which can lead to fatal injury to any persontouching the metal part. Earthing the electrical equipment needs electrode, whichhas reasonably low resistance to activate the safety devices like earth circuitleakage breaker, fuses to open the faulty circuit, and thereby protect men andmaterial.

System Earthing

Earhing associated with current-carrying conductors is normally essentially to thesecurity and is generally known as system earthing. It is done at generating stations

and substations.Purpose:

To Maintain ground as zero reference potential, thereby ensuring that the voltageon each live conductor is restricted to such a value with respect to the potential ofgeneral mass of the earth as is consistent with the level of insulation applied.Protect the system when any fault occurs against which earthing is designed to give

protection, by making the protective gear to operate and make the faulty portion ofplant harmless.

Equipment EarthingThis is a permanent and continuous bonding together (i.e. connecting together) ofall non-current carrying metal parts of the electrical equipment to the system andearthing electrode. Provided to ensure that the exposed metallic parts in installationdo not become dangerous by attaining a high touch potential under conditions offaults. It should also carry the earth fault currents, till clearance by protectivedevices, without creating a fire hazard.

Special Requirement Earthing

Static earthing is provided to prevent building up of static charges, by

connections to earth at appropriate locations. Example: Theatres and Hospitals

Multiple earthed neutral system

A system of earthing in which the parts of installation specified to be earthed areconnected to the general mass of earth, and in addition are connected within theinstallation to the neutral conductor of the supply system. Bikash Sah, 4thyear EEE


44


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46


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48

PERSONAL INTERVIEW

The Purpose:

Interviewing provides you with an opportunity to explain, in your own world, the

way in which your experience, knowledge, skills and aspiration combine to makeyou a desirable candidate for the organization. Additionally, the interview settingallows you to demonstrate your interpersonal skills, professionalism and personalstyle. While most people claim (in resumes, profile sheet, and cover letters) to

possess interpersonal or communication skills, interviews provide you with anopportunity to actually demonstrate such skills. Another benefit of interviewing isthe depth research you can perform on an organization as you prepare for and

participate in different interviews.While there are many types of interview, it is safe to say that the general

purpose of an interview is to:

1. Get to know you on a personal level2. Learn more about your qualification/ achievement3. Allow for the gathering of information relevant to organizational needs


49

The preparation:

Preparation is key to a successful interview1. Find out all you can about the b-school that you are aiming at before you go

to an interview

2.

Practice your answers to common question like:Tell me about yourselfWhere do you see yourself five years from now?Describe a major goal youve set for yourself recently

What are your strengths?We all have weaknesses. What are some of your major weakness?Why engineering?Why should we be considering you?How do you spend your free time?Tell me something about yourself that I didnt know from your resume/

profile sheet3. Make a list of question to ask too. Almost all interviewers will ask if you

have question. This is a great opportunity for you to show that you havedone your homework and have put some thought into your questions.Preparation will give you the confidence you need to perform well duringyour interviews.

During the interview:

1.

Make sure you are well groomed

Grooming For Men:

Wear shirts and trouser

It is important to button up your shirt till the collar button

Wear socks and shoes & wear clean socks to avoid bad odor

Shoes must be polished everyday

Accessorieso Not many rings, two rings- at mosto

No earing &chain should be out of sightFunctional wrist watch & good pen in pocket

Grooming for women:

Wear Salwaar Kameez or formal shirts/trouser

Wear a pair with smaller heels or a flat pair. Prefer a black/brown pair

Be sure your shoes are polished and that tour heels are intact

Carry a bag for your belonging

Accessories Earring: wear small rings


50

Do not wear hoops or dangling earring Bracelets/bangles: you may wear either a bracelet or a bangle Avoid chunky bracelets or too many bangles Rings:keep them simple and not chunky Chains: you may wear thin chains with small lockets

2.

Make a great impression: The interviews is your chance to show that you are the best person for

the job The employer will be looking and listening to determine if you are a

good fit To make the best impression, sell your strength;

o arrive early, by about 10-15 minutes

o be enthusiastico shake hands firmlyo

be an active listenero sit up straight and maintain eye contacto

dont lean on the table, and dont sloucho dont argue but can present you point

Dont forget to say thank you to the interviewers

3.

End of the interview Thank everyone

For a few step from your seat dont show your back

Dont rush. But move out with dignity

Shut the door gently when you leave

Guidelines to be well prepared for GD:

Expand your horizon of knowledgeBe optimistic have a friendly but optimistic attitudeStay focused and put in efforts to improve your GDPI related skills

Practice with your friend/familyRespect others view

Ankit Kumar Garg3

rd Year, EEE


51

CAREER IN ELECTRICAL ENGINEERING

The very common trait among students completing their higher secondary

and thinking of choosing an Engineering subject for further higher studies think

that Electrical engineering is a kind of advanced work that of an electrician, whocomes to home to repair our electric fans and lights. But in reality its entirelydifferent from that and you will be learning whole lot of Electrical engineeringtechniques and related stuff in the course.

During first year of engineering, EE students learn about commonengineering courses like Engineering mathematics, Physics, Engineering Drawingand fundamentals of computing. From second year they will start learning about

Thermodynamics, introductory electronics, signal processing and instrumentation,signals, systems and electric networks, microelectronics, control systems,

communication systems, power systems, electromagnetic systems, electricalmachines, and power generation techniques. By the end of final year students can

be well equipped with the understanding of working and application of electricsystems and engineering.

There are equally good opportunities for jobs in electrical engineeringindustry and higher education. There is lot of multidisciplinary research fordeveloping electric vehicles with great funding and scope all over there world. On

the same time good opportunities back home in industry.

Major core companies of EE of private sectors are, ABB, Bajaj InternationalPrivate Ltd., Crompton Greaves Limited (CGL), Siemens Ltd., Reliance powerLtd., Schneider Electric and Wipro Lighting are name to few. Besides this we haveenormous PSUs offering great scope for an Electrical Engineer to start his/hercareer, which are namely as NHPC, NTPC, NPCIL, NEEPCO, THDC, DVC,Delhi Metro Corporation, PGCIL, ASEB, BHEL, BPCL, HPCL, ONGC, NALCO,IOCL, GAIL, etc. An engineering fresher generally starts the career with the role

of GET which commonly involves one year grace period in which the firm expectshim/her to get well acquainted with the operations and working. With performance

evaluation and on fulfillment of experience criterias one gets promoted to the tierof AM (Asst. Manager), DM (Deputy Manager), GM (General Manager)subsequently in various works of under different heads.

Most electrical engineers work in a multi-disciplinary project team, which islikely to include engineers from other specialist areas as well as architects,


52

marketing and sales staff, manufacturers, technicians and customer servicepersonnel. They may also work with representatives from client organizations.

Depending on the employer, the electrical engineer may be involved at every

stage of design and development or may just be involved at one particular stage.The nature of the role varies according to industry or sector, but the range ofactivities common to many posts is likely to include:

Identifying customer requirements; Designing systems and products; Reading design specifications and technical drawings; Researching suitable solutions and estimating costs and timescales; Making models and prototypes of products using three-dimensional design

software;

Working to British (BS), European (EN) and other standards; Liaising with others in the design team; Liaising with clients and contractors; Attending meetings on site; Designing and conducting tests; Recording, analyzing and interpreting test data; Proposing modifications and retesting products; Qualifying the final product or system; Servicing and maintaining equipment; Preparing product documentation, writing reports and giving presentations;

Monitoring a product in use to improve on future design.

A degree in electrical engineering can allow you to pursue a job in almost any

industry you can think of. After all, nearly everyone uses electricity and electrical

devices, so industries demand skilled professionals to build, repair, and improve

these devices. Electrical engineers work in businesses such as:

1. Scientific research and development firms.

2. Electrical component manufacturing companies.

3. Power generation, distribution, and transmission.

4. Manufacturers of navigation controls, medical equipment, and measurement

devices

5. Architectural firms


53

although these industries employ the most engineers, they may not be right for

everyone. Electrical engineering majors many options, more than enough for any

student to find a job in a field they love.

The following job titles represent only a handful of the choices available:

1. Research Engineer: These engineers work in the lab, testing and inventing.This job requires a high level of creativity on the part of the engineer, aswell as a great deal of patience. Whether inventing a new optoelectronicdevice or simply designing a better electric can opener, research engineersare responsible for the discovery stage technology behind any new electronic

product.2. Design Engineer: Once a new technology is invented, it must be applied.

The design engineer uses computer simulations and models in order to turninnovations like wireless technology into plans for the tiny parts that makeup an actual cell phone. Design engineers must visualize how the insides ofa future product could look, while inventing several possible scenarios forthe applications of new technologies.

3. Project Engineer: The project engineer oversees many specialist engineersthrough the construction of a working prototype of a new product ortechnology. The project engineer must have natural leadership ability, aswell as a high proficiency in a variety of electrical engineering disciplines.

4.

Test Engineer: These engineers design programs to test the functions ofelectronic device and to troubleshoot those devices when things go wrongthese engineers keep technology working properly, and understand which

elements to test and in what order. Successful test engineers remain sharp,even after long hours on the job.

5. System Engineer: Power grids, phone lines, and wireless networks allrequire the skills of a system engineer for proper installation andmaintenance. High attention to detail is important for students who enter this

profession. Experienced system engineers rely on their ability to thinkholistically about the systems they create.

6.

Application Engineer:Application engineers work with whatever resourcesare available, adapting existing equipment and technologies to fill the needsof their employers. They need to be resourceful, while counting on theirkeen understanding of the capabilities and the potential modifications ofexisting equipment.


54

Salary Expectations for Electrical Engineers

According to the National Association of Colleges and Employers, startingoffers for students graduating with a Bachelor's degree in electrical

engineering in 2011 averaged around Rs. 3.5 Lacs p.a. Those graduatingwith a Master's were offered about Rs. 4.0 lacs p.a. to start, and PhDgraduates began at around Rs. 6.0 p.a.

Electrical engineering is the largest segment of the engineering population,with 292,000 professionals employed in the PSUs of India in 2010 alone.The number of jobs available for electrical engineers in has been predictedto increase by nearly 30% in the ten years between 2013 and 2014 because

of various upcoming projects. During the same period of time, abroadexpects a 46% increase in electrical engineering jobs.

Mr. Brajagopal Datta

Visiting FacultyDept. of Electrical and electronics Engg.

NIT AP


55

BEING IN THE FIRST BATCH OF NIT ARUNACHAL PRADESH

Yupia was selected as the temporary site of NIT Arunachal Pradesh. I remember

my first day here. August 16, 2010 was the reporting day for us. As the institute

was completely new for everyone no one knew about the exact location of the

institute and hostels, after so many searchings I reached the hostel with my

parents. But to my surprise, no one was there in the hostel, I was sure that I had

been cheated, in those 2-3 minutes I remembered all the advertisements that

warned students about fake colleges and admissions. I started calculating all the

time and money that I would be wasting. But thank God!!!Dr. J P Sarkar Sir, our

coordinator from Durgapur was in boys hostel-guiding the boys who came before

me.

The formal governor of Arunachal Pradesh, Gen J. J. Singh inaugurated the

institute on 17 august 2010.In first semester faculties from Durgapur used to come

and teach us. At a time two faculties used to visit and before leaving they took the

class tests for the subjects they taught. In this way we interacted with large number

of faculties from Durgapur.

Practicals were done in NERIST. Apart from institute bus, special vehicles used to

be booked for practicals. I could remember the first day of the practical at

NERIST-we got a grand party at NERIST VIP guest house that was special packedfood on the practical days.

I could remember my first birthday in Yupia. I got the institute bus for my birthday

celebration. All the seventeen girls of our batch enjoyed the party in Malabar only

because we got the bus to go to Naharlagun. Today in the same bus I am not

allowed to travel because driver calls this as staff bus and I am a student.

But the real journey started with the second semester. Teachers from Durgapur

stopped coming. We were having classes only on weekends when faculties ofNERIST were free. For the whole week we were not having any classes.

Second semester also included water problem. Water was scarce as it was supplied

by Tata Mobile in Syntax and it did not come for a complete week in girls hostel.

The trouble faced was ultimate. We used to carry full buckets from academic


56

blocks. We learnt to collect rainwater. I can recollect the memories of silly fights

amongst us for collecting water.

In Yupia hostels we were living alone without any teacher and warden. We were

having only Mai Bhaiya to share our problem. We used to call him for water,teacher-he used to bring faculties from NERIST. He was our only helper.

Library wasnt there for us. We gave many subjects exams without books. No one

was there to guide us-neither our teacher nor any senior.

Today the institute has got its own director, Dr. C.T. Bhunia. Under his guidance

there are uncountable improvements in the institute. Today there is no problem of

teachers. Every department has a number of teachers, well-equipped laboratories

and a number of lab assistants. No water problem is there-even if supply water is

not there, we get water in Syntax. Library is full of books-with more than 5 books

per subject.

As the witness of the rapid growth of the institute, I sometimes feel sad that we

faced problems and stayed here when there was nothing, but today when the

institute is improving its the time for us to leave the institute. Before admission I

felt proud to be the first batch but these government policies did not allow us to

avail the facilities that we deserved. Without teachers and infrastructures, students

are admitted to the institute. A random building was selected in Yupia-which issituated far from city. There were no transportation facilities. We were compelled

to take lifts while going to Naharlagun.

But in spite of many problems and difficulties I enjoyed my stay in Yupia with my

friends and classmates. These memories will always make me happy. Though there

is no advantage of being in first batch-still I am proud to be its first batch. Hope

this institute reaches to the top colleges of India and I could proudly introduce

myself as the first batch of this institute.

Nupur4

th Year, EEE


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POSITIVITY OF EXAMS

Examination brings you to a momentous period in your life when you can showyour progress as a mature person capable of handling the task that is going to be

deciding factor of your future career. Ignore the popular notion that exams aredrudgery. One cant learn something if it is unpleasant. You may like the subject

but it is necessary for you to love the learning process.

Most students get jittery when they watch their classmate studying. Preparationand learning may be different for different people. It depends on ones mentalcapacity, Comparison kills Confidence.

Exam you are going to take up are a test for endurance, self-confidence and grit. Ifyou cannot face these exams how will you face the obstacles that come your wayletter in life.

Stress is a mental block that itself springs from within. Be methodical and planwell. Finish the days agenda well in time.

Take care of your health Eat well Sleep well and remember to take a break torelive the monotony of study.

Mr. Tarak Takang

3rd

Year, EEE


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ATULYAM13

GLI TZ, GLAMOUR, CREATIVI TY, WIT, SKI LL

These are perfect ingredient for an extravaganza to be remembered.

ATTITUDE SPELLS ACHIEVEMENT-- These words surely go with theidea behind organizing Atulyam as it is attitude of students of NIT AP that hasmade this festival a grand success in this 1

st version. Atulyam, the Inter College

annual cultural festival of NIT AP was held in the premises of NIT AP during 3rd

-4

th Oct 2013 with theme Stravaganza Infinite. This 1

st version of Atulyam was

inaugurated by Dr.(Prof.) C. T. Bhunia, Director NIT AP in the august presence ofDr. Sujit Kr. Dutta, Chairman Team Atulyam, Prof. P. D. Kashyap, DeanAcademics. The fest included events namely Rodies, Voice of NIT, Eat 2 Beat,

CID, Sports Event, Dance, Sur-e-azam, laughter express, literatureand manymore.

The event took off to a rhythmic start with the traditional dance performed thelocal girls and students of NIT AP. The next event was music maestro, Antakshriwhich saw the amazing participation. Various teams competed with each other in amelodious manner by striking the right tunes and nodes. The competition was

brought to rest by a scintillating and vibrant performance by various groups.Various dance performance and songs were given by the students.

We wont doing justice here, if we do not mention about the most glamorous andtalk about event CAPRICIOUS, the night show. The show depicted the trueessence of music. It was the live concert by Mr. Amit Sana, the most genuine voicerunner up 1

stIndian Idol. It was indeed a brave and bold effort on the part of team

ATULYAM, for having added more colors to the large canvas of this festival, thatmade it grand extravagant and worthwhile.

The one week festival came to an end with the most awaiting event Mr. and Ms.

ATULYAM fashion show.Hence the programe was of great success and brought

out the best in students.


59


60

Addovedi13

During may this year, in the portals of our institution, the staff and students puttheir heads together to come up with a vent for their creative outbursts.Addovedi13 took shape in its maiden year as a technical festival. The college took

the promise of handing the torch down every year with a commitment to thehighest levels of quality in the event.

Addovedi launched itself with a host of 17 events spanning across 6 genres,addovedi 13 presented an opportunity to innovate. Innovate with creativity.

Innovate for the betterment of life. Innovate for the countrys progress and

development. And while innovation is not separate from technology, thus lays theneed to know technology, use technology and celebrate technology. Addovedi 13

gave the call to celebrate technology, to celebrate talent, to celebrate innovation.

There were almost 42 volunteers working in tandem to make this event a grandsuccess.

The events which addovedi13 offered included robotics, general events,management events, presentation events, events pertaining to the areas ofelectrical, electronics and computer science, software events and modeling events.

IEEE Student Chapter

The Student Chapter of NIT Arunachal Pradesh was set-up in our institute for the

need of research and development. This chapter promotes research in the field of

Engineering and let students aware of various advancement in Engineering and

Technology. Faculty in-charge for this Chapter is Mr. Subhasish Banerjee. There

are 28 students members and almost all the faculty are registered members of

IEEE. This chapter organizes monthly meeting of members and various events toignite students and promote the concern and the need of research in our institute

for the development of Nation and the serve the whole world with its advanced

engineering works keeping ethics and values in mind.


61

Spoken Tutorial Project

Spoken Tutorial Project- an initiative of IIT Bombay and one of the Talk to a

Teacher projects supported by NMEICT, MHRD was undertaken in the month of

March, 2013 by this institute. The mission of this project is to make India an IT

literate country. We have a setup of RESOURCE(Robust Extensions for Spoken

Tutorial project on Open Source Software Usage for Recruitment, Communityand Education) center for promoting this project. We are rolling out workshops all

over Arunachal in various colleges and schools. Bikash Sah, a student from the

NIT Arunachal Pradesh is the Promoter for this Project in Arunachal Pradesh.

Faculty in-charges for the RC are Dr. K.R. Singh and Mr Anish Kr. Saha.

Presently Ms. Reshmi Pillai, Training Coordinator, North East India for Spoken

Tutorial Project is assisting and guiding from IIT Bombay to take steps in making

this project a success.


62

Project Roshni

Roshni an initiative by Atulyam is a social activity for integrated and

comprehensive social development for the deprived people of the Arunachal

Pradesh. It helps the local people of Arunachal Pradesh by various social activities,especially in education development and awareness. It is running by the students

themselves, and both students and teachers through their combined participation

in community service, get a sense of involvement in the tasks of nation building.

ROSHNI with focussing on empowerment of women has taken essential steps for

the female society. ROSHNI has collaboration with State Women Commissionand

OJU Welfare Association. To attain its objective, the students of NIT are imparting

and extending various welfare activities for orphans, needy and destitute womenand children, to serve the oppressed humanity, irrespective of cast creed and

community.


63

Entrepreneurship, Design and Innovation Centre (EDIC)

EDIC is an emphatic brainchild of our Director, Prof. C. T.

Bhunia who is a decisive & firm believer that Technical

Education should be redesigned & reframed to meet the

considerate aspiration of the nation, and the global challenges

for which it is essential &imperative to produce

Technical Engineer rather than academic engineer

And

Engineer who will create jobs rather than run after the job

in and with innovative practices. This is how the establishment

EDIC was placed in the BoG & got approved with a seed money

Rs. 27 lacs in the year 2012.


64

SILICA-GEL BREATHER

Did you know, a transformer also breaths??Might sound weird but yes, indeed a transformer

breaths!!! Well lets find out how?

BREATHING PROCESS OF TRANSFORMER:

Breathing is a process where in a transformer sucks,in or pushes out the air from its body. Whentransformer is loaded or unloaded, the oiltemperature inside the transformer tank rises or falls.Accordingly, the air, which is being sucked in,contains either foreign impurities and/or humidity,

which changes dielectric strength of oil. For properworking of transformer, it is absolutely necessary that dielectric strength oftransformer oil remains unimpaired. Hence, it is necessary that, the air enteringinto the transformer is free from moisture and foreign impurities

OPERATION AND WORKING:

The breather is connected to an outlet pipe of the conservator vessel and the air,which is being sucked by transformer, is made to pass through the silica gel

breather to dehumidify the air to remove foreign impurities.

The silica gel, which is filled in the breather, is hard blue crystals, which hasconsiderable absorption power for moisture. When, it gets saturated with moisture,it changes its color to pinkish white. For proper dehumidification of air, it isabsolutely necessary that this change of silica gel is reconditioned from pinkishwhite to deep blue by heating it to a temperature up to 200

oc.

The air, which is passed through gel is first made to pass through the oilcompartment of the breather. This oil removes all foreign impurities from air

which enters the gel compartment. Hence, oil sealed type silica gel breather willkeep the oil properties constant, thereby ensuring proper working and hence longer

life of the transformer.Above is a picture of a silica gel breather.So next time when you see a transformer, dont forget to take note of the

breather

Santosh ShuklaFourth Year, EEE


65

Face 2 Face with The Best Teacher of the Year

Dr. Nabakumar Pramanik,

Assistant Professor (Chemistry) and Assistant Dean (Exam), Department

of Applied Sciences.

Ph.D. from IIT Kharagpur, India in Chemistry in 2009. He worked as research

associate (RA) in Materials Science Centre, IIT kharagpur from 2009 to 2010. He

was a postdoctoral Research Associate (PDF) at National Taiwan University of

Science and Technology (NTUST), Taiwan during 2010 to 2011. He has published

a number of scientific papers in various journals of international repute and also

presented his research work in various national and international conference/

workshops. He wa

Vidyut Sanchaar Electrical Magazine NIT Arunachal Pradesh

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