mostafa hassan presentation-no3

7/30/2019 Mostafa Hassan Presentation-No3

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Under Supervision of

Prof. Dr. D. Sc. M. A. Ahmed

Prof. Dr. M.M. Eissa

Dr. S. I. El-Dek

Prepared by

Mustafa M. Hassan


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Current Transformer Function

1.Reduce Power

System Current

to Lower value

for measurement

and Protection


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5

I1=1000A I2=1A

N1=1

v1+

_ N2

=1000

e2 zburden

+

_

PrimarySecondary

Z load

Current Transformer


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11

1111

1 0

I

Z

V

Z

eV

I

e

LoadLoad

21

22

22

22

I

zeI

dt

dNe

burden


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occuresmaySaturation

increase

increase

increase

21

1

11

1

I

I


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9

i1 i2

N1V1 e1

+

_ N2 e2 zLoad

+

_

PrimarySecondary


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1

11

1

11

z

eVI

dtdNe

22

2

2

22

I

Z

eI

dt

dNe

Load

Constant

Increase

increase

decreased

decrease

1

1

1

total

total

I

eif

21

decreased

increase

increase

IncreaseLoadif

total

2

2

I


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occuretdoesn'Saturation

Constantapprox.

increaseincrease

increaseincrease

21

1111

2222

total

total

II

II


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Normal Primary Current NII ps /

Very high primary currents

or at high burden

secondary current are distortedSo

that protection devices operate delayed

or blocked


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1-When faults occur, the current magnitudes

could be much larger,

2- the fault current may have substantial

amount of d.c components 3-

and they may be remanence in the CT core

all of these factors may lead to


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CT Magnetizing Characteristic

Magnetizing characteristic of a typical currenttransformer.

Each curve corresponds to one turns ratio of the secondarywinding.


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Current Transformer Saturation


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20

The factors affecting the CT saturation

1. Primary current.

2. Asymmetry in the Primary current.3. Secondary burden

4. Remanent flux in the CT core


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Dec-12

The methods which used to avoid the CT saturation

1- Eliminated by air-core CTs, increase the size of the CT core,

and special core material to withstand large flux density.

These options present mechanical and economic difficulties.

2- Some techniques uses a DC component equal and opposite

of that in the primary circuit generated by a circuit added to

the secondary winding.

3- Other techniques used a magnetization curve and the

equivalent circuit of a CT for compensating secondary currentof CT during saturation.


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Research Objects


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NANOTECHNOLOGY(X10

-9)


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What is Nanoscale?

1.27 107 m 0.22 m 0.7 10-9 m

Fullerenes C60

12,756 Km22 cm 0.7 nm

60 millions

times smaller

6000 millions

times smaller


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How Small Is The Nano Scale?

One nanometer (nm)

is one billionth, or 10-9of a meter.

is one millionth, or 10-6of a m.m.

One human hair (cross-section) is about100,000 nanometers.

Larger than the Nanoscale is the microscale, andsmaller than that is the atomic scale.


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At the nanoscale, the mechanical, electric, optical

and magnetic properties of materials change,

allowing the creation of new functional materials.

. A particle measuring

1 nm 1 nm 1 nm = 64 atoms

with only 8 on the insidethe remaining 56 atoms are at the surface.

Therefore the properties of nanoparticles are

dominated by surface atoms, which allows the

creation of new properties.

Insulators can become conductors,


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With NT, we can create unique materials and products which

are: Stronger Lighter Cheaper

Durable Precise

Wh is nanotechnolog


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Why is nanotechnologyimportant ?

1

10

100

1000

10000

2001 2003 2005 2007 2009 2011 2013 2015

Year

MarketVolume(billion)

Analysts estimate that the market for products based on

nanotechnology could rise to hundreds of billion by 2010 and exceed

one trillion after

Total research budget: 1300 million


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Nanotechnology Applications

MedicineandHealth

InformationTechnology

MaterialsScience

Food, Waterand theEnvironment

InstrumentsEnergyProduction/ Storage

GMR HardDisk

HydrogenFuel Cells

Lightweightand strong

Drugdelivery

Tunnelingmicroscopy

Remediationmethods

Expected to impact upon virtually all technological sectors as an enabling

or key technology


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End of Illnesses(i.e. cancer,heart disease)

UniversalImmunity (i.e.aids, flu)

Body Sculpting(i.e. change

your

appearance)


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Textiles

Water retardant

Fire retardant

Mud retardant

Optical absorption


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Rust retardant


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Reduce Water Pollution

filter only a few nanometers in diameter is

currently being developed that should be

capable of removing virus cells from water.

(Silver nano particles)

Another challenge is the removal of salt or

metals from water. A deionization method using

electrodes composed of nano-sized fibers forreducing the cost and energy requirements of

turning salt water into drinking water.


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Nanotechnology ApplicationsNanometric Cars

Different Colors are Atoms


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http://localhost/var/www/apps/conversion/tmp/scratch_2/Nano/NanoEnergy_web.pdf


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Power Transmission

Super Conducting Cables:

based on carbon Nanotubes

Graphene (2010)

Electrical conductivityis 3 times more than best metal


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Power Transmission

High Voltage insulators:

Dust and Mud retardant

lessMaintenance


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Power Transmission

Transformers oils:

Increase the insulation of the oil transformer


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Nanotechnology ApplicationsMotors

Increase efficiency, frictionless.

Increase the insulation of the conductors.

Nano Hard ferrite increase flux density,

low volume, low weight.


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Nanotechnology ApplicationsGenerators

If insulation increased from 23kV to 220 kV

Step up transformers (substation) can be neglected

Increase efficiency


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Power Cables

Increase the insulation of cables

Increase conductivity


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Increase efficiency from 19 to 39%


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Nano Battery

Battery (Nano Battery) Increasing the available power from a battery

increase the efficiency and reducing the weight of

the batteries decreasing the time required to recharge a battery.

Reducing the possibility of batteries catching fire byproviding less flammable electrode material.

. These benefits are achieved by coating the surfaceof an electrode with nanoparticles. This increasesthe surface area of the electrode thereby allowingmore current to flow between the electrode and

the chemicals inside the battery.


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Nanotechnology ApplicationsSuper Capactors

Increase the capacity using thin films


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Tools In Nanotechnology

The main tools used in nanotechnology are

three main microscopes

Transmission Electron Microscope (TEM)

Atomic Force Microscope (AFM)

Scanning Tunneling Microscope (STM)


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Transmission Electron

Microscope (TEM)

Uses high-energy electron

beam to probe material with

thickness < 100 nm.

Some electrons areabsorbed or bounced off

object; some pass through

the object and make

magnified images

Digital camera records

images.
http://images.google.com/imgres?imgurl=http://www.sandia.gov/media/images/senscoat.gif&imgrefurl=http://www.sandia.gov/media/porosity.htm&h=258&w=250&sz=77&tbnid=Vt9y3SrtwAEJ:&tbnh=106&tbnw=103&start=21&prev=/images?q=Transmission+Electron+Microscope+GIF&start=20&hl=en&lr=&sa=Nhttp://images.google.com/imgres?imgurl=http://www.phy.cuhk.edu.hk/centrallaboratory/TecnaiF20/TecnaiF20c.jpg&imgrefurl=http://www.phy.cuhk.edu.hk/centrallaboratory/TecnaiF20/TecnaiF20.html&h=1712&w=1368&sz=104&tbnid=kOWSBQZpzHcJ:&tbnh=148&tbnw=119&start=7&prev=/images?q=Transmission+Electron+Microscope&hl=en&lr=


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Scanning Tunneling Microscope

(STM)

Uses nanosized probe to

scan objects and materials

Uses tunneling to detect

surface and creates a map ofsurface

Rate of electrons that tunnel

from probe to surface

related to distance between

probe and surface
http://images.google.com/imgres?imgurl=http://materials.chem.utk.edu/STM.gif&imgrefurl=http://materials.chem.utk.edu/microscopy.htm&h=328&w=336&sz=32&tbnid=14-VJp6QnN4J:&tbnh=112&tbnw=114&start=113&prev=/images?q=Scanning+Tunneling+Microscope&start=100&hl=en&lr=&sa=Nhttp://images.google.com/imgres?imgurl=http://www.bradley.edu/las/phy/research/Stm4.jpg&imgrefurl=http://www.bradley.edu/las/phy/research/STM.html&h=894&w=1192&sz=255&tbnid=2RDzVkqifx4J:&tbnh=111&tbnw=149&start=167&prev=/images?q=Scanning+Tunneling+Microscope&start=160&hl=en&lr=&sa=N


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Atomic Force Microscope (AFM)

Use small silicon tip as probe

to make images of sample

material

Probe moves along surface Electrons of atoms in sample

repel those in probe

Creates 3-D images
http://images.google.com/imgres?imgurl=http://www.physics.purdue.edu/nanophys/images/cluster.gif&imgrefurl=http://www.physics.purdue.edu/nanophys/afm.html&h=300&w=300&sz=28&tbnid=l1ihWjLrWr4J:&tbnh=111&tbnw=111&start=15&prev=/images?q=Atomic+Force+Microscope&hl=en&lr=&sa=Ghttp://images.google.com/imgres?imgurl=http://lfw.kist.re.kr/Teams/lfwl/image/Atomic-Force-Microscope.gif&imgrefurl=http://lfw.kist.re.kr/Teams/lfwl/facility_en.html&h=600&w=1000&sz=356&tbnid=gU02uLMvz_QJ:&tbnh=88&tbnw=148&start=12&prev=/images?q=Atomic+Force+Microscope&hl=en&lr=&sa=G


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Soft Ferrites Hard Ferrites

*Have unique axis of

magnetization (easy) even in

the absence of magnetic field

*High coercive field

*High saturation

magnetization

*High remenant

magnetization*used in permanent magnets

*ex: hexagonal ferrites

*have no direction of

magnetization*Low coercive field (HC)

*Low saturation

magnetization

*Low remenantmagnetization

*Used in electromagnets

*ex: Spinels ferrites


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http://d/DR/Nanotechnology/Dr.Ali%20Azab-Mag%20spintronic%20Lec%203.pdf


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IMPS College Of Engineering & Technolgy.


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g g g gy

Nanoscale Approaches and

FabricationTop-down Approaches Bottom-up Approaches

Ferrite preparation


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Ferrite preparation

Solid State reaction

(Dry method)Wet methods


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Sol

gel

Citrate Flash


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Standard ceramic

Mn oxide and,

Fe2O3

Mixing, grounded (3 hrs), pressing

Presintering at 900C, 8h

Final sintering at about 1100C, 2h,

2oC/min

Grounded (1 hr) , pressing


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Flash combustion

Mixture of metal nitrates and Urea

Urea ratio= 6.67xMol.wt of urea

Good mixing

Heating on magnetic stirrer

Self ignition, auto combustiontakes place

Cit t


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Citrate

Metal nitrates,

citric acid (1:1),

Mixing, deionized water and

adjusting the PH value to 7 using

ammonia

Fluffy gray powder after self

combustion

Heating on magnetic stirrer

S G


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Sol-Gel

Mn nitrate,Fe nitrate

Mixing with droplets of

ethylene glycol,

Thermolysis 80C, 24 hrs

Presintering: 400C, 2hrs


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CT equivalent circuit for transient


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CT equivalent circuit for transient

analysis


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(1)]cospt/

e)t[cos(maxI(t)pi

(2)]cospt/

e)t[cos(smaxI(t)si

The basic principle of the proposed scheme

mostafa hassan presentation-no3

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