properties piezoelectricity pyroelectricity ferroelectricity conclusion
TRANSCRIPT
Soft Transducer Materials For
Energy Conversion
CONTENTS
PropertiesPiezoelectricity
Pyroelectricity
Ferroelectricity
Conclusion
PIEZOELECTRICITY
What is piezoelectricity?
Response of applied mechanical stress on the material
Piezoelectricity
Mechanical Stress Electric Potential
A piezoelectric disk generates a voltage when deformed
MECHANISMIn the crystal +ve and –ve charges gets aligned symmetricallyso each of the side forms an electric dipole.when a mechanical Stress is applied this symmetry is disturbed and voltage is generated
Materials used in
piezoelectricityNatural crystals
Man-made crystalsMan-made ceramics
Lead free piezoceramics
Polymers
1. Natural crystals
1. Berlinite (AlPO4), a rare phosphate mineral that is structurally identical to quartz2. Cane sugar3. Quartz4. Rochelle salt5. Topaz6. Tourmaline-group minerals
crystals:-
1.quartz :- hexagonal structure, pure and contains traces of other elements Al3+,
fe3+,Ti4+,P5+, H+, Li+, Na+,
K+.
Density=2.65gm/cm3 Shows piezoelectric effect perpendicular to prism axis.
2]aluminium orthophosphate:-Rhombic crystal,Density: 2560 kg/m³Mol mass: 121,95 g/mol
[3]gallium orthophosphate:- colourless trigonal crystal system, similar structure to that of Quartz. It is not naturally found as the Quartz. Its piezoelectric effect is twice to that of Quartz
2.Ceramics
•Barium titanate (BaTiO3)—Barium titanate was the first piezoelectric ceramic discovered.•Lead titanate (PbTiO3)•Lead zirconate titanate •Potassium niobate (KNbO3)•Lithium niobate (LiNbO3)•Lithium tantalate (LiTaO3)•Sodium tungstate (Na2WO3)
3.man-made crystals
1.Gallium orthophosphate (GaPO4), a quartz analogic crystal2.Langasite (La3Ga5SiO14), a quartz analogic crystal
4.polymers
Polyvinylidene
fluoride (PVDF)Typical PVDF Applications
•Pressure Pick Ups: distribution of pressure on surfaces, accelerometers, keyboards.•Acoustic Components: microphones, ultrasonic detectors, hydrophones, sonar•Optical Devices: laser diameter measurement,
Applications
1.electric cigarette lighter2.Piezoelectric transformer3.Sensor4.Loudspeaker5.Microphone6.Inkjet printers7.DANCE FLOOR
Pyroelectricity
Temprature Variation Electric Potential
pyroelectric Materials
Single Crystal
Ceramics
Polymers
1. Single crystal
1. Triglycine Sulphate(TGS) or ((NH2 CH2COOH)3H2SO4)
TGS has been extensively studied forthermal imaging applications and is well known for its use in infrared detectors.
2 .LiTaO3 (Lithium Tantalate)
3. LiNbO3 (Lithium Niobate)4. Sr1-x BaxNb2O6 (Strontium Barium Niobate)
2. Ceramics
1. lead zirconium titanate (PZT)
2 . Mn-doped leadzirconate-lead-titanate-lead magnesium niobate (Pb(Mg1/3Nb2/3)O3-PbTiO3-PbZrO3)
3. Polymers
1. Ferroelectric poly(vinylidene fluoride) [p(VdF), PVDFor PVF2)]
Applications
1.Flame and Fire Detectors2.IR Detector3.Radiometers4.Thermometers5.Imaging
Ferroelectricity
1.Spontaneous Polarization 2.Reorientation of Polarization
FERROELECTIC MATERIALS
1.Tungston-Bronze group2.Oxygen Octahedral group
3.Pyroshlore group 4.Bismth-layer Structure group
FERROELECTIC MATERIALS
Oxygen Octahedral group
ABO3perovskite typeA=Pb2+ and La3+ ionsB=Zr4+ and Ti4+ ions
FERROELECTIC MATERIALS
Applications
1.Piezo- & Pyroelectricity2.Capacitor3.Ferroelctric Memory Technology4.FeFET
CONCLUSIONIt has very large importance in our daily life
as we have seen the electricity generation by soft transducer material is very easy and at
very low cost
BIBLIOGRAPHY1. http://www.imit.kth.se/info/SSD/KMF/2B1750/07_Pyro
.ppt2. http://www.ims.uconn.edu/~alpay/Courses/MMAT317/
Ferroelectrics3. http://
eng-sci.udmercy.edu/courses/e478/dass/courses/E452-SensorsActuators/projects/heat%20sensor.ppt
4. http://bayes.wustl.edu/etj/articles/ferroelectricity.pdf5. http://eng.sut.ac.th/ceramic/old/images_news/217.pdf6. http://
butane.chem.illinois.edu/murphycj/chem204spring2011/handouts/FerroelectricReview.pdf
7. http://theory.caltech.edu/~politzer/supplements/ferroelectricity.pdf
8. http://r8---sn-o097zuel.c.youtube.com/videoplayback?algorithm=throttle-factor&burst
9. http://www.lboro.ac.uk/research/iemrc/documents/EventsDocuments/2012%20conference/presentations/whatmore.pdf
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Insulators for overhead transmission line
Types of insulators
1. Sackle type-Used in 230v-440v, Dumpy shape2.Pin type-For 11 kv-33kv, small & cheap.3.Strain type-Above 33kv, used in vertical plane. 4.Suspension type-Above 33kv, used in horizontal plane
Characteristics of insulatorsThere should be not any pores or air space.There should not be any impurities.There should be perfectly homogeneous material.Leakage current should be minimum. Insulators should be able to withstand over voltage and normal working voltage.It should be mechanically strong to bear the conductor load.
Underground transmission lines
It can assists the transmission of power across:•Densely populated urban areas •Areas where land is unavailable or planning consent is difficult .•Rivers and other natural obstacles •Land with outstanding natural or environmental heritage. •Areas of significant or prestigious infrastructural development.
It can assists the transmission of power across:•Densely populated urban areas. •Areas where land is unavailable or planning consent is difficult .•Rivers and other natural obstacles •Land with outstanding natural or environmental heritage. •Areas of significant or prestigious infrastructural development.
Cross-section of Underground transmission lines
Transmission line parameters
R=resistance per unit lengthL=Inductance per unit length G=conductance per unit length C=Capacitance per unit length
Transmission line equations
For harmonic variation
V(z, t)=v e^(-αz)cos(wt-βz)I(z, t)=I e^(- αz)cos(wt-βz)
For harmonic variationV(z, t)=V’ e^(-αz)cos(wt-
βz)I(z, t)=I’ e^(- αz)cos(wt-
βz)
WhereV=voltage across z-axisI=current across z-axisV’=maximum voltageI’=maximum current
α= Attenuation factorβ= phase factor
Loss in transmissi
on line
Lossless transmissi
on line
Conditions for lossless line
1.Resistance=o
2.Attenuation factor(α)=03.Conductance=infinity4.Characteristic impedence=√(L/C)
ELECTRIC POWER
DISTRIBUTION
TWO TYPES OF DISTRIBUTION
SYSTEMS
1. High voltage or Primary distribution systems.
2. Low voltage or Secondary distribution systems.
PRIMARY DISTRIBUTION SYSTEMS
A 3-phase 3-wire system. Operates at voltages such as 3.3,6.6,11 kV or higher even some what
higher than 230 V.A primary distribution line is used Called
FEEDER. Each feeder can carry a load of 1-2 MVA.
33/11 kV substations – Load requirement order of 5 MVA. No of feeders required 3-4.
For the Load exceeding 8 MVA the secondary transmission is carried out at 66 kV. So as to
reduce the line losses, and therefore secondary substations are 66/11 kV.
66/11 kV substations –Load requirement order of 8 MVA. No of feeders required 6-8.
FEEDERSFeeders are of 4 types
1. Radial Feeders.2. Parallel Feeders.
3. Loop Feeders.4. Inter connected.
RADIAL FEEDERSRadiates from the secondary substation and branches into distribution transformer connected (11 kV/415 kV) sub feeders and laterals. Advantageous for supplying
power to heavy industrial load near the secondary substation, isolated loads such as tube wells and areas
of low load density such as villages.Drawbacks:
1.When a fault occurs at any point on the feeder supply to all consumer beyond the fault point towards the tail
end gets interrupted.2. In case of increase in load demand , the length of the
feeder has to be extend and may results in a greater voltage drop. It may cause the voltage towards the tail
end to reach a value below the permissible value.
PARALLEL FEEDERS
In this system 2 radial feeders originating from the same or different secondary substation are run in parallel. Each feeder though capable of supplying the entire load, shares the total load equally in normal conditions. As in case of fault on one feeder, the total load can be supplied by the healthy feeder. Interruption of supply is only for the time duration i.e. taken in transferring the load from the faulty feeder to the healthy one either by manual or by automatic switches. Such a system is used when the continuity of supply is of greater importance.
LOOP FEEDERS
In a loop feeder system 2 or more radial feeders originating from the same or different secondary substations are laid on different routes of load areas. The arrangement having the ends of 2 feeders tied together through normally open switching devices is known as open loop system while the arrangement having the ends of 2 feeders tied together through normally closed switching devices is called ring main feeder or the ring loop. This system is most reliable for continuity of supply and gives better voltage regulation and less power losses.The use of this system is prohibitive on account of very large investment involved.
INTER-CONNECTED NETWORK SYSTEM
When the feeder ring main is energized from 2 or more than two generating stations or substation and it is called the Inter connected network system. Because of inter connected feeders, power can be supplied to all the distribution transformers even though a part of network may be out of service such a system is employed in large metropolitan cities where continuity of the supply is more important.
SECONDARY DISTRIBUTION
SYSTEM
In this system distribution occurs in 2 way
1. 3-phase 4-wire distribution.2. Single-phase 2-wire
distribution.
3-PHASE 4-WIRE DISTRIBUTION SYSTEM
Transformer substation contains (1) High voltage switch gears and bus bars and (2) Low voltage fuses
or Links.High or extra high voltage feeder cable supplies to primary from the generating station. Low voltage bass bars are distinguished by their colour RED,
YELLOW, BLUE for phases and BLACK for the neutral. The local 4-wire distributors are connected
in parallel to the bus bars through the fuses or links.Domestic and other low consumers -> 2 wire service
cables.Larger Non domestic consumers -> 4 wire service
{230 V single phase for lightning , 400 V 3-phase for power}
SINGLE PHASE 2-WIRE DISTRIBUTION SYSTEM
Employed for supplying purely domestic loads. These are connected to single phase & neutral at the sub station bus bars.
CLASSIFICATIONSecondary distribution system
can be classified as
1. Radial System2. Open loop System
3. Network distribution system
RADIAL SYSTEMIn this system the low voltage distributors
radiate out from the distribution transformer and run through the areas of supply. A simplest
less expensive system.DRAWBACKS :
1. The end of the distributor nearest to the supply end would be heavily loaded.
2. The consumers at the furthest end of the distributor would be subjected to serious
voltage fluctuations with the variation in load.3. Fault on a distributor can affect a lots of
consumer.
OPEN LOOP SYSTEMIn this system 2 low voltage distributors take off from the same distribution transformer and run in different directions and so supply in different areas. The far ends of the 2 distributors are tied together by a normally open switching device. In the case of a fault on one line, the load can be supplied though partially from the other line. Thus in this system the reliability of supply is improved and cost is increased marginally in comparison to the previous one.
NETWORK DISTRIBUTION SYSTEM
It consisting of a number of interconnected distributing lines is supplied from 2 or more
distribution transformers operating in parallel.
It is an advantageous system because in case of one transformer fails load can be supplied
by other one. Such a system is used in High load density
METROPOLITAN areas.
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