ELEMENTS OF THE ELEMENTS OF THE POWER SYSTEMPOWER SYSTEM

Submitted ToSubmitted To

Mr. Shahbaz Pervez Mr. Shahbaz Pervez

Submitted BySubmitted By

Bilal Aslam 03F -EE-17Bilal Aslam 03F -EE-17Salman Tahir 03F-EE-55Salman Tahir 03F-EE-55

POWER POWER SYSTEMSYSTEM

The electrical power system provides a The electrical power system provides a means of means of generatinggenerating, , transmittingtransmitting and and distributingdistributing energy in the form of electric energy in the form of electric current, to the ultimate users, the current, to the ultimate users, the loadload..

GenerationGeneration, , TransmissionTransmission, , DistributionDistribution and and LoadLoad form the four basic elements or form the four basic elements or subsystemssubsystems of a power system of a power system

SUBSYSTEMSSUBSYSTEMS

GENERATIONGENERATION

Generation is simply the conversion of Generation is simply the conversion of energy from one form to another.energy from one form to another. The three major types of generation The three major types of generation are:are:

FOSSILFOSSIL HYDROHYDRO NUCLEARNUCLEAR

FOSSILFOSSIL

Fossil fuels such as Fossil fuels such as coal, oil and gascoal, oil and gas are are burned to generate electricityburned to generate electricity

The machines used in fossil generation are The machines used in fossil generation are high speed but slow startinghigh speed but slow starting

The main issues are environmental as The main issues are environmental as burning of fuel causes pollution therefore burning of fuel causes pollution therefore low sulphurlow sulphur content fuelcontent fuel is used is used

HYDROHYDRO

In hydro plants, electric power is In hydro plants, electric power is generated by the water flowing generated by the water flowing through a turbine which is coupled through a turbine which is coupled solidly to a generatorsolidly to a generator

Hydral machines are Hydral machines are slow machinesslow machines but they are quick starting and have but they are quick starting and have a good a good ramping rateramping rate

NUCLEARNUCLEAR

In nuclear plants the basic cycle is similar to In nuclear plants the basic cycle is similar to that of fossil plant but the required heat is that of fossil plant but the required heat is provided by the provided by the nuclear reactionnuclear reaction rather rather from burning fuels from burning fuels

Due to the stringent government Due to the stringent government requirements about the safety of nuclear requirements about the safety of nuclear plants, their design and operation are plants, their design and operation are much more complicated than the fossil or much more complicated than the fossil or hydro unitshydro units

TRANSMISSIONTRANSMISSION

The transmission system consists of a The transmission system consists of a network of network of overhead linesoverhead lines or in or in densely populated areas, densely populated areas, underunder ground cablesground cables

The lines are designed to transmit The lines are designed to transmit large amounts of power from point of large amounts of power from point of generation to the load areageneration to the load area

CLASSIFICATION OFCLASSIFICATION OF TRANSMISSION LINESTRANSMISSION LINES

We classify transmission lines with We classify transmission lines with reference to:reference to:

VoltageVoltage

DistanceDistance

A.C or DCA.C or DC

VOLTAGEVOLTAGE

Ultra high voltage transmission lines(1000 Ultra high voltage transmission lines(1000 KV) KV)

Extra high voltage transmission lines(745 Extra high voltage transmission lines(745 KV)KV)

High voltage transmission lines(200 KV)High voltage transmission lines(200 KV)

Medium voltage transmission line(132 KV)Medium voltage transmission line(132 KV)

DISTANCEDISTANCE

Long length T.L (> 150 KM )Long length T.L (> 150 KM )

Medium length T.L (50-150 KM)Medium length T.L (50-150 KM)

Short length T.L (<50 KM )Short length T.L (<50 KM )

A.C OR D.CA.C OR D.C

The transmission line may be ac or dc The transmission line may be ac or dc depending upon the applicationdepending upon the application

TYPES OF POWERTYPES OF POWER TRANSMISSIONTRANSMISSION

The two general types of power The two general types of power transmission are :transmission are :

Overhead linesOverhead lines

Underground cablesUnderground cables

OVERHEAD LINESOVERHEAD LINES

Overhead lines are of two typesOverhead lines are of two types

AC lineAC line

DC lineDC line

AC LINESAC LINES

The overhead ac lines are applied on The overhead ac lines are applied on power systems at voltages in the power systems at voltages in the range of range of 115 KV115 KV to to 800 KV800 KV

COMPONENTS OF A COMPONENTS OF A TRANSMISSION LINETRANSMISSION LINE

Conductors Conductors

Ground wiresGround wires

InsulatorsInsulators

TowersTowers

ConductorsConductors are either solid round,stranded or are either solid round,stranded or bundled. Stranding provides flexibilitybundled. Stranding provides flexibility

The The Ground wireGround wire acts as a shield to protect the acts as a shield to protect the energized conductors from lightning strokesenergized conductors from lightning strokes

InsulatorsInsulators suspend the energized phase conductors suspend the energized phase conductors and insulate them from grounded towerand insulate them from grounded tower

The The TowerTower support the conductors and is the most support the conductors and is the most visual part of a T.L visual part of a T.L

DC TRANSMISSION LINEDC TRANSMISSION LINE

In this mode of transmission, the In this mode of transmission, the threethree phase, 60 Hzphase, 60 Hz voltages and currents voltages and currents are converted to dc, transmitted on a are converted to dc, transmitted on a dc line and are converted back to ac dc line and are converted back to ac at the other endat the other end

USES OF THE DCUSES OF THE DC TRANSMISSION LINETRANSMISSION LINE

To connect two systems operating at To connect two systems operating at different frequenciesdifferent frequencies

For long underground or under water For long underground or under water transmission transmission

For long distance overhead For long distance overhead transmission transmission

DC lines are sometimes called DC lines are sometimes called asynchronous tiesasynchronous ties since they can be since they can be used to inter connect two systems used to inter connect two systems operating at different frequenciesoperating at different frequencies

Moreover DC transmission is chosen Moreover DC transmission is chosen over AC because it is less expensive over AC because it is less expensive than AC over very long distancesthan AC over very long distances

CABLESCABLES

Underground cables are used in very Underground cables are used in very densely populated areas but they are densely populated areas but they are rarely used because they are more rarely used because they are more expensive as they require insulating expensive as they require insulating materials instead of air to separate materials instead of air to separate the conductors from each other and the conductors from each other and from groundfrom ground

DISADVANTAGES OF CABLESDISADVANTAGES OF CABLES

There are also some technical There are also some technical disadvantages associated with disadvantages associated with underground cables. One major underground cables. One major problem is the very high capacitance problem is the very high capacitance inherent in the underground cables. inherent in the underground cables. This capacitance give rise to This capacitance give rise to chargingcharging currents.currents. Special Special equipments must be installed to equipments must be installed to compensate for the effect of charging compensate for the effect of charging currents, which adds to the costcurrents, which adds to the cost

TYPES OF CABLESTYPES OF CABLES

OIL FILLED PIPE TYPE CABLEOIL FILLED PIPE TYPE CABLE

OIL FILLED SELF CONTAINED CABLEOIL FILLED SELF CONTAINED CABLE

SOLID DIELECTRIC CABLESOLID DIELECTRIC CABLE

SF6 CABLESF6 CABLE

DISTRIBUTIONDISTRIBUTION

The distribution system consists of a The distribution system consists of a network overhead lines and network overhead lines and underground cables by which the underground cables by which the power is distributed to the ultimate power is distributed to the ultimate users of electricity that is the users of electricity that is the loadload

LOADLOAD

The The utilizationutilization of electric power is of electric power is collectively called collectively called loadload. This includes . This includes the uses of electricity in the uses of electricity in homes,homes, factories, offices and for recreation,factories, offices and for recreation, entertainment, etcentertainment, etc

SYSTEM VOLTAGESSYSTEM VOLTAGES

Generation voltages are in the range of Generation voltages are in the range of 12-12-35KV35KV

Transmission voltages are in the range of Transmission voltages are in the range of 115-800 KV.115-800 KV.

Distribution voltages are in the range of Distribution voltages are in the range of 4-35 4-35 KV.KV.

Loads operate at variety of voltages due to Loads operate at variety of voltages due to their diverse naturetheir diverse nature

POWER IS TRANSMITTED POWER IS TRANSMITTED AT HIGH VOLTAGE AT HIGH VOLTAGE

RATHER HIGH CURRENTRATHER HIGH CURRENT

Power transmitted is directly Power transmitted is directly proportional to product of proportional to product of V V and and I I but but losses are directly proportional to losses are directly proportional to II22 , ,

therefore to transmit power with therefore to transmit power with minimum loss we use high voltageminimum loss we use high voltage