presentation on power distribution, operation and maintenance in comilla pbs 1

Slide 1

WELCOME TO MY PRESENTATION101-May-16Department of Electrical & Electronics Engineering of IUBAT

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Presented by

Kawsar AhmedID# 12105297Program: BSEEE

01-May-16Department of Electrical & Electronics Engineering of IUBAT2

Presentation on Power Distribution, Operation and Maintenance of Comilla Palli Bidyut Samity-1

IUBAT- International University of Business Agriculture and Technology3

01-May-16Department of Electrical & Electronics Engineering of IUBAT

ContentsObjectivesCompany OverviewClassification of TransformersVarious parts of TransformerPower DistributionSubstation EquipmentsMaintenanceRecommendationConclusion


ObjectivesObservation of rural distribution network About the system of BREBAbout the system of Palli Bidyut SamityAbout substationAbout transformer Maintenance system of BREBThe main objective is that how to improve our Socio-Economic Development by utilizing electricity.01-May-16Department of Electrical & Electronics Engineering of IUBAT5

Company OverviewRural Electrification Board Act, 2013 has been established instead of Rural Electrification Board Ordinance, 1977 and the name of Board is Bangladesh Rural Electrification Board which was responsible for electrifying rural Bangladesh.VisionElectricity for all by 2021. Mission Statement Provide quality electricity at grass root level in a democratic manner01-May-16Department of Electrical & Electronics Engineering of IUBAT6

Comilla Palli Bidyut Samity-1Since its inception in 1981, Comilla Palli Bidyut Samity-1 is playing a vital role in Agricultural, Industrial and Socio-Economic Development of Comilla District. It is a consumer owned entity organized on the basic principles of Co-operative for distribution of electric power to its members and operates on No Loss - No Profit basis for the mutual benefits of all its Members.701-May-16Department of Electrical & Electronics Engineering of IUBAT

Organizational chart of Comilla Palli Bidyut Samity-1Department of Electrical & Electronics Engineering of IUBAT8

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Consumer Information of Comilla PBS-1 Tariff-wise Consumer No (As on December 2014):TariffConsumer No.Percentage (%)Cunsumer Connected in Current MonthBilled ConsumerDomestic5650072.7320652362Commercial67788.7273146Charitable Institute15421.9831468Irrigation67788.7273146General Power67788.7273146Large Power2002Street Light6003


Classification of TransformerAccording to procedureAccording to structure of coreAccording to application According to frequency According to number of phase01-May-16Department of Electrical & Electronics Engineering of IUBAT10

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Various parts of transformerConservator tankBreatherBuchholz Relay RadiatorBushingArc hornsTap ChangerTransformer TankTemperature meterOil level indicator Name PlateInsulating Materials


Conservator TankIt is transformer oil storage tank and if the main tank oil reduces, the conservator will feed the oil to main tank.Its function is to ensure that the transformer tank is completely filled with oil every time.

Fig: Conservator tank


Breather It is connected to the conservator tank. It consists of silica gel material and silica gel absorbs the moisture from the air


Buchholz RelayBuchholz relay is a safety device mounted on oil-filled power transformers equipped with conservator.

Fig: Buchholz relay


Radiator Radiators are used in a transformer to cool the transformer oil.

Fig: Radiator


A bushing is the arrangement of insulating material that allows the terminals of winding to bring out the transformer tank. The bushing is made of the highest quality of porcelain clad.

Bushing


Arc Horns Arc horn is a mechanical arrangement of metallic conductor to perform flashover in a guided way in order to protect bushing.

Fig: Arc horns in the transformer bushing

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Tap Changer Tap changer in a transformer works like a switch, it connects or disconnects some coil turns of transformer winding so that voltage will be varied to make specific output.

Fig: Tap changer


Temperature meter Thermometer is used in transformer to measure the temperature inside the transformer tank.

Fig: Dial type thermometer.


Oil level indicator Oil level indicator indicates the oil level of the oil in conservator tank. Oil level indicator is connected with conservator tank.

Fig: Oil level indicator


Transformation Ratio Voltage ratio: Ep/Es = Np/Ns

Current ratio: Ep/Es = Is/Ip or EpIp=EsIs

Turns ratio: Ep/Es=Np/Ns=Is/Ip=a(a=Transformation Ratio)


Voltage regulation of transformerThe difference between the output voltage at no load and the output voltage at rated load, divided by the output voltage at rated load, is called the voltage regulation of the transformer.


Efficiency of transformer The output of a transformer is slightly less than the input because of the losses in the windings and the iron core. The ratio of the two, expressed as a percentage in the efficiency of the transformer. The output and input are expressed in watts or kilo-watts.

Efficiency= Output/Input01-May-16Department of Electrical & Electronics Engineering of IUBAT23

Power Distribution System


Equipment of the SubstationPower TransformersBus-bar InsulatorsIsolating SwitchesCircuit BreakerCurrent Transformer (C.T)Potential Transformer (P.T)FuseFeeder01-May-16Department of Electrical & Electronics Engineering of IUBAT25

Substation of Comilla Palli Bidyut Samity-101-May-16Department of Electrical & Electronics Engineering of IUBAT26

Cont.


Circuit BreakerIn Comilla PBS-1 use auto circuit recloser (ACR) instead of circuit breaker. The rating of this ACR is 360 ampere and 33KVIn this substation use two ACR one in the beginning and other in the ending point of substation. Both of them use for protection of the substation equipments though they use it as like switch.01-May-16Department of Electrical & Electronics Engineering of IUBAT28

Lightning ArresterLightning arrester use for protect from over voltage generally from thunder. In Comilla PBS-1 lightning arrester rating is 36KV.01-May-16Department of Electrical & Electronics Engineering of IUBAT29

Fig: lightning arrester

CT and PTCurrent Transformer (CT) and Potential Transformer (PT) use for measuring current and voltage in high voltage and current. If we want to calculate higher voltage and current directly we will need bigger measuring instrument which will be higher cost. For this reason we use CT and PT.Here Current Transformer (CT) ratio is 600:5Potential Transformer (PT) ratio is 6350:24001-May-16Department of Electrical & Electronics Engineering of IUBAT30

FuseA fuse is a short pitch of metal, inserted in the circuit, which melts when excessive current flows thought it.Fuse generally use for protect from over current. In this substation use drop down fuse or air break fuse.01-May-16Department of Electrical & Electronics Engineering of IUBAT31

Fig: fuse

Fuse characteristic 1. Low melting point. 2. High conductivity. 3. Least deterioration due to oxidation. 4. It carries the normal current without overheating.01-May-16Department of Electrical & Electronics Engineering of IUBAT32

Fig: Fuse on over head line

MeteringBy the meter we can measure present current, voltage, power factor and maximum current, voltage etc. There was analog meter now they are using digital meter.


Fig: meter

IsolatorIsolator is like a switch. It use after the circuit breaker for ensure line are totally off mode. Mainly it use while substation or line need maintenance. Isolator has a manual system for operation. 01-May-16Department of Electrical & Electronics Engineering of IUBAT34

Fig: Isolator

Power TransformerPower Transformer is the main part of a substation. In Comilla PBS-1 use 10MVA power transformer.


Voltage RegulatorVoltage regulator is a device which can voltage up or down in a limitation range according to consumer demand. Actually voltage regulator is an auto transformer. In Comilla PBS-1 those transformer we use they can voltage up or down up to 10%.

Fig: voltage regulator01-May-16Department of Electrical & Electronics Engineering of IUBAT36

FeederDistribution feeder circuits are the connections between the output terminals of a distribution substation and the input terminals of primary circuits. The distribution feeder circuit conductors leave the substation from a circuit breaker. In Comilla PBS-1 have 9 feeders. Every feeder have own controlling system and also there has a display which shows maximum current, voltage, power factor and present current , voltage, power factor and the times its operation. It shows up to one month data.01-May-16Department of Electrical & Electronics Engineering of IUBAT37

MaintenanceGenerally Comilla PBS-1 has three type of maintenance those are:Substation maintenanceLine maintenanceTransformer maintenance


Substation MaintenanceEvery time substation needs maintenance if any problem arises. Without problem substation needs check all equipment of its quality and condition at least one time in a year. For maintenance purpose every time substation has to be shut down and line has to ground.First of all we have to check circuit breaker whether it has any problem or will be any problem. In the time of power transformer checking it have to be 1000M of insulation test in megger. 01-May-16Department of Electrical & Electronics Engineering of IUBAT39

Line MaintenanceThere are many types of line maintenance:Some of maintenance has to be done immediately which mean whenever problem creates it had to be solved within four hours. Like over head line tear. For this type of problem immediately line has to be shut down.Some of maintenance can be done within 1-2 days like transformer problem.Some of maintenance can be done within a week like pole or tower got slanted to ground also trees came to the line.


Transformer MaintenanceIn REB have two type of transformer maintenance.One is single phase transformer and another is power transformer.Thy repair single phase transformer in there PBS workshops. And power transformer repair in central workshop at Savar in Dhaka. I visited both place and saw maintenance.


Single phase transformerIf any transformer create problem it bring in the workshop and the worker see it what type of problem. Workers open the transformer and take transformer oil into a separate tank. Then separate every part from the transformer and mark every part by serial a number.If any transformer core damage badly which is not possible to repair those type of transformer rejected totally by workshop worker.If any transformer coils damage any other problem thy repair it. 01-May-16Department of Electrical & Electronics Engineering of IUBAT42

Cont.Now I am describing how the worker repairs a single phase transformer.After marking transformer every part when they get time to repair it they take it.The main part of a transformer is coil binding. In Comilla PBS-1 they bind coil manually by the worker.There have two type of coil one is primary coil and another is secondary coil. Secondary coil strong and hard but primary coil is thin and weak. That is why secondary coil normally do not damage. Primary coil damage normally and need to repair it. 01-May-16Department of Electrical & Electronics Engineering of IUBAT43

Figure: Coil binding01-May-16Department of Electrical & Electronics Engineering of IUBAT44

Figure: complete coil binding01-May-16Department of Electrical & Electronics Engineering of IUBAT45

Figure: core binding of transformer01-May-16Department of Electrical & Electronics Engineering of IUBAT46

In figure transformer coil into the tank After binding coil they bind core in transformer then they keep coil in heat chamber for absorbing moisture from the coil.


Power transformerSingle phase transformer and power transformer maintenance procedure are same.


Figure: Power transformer coil binding in Savar central workshop.01-May-16Department of Electrical & Electronics Engineering of IUBAT49

Recommendation During my internship I came to know that BREB faces lots of problems and also has some limitations.Transformer stealing is one of the major problems of BREB. For this reason transformer with chain and lock would be better also transformer can be installed in near of the people house. BREB uses 3 single phase transformers for three phase distribution system which is costly and not efficient. Here three phase transformer would be more efficient.Comilla PBS-1 maintains substation manually it can be error in some time. Here automatic control system or programmable logic controller would be better and accurate.01-May-16Department of Electrical & Electronics Engineering of IUBAT50

Cont.Comilla PBS-1 is operated by workers for maintenance system. Likes winding binding, core binding, core cutting etc. During my internship I saw a worker cut down his hand badly by core which is terrible thing. At least in some specific tasks machine would be superior.To complete my internship and to understand the technical terms properly Switchgear and Protective Relays and Power Station these two courses helped me. So if someone wants to do internship at BREB, they need to complete these two courses and stay in BREBs quarter.01-May-16Department of Electrical & Electronics Engineering of IUBAT51

ConclusionBangladesh Rural Electrification Board (BREB) has the vast electricity distribution network all over the country and the electric power plants are connected with the transmission line to assure the continuity of electric power. The electric power plants produce power and feed in to the transmission line. All power plants are connected parallel with the transmission and distribution line. BREB is now more developing system day by day. As the part of this now BREB are using digital meter instead of analog meter for the consumer. However we have huge lack of electricity in Bangladesh but all of generation, grid supply, sub-station, consultancy, local member service of BREB is more efficient and taking important role to cover lack of electricity.01-May-16Department of Electrical & Electronics Engineering of IUBAT52

Thank you for your attention01-May-16Department of Electrical & Electronics Engineering of IUBAT53

Any Question?01-May-16Department of Electrical & Electronics Engineering of IUBAT54