tna transformer

8/9/2019 TNA Transformer

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TransformerTransformer

Maintenance and TestingMaintenance and Testing

Presented By.Presented By.

Muhammad BilalMuhammad Bilal

EEEE--I BlockI Block--IIII


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Transformer PrincipleTransformer Principle

Faraday's law of electromagnetic induction.Faraday's law of electromagnetic induction.

E = M di/dtE = M di/dt


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TapchangerTapchanger

Voltage of the system can be varied byVoltage of the system can be varied by

changing the turn ratio of transformer. Thechanging the turn ratio of transformer. The

device tapchanger is used for adding or cuttingdevice tapchanger is used for adding or cuttingout turns of primary or secondary winding of aout turns of primary or secondary winding of a

transformer.transformer.


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Insulating oilInsulating oil

Insulating oil forms a very significant part ofInsulating oil forms a very significant part oftransformer insulating system and has the importanttransformer insulating system and has the importantfunction of acting as an electrical insulation as well asfunction of acting as an electrical insulation as well as

a coolant to dissipate heat lossesa coolant to dissipate heat losses Insulating oil is hydrocarbon mineral oil consist ofInsulating oil is hydrocarbon mineral oil consist of

four major organic compoundsfour major organic compounds

ParaffinsParaffins

NaphtanesNaphtanes AromaticsAromatics

OlefinesOlefines


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Various type of coolingVarious type of cooling

ONAN = oil natural air naturalONAN = oil natural air natural

ONAF = oil natural air forcedONAF = oil natural air forced

OFAF = oil forced air forcedOFAF = oil forced air forced OFWF = oil forced water forcedOFWF = oil forced water forced

ODAF = oil directed air forcedODAF = oil directed air forced

ODWF = oil directed water forcedODWF = oil directed water forced


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Buchloz RelayBuchloz Relay

The relay serves as main protection for anyThe relay serves as main protection for any

minor or major faults that may develop insideminor or major faults that may develop inside

a transformer. Such faults always results ina transformer. Such faults always results in

generation of gases which cause the operationgeneration of gases which cause the operation

of mercury switches giving signal for alarm orof mercury switches giving signal for alarm or

isolates the transformer from the network.isolates the transformer from the network.

The relay is mounted in the pipe at anThe relay is mounted in the pipe at an

inclination of 3inclination of 3--77


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What to do when BUCHLOZ relayWhat to do when BUCHLOZ relay

operatedoperated BUCHLOZ relay operates due to presence ofBUCHLOZ relay operates due to presence of

gases.gases.

Analyzing the gases dissolved in the oil orAnalyzing the gases dissolved in the oil orcollected from the buchloz relay greatlycollected from the buchloz relay greatly

facilitates detection of fault in the transformer.facilitates detection of fault in the transformer.


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NonNon--inflammable gasesinflammable gases

If gases are nonIf gases are non--inflammable then transformerinflammable then transformer

can put back into service as it is due to entry ofcan put back into service as it is due to entry of

air which can be removed by purging.air which can be removed by purging.


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Inflammable gasesInflammable gases

Inflammable gases may be due to serious fault.Inflammable gases may be due to serious fault.

It is therefore essential to disconnect theIt is therefore essential to disconnect the


Then measure the acid content. Acidic natureThen measure the acid content. Acidic nature

of gases imply the serious fault in theof gases imply the serious fault in the



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Transformer Vector GroupTransformer Vector Group

It shows the angular displacement b/w H.V.It shows the angular displacement b/w H.V.

and L.V. winding.and L.V. winding.

The phase displacement is indicated by theThe phase displacement is indicated by theangle in terms of clock face. The HV vectorangle in terms of clock face. The HV vector

being at 12 o, clock (zero) and thebeing at 12 o, clock (zero) and the

corresponding LV vector at hour hand number.corresponding LV vector at hour hand number.


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Standard Vector GroupsStandard Vector Groups

GroupGroup PhasePhase

DisplacementDisplacement

ConnectionsConnections

11 ZeroZero Yy0, Dd0Yy0, Dd0

22 180180 Yy6, Dd6Yy6, Dd6

33 3030 laglag Dy1, Yd1Dy1, Yd1

44 3030 leadlead Dy11, Yd11Dy11, Yd11


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