Welcomeby

Md. Nirob Dhilon Chowdhury

ID# 11105149

Department of EEE

International University of Business, Agriculture and Technology

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Completed internship in

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Manufacturing of 11KV/.415KV distribution transformer of

Green Power Electrical & Electronics

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To introduce Green Power Electrical & Electronics.

To discuss about transformer.

To reveal the manufacturing of distribution X-former of GPEE.

To recommend.

OBJECTIVE

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About Green Power Electrical & Electronics

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Name: Green Power Electrical & Electronics.

Sister Concern: Green Power Transformer Company

Organization Type: Proprietorship.

Year of Establishment: 2004.

Founder & CEO: Engr: Gulzer Rahman

Head Office: Hakim Plaza , 209/B, 1st Colony, Mazar Road, Mirpur , Dhaka-

1216.

Factory Location: 382 Harindhara, Hemayetpur, Savar, Dhaka.

Products

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AVR IPS IVS UPS

Products

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TransformerHT switchgear

LT Switchgear PFI

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Working Sequence

• Transfers electric power from one circuit to another

• It does so without a change of frequency

• It accomplishes this by electromagnetic induction

• It can raise or lower the voltage in a ckt but with a corresponding decrease or increase in current.

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Basic Functions Of Transformer

Transformer is a static machine that…..

Input connection

Output connection

Winding

Core

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Working Procedure of a Transformer

Primary parts to the basic transformer

Generally used in transmission network

It’s rating is given in terms of the secondary's maximum voltage and current-delivering capacity

Operates at high voltage greater than 33 KV with 100% efficiency

Has a big size

Used in generating station and transmission substation at high insulation level

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Common Types of TransformerPower Transformer

• Used for the distribution of electrical energy

• Operates at low voltage as less than 33KV in industrial purpose and 440v-220v in domestic purpose

• It works at low efficiency at 50-70%

• Has small size easy in installation

• Has low magnetic losses & it is not always fully loaded

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Common Types of Transformer

Distribution Transformer

Combined with current transformer & potential transformer

Used for both metering purposes & protection purposes

Used for network control to supply important information for determining the state of the operating conditions of the network 13

Common Types Of Transformer

Instrument or accurate ratio Transformer

Current Transformer

Potential Transformer

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Installation of Transformers

Power Tx

Distribution Tx

1. Active Part- Core and Windings.

2. Passive Part- Tank, cooling liquid, Fans, Protection devices etc.

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Manufacturing of 3-phase Distribution Transformer

The construction of transformer is divided into two fundamental parts:

Active Parts

Core

winding

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Main Components of a Transformer

Tap Changer

Buchholz Relay

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Steps of Transformer manufacturing

Low reluctance

Higher reliability

Lowering material cost

Reduction in iron loss & magnetizing current

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Manufacturing of Transformer Core

Factors that are taken into consideration…..

Steel that has under gone through both the Silicon Alloying and Cold Rolling treatment.

Basic material are Alloy Steel having main content Silicon & carbon

Which increases permeability & reduces losses

Hysteresis loss in transformer mainly depends upon its core materials

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Core Materials

For core manufacturing we use…

The commercially available CRGO steel sheets will have 3% of Silicon

Thickness of the CRGO sheets will be of the order of 0.25mm to 0.33mm

CRGOS shows excellent Magnetic properties

This material has low specific iron loss

Oxide coating is provided for CRGO laminations to reduce eddy current losses

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Core Materials

CRGOS

Steel

Hot Rolled Steel (HRS)

Cold Rolled Grain Oriented Steel (CRGOS)

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Core Cutting

A bar: Length: (590-540) mm

Width: (130-40) mm

Total A bar used: 1392

B bar:Length: 255 mm

Width: (130-80) mm

Total B bar used: 928

C bar:Length: (380-470) mm

Width: (130-80) mm

Total C bar used: 464

Types of cutting (200KVA)

Thickness 0.27 mm

The channels are combined in

stepped round shape with a

square mid-section.

This gives flexibility and allows to

select ideal individual core

section.

Four channels are to set, two in

top and two in bottom. 22

Channel Setting

Channel

This is the simplest form of joints

The flux leaves and enters at the joint in perpendicular

Preferable to use in small rating transformer

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Core Assembling

There are normally two types of joints used in transformer core: Interleaved joints Mited joints

Interleaved Joints

Yoke

Here the lamination’s are cut at 45°

The limbs and yoke lamination

edges are placed face to face

Here the flux enters and leaves

the lamination, gets smooth path in

the direction of its flow. Hence,

cross grain loss is minimum.

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Core Assembling

Mitred Joints in Transformer Core

Mirted Joints

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Influence of Diameter of core

Then, cross-sectional area of the core,

Now, Voltage per turn,

[Bm= Max. flux density]

So, E ∞ D2

Again, V = E*N, [where N is the number of turns in winding & voltage across the winding of transformer is V]

When, v is constant then, E∞1/N

Finally, N∞1/D2

Core diameter is increased, the number of turns of winding reduced.

This increases steel weight that leads to increased core losses in transformer.

On the other hand, copper loss in transformer is reduced.

If diameter of the core is decreased, the weight of the steel in the core is reduced.

Which leads to less core loss of transformer, but increases extra copper loss.

So, core diameter must be optimized during designing considering both the aspects. 26

Since, N∞1/D2

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Manufacturing of Transformer Windings

Primary/High voltage winding Secondary/Low Vol. winding

Horizontal machine is used to prepare the HV windings

The HV winding is wound directly onto the low voltage winding

HV windings are of layered construction

The conductors are made of more round wires, either with an insulating paper

The insulation between the layers consists of DPC paper

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Primary or High Voltage Windings

LV windings are usually made of copper

Vertical machine is used to prepare the LV winding

Stripe paper is used to insulate the conductor

Number of turns varies on KVA rating

More even heat distributed through the windings.

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Secondary or Low Voltage Windings

Insulation

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DPC paper and fabric tape are used to insulate between two layers

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Insulation between core and LV windings

Cotton TapeDamn Proof Course Paper

Insulation

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Insulation between LV & HV

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Press board cutting & DPC paper are used to isolate HV from LV winding

Secondary coil insulation (stripe paper)

Press board cutting

DPC paper

The core is covered with

cotton tape and the LV

coil winding is mounted

with the core limb. They

are fitted tightly in all

three limbs using

pressed board.

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Placement of LV Windings

The HV winding is placed on LV winding as second layer of core

LV coil then after HV coil

The gap between the LV and HV coil is filled with runner of pressed board using cotton

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Placement of HV Windings

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Connections

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Tap Changer

Tap Changer

Tapping is terminated just bellow oil level

External handle

Taping is done on HV winding

Used to regulate the output voltage to required levels

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Function of Tap Changer

Changer

Taping wire connected to HV coil

The whole active part of the transformer is put into the Vacuum Drying Plant

It is kept there for three days with a continuous heating temperature of 100° - 141° C to clean the moistures in it

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Moisture Removing

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Tank of a Transformer

It forms a container for the cooling liquid

It acts as a heat exchange surface for the dissipation of heat losses

It is a protective earthed safety shell

Provides shielding against electromagnetic field leakage caused by current carrying conductors

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Functions of X-former Tank

Whole active part is covered by press board

Crane is used to elevate the active part

By handling a chain the active part is put slowly in the tank

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Tanking Up the Active Part

It is placed to withstand the electrical field strength produced in the insulation

Bushing has a conductor (Horn) surrounded by insulation

Used to insulate the incoming or outgoing conductor into or out of the transformer tank

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Bushings

Bushing

The function of conservator is to provide adequate space for expansion of oil inside the tank

It also acts as a reservoir for transformer insulating oil.

The oil level indicator indicates the oil level

Oil level should not fall below the alarm limit 43

Conservator

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Oil Filling

To provide insulation (liquid) to the x-former.

To dissipate heat of the transformer e.i. acts as coolant.

To protect the transformer core and coil assembly from chemical attack

To prevent the build up of sludge in the transformer

Oil is used….

Poly Chlorinated Bi Phenyl

(Crude oil)

continuity test

Ratio test

Magnetizing test

No load current test

Short circuit test

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Quality Control Test

Testing of transformer

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Overview

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Identification

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Recommendations

Working environment of Green Power Transformer Company should be more modern and ecological for technicians.

Every division should be provided more training facilities for manufacturing purpose.

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Thank You

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Do you have any question?