This ppt is related to the transformer and how to reduce transformer losses.

1. Bhartiya Institute of Engineering & Technology, Sikar
A Presentation
on Transformer
& How to
reduce losses
Presented By:-
Jaiprakash
16EBTEE010

2. Transformer:-
Transformer is a static device that:
• Transfer electric power from one circuit to another.
• It does so without a change of frequency.
• It accomplishes this by electromagnetic induction.
• Where the two electric circuits are in the mutual inductive influence of
each other.

3. To overcome losses, the electricity from a generator is passed through a
step-up transformer, which increases the voltage. throughout the
distribution system, the voltage is changed using the stepdown
transformer to voltage suitable to the application at industry and homes.
Transformer:-
Generation
unit
Step up
transformer
Transmission
power line
Step down
transformer
Distribution
power line
Customer
End

4. Types of Transformer
According to construction
According to nature of supply
According to voltage level
According to core material
According to usage

5. According to construction
 Shell type  Core type

6. According to nature of supply
Single phase Poly phase

7. According to voltage level
Step up Step down

8. According to core material
According to core
material
Iron core
transformer
Ferrite core
transformer
Toroidal core
transformer
Air core
transformer

9. According to usage
Power domain
1.Power transformer 2.Measurement transformer 3.Distribution transformer

10. Losses of transformer
Transformer
losses
Dielectric
losses
Copper or
ohmic losses
Stray losses
Iron or core
losses
Hysteresis
losses
Eddy current
losses

11.  Dielectric losses
 It occurs in the insulating materials of the transformer that is
in the oil of the transformer.
 It occurs when the insulating materials and the oil losses it's
quality.
 The transformer oils are subject to change its parameters such
as dielectric strength, moisture, chemical parameters
(dissolved impurities – the dissolution of copper), physical
parameters, etc.
Periodic testing of oil and maintaining insulation
quality is an effective way to reduce dielectric loss.

12.  Copper or ohmic losses
 Copper loss occurs due to the ohmic resistance in both primary
and secondary winding.
The windings of the transformer are made thick so that the
resistances are minimized.
Another technique is Vaccum Pressure Impregnation(VPI). In
this technique the transformer is kept in a vacuum then high-
pressure varnish is passed so that the smallest of the air gaps are
also filled. Hence reducing the copper losses.
Calculating the copper loss in the primary and secondary
winding,
Total Copper Loss, Pcu = I1
2R1 + I2
2R2

13.  Stray losses
Stray losses are due to the leakage flux in the transformer.
 This leakage flux induces eddy current that appears all
over in metal parts which are under the magnetic leakage
field called the stray loss.
 Stray loss can be reduced by minimizing the
leakage flux.

14.  Iron or core losses
Iron loss occurs in the transformer core due to the alternating magnetic
flux.
It consists of eddy current loss and hysteresis loss.
 Iron loss = Hysteresis loss + Eddy Current loss
 Both the Eddy current loss and hysteresis loss depend upon
the magnetic properties of the core material
 f-frequency
 Bm– maximum flux density
 Iron loss (Hysteresis loss, eddy current loss) and dielectric loss are no-
load losses which are independent of the transformer load.

15. 1.Hysteresis Loss
 Hysteresis loss causes due to the reversal of magnetization for
changing the orientation of magnetic domains during each half cycle
of the alternating current.
Wh =Kh f Bm
1.6 w/m3
Kh – hysteresis constant
Choosing proper core material which has a low hysteresis coefficient
and high permeability can minimize the hysteresis loss.

16. 2. Eddy Current Loss
 It is the result of induced current in the core due to the
electromagnetic induction in ferromagnetic material, which flows as
loops of electrical current within the conductor
We = Ke f 2 Bm
2 t 2 w/m3
Ke – co-efficient of eddy current
t – Thickness of the sheet
Eddy current loss can be reduced by using an iron core made of
thin laminated sheets and material with high electrical
resistivity.
It reduces the induced EMF and the amount of current flow.
 Iron loss is determined by the open circuit test.

17.  How reduce losses in transformer
We conclude that the Transformer can achieve the efficiency of about
98-99% if the following things are applied successfully:
Cooling the transformer properly.
Shredding of core must be greater.
The Permeability of core material must be higher.
Resistance of windings must be less.
Proper configuration of transformer core.
Primary and secondary windings must be interleaving.