transformer

1. Power Transformer
‫وترتيب‬ ‫جمع‬
‫مهندس‬
/
‫محمد‬ ‫محمود‬
Mahmoud.ali8585@gmail.com

2.  Objective :
1-Introduction
2-Calssification
3- Construction and manufacture of the
Transformers
4- Cooling systems
5- Components of transformer
6-Acccessories
7-Effect harmonic in connection
8-Effect the earthing on transformer
9-Types of the connection
10-Operation the transformers in parallel

3. The objective of the use of
electrical transformers in the
electrical networks

5.  Other advantages of the
transformer:
1. Reduce lost power during the transfer of
electrical power
1. Reduce the value of the voltage
drob(I*X)
1. Reduce the cost of electrical transmission
lines and towers

6.  Transformer :
S=100KVA
Can any connection any voltage on
Transformer where V*I=100KVA:

7.  Classification of transformer:
1- For use:
 Power Tr for Transmission network.
 Distribution Tr for distribution
network.

8. 2- For cooling:
 ONAN (oil natural air natural)
 ONAF (oil natural air forced )
 OFAF (oil forced air forced )
 ODAF (oil Direct air forced)

9. 3. For turns ratio :
 Step up Tr
 Step down Tr
4. For phases :
 Single phase
 Three phase

10.  For power transformer :

13.  Areas of use of power transformers
in power plants:
1. Main transformer
2. Auxiliary transformer
1. Start up transformer

14.  The different of power transformer
and distribution transformer:
1. For loading
2. Size
3. power

15.  Why is turn the coils around core :

16.  The manufacturing of three phase
transformer :
1. Use three single phase transformer

18. 2. Use core type or shell type :
 core type:

19.  Shell type :

20.  The different between two
methods:
1- Three single phase Tr &Three phase
Tr
 Easy in Maintenance and
installation
 large area in station
 Other Tr for Emergency
 The cost is greater than Three
phase Tr about 25%
 The weight is large

21.  The Methods of windings connection
in three phase Transformers:

22.  The relations in Voltage and power in
Tr:

23.  What is the difference between the
use of Amp and Volt-Amp in the
expression about three phase
Transformer :
 Power for Tr is ( KW or KVA) and
why:

24.  Three Winding Transformer:
 In most Transformers have two
groups of Windings (primary/
secondary) as known Two Windings
sush as ( star/star or delta/star )
 Other type of transformer as known
3- Winding Transformer where
added tertiary winding to the
transformer

25.  Tertiary winding has two use :
1- Produce different voltage :
( 220/6/11 )kv
2- circulate zero sequnce currents in
delta

26. Construction and manufacture
of Transformers
1- Active parts :Core and Windings
2-Unactive parts :components of Tr
and accessories

27. 1
2
3
4
5
6
7
11
12
13
14
19
20
17
8
18
1- Winding
2- Core
3- High Voltage Bushing
4- Low Voltage Bushing
5- Conservator
6-Explosion vent
7- Bulb of temp. indicat
8-Temp. indicator
9- Control cabinet of
10- Control cabinet of ta
11-Buchholz relay
12- Vacuum valve
13- Breather ( silica gel)
14- Radiator and fan
15- Pump
16- Oil drain valve
17- Oil level gauge
18- Insulating oil

28.  Core and Windings:
1- Core:
Made from sheets of steel material
grained silicon prompt rolled and cold:
CRGO (Cold rolled grain oriented
silicon steel
 Flux density inside magnetic circuit
about (1.6: 1.8 ) Tesla

29. The Characteristics of the materials
used in the manufacture of core :
1- Permeability
2- Saturation
3-Residual flux

30.  The types of core :
1- Core type
2- Shell type
 The core type use in small power
transformer under 50 MVA

33.  1- Core type :

35.  2- Shell type :

37.  The different between core type
and shell type :
1- single core type has 2-limb while in
shell type has 3-limb
2- in shell type has cross section area
large and copper turns low
3- in shell type has high ability against
Short circuit
4- Difficult maintenance in shell type

38.  Made of Sheets of core :

40.  The earthing of core :

41.  Transformers windings conductors:
1- Copper
2- Aluminum

42.  Transposition in Conductors :
Conductors manufactured in this way
Called ( Continuous Transposed
Conductors ), CTC

43.  Types of windings :
1-Helical winding:
 Its called Screw or Spiral
 Its carries high currents
 It has large area
 Easy in the manufacturing

44. 2- Disk winding :
 It use in Tr’s contain on large turns
and it carry low current
 It use with voltage greater than 25kv
 Insulation between Conductors only

45. 3- Layer winding :
 It use in Tr’s have load Tap changer

46. 4- Ban cake winding :
 It use in shell type Tr’s

47.  The insulators in Transformers:
 Enamel ( for conductors )
 Paper insulation
 Kraft paper for (Layers)

48.  Drying effect on the insulation
transformer :
 Use spiceal Furnace
 Use Ac Current

49.  Cooling systems :
1- Air
2- Oil
 Air use in Dry Transformer

50.  Disadvantage :
1- Not allowed to download transformers
except for a small period of time
2-Low durability insulation
3-The windings effect Dust and dirt
4-Increasing the size of the windings
to follow the air

51.  Oil filled transformer in power Tr:
 The basic elements:
1-Oil
2- Radiators
3-Fans
4-Pumps
5-Cooling pipes

52.  Transformer Oil :
 Function:
 1- Cooling
 2- Insulation
 The Properties Transformer Oil:
1-Dielectric strength
2-Viscoisty
3-Flash Point(145 c)
4-denisty (.88/cm3 at 15 c),the
efficiency of transfer the
temperature about 21 times of Air

53.  Radiators:

55.  Fans:
 Increase the efficiency of cooling
( Forced Circulation)
Note:
1- Small Fans put in the front the
Radiators cause Vibration
2- Large Fans put Under the Radiators

56.  Cooling Class :
 The Characterization IEC:
1 2 3 4
internal
cooling
type
Circulation
type
External
cooling
type
Circulati
on type

57. O N A N
Oil Natural Air Natural

58.  ONAN:

59.  Use in Small Transformer
 Advantages :
1-Simple
2-low cost
3-High Reliability
4-low noise
Disadvantages:
1-Large Radiators and high cost
2- Limited in small transformer

60.  ONAF:
 Use in High power Tr
 Use two fans groups and work
automatic
 Distribution fans regularly

61.  OFAF :

62. ODAF:

63.  Multi-stage cooling :
 Change in rating value with Cooling

64.  What's the meaning :
ONAN/OFAF/OFAF cooling class
transformer with”45/60/75 MVA
continuous at 65 c Temperature rise: