WHAT IS TRANSFORMER, DEFINE TRANSFORMER, TYPES OF TRANSFORMER, RATINGS OF TRANSFORMERS, MANUFACTURING PROCESS OF TRANSFORMER, PARTS OF TRANSFORMER, TESTS OF TRANSFORMER, COSTING OF COPPER.

1. MADE BY :-
MOHIT
ELECT. ENGG.

2. WHAT IS TRANSFORMER ?
Transformer is an electrical device which converts
electrical energy from one circuit to another circuit by
STEP UP/STEP DOWN the AC voltage without changing
frequency.

3. TYPES OF TRANSFORMERS :-
 CORE TYPE TRANSFORMER
In core type transformer windings
encircles the core. (also known as
power transformer)
 SHELL TYPE TRANSFORMER
In shell type transformer core
encircles the windings.

4. SOME RATING OF TRANSFORMERS :-
6.3 kva 200 kva
10 kva 500 kva
16 kva 1000 kva
25 kva 1500 kva
63 kva 2000 kva
100 kva 2500 kva

5. MANUFACTURING PROCESS OF TRANSFORMERS :-
(According to kva)
 CORE SLITTING
 CORE CUTTING
 CORE ASSEMBLY (CA)
 WOUND LV WINDING
 WOUND HV WINDING
 COIL CORE ASSEMBLY (CCA)
 LV CONNECTIONS (STAR CONNECTION)
 HV CONNECTIONS (DELTA CONNECTION)
 OVENING PROCESS
 CHECK MEGGER VALUE
 CHECK RATIO VALUE

6.  TANKING PROCESS
 BUSHING FITTINGS
LV BUSHING FITTINGS
HV BUSHING FITTINGS
 TIGHT TOP COVER OF TANK
 OIL FILLING PROCESS
 TESTING PROCESS :-
RESISTANCE TEST
HIGH VOLTAGE TEST
DVDF TEST
NO LOAD LOSS TEST
FULL LOAD TEST
HEAT RUN TEST
OIL PRESSURE TEST
 PAINT THE TRANSFORMER

7. PARTS OF TRANSFORMERS :-
 Transformer tank
 Channel
 Laminated Core
 Radiator
 Windings
LV WINDING
HV WINDING
 Bushing
LV BUSHING
HV BUSHING
 Breather
 Oil Conservator
 Transformer Oil

8.  Air Release Plug
 Cable Box
 Lifting Lugs
 Pressure Relief Valve
 Pressure Relief Pipe
 Thermometer
 Buchholz Relay
 Oil Gauge
 Silica Gel
 Earthing Terminal
 MOG
 Stiffener
 Inspection Vent
 5 pos. TAP CHANGER
 7 pos. TAP CHANGER
 On Load TAP CHANGER (OLTC)

9. TESTS PERFORMED ON TRANSFORMERS :-
TURN RATIO TEST
Turn ratio test is perform to see the turns of HV
winding is proper or not.
TURN RATIO FOR TRANSFORMER :-
MAX. – 44.20
MIN. – 43.80
 MEGGER TEST
Megger Test is perform to check the insulation
of the coils used in transformer. Megger value
can always above 500Ω.
•LV – EARTH
•HV – EARTH 500Ω
•LV – HV

10. RESISTANCE TEST
Resistance test is perform to see that any coil is break or not,
each circuit is wired properly and all connections are tight.
For HV SIDE :- R PHASE – Y PHASE
Y PHASE – B PHASE
B PHASE – R PHASE
For LV SIDE :- R PHASE – NEUTRAL
Y PHASE – NEUTRAL
B PHASE – NEUTRAL
TEMPERATURE TEST
In temperature test see the temperature of transformer (37°c).

11.  TRANSFORMER OIL TEST
Transformer Oil test is performed to see the quality of oil. If the
quality of oil is poor then transformer will fail in HIGH VOLTAGE
TEST.
 HIGH VOLTAGE TEST
High Voltage Test is perform to see the capacity of Transformer.
In high voltage test connect LV side of Transformer with earthing
wire and HV side of transformer with high voltage wire. Give
28000 volts to HV side of transformer for 1 minute.

12. DOUBLE VOLTAGE DOUBLE FREQUENCY TEST
(DVDF)
In DVDF test connect R Y B wires on HV side to see any LV/HV coil is break or
not. In this test give double voltage (866v), double frequency (124hz) to HV
side for 48 seconds.
 NO LOAD LOSSES TEST
No Load Losses are the losses used to find out the Core losses. In
these losses open the HV circuit and connect RYB cable to LV side
except neutral, then apply voltage on LV side and check the readings
of current and losses in watts so these losses are also called Open
Circuit Losses.

13.  FULL LOAD LOSSES TEST
Full Load Losses are the losses used to find out the Winding losses. In
these losses short the LV circuit except neutral and connect RYB cable to
HV side, then apply current on HV side and check the readings of voltage
and losses in watts so these losses are also called Short Circuit Losses.
HOW TO FIND THE LOSSES :-
Losses X 300 = 1522 X 300 = 456600 = 1776.6 W
225 + TEMP. 225 + 32 257

14. HOW TO FIND THE CURRENT FOR FULL LOAD LOSSES :-
(ex – 500 KVA)
-:HV:-
KVA X 1000 = 500 X 1000 = 500000
HV / LV = 11000 = 11000 = 26.24 Amp.
√3 = 1.732 = 1.732
-:lV:-
KVA X 1000 = 500 X 1000 = 500000
HV / LV = 433 = 433 = 666.70 Amp.
√3 = 1.732 = 1.732

15.  OIL PRESSURE TEST
Oil pressure test is perform to see the leakage in the transformer tank.
 HEAT RUN TEST
Heat run test is one of the important tests on power transformer. This test
is also called temperature rise test. In this test give continuous rated load
and the temperature will rise during the load. This test is done for 12
hours and take 12 reading every hour of changing temperature that how
much temperature will rise.

16. COSTING OF COPPER :- (07/05/2019)
 LME (London Metal Exchange) $ 6161.00
 PREMIUM $ 190.00
 M.F x 1.05
 DOLLAR RS. 70.82
 GODOWN CHARGES RS. 4000/ton
 FABRICATION COST RS. 18/kg
LME + PREMIUM x M.F x DOLLAR + GODOWN CHARGES + FABRICATION
1000 COST