Checklist for Erection Power Transformer

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GREENKO INTEGRATED MANAGEMENT SYSTEMS
CHECKLIST FOR ERECTION OF
POWER TRANSFORMER
Project:

Rating:

Location

Make:

FQAP/ITP
No:

Drawing
no:

Sl.
No
.
I
1

2

3

II

Parameters to be
Checked
N2 Pressure & Dew
point record: ( If
transformer oil sent
separately to site)
During dispatch at
factory
After receipt at site
Storage at site before
commissioning
Impact recorder analysis
:
Received at in a healthy
condition
Analysis report received
from manufacturer
before charging
Insulating oil checks

Acceptance reference /criteria

Start
Date/Time:
Finish
Date/Time:
Contractor
:
Observati
ons

Remar
ks

Pre Erection Checks.
At 40° C
Min 0.185 Kg/cm2
Max 0.32 KF/Cm2
Refer manufacturer limits also for
different Temp

Shocks ≤ 3g

1. Break Down voltage (BDV) : 70 kV
(min.)
2. Moisture content: 5 ppm (max.)
3. Tan-delta at 90 °C: 0.01 (max.)
4. Total Gas Content : < 1%
5. Resistivity at 90 °C : 6 X 1012
ohm-cm (min.)
6. Interfacial tension : 0.035 N/m
(min.)
7. *Oxidation Stability (Test method
as per IEC 61125 method C, Test
duration: 500
hour for inhibited oil)
a) Acidity: 0.3 (mg KOH /g) (max.)
b) Sludge: 0.05 % (max.)
c) Tan delta at 90 °C: 0.05 (max.)
8. * Total PCB content : Not
detectable (2 mg/kg total)
* For Sr. No. 7 & 8 separate oil
sample shall be taken and test
results shall be submitted within 45
days after commissioning for
approval of Power grid.
Pre –Erection Test( Below tests has to be Conducted by third party testing
Agency & Test report has to be attached with this check list)

Format Number: F-CO-QA-06

Effective Date: 10.10.2015

Page |1

GREENKO INTEGRATED MANAGEMENT SYSTEMS
CHECKLIST FOR ERECTION OF
POWER TRANSFORMER
1
2
3
4
5
6

Insulation resistance
test of Bushings CT’s.
Continuity test of
Bushings CT’s.
Secondary windings
resistance of Bushings
CT’s.
Polarity test of Bushings
CT’s.
Current ratio test of
Bushings CT’s.
Knee point voltage test
of Bushings CT’s.

7

Measurement of Tan
Delta & Capacitance of
Bushings.

8

Core insulation test (1
KV DC between Core to
ground)

III
1
2
3

4

5

6
7

All fittings as per out
line General
Arrangement Drawing
Check Main Tank has
been provided with
double earthing
Check neutral is
grounded through
separate connections.
Ensure metallic
requirements as per
specification (e.g. Cu) in
earthing strips used
Check that Marshalling
Box, T/C Driving Gear,
Diverter, Radiator Bank
Pump & Fan Motor etc.
has been earthed
All nuts and bolts are
tightened correctly as
per specified torque (as
per manufacturers
recommendation)
Check tightness of
Terminal Connectors
Check levelling of
Transformer and its
accessories

Format Number: F-CO-QA-06

**
No open loop
The expected deviation for this test
in the field is not more than 5.0% of
the factory test value.
Whether the polarity markings are
correct or not as per drawing.
Turns-ratio tolerance should be within
3 % of the nameplate specifications.
The magnetizing currents at KPV
(Knee point voltage) shall be less
than the specified value.
Tan delta & Capacitance values shall
be comparable with factory test
results and in no case shall be more
than 0.5 %.
Minimum 10 Mega ohm during
Commissioning after 1 minute.
( But minimum 100 Mega ohm during
factory test)
Pre commissioning checks
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Effective Date: 10.10.2015

Page |2

GREENKO INTEGRATED MANAGEMENT SYSTEMS
CHECKLIST FOR ERECTION OF
POWER TRANSFORMER
8
9
10
11
12
13
14
15

16
17
18
19
20
21

22

23

24

Any Paint removed /
scratched in transit has
been touched up
Bushings are clean and
free from physical
damages
Oil level is correct on all
Bushings
Check Hermitically
sealing is intact in all
Bushings
Check oil leakage
through any Joints /
Valves etc.
Check oil drain valves
are properly closed and
locked
Check oil level in Main /
OLTC Conservator tank
Check oil level at
conservator matches
with oil temperature of
transformer
Check Gear box oil level
in OLTC
Check OTI and WTI
pockets and replenish
the oil, if required
Check all valves for
their opening & closing
sequence
Check the colour of the
breather silica gel (blue
when dry)
Check availability of oil
in the breather cup
Check all rollers are
locked and tack welded
with rails (wherever
applicable)
Check no debris, loose T
& P and oil strains on
and around the
Transformer
Check door seals of
Marshalling Box is intact
and all cable gland
plates unused holes are
sealed
Check that pressure
relief valve is correctly
mounted

Format Number: F-CO-QA-06

yes
yes
yes
yes
yes
yes
yes
yes

yes
yes
yes
Yes, blue

Yes

yes

yes

Effective Date: 10.10.2015

Page |3

GREENKO INTEGRATED MANAGEMENT SYSTEMS
CHECKLIST FOR ERECTION OF
POWER TRANSFORMER
25

26

27
28

29

30

31
32

33
34

35

36

37

Ensure unused
secondary cores of
Bushing CT’s, if any, has
been shorted
Check CT star point has
been formed properly
and grounded at one
end only as per scheme
Check that permanent
and adequate lighting
arrangements are ready
Check that labelling and
identification is
permanent and
satisfactory
Check that Buchholz
Relay is correctly
mounted with arrow
pointing towards
conservator
Check cables are
properly fixed and
ensure cable entry at
the bottom
Ensure all Power and
Control cable Terminals
are tightened
Check all cables and
Ferrules are provided
with Number as per
Cable Schedule (Cross
Ferruling to be checked)
Check that all cables are
correctly glanded
Check external cabling
from Junction Box to
Relay / Control Panel
Completed
Check that air has been
released from the
Radiators and their
headers/OLTC Buchholz
relay/Main
tank/tank/Bushing
turrets etc
Check that all radiator
bank valves on top and
bottom headers are
open
Check the flanges of
bushing & OLTC for any
crack after fixing

Format Number: F-CO-QA-06

yes

yes

Yes
yes

yes

Yes

Yes
yes

yes
yes

yes

yes

yes

Effective Date: 10.10.2015

Page |4

GREENKO INTEGRATED MANAGEMENT SYSTEMS
CHECKLIST FOR ERECTION OF
POWER TRANSFORMER
38
39
IV
1

Calibration of OTI & WTI
performed as per
procedure
Measurement of earth
resistance of Electrode
SFRA test

2

Tan Delta & Capacitance
Measurement of
windings

3

Tan Delta & Capacitance
Measurement of
Bushings.

4

Insulation Resistance
Measurement Including
PI & CC- CL:**

5

Magnetization Current
Test :

6

Turn Ratio Test (Voltage
Ratio Test) :

7

Magnetic balance test:
Apply voltage on one
phase to neutral 230V=
sum of other two phase
voltage to neutral.

8

Short Circuit Test

9
10

Measurement of
Winding Resistance :
(Results in Ohms)
Vector Group Test:

11

Protection & Alarm

Format Number: F-CO-QA-06

yes
Should be ≤ 1 ī—
Pre –Commissioning Tests:
Results should match with Factory
test results.
Tan delta & Capacitance values shall
be comparable with factory test
results and in no case shall be more
than 0.5 %.
Tan delta & Capacitance values shall
be comparable with factory test
results and in no case shall be more
than 0.5 %.
Permissible limit of IR,
DAI(60sec/15sec) should be >1.3 and
PI(600sec/60sec) should be >1.25 To
2
If the excitation current is less than
50 milli-Amperes (mAmp), the
difference between the two higher
currents should be less than 10%. If
the excitation current is more than
50 mAmp, the difference should be
less than 5%. The value on the
outside legs should be within 15% of
each other and values for centre
leg should not be more than either
outside for a three phase
transformer. Results between similar
single phase units should not vary
more than 10%.
The variation of result should be
within ± 0.5 % from specified values
or factory test result.
When outer phase is excited, voltage
induced in the center phase shall be
50 to 90% of the applied voltage.
However, when the center phase is
excited then the voltage induced in
the outer phases shall be 30 to 70%
of the applied voltage.
The results should match with
Factory test results.
The expected deviation for this test
in the field is not more than 5.0% of
the factory test value.
Vector group & polarity has to be
conformed as per GTP
Protection settings as per approved
Effective Date: 10.10.2015

Page |5

GREENKO INTEGRATED MANAGEMENT SYSTEMS
CHECKLIST FOR ERECTION OF
POWER TRANSFORMER
Checks

Engineering Settings

Remarks:

Contractor

GreenkoExecution

Greenko - Quality

Name
Signature
Date
Minimum Ground Clearance :
S.
Voltage Category
No

11
KV

Nominal System Voltage
1.

2.

High Voltage

Clearance
Clearance to Ground
a. Across street
b. Along street
c. Other areas
Clearance to buildings
a. Vertical from highest
object
b. Horizontal from nearest
point

22
KV

Extra High Voltage

13
2
220 KV
KV
Minimum value in Meters

33
KV

6.1
5.8
4.6

6.1
5.8
5.2

6.1
5.8
5.2

2.5

3.66

3.66

1.2

1.83

1.83

66
KV

110K
V

6.1
6.1
5.5

6.1
6.1
6.1

3.9
7
2.1
4

4.58
2.75

6.1
6.1
6.1
4.5
8
2.7
5

7.0
7.0
7.0
5.49
3.66

** Insulation Resistance – Acceptable limits:
Rated System Voltage in KV
Up to & Including 11 KV
Up to & Including 33 KV
66 KV & above

Format Number: F-CO-QA-06

Minimum desired IR value at 1minute( Mega
OHM)
300 Mī—
400 Mī—
500 Mī—

Effective Date: 10.10.2015

Page |6

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