Measurement of Dielectric Performance
Measurement of Dielectric resistance
( 5000V scope 100000 MΩ meter oil temperature:21.6℃)
|
Measured part
|
Insulation resistance(MΩ)
|
Absorption rate
|
Polarized index
|
||
|
R15
|
R60
|
R600
|
R60/R15
|
R600/R60
|
|
|
HV～LV and earth
|
49400
|
56900
|
84300
|
1.15
|
1.48
|
|
LV～HV and earth
|
33000
|
57800
|
97800
|
1.57
|
1.69
|
|
HV, LV～earth
|
19000
|
30000
|
50500
|
1.58
|
1.68
|
|
Upper clamp～core and earth
|
-
|
79700
|
-
|
-
|
-
|
|
Iron core～earth
|
-
|
37900
|
-
|
-
|
-
|
|
end side of HV bushing～earth
|
-
|
4000
|
-
|
-
|
-
|
Measurement of Medium loss
|
Measured winding
|
Applied voltage kV
|
tgδ%
|
Cx(nF)
|
|
HV～LV and earth
|
10
|
0.17
|
10.08
|
|
LV～HV and earth
|
10
|
0.16
|
31.76
|
|
HV, LV～earth
|
10
|
0.15
|
33.30
|
|
HV bushing
|
10
|
0.36
|
0.493
|
Measurement of voltage ratio and check of phase displacement
|
HV winding
|
LV winding
|
Measure tolerance (%)
|
Phase displacement
|
|
|
Tap
|
Voltage (V)
|
Voltage (V)
|
(1.1-1.2)/ (2.1-2.2)
|
|
|
A
|
317543
|
20000
|
+0.10
|
I, I0
|
|
B
|
309604
|
+0.04
|
||
|
C
|
301666
|
-0.03
|
||
Measurement of winding resistance oil temperature: 19℃
|
Winding
|
Tap
|
Measured value(Ω)
|
|
1.1-1.2
|
||
|
HV
|
A
|
0.3569
|
|
B
|
0.3483
|
|
|
C
|
0.3398
|
|
|
LV
|
2.1-2.2
|
|
|
0.0013121
|
||
Measurement of no load loss and current
|
Power supply terminal
|
Applied voltage(kV)
|
No load current(%)
|
No load loss(kW)
|
||
|
Standard value
|
Measured value
|
Standard value
|
Measured value
|
||
|
2.1-2.2
|
20
|
0.25＋30%
|
0.11
|
103＋15%
|
83.2
|
Measurement of loss and short circuit impedance oil temperature: 21.6℃
|
Winding
|
Measured item
|
Tap
|
Standard value
|
Measured value
|
|
HV power supply, LV short circuit
|
Uk75℃(%)
|
A
|
13.35±7.5%
|
13.00
|
|
Pk75℃(kW)
|
445＋15%
|
387.6
|
||
|
Uk75℃(%)
|
B
|
-
|
13.17
|
|
|
Pk75℃(kW)
|
-
|
398.2
|
||
|
Uk75℃(%)
|
C
|
-
|
13.21
|
|
|
Pk75℃(kW)
|
-
|
408.6
|
Applied voltage withstand test
|
Voltage applied part
|
Test voltage(kV)
|
Test time (s)
|
conclusion
|
|
HV(neutral)～LV and earth
|
140
|
60
|
Qualified
|
|
LV～HV and earth
|
55
|
60
|
Qualified
|
Switching wave test
|
Tap
|
Voltage applied part
|
Earthed point
|
Test voltage(kV)
|
Test wave
|
Conclusion
|
|
A
|
1.1-1.2
|
1.2, 2.2
|
1175
|
Show in the following
|
Passed
|
Test Procedure:
One time negative switching wave impulse with 50% reduced voltage;
Three times negative switching wave impulse with 100% voltage;
There is no distortion between the wave of 50% voltage and 100% voltage.
The wave and parameters are as following:
50% 100%
100% 100%
Lightening impulse test
Tested items and conclusion
|
Withstand terminal
|
Rated withstand voltage(kV)
|
Tap
|
|
|
Lightening, full wave
|
Lightening, chopped wave
|
||
|
1.1
|
1425
|
-
|
A
|
Test Procedure:
One time negative switching wave impulse with 50% reduced voltage;
Three times negative switching wave impulse with 100% voltage;
There is no distortion between the wave of 50% voltage and 100% voltage.
The wave and parameters are as following:
50% 100%
100% 100%
Measurement of partial discharge (ACLD power frequency 200 Hz)
|
Applied voltage, phase to earth(kV)
|
Measure time
|
Partial discharge(pc)
|
||
|
Measure when the oil pump stops
|
-
|
HV
|
||
|
1.1Um
|
349.3
|
5min
|
50
|
|
|
1.5Um
|
476.3
|
5min
|
90
|
|
|
1.7Um
|
540
|
5s
|
-
|
|
|
1.5Um
|
476.3
|
0min
|
90
|
|
|
1.5Um
|
476.3
|
10min
|
90
|
|
|
1.5Um
|
476.3
|
20min
|
90
|
|
|
1.5Um
|
476.3
|
30min
|
90
|
|
|
1.5Um
|
476.3
|
60min
|
90
|
|
|
1.1Um
|
349.3
|
5min
|
50
|
|
Measurement of partial discharge when the oil pump starts(special) (ACLD power frequency 200 Hz)
|
Applied voltage, phase to earth(kV)
|
Measure time
|
Partial discharge(pc)
|
||
|
Measure when the oil pump starts
|
-
|
HV
|
||
|
1.1Um
|
349.3
|
0-5min
|
50
|
|
|
1.5Um
|
476.3
|
0min
|
90
|
|
|
1.5Um
|
476.3
|
10min
|
90
|
|
|
1.5Um
|
476.3
|
20min
|
90
|
|
|
1.5Um
|
476.3
|
30min
|
90
|
|
|
1.5Um
|
476.3
|
60min
|
90
|
|
|
1.1Um
|
349.3
|
5min
|
50
|
|
Test of Temperature rise
|
Test method
|
Short-circuit
|
tapping
|
C tap
|
|
Temperature rise of top oil(K)
|
47.5
|
||
|
Average temperature rise of HV winding(K)
|
55.7
|
||
|
Average temperature rise of LV winding(K)
|
60.3
|
||
|
Temperature rise of hot spot of enclosure(K)
|
46
|
||
Long-time no loading of 12 hours
|
Power supply terminal
|
Applied voltage(kV)
|
No load current(%)
|
No load loss(kW)
|
Test time
|
|
2.1-2.2
|
22000
|
0.22
|
104500
|
12h
|
Test of transformer oil
|
Oil No.: 45#
|
Sampling from the bottom of oil tank
|
|
Appearance:
|
Transparent, no suspended substance and foreign matters
|
|
flashover(closed)(℃):
|
142
|
|
Coefficient of medium loss(90℃)
|
0.002
|
|
Penetrating voltage(kV):
|
62
|
|
moisture(mg/kg)
|
8
|
|
Chromatogram of transformer oil
|
||||||||
|
Content (uL/L)
|
Items
|
H2
|
CO
|
CO2
|
CH4
|
C2H6
|
C2H4
|
C2H2
|
|
Before test
|
0.00
|
0.00
|
67.38
|
0.29
|
0.00
|
0.00
|
0.00
|
|
|
After impulse test(switching, lightening)
|
0.00
|
0.00
|
58.12
|
0.32
|
0.00
|
0.00
|
0.00
|
|
|
After partial test(before temperature rise)
|
0.00
|
0.00
|
64.45
|
0.18
|
0.00
|
0.00
|
0.00
|
|
|
After temperature rise(before long time no load)
|
0.00
|
0.00
|
69.00
|
0.21
|
0.00
|
0.00
|
0.00
|
|
|
After test of long time no loading
|
0.00
|
0.00
|
62.11
|
0.23
|
0.00
|
0.00
|
0.00
|
|
|
After oil flow test with electricity(partial discharge)
|
0.00
|
0.00
|
68.10
|
0.25
|
0.00
|
0.00
|
0.00
|
|
|
Gas content
|
0.8 %
|
|||||||
Measurement of Harmonics of No load current(special)
|
Distortion of total harmonic
|
--
|
|||
|
U(kV)
|
U (%)
|
I(A)
|
I(%)
|
|
|
THD
|
2.400
|
12.0
|
9.187
|
110.5
|
|
Harmonic times
|
--
|
|||
|
U(kV)
|
U (%)
|
I(A)
|
I(%)
|
|
|
01
|
19.88
|
--
|
8.312
|
--
|
|
02
|
0.001
|
0.0
|
0.007
|
0.0
|
|
03
|
1.907
|
9.5
|
8.227
|
98.9
|
|
04
|
0.003
|
0.0
|
0.012
|
0.1
|
|
05
|
1.313
|
6.6
|
3.827
|
46.0
|
|
06
|
0.003
|
0.0
|
0.007
|
0.0
|
|
07
|
0.478
|
2.4
|
1.193
|
14.3
|
|
08
|
0.002
|
0.0
|
0.010
|
0.1
|
|
09
|
0.371
|
1.8
|
0.728
|
8.7
|
|
10
|
0.001
|
0.0
|
0.001
|
0.0
|
|
11
|
0.155
|
0.7
|
0.200
|
2.4
|
|
12
|
0.001
|
0.0
|
0.005
|
0.0
|
|
13
|
0.061
|
0.3
|
0.057
|
0.6
|
|
14
|
0.000
|
0.0
|
0.004
|
0.0
|
|
15
|
0.034
|
0.1
|
0.086
|
1.0
|
|
16
|
0.002
|
0.0
|
0.002
|
0.0
|
|
17
|
0.003
|
0.0
|
0.025
|
0.3
|
|
18
|
0.002
|
0.0
|
0.002
|
0.0
|
|
19
|
0.006
|
0.0
|
0.009
|
0.1
|
Measurement of sound level (special)
|
Standard value(sound power level)
|
Cooling device
|
A-weighted surface sound pressure level
|
A-weighted surface sound power level
|
|
101dB
|
stop(0.3 m)
|
76 dB
|
96 dB
|
|
start(2 m)
|
78.6 dB
|
99.3 dB
|
Measurement of the oil flow with electricity (special)
Test method: Start the oil pump for 4 hours, measure the leaking current of HV winding to earth, core to earth, which should be up to specified values.
Measure the partial no discharge signal without stopping the pump.
|
Pump starting time
|
HV winding to earth
|
Core to earth
|
|
Leaking current
|
Leaking current
|
|
|
4 hours
|
<0.1uA
|
<0.1uA
|
|
Partial monitor
|
No discharge signal
|
No discharge signal
|
Measure the partial discharge at 1.5Um/√3 voltage without stopping the pumping, see the item 3.10, there is no change between the above measured value and that value measured without starting pump.