Insulating oil oxidation stability tests
The text describes in general tests of accelerated ageing of insulating oils and enumerates disadvantages of different tests. It shortly describes the test of accelerated ageing according to the ELDIAG methodology, which should eliminate the mentioned faults and which enables to determine the moment of sediments drop out in test conditions. The text also provides examples of some test parameters changes and their effect on the test result can be seen at the pictures. In the conclusion you can find criteria that, on the basis of the test result, assess the suitability of using the oil in a particular appliance. The text also offers a list of tested oil types.
Table 1:
|
Standard
|
Test
period
[hours]
|
Tepera-
ture
[°C]
|
Catalyzers
|
Cooper
[cm2/kg of oil]
|
Oxidant
[1/hour]
|
|
IEC 1125, method A
|
164
|
100
|
388
|
oxygen-1
|
|
IEC 1125, method B
|
note 1
|
120
|
1144
|
oxygen-1
|
|
IEC 1125, method C
|
164
|
120
|
1144
|
air-0,15
|
|
DIN 51554 (Baader)
|
140
|
110
|
344
|
air contact
|
|
ASTM D1934, method A
|
96
|
115
|
-
|
air contact
|
|
ASTM D1934, method B
|
96
|
115
|
57
|
air contact
|
|
ASTM D2440
|
72 (164)
|
110
|
376
|
oxygen-1
|
Note: The test is terminated after reaching the volatile acidity of 0,28 mgKOH/g
Table 2: Dissipation factor
|
days
|
(1)N2
|
(2)Cu
|
(3)0,5 Cu
|
(1)Cui
|
|
0
|
1
|
1
|
1
|
1
|
|
7
|
-
|
-
|
-
|
-
|
|
14
|
-
|
-
|
-
|
-
|
|
21
|
3,09
|
14,22
|
10,41
|
8,19
|
|
28
|
3,09
|
21,29
|
14,71
|
11,2
|
|
35
|
3,37
|
27,95
|
22,22
|
17,74
|
|
42
|
4,68
|
|
|
22,37
|
|
49
|
5,71
|
|
|
|
|
56
|
7,57
|
|
|
|
|
63
|
8,12
|
|
|
|
|
70
|
8,16
|
|
|
|
|
77
|
11,71
|
|
|
|
|
84
|
10,43
|
|
|
|
Note: Table 2 gives the measured dissipation factor values (x0,01) until the sediments drop out. Heading stands for a sample: N2 – in nitrogenous atmosphere, Cu – conventional test parameters, 0,5 Cu – reduction of catalyzer content, Cui – inhibitor adding.
Table 3: Interfacial tension
|
Days
|
(1)N2
|
(2)Cu
|
(3)0,5 Cu
|
(1)Cui
|
|
0
|
48
|
48
|
48
|
48
|
|
7
|
49
|
46
|
46
|
46
|
|
14
|
48
|
42
|
42
|
44
|
|
21
|
48
|
38
|
39
|
40
|
|
28
|
46
|
36
|
38
|
39
|
|
35
|
45
|
34
|
35
|
36
|
|
42
|
43
|
34
|
35
|
35
|
|
49
|
43
|
|
|
|
|
56
|
44
|
|
|
|
|
63
|
44
|
|
|
|
|
70
|
43
|
|
|
|
|
77
|
43
|
|
|
|
|
84
|
41
|
|
|
|
Note: Table 3 gives the measured interfacial tension values. The conditions and key are the same as in table 2.
Table 4:
|
Methodology
|
Manufacturer(supplier)
|
Insulating oil type
|
|
ELDIAG
|
ESSO
|
UNIVOLT N-53, UNIVOLT N-61
|
|
KORAMO
|
MOGUL TRAFO CZ
|
|
ARAL
|
ISOLAN TI, ISOLAN 456
|
|
AGIP
|
ITE 360, ITE 360
|
|
EXEL
|
MIDEL 7131, 3800, 3800X
|
|
OMV
|
ADDINOL TRF-H
|
|
TECHNOL
|
US-4000, Y-3000, TECHNOL 2000, REGENOL
|
|
NYNAS
|
NYTRO 10X
|
|
PETROCHEMA
|
ITO 300, ITO 200, ITO 100
|
|
MOTTAY PISART
|
HB 2000X, HB 20012PX
|
|
TOTAL
|
IZOVOLTINE IIA
|
|
BAADER
|
KORAMO
|
MOGUL HC10, MOGUL TRAFO D
|
|
IEC 1125
|
|
|
|
metoda A
|
KORAMO
|
MOGUL HC10, MOGUL TRAFO D
|
|
metoda B
|
KORAMO
|
MOGUL 1A, MOGUL TRAFO CZ
|
|
TECHNOL
|
Y-3000
|
|
PETROCHEMA
|
ITO 100, ITO 200
|
|
ESSO
|
UNIVOLT N-53
|
|
metoda C
|
ESSO
|
UNIVOLT N-53
|
|
OMV
|
ADINOL TRF-H
|
