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END-OF-LIFE MANAGEMENT OF POWER TRANSFORMERS. METHANOL AGAINST FURANS
Laboratorio de Análisis para la Industria Energética
END-OF-LIFE MANAGEMENT OF POWER TRANSFORMERS. METHANOL AGAINST FURANS
Cellulosic paper degradation: • Tensile strength • Folding resistance • Tear strength • Burst strength • Changes in electrical properties
But no in transformers in service due to paper inaccessibility from outside
END-OF-LIFE MANAGEMENT OF POWER TRANSFORMERS. METHANOL AGAINST FURANS
“While the emphasis on the physical and electrical properties is justified, the omission of the much more fundamental evaluation of the molecular level properties such as chain length has been a drawback because true aging is related to the deterioration of the polymer chain. Thus, if we state that loss of 50 percent of the initial tensile strength is the ˈend of lifeˈ, there is no clear understanding of the degree of aging, though for practical purposes the limit may indicate the loss of useful tensile property to the minimum acceptable level” T. V. Oommen and L. N. Arnold, Cellulose insulation materials evaluated by degree of polymerization measurements, Proc. 15th Electr. Electron. Insul. Conf. 257-261 (1981)
END-OF-LIFE MANAGEMENT OF POWER TRANSFORMERS. METHANOL AGAINST FURANS
W. G. Lawson, M. A. Simmons and P. S. Gale
IEEE Rrans. Electr. Insul., Vol. EI-12, 61-66 (1977)
T. V. Oommen and L. N. Arnold
Proc. 15th Electr. Electron. Insul. Conf., 257-261 (1981)
END-OF-LIFE MANAGEMENT OF POWER TRANSFORMERS. METHANOL AGAINST FURANS
Chemical markers of paper degradation: • Carbon oxides
• Furfuraldehyde
• Methanol
END-OF-LIFE MANAGEMENT OF POWER TRANSFORMERS. METHANOL AGAINST FURANS
Y. Bertrand, C. Tran-duy, V. Murin, A. Schaut, S. Autru and S. Eeckhoudt. CIGRE 2012. Paper D1-103
MeOH (CH3OH)
END-OF-LIFE MANAGEMENT OF POWER TRANSFORMERS. METHANOL AGAINST FURANS
M. Ryadi, A. Tanguy, J. Jalbert and C. Rajotte, CIGRE SC A2 & D1 Joint Colloquium 2011, Kyoto, Japan. Paper PS2-O-4
END-OF-LIFE MANAGEMENT OF POWER TRANSFORMERS. METHANOL AGAINST FURANS
A. Schaut and S. Eeckhoudt, CIGRE 2012. Paper A2-107
END-OF-LIFE MANAGEMENT OF POWER TRANSFORMERS. METHANOL AGAINST FURANS
M. Ryadi, M.-C. Lessard and J. Jalbert, TecCon North America 2017.
Marker a B
H2O (IEC 60422) 2.24 0.04
H2O 2.59 0.04
CH3OH 2.06 0.04
C2H5OH 1.65 0.03
2-FAL 1.23 0.01
Correction factor as per water in IEC 60422
END-OF-LIFE MANAGEMENT OF POWER TRANSFORMERS. METHANOL AGAINST FURANS
Y. Bertrand, C. Tran-duy, V. Murin, A. Schaut, S. Autru and S. Eeckhoudt. CIGRE 2012. Paper D1-103.
END-OF-LIFE MANAGEMENT OF POWER TRANSFORMERS. METHANOL AGAINST FURANS
0
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DP
un
its
[2-FAL] (mg/kg)
CHENDONG STEBBINS
Furfuraldehyde (2-FAL)
END-OF-LIFE MANAGEMENT OF POWER TRANSFORMERS. METHANOL AGAINST FURANS
OO
O O
O
H
HO
H
H
CH OH2
CH OH2
H
HO
H H
HO
H
HH
OH
H
O CHO
30%
END-OF-LIFE MANAGEMENT OF POWER TRANSFORMERS. METHANOL AGAINST FURANS
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[2-FAL] (mg/kg)
De Pablo 2% De Pablo 5% De Pablo 10%
END-OF-LIFE MANAGEMENT OF POWER TRANSFORMERS. METHANOL AGAINST FURANS
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[2-FAL] (mg/kg)
CHENDONG STEBBINS De Pablo 2% De Pablo 5% De Pablo 10%
END-OF-LIFE MANAGEMENT OF POWER TRANSFORMERS. METHANOL AGAINST FURANS
End-of-life
D.H. Schroff and A. W. Stannett, IEE Proc., 132, C, 6, Nov 1985
END-OF-LIFE MANAGEMENT OF POWER TRANSFORMERS. METHANOL AGAINST FURANS
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DP
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CHENDONG De Pablo 2% De Pablo 5% De Pablo 10%
END-OF-LIFE MANAGEMENT OF POWER TRANSFORMERS. METHANOL AGAINST FURANS
Case History – 25 MVA – 132/11 kV – ONAN – mfg 2008
Date H2 CH4 C2H6 C2H4 C2H2 CO CO2
22/09/17 14 14 14 17 0 541 7735
22/12/17 17 17 16 21 0 941 16743
24/08/18 20 20 19 22 0 913 21307
Date 2-FAL 5-HMF 2-ACF 5-MEF Sampling Temp.
22/09/17 7.26 0.14 0 0.11 30°C
22/12/17 13.91 0.22 0.17 0.28 45°C
24/08/18 12.42 0.24 0.16 0.33 72°C
Chendong: DP = 105
END-OF-LIFE MANAGEMENT OF POWER TRANSFORMERS. METHANOL AGAINST FURANS
EUROPE - 6 laboratories- 5.005 transformers
Concentration Transformers
< 0,10 ppm 2.700 (54,0 %)
0,11 – 0,50 ppm 1.347 (26,9 %)
0,51 – 1,00 ppm 415 (8,3 %)
1,01 – 5,00 ppm 466 (9,3 %)
5,01 – 10,00 ppm 57 (1,1 %)
> 10,00 ppm 20 (0,4 %)
A. De Pablo et al., CIGRE Symposium Berlin 1993. Paper 110.09
END-OF-LIFE MANAGEMENT OF POWER TRANSFORMERS. METHANOL AGAINST FURANS
D. Urquiza, B. García and J. C. Burgos, IEEE Electr. Insul. Magazine, 31(4), (2015)
Chendong DP = 25; De Pablo 2% DP = 27 De Pablo 5% DP = 64; De Pablo 10% DP = 119
END-OF-LIFE MANAGEMENT OF POWER TRANSFORMERS. METHANOL AGAINST FURANS
B. Pahlavanpour, M. A. Martins and A. de Pablo. IEEE ISEI 2002
E A
1/T
Between 90°C and 150°C, activation energy is relatively constant and reaction yield is close to 30%
At higher temperatures (>140/150°C), activation energy is not constant and reaction yield increases up to 83%
A. de Pablo and B. Pahlavanpour. Electra 175, 8-32, 1997
END-OF-LIFE MANAGEMENT OF POWER TRANSFORMERS. METHANOL AGAINST FURANS
Estimation of transformer remaining life
END-OF-LIFE MANAGEMENT OF POWER TRANSFORMERS. METHANOL AGAINST FURANS
Estimation of transformer remaining life
END-OF-LIFE MANAGEMENT OF POWER TRANSFORMERS. METHANOL AGAINST FURANS
Estimation of transformer remaining life
END-OF-LIFE MANAGEMENT OF POWER TRANSFORMERS. METHANOL AGAINST FURANS
Reasons for transformers end-of-life other than high furans content
Cupper sulfide deposits
Although Cu2S lowers the PD-initiation level, depositions of copper sulphide on the windings alone are not sufficient to create a short circuit or partial discharge between two turns.
J. Hajek, M. Dahlund, L. Pettersson and G. Bennstam, ABB Review 61-63 (2004)
END-OF-LIFE MANAGEMENT OF POWER TRANSFORMERS. METHANOL AGAINST FURANS
Reasons for transformers end-of-life other than high furans content
Switching transients
When a transformer is switched into or out of a system, the transient voltage produced at the terminals of the transformer may contain several high frequency oscillatory components. When this oscillatory transformer terminal voltage has a frequency component near one of the natural frequencies of the transformer and is of sufficient magnitude and duration, permanent damage to the transformer internal insulation structure may result
IEEE Std. C57.142
END-OF-LIFE MANAGEMENT OF POWER TRANSFORMERS. METHANOL AGAINST FURANS
Reasons for transformers end-of-life other than high furans content
Lightning impulses
S. P. Balaji et al., IEEE Trans. Dielectr. Electr. Insulation. 18, 2069-2073(2011)
END-OF-LIFE MANAGEMENT OF POWER TRANSFORMERS. METHANOL AGAINST FURANS
Reasons for transformers end-of-life other than high furans content
Lightning impulses
W. Sima et al., IEEE Trans. Dielectr. Electr. Insulation. 21(4), 1933-1940 (2014)
Sample number Applied times for the time Interval of 80 s
Applied times for the time Interval of 100 s
1 1183 1248
2 841 1032
3 1272 1459
4 1033 1282
5 1255 1317
Average 1116.8 1267.6
Applied times of OIP samples before breakdown occur with the time Interval of 80 s and 100 s
END-OF-LIFE MANAGEMENT OF POWER TRANSFORMERS. METHANOL AGAINST FURANS
CONCLUSIONS
Methanol is a promising cellulose degradation marker, but much work is needed to understand some weaknesses of this method (is valid only for the first stages of degradation? How does its dependence on temperature affect the diagnosis? Are there more degradation models other that that of Bertrand?)
END-OF-LIFE MANAGEMENT OF POWER TRANSFORMERS. METHANOL AGAINST FURANS
CONCLUSIONS
Furfural has been used as cellulose degradation marker for almost 40 years now. However, from the review of several databases, it seems that the widely used Chendong formula does not works because it does not considers the actual amount of paper that is being degraded at any time. How to solve this shortcoming?
END-OF-LIFE MANAGEMENT OF POWER TRANSFORMERS. METHANOL AGAINST FURANS
CONCLUSIONS
To determine the end-of-life of a transformer, one trick could be to assume that ageing factor is constant all the life of the transformer. Then, the ratio of the consumed life to the total life leads to the residual life
END-OF-LIFE MANAGEMENT OF POWER TRANSFORMERS. METHANOL AGAINST FURANS
CONCLUSIONS
However, it is important to note that there could be other degradation mechanisms that no necessarily produce furans or alcohols and, thus, paper degradation can not be traced with the aid of chemical markers. These mechanisms are: • Contaminants (i. e., copper sulfide deposits) • Switching transients • Lightning impulses.
END-OF-LIFE MANAGEMENT OF POWER TRANSFORMERS. METHANOL AGAINST FURANS
THANK YOU VERY MUCH FOR YOUR ATTENTION
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