An Experimental Analysis To Check Accuracy of DGA.....
An Experimental Analysis To Check Accuracy of DGA.....
An Experimental Analysis To Check Accuracy of DGA.....
Abstract
Analysis of Dissolved gas method is very sensitive and reliable method for detection of internal fault
in power transformer. One of the most used method for DGA is duval triangle method. Duval triangle is
not considering two combustible gases like, ethane C" H$ , 𝑎𝑛𝑑 ℎ𝑦𝑑𝑟𝑜𝑔𝑒𝑛 H". . so, Duval triangle method
has low accuracy for fault interpretation. Then, Duval pentagonal method is used for fault detection in
power transformer. In this paper, we have get data for power transformer from Torrent Power Ltd. This
experiment has done on various 20 power transformer rating of 15MVA,21kV/400kV. But, In this paper,
We have shown six data of fault in case study and found fault by Duval Triangle method and Duval
pentagonal method. Then, we will verify this fault interpretation with actual fault. And, we will see that
Duval Pentagonal method have higher accuracy (above 80%) for fault interpretation.
A. Shukla, J.M. Patel, P.D. Solanki, K.B. Judal, R.K. Shukla, R.A. Thakkar, N.P. Gajjar, N.J. Kothari, S.
Saha, S.K. Joshi, S.R. Joshi, P. Darji, S. Dambhare, B.R. Parekh, P.M. George, A.M. Trivedi, T.D. Pawar,
M.B. Shah, V.J. Patel, M.S. Holia, R.P. Mehta, J.M. Rathod, B.C. Goradiya and D.K. Patel (eds.),
ICRISET2017 (Kalpa Publications in Engineering, vol. 1), pp. 394–401
Experimental Analysis to Check Accuracy of DGA.....
An Jatinkumar Soni and Dhaval Suthar
1. Introduction
Transformer is static electromagnetic device. Electrical, mechanical, chemical and
environment effect the condition of the transformer. At initial stage, degradation of insulation
occurs slowly. And as time passes, it will lead to failure of transformer. So, to overcome this
situation, it required to continues operation. Power transformer should be very reliable and
routinely be monitored [1]. The average life period of power transformer is around 30 years.
Analysis of Dissolved Gas method is used for fault interpretation. It detects internal fault in
power transformer [2]. So we can also maintain transformer action [3]. If we take small part of
pure oil in transformer. It can determine which gases are available and level of quantity. It shows
that the hydrocarbon gases produced at very fast rate of failure of organ are acetylene, methane,
ethylene and ethane. Internal faults may in two classifications: short circuit fault and incipient
fault. Internal incipient fault develops slowly, a gradual increment of the insulation by some
causes. Transformer core puzzle is concentrate on insulation failure or shorted laminations. Other
several fault in current transformer is due to oil leakage in tank, oil fouling or defilement from
metal atoms and overloads. Recently, DGA is identify transformer, facilitating a proper asset
management decision [5]. When an incipient fault happen, thermal or electrical, the generated
energy breaks bonds of oil. Gases are generated. These gases are Ethane (𝐶𝟐 𝐻𝟔 ), Carbon dioxide
(C 𝑂𝟐 ) Hydrogen ( 𝐻𝟐 ), Ethylene ( 𝐶𝟐 𝐻𝟒 ), Methane(C 𝐻𝟒 ), Acetylene (𝐶𝟐 𝐻𝟐 ), and Carbon
monoxide (CO) and will generated if cellulose inclination is involved, depend on the
classification and quantity of produced gases.
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An Experimental Analysis to Check Accuracy of DGA..... Jatinkumar Soni and Dhaval Suthar
1 100 120 35 60 70
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An Experimental Analysis to Check Accuracy of DGA..... Jatinkumar Soni and Dhaval Suthar
4) Rogers method:
In Rogers ratio, We firstly get ratio of three gases like𝐶𝟐 𝐻𝟐 / 𝐶𝟐 𝐻𝟒 , C𝐻𝟒 /𝐻𝟐 , and 𝐶𝟐 𝐻𝟒 /𝐶𝟐 𝐻𝟔 to
indicate four probable faults interpretation as normal operation, HED, low temperature thermal,
low energy discharge and arcing and shown in table 4.
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An Experimental Analysis to Check Accuracy of DGA..... Jatinkumar Soni and Dhaval Suthar
The relative percentage of 𝐻" = (ppm of 𝐻" ) / (ppm of 𝐻" +𝐶𝟐 𝐻𝟒 +𝐶𝟐 𝐻𝟐 +C𝐻𝟒 + 𝐶𝟐 𝐻𝟔 )
The coordinates (xi, yi) of all these of the five points are calculated. For the point on the 𝐶𝟐 𝐻𝟔
axis, the corner or nook between 𝐶𝟐 𝐻𝟔 and x axis are 18 degrees. The centre (“centroid”) of the
irregular polygon plotted from five points were calculated mathematically [10].
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An Experimental Analysis to Check Accuracy of DGA..... Jatinkumar Soni and Dhaval Suthar
2. Case Study
We have get data of gases in various power transformer 15MVA, 21kV/400kV from Torrent Power
Ltd. We have shown some of it in table 6.
Then we have done duval pentagon method and duval triangle method for detecting fault in these
all cases. These received result is shown in table 7.
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An Experimental Analysis to Check Accuracy of DGA..... Jatinkumar Soni and Dhaval Suthar
This result of fault by duval pentagonal method is compared with actual fault in power transformer
table 8.
Table 8: Comparison between fault by duval pentagonal and actual fault in transformer
Case Fault by duval Actual fault
pentagonal
method
1 LT LT
2 MT MT
3 HT HT
4 LED LED
5 HED HED
6 LED PD
3. Conclusion
We have seen from result that fault interpretation by duval pentagonal is same as actual fault in
transformer. So, this duval pentagonal method is very accurate for fault interpretation.
Acknowledgment
First of all for providing good environment for doing this work by my institute L. E. College, Morbi
and chemical department for giving good knowledge and thanks to S.N.Pandya sir,head of electrical
department, for giving support. And thanks to Torrent power for giving data of power transformer.
References
[1] M. J. Heathcote, The J & P Transformer Book, Twelfth ed., Reed Educational and
Professional Publishing Ltd, 1998M. Duval, “A review of faults detectable by gas-in-oil
analysis in transformers”, IEEE Electrical. Insulation. Mag., Vol. 18, No.3, pp. 8-17, 2002.
[2] T. K. Saha, “Review of modern diagnostic techniques for assessing insulation condition
in aged transformers”, IEEE Transactions on Dielectrics and Electrical Insulation, Vol. 10,
pp. 903-917, 2003.
[3] A. Abu-Siada and S. Islam, “A new approach to identify power transformer criticality
and asset management decision based on dissolved gas-in-oil analysis”, IEEE Transactions
on Dielectrics and Electrical Insulation, Vol. 19, pp. 1007-1012, 2012.
[4] F. R. Barbosa, O. M. Almeida, A. P. S. Braga, M. A. B. Amora and S. J. M. Cartaxo,
“Application of an Artificial Neural Network in the Use of Physicochemical Properties as
a Low Cost Proxy of Power Transformers DGA Data”, IEEE Trans. Dielectric and
Electrical Insulation, Vol. 19, pp. 239-246, 2012.
[5] Ekkarach Wannapring and Cattareeya Suwanasri, “Dissolved Gas Analysis Methods
for Distribution Transformers” IEEE Conference Publications
[6] Sobhy S. Desouky, Ahmed E.Kalas,Abdel moneim M. Hassan,Modification of Duval
Triangle for Diagnostic Transformer Fault Through A Procedure of Dissolved Gases
Analysis IEEE Conference Publications
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