A New Index to Evaluate the Severity of Discharges Based on Energy Calculation

Abstract:

Discharges in the transformer are important symptoms to assess degration of its insulating structure. The indexes of q, φ, n and dissolved gases have been used for many years for diagnosis discharges of oil filled transformers. In this paper, one discharge experiment for needle-plate model is performed. To investigate the difference of indexes to evaluate the severity of discharges, a new energy index is proposed and all the indexes including maximum apparent discharge (Qmax), average apparent discharge (Qave), frequency of apparent discharge (Qfre), phase position of apparent discharge (Qpha), total hydrocarbon concentration (THC) and the new energy index are analysed. It is found that the best performance of all these indexes to evaluate the severity of discharges is W which rises with discharge process and increase rapidly in the end.

• Periodical: Applied Mechanics and Materials (Volumes 716-717)
• Pages: 1217-1220
• DOI: https://doi.org/10.4028/www.scientific.net/AMM.716-717.1217
• Online since: December 2014
• Authors: Xin Yun Lu*
• Keywords: DGA, Discharges, Energy Index, Severity

References

[1] T. K. Saha, Review of modern diagnostic techniques for assessing insulation condition in aged transformers, IEEE Trans. Dielectr. Electr. Insul., Vol. 10, No. 5, pp.903-917, (2003).

DOI: 10.1109/tdei.2003.1237337

[2] IEEE Guide for the Interpretation of Gases Generated in Oil-Immersed Transformers, IEEE Std C57. 104-2008, pp. C1-27, (2009).

[3] V. G. Arakelian, Effective diagnostics for oil-filled equipment, IEEE Electr. Insul. Mag., Vol. 18, No. 6, pp.26-38, (2002).

DOI: 10.1109/mei.2002.1161456

[4] R. Rogers, IEEE and IEC codes to interpret incipient faults in transformers, using gas in oil analysis, IEEE Trans. Electr. Insul., Vol. 13, No. 5, pp.349-354, (1978).

DOI: 10.1109/tei.1978.298141

[5] M. Duval, The Duval triangle for load tap changers, non-mineral oils and low temperature faults in transformers, IEEE Electr. Insul. Mag., Vol. 24, No. 6, pp.22-29, (2008).

DOI: 10.1109/mei.2008.4665347

[6] M. Duval, New techniques for dissolved gas-in-oil analysis, IEEE Electr. Insul. Mag., Vol. 19, No. 2, pp.6-15, (2003).

DOI: 10.1109/mei.2003.1192031

[7] Wang, Zhongdong, et al. Gas generation in natural ester and mineral oil under partial discharge and sparking faults, IEEE Electr. Insul. Mag., Vol. 29, No. 5, pp.62-70, (2013).

DOI: 10.1109/mei.2013.6585858

[8] Electrical strength of insulating materials-Test methods, IEC 60243, (1998).

[9] The People's Republic of China national standards about transformer oil dissolved gas analysis and judgment guide, GB/T7252-2001, 2001 (in Chinese).