Comparative Study on Effect of Temperature & Moisture on Transformer Insulation Conductivity

Abstract:

It has been acknowledged that the insulation of the power transformers is the main cause of their failures. This can easily be attributed to the fact that all power transformers connected to electrical power networks bears loads and the load causes temperature rise and degradation of the cellulose paper. The by-product of the degradation includes moisture. The high temperature and moisture combine to accelerate the rate of insulation breakdown by increasing the material conductivity, σ and also increase the aging rate of the transformer. This paper has reviewed some transformer assessments and tests as sample data to study the effects of temperature and moisture on power transformer insulation conductivity. The results from the tests and measurements were analyzed and presented accordingly. The analyses of results found that irrespective of the assessment technique used, be it FDS, PDC or RVM, conductivity of the transformer insulating materials increases with any increase in both temperature and moisture content.

• Periodical: Applied Mechanics and Materials (Volumes 284-287)
• Pages: 1126-1130
• DOI: https://doi.org/10.4028/www.scientific.net/AMM.284-287.1126
• Online since: January 2013
• Authors: Abubakar Abdull Suleiman, Rubiatul A. B. Zainir, Nor Asiah Muhamad, Nouruddeen Bashir
• Keywords: Aging, Conductivity, Insulation, Moisture, Power Transformer

References

[1] W. H. Bartley, Analysis of Transformer Failures, " presented at the 36th Annual Conference International Association of Engineering Insurers @ http: /www. bplglobal. net/eng/knowledge-center/download. aspx, id=191 (accessed 10/4/12), Stockholm, (2003).

[2] T. Judendorfer, et al., Conductivity measurements of electrical insulating oils, in Dielectric Liquids (ICDL), 2011 IEEE International Conference on, 2011, pp.1-4.

DOI: 10.1109/icdl.2011.6015456

[3] S. Aditama, Dielectric properties of palm oils as liquid insulating materials: effects of fat content , Proceedings of 2005 International Symposium on Electrical Insulating Materials (ISEIM 2005), vol. 1, pp.91-94, (2005).

DOI: 10.1109/iseim.2005.193334

[4] N. H. Malik, et al., Electrical Insulation in Power Systems. New York: Marcel Dekker, (1998).

[5] M. S. Naidu and V. Kamaraju, High Voltage Engineering. Singapore: McGraw Hill Companies, (2004).

[6] S. S. Rao, Power Transformers and Special Transformers. Delhi: Khanna Publishers, (2004).

[7] U. Gafvert, et al., Dielectric Spectroscopy in Time and Frequency Domain Applied to Diagnostics of Power Transformers, " in Proceedings of the 6th International Conference on Properties and Applications of Dielectric Materials, Xi'an Jiaotong University, Xi, an, China, 2000, pp.825-830.

DOI: 10.1109/icpadm.2000.876357

[8] R. B. Jadav, et al., Dielectric response of transformer insulation - comparison of time domain and frequency domain measurements, in IPEC, 2010 Conference Proceedings, 2010, pp.199-204.

DOI: 10.1109/ipecon.2010.5697105

[9] P. K. Poovamma, et al., Evaluation of transformer oil by Frequency domain technique, in Dielectric Liquids, 2008. ICDL 2008. IEEE International Conference on, 2008, pp.1-4.

DOI: 10.1109/icdl.2008.4622491

[10] T. K. Saha and P. Purkait, Effects of temperature on time-domain dielectric diagnostics of transformers, presented at the Australian Universities Power Engineering Conference, Australia, (2003).

[11] T. K. Saha and P. Purkait, Investigation of Polarization and Depolarization Current Measurements for the Assessment of Oil-paper Insulation of Aged Transformers, IEEE Transactions on Dielectrics and Electrical Insulation, vol. 11, pp.144-154.

DOI: 10.1109/tdei.2004.1266329

[12] Setayeshmehr, et al., Dielectric spectroscopic measurements on transformer oil-paper insulation under controlled laboratory conditions, IEEE Transactions on Dielectrics and Electrical Insulation, vol. 15, pp.1100-1111, (2008).

DOI: 10.1109/tdei.2008.4591233

[13] R. Patsch, et al., Return voltage measurements Diagnostic interpretations based on the dielectric time constants, Materials Science-Poland, vol. 27, pp.1157-1169, (2009).

[14] S. Bhumiwat, et al., Performance of oil and paper in transformers based on IEC 61620 and dielectric response techniques*, Electrical Insulation Magazine, IEEE, vol. 26, pp.16-23, (2010).

DOI: 10.1109/mei.2010.5482784

[15] T. K. Saha and P. Purkait, Investigating the impacts of ageing and moisture on dielectric response of oil/paper insulation systems, presented at the XIIIth International symposium on high voltage engineering, Rotterdam, Netherlands, (2003).