Insulation Condition Assessment of Power Transformers Using Accelerated Ageing Tests
Thermal stress due to losses and environment temperature causes degradation to paper/oil insulation systems in transformers, even at operating temperature. Experience indicates that thermal ageing of oil and paper in power transformers leads to the change of some insulation characteristics. In this paper, insulating papers immersed in oil have been acceleratory aged at 140, 150, and 160 °C under laboratory conditions. Some of the oil properties, such as water content, breakdown voltage, acidity, together with the aged insulating paper properties such as electric strength, dielectric dissipation factor and tensile strength were measured and analyzed. Also, insulation system conditions under thermal stress have been evaluated by electrical/distinctive techniques like recovery voltage, polarization and depolarization currents. Correlations between these parameters have been investigated. Finally, paper tensile strength has been used as a criterion to estimation of insulating paper life time.
Anahtar Kelimeler:
Transformer, insulation assessment, monitoring, polarization, recovery voltage
Insulation Condition Assessment of Power Transformers Using Accelerated Ageing Tests
Thermal stress due to losses and environment temperature causes degradation to paper/oil insulation systems in transformers, even at operating temperature. Experience indicates that thermal ageing of oil and paper in power transformers leads to the change of some insulation characteristics. In this paper, insulating papers immersed in oil have been acceleratory aged at 140, 150, and 160 °C under laboratory conditions. Some of the oil properties, such as water content, breakdown voltage, acidity, together with the aged insulating paper properties such as electric strength, dielectric dissipation factor and tensile strength were measured and analyzed. Also, insulation system conditions under thermal stress have been evaluated by electrical/distinctive techniques like recovery voltage, polarization and depolarization currents. Correlations between these parameters have been investigated. Finally, paper tensile strength has been used as a criterion to estimation of insulating paper life time.
Keywords:
Transformer, insulation assessment, monitoring, polarization, recovery voltage,
___
- T.K. Saha, M. Darveniza, D.J.T. Hill, T.T. Le, “Electrical and Chemical Diagnostics of Transformer Insulation-part B: Accelerated Aged Insulation Samples” , IEEE Transactions on Power Delivery, Vol. 12, No. 4, October 1997, pp. 1555–1561.
- A.J. Kachler, I. Hohlein, “Ageing of Cellulose at Transformer Service Temperatures. Part 1: Influence of Type of Oil and Air on the Degree of Polymerization of Pressboard, Dissolved Gases, and Furanic Compounds in Air” , IEEE Electrical Insulation Magazine, Vol. 21, No. 2, March / April 2005, pp. 15–21.
- M.C. Lessard, L. Van Nifterik, J.F. Penneau and Robert Grob, “Thermal Ageing Study of Insulating Papers Used in Power Transformers” , Conference on Electrical Insulation and Dielectric Phenomena, San Francisco, October 20–23, 1996, pp. 854–859.
- M. Darveniza, D. Hill, Tri Le. T.K. Saha, “Studies of the Condition of Insulation in Aged Power Transformers Part 2: Fundamental Electrical and Chemical Consideration”, 3rd International Conference on Properties and Applications of Dielectric Materials, July 8–12, 1991, Tokyo-Japan, pp. 1120–1123.
- J.P. Van Bolhuis, E. Gulski, J.J. Smit, “Interpretation of RVM Measurements, Beyond the Polarization Spectrum”, Conference Record of the 2002 IEEE International Symposium on Electrical Insulation, Boston, USA, April 7–10, 2002, pp. 179–182.
- T.K. Saha, 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, No. 1, February 2004, pp. 144–154.
- M.K. Pradhan, T.S. Ramu, “On the Estimation of Elapsed Life of Oil-Immersed Power Transformers”,IEEE Transactions on Power Delivery, Vol. 20, No. 3, July 2005, pp. 1962–1969.
- L.E. Lundgaard, W. Hansen, D. Linhjell, T.J. Painter, “Ageing of Oil-Impregnated Paper in Power Transformers”, IEEE Transactions on Power Delivery, Vol. 19, No. 1, January 2004, pp. 230–239.
- M. Darveniza, D.J.T. Hill, T.T. Le, T.K . Saha, B. Williams, “Chemical Degradation of Cellulosic Insulation Paper for Power Transformers”, Proceedings of the 4th International Conference on Properties and Applications of Dielectric Materials, July 3–8, 1994, Brisbane Australia, pp. 780–783.
- B. Garcia, J.C. Carlos Burgos, A.M. Alonso, J. Sanz, “A Moisture-in-Oil Model For Power Transformer Monitoring- Part I: Theoretical Foundation”, IEEE Transactions on Power Delivery, Vol.20, No. 2, April 2005, pp. 1417–1422. [11] S. Birlasekaran, Yu Xingzhou, “Relaxation Studies on Power Equipment”, IEEE Transactions on Dielectrics and Electrical Insulation, Vol. 10, No. 6, December 2003, pp. 1061–1077.
- T.K. Saha, P. Purkait, F. Muller, “Deriving and Equivalent Circuit of Transformers Insulation for Understanding the Dielectric Response Measurements”, IEEE Transactions on Power Delivery, Vol. 20, No.1, Junuary 2005, pp.149– 157.
- T.K. Saha, “Review of Time-Domain Polarization Measurements For Assessing Insulation Condition In Aged Transformers”, IEEE Transactions on Power Delivery, Vol. 18, No. 4, October 2003, pp. 1293–1301.
- U. Gafvert, L. Adeen, M. Tapper, P. Ghasemi, B. Jonsson, “Dielectric Spectroscopy in Time and Frequency Domain Applied to Diagnostics of Power Transformers”, IEEE 6the International Conference on Properties and Applications of Dialectic Materials,China, Vol. 2, pp. 825–830, 2000.
- ANSI/IEEE C57.92-1981, “IEEE Guide for Loading Mineral-Oil-Immersed Power Transformers Up to and Including 100 MVA With 65 C or 55 ◦
- C Average winding Rise.”
- ISSN: 1300-0632
- Yayın Aralığı: Yılda 6 Sayı
- Yayıncı: TÜBİTAK
Sayıdaki Diğer Makaleler
Accurate Prediction of Crosstalk for RC Interconnects
Selahattin SAYIL, Merlyn RUDRAPATI
Voltage Control of Self-Excited Induction Generator using Genetic Algorithm
Dheeraj JOSHI, Kanwarjit Singh SANDHU, Mahender Kumar SONI
Insulation Condition Assessment of Power Transformers Using Accelerated Ageing Tests
Mohammad MIRZAIE, Ahmad GHOLAMI, Hamid Reza TAYEBI
Electronic Differential with Direct Torque Fuzzy Control for Vehicle Propulsion System
Kada HARTANI, Mohamed BOURAHLA, Yahia MILOUD, Mohamed SEKOUR
A Novel EP Approach for Multi-area Economic Dispatch with Multiple Fuel Options