22 1 2018 1 Electri c Machines and Control Vol. 22 No. 1 Jan. 2018 1 1 2 1. 150080 2. 150040 45-50 ~ 20 DOI 10. 15938 /j. emc. 2018. 01. 010 TM 404 A 1007-449X 2018 01-0072- 05 Effect of moisture on dielectric properties of transformer oil during cooling process GUO Wen-min 1 HOU Xian-kun 1 LIU Dan 2 1. Key Laboratory of Engineering Dielectrics and Its Application Ministry of Education Harbin University of Science and Technology Harbin 150080 China 2. Fourth Construction Branch Heilongjiang Power Transmission and Transformation Engineering Company Harbin 150040 China Abstract Stable operation of transformer is directly determined by the dielectric properties of transformer oil as the main insulation type of large transformers. In order to explore the effect of moisture on the dielectric properties of transformer oil during the cooling process 45# transformer oil was taken as the research object initial moisture content special location and average cooling rate on the dielectric properties of the transformer oil was studied in the range of - 50 ~ 20 with high voltage and low temperature experimental platform. The results show that when the initial moisture content is the same the conductivity the relative dielectric constant and loss factor of transformer oil increase from top to bottom of the special location in vessel and at the same location the above parameters increases with the increase of average cooling rate. These phenomena indicate that the existence of moisture during the cooling process leads to the deterioration of dielectric properties of the transformer oil. It is necessary to strictly control the moisture content in the transformer oil in order to ensure the stable operation of the transformer in the low temperature environment. Keywords insulation transformer oil moisture dielectric properties low temperature 2016-01 - 12 51207037 1977 1990 1989
1 73 0-50 ~ 20 700 mm 300 mm 280 mm 1-5 1 5 6-7 1 2 5 8-9 10-11 1 Fig. 1 Schematic diagram of insulation support and electrode system 5 1 1. 2 2 2. 1 22. 5 ppm 1. 1 1. 7 /h 45 2 2-10 80 1 ~ 5
74 22 2 Fig. 2-3 - Curves of conductivity vs. temperature of transformer oil at different spatial location 2. 3-10 22. 5 ppm 1 ~ 5 3 3-4 2. 2 16. 9 ppm 22. 5 ppm 29. 6 ppm 1. 7 /h 2 3 3 4 Fig. 3 Curves of conductivity vs. temperature of transformer oil with different initial moisture content - 3 Fig. 4 Curves of conductivity vs. temperature of transformer oil with different average cooling rate 4
1 75 3 81 3. 2 3. 1 23. 8 ppm 20. 1 1. 7 /h ppm 30. 3 ppm 5 2. 1 3 6 5 6 Fig. 5 Curves of AC dielectric parameters vs. temperature of transformer oil at different spatial location Fig. 6 Curves of AC dielectric parameters vs. temperature of transformer oil with different initial moisture content
76 22 6 2 3. 3 23. 8 ppm 1. 7 /h 1. 5 /h 1. 2 /h 3 7 7 1 KAMAL M. Particles and moisture effect on dielectric strength of 2003 proceedings of the 7th International Conference on Properties 7 and Applications of Dielectric Materials Nagoya June 1-5 2003 Fig. 7 Curves of AC dielectric parameters vs. C. Piscataway IEEE 2003. temperature of transformer oil with 7 KHAWAJA R H ARIASTINA W G BLACKBURN T R. Partial different average cooling rate discharge behavior in oil-impregnated insulation C. ICPADM 2003 proceedings of the 7th International Conference on Properties and Applications of Dielectric Materials Nagoya June 1-5 4 1 3 transformer oil using VDE electrodes J. IEEE Transactions on Power Apparatus and Systems 1982 101 3 756. 2. J. 2013 17 7 60. CHEN Qingguo CHI Minghe WANG Gang et al. Moisture influence on the electric filed distribution of oil-pressboard insulation under compound electric field J. Eletric Machines and Control 2013 17 7 60. 3. J. 2012 27 5 42. LIAO Ruijin SUN Huigang YIN Jianguo et al. Influence on the thermal aging rate and thermal aging characteristics caused by water content of oil-paper insulation J. Transactions of China Electro technical Society 2012 27 5 42. 4. J. 2015 35 6 1532. CHI Minghe CHEN Qingguo WANG Xinyu et al. Influence of temperature on electric field distribution of oil-paper insulation under compound voltage J. Proceedings of the CSEE 2015 35 6 1532. 5 WASSERBERG V BORSI H GOCKENBACH E. Challenge of mixed insulating liquids for use in high-voltage transformers part 1 investigation of mixed liquids J. IEEE Electrical Insulation Magazine 2002 18 3 31. 6 SHIOTA H MUTO H FUJII H et al. Diagnosis for oil-immersed insulation using partial discharge due to bubbles in oil ICPADM 2003. Piscataway IEEE 2003. 85
1 H APF 85 J. 2003 27 17 35. GENG Juncheng LIU Wenhua YUAN Zhichang. Research on the voltage unbalance of DC capacitors of cascaded STATCOM Part two mathematical model J. Automation of Electric Power System 2003 27 17 35. J. 2011 35 21 96. HU Yinghong REN Jiajia WANG Jianze. Unbalanced phenomenon and reason analysis for DC side voltage of cascaded STATCOM J. Automation of Electric Power System 2011 35 21 96. 7. 50MVA J. 2004 24 4 145. LIU Wenhua SONG Qiang TENG Letian. Balancing control of DC voltage of 50 MVA STATCOM based on cascade multilevel inverters J. Proceedings of the CSEE 2004 24 4 145. 8 AKAGI H S INOUE T YOSHII. Control and performance of a transformer-less cascade PWM STATCOM with star configuration J. IEEE Transactions on Industry Applications 2007 43 4 1041. 9. H APF J. 2015 29 12 1836. LIU Yayun WANG Haixin WEI Yangchao et al. Study of DC voltage balance control for cascaded H-bridge APF J. Journal of Electronic Measurement and Instrument 2015 29 12 1836. 10. H STATCOM J. 2015 35 5 15. 6. STATCOM XU Rong YU Yong YANG Rongfeng et al. DC capacitor voltage balance control of H-bridge cascaded STATCOM J. Electric Power Automation Equipment 2015 35 5 15. 11. STATCOM J. 2011 31 11 33. HU Yinghong REN Jiajia SHEN Ke et al. Balancing control of DC capacitor voltage for cascaded H-bridge STATCOM based on voltage redundant states J. Electric Power Automation E- quipment 2011 31 11 33. 12. J. 2016 36 4 40. HUANG Haihong WANG Yu XU Ruobing et al. Three-phase four-wire active power filter with dual-loop repetitive control J. Electric Power Automation Equipment 2016 36 6 40. 檪檪檪檪檪檪檪檪檪檪檪檪檪檪檪檪檪檪檪檪檪檪檪檪檪檪檪檪檪檪檪檪檪檪檪檪檪檪檪檪檪檪檪檪檪檪 76 8. 10 OOMMEN T V. Moisture equilibrium in paper-oil systems C. J. 2007 35 4 14. LIANG Yiming CHEN Yan AO Ming. Gas protection malfunction caused by transformer oil in cold area J. Jilin Electric Power EIC 1983 Proceedings of the 6th Electrical /Electronical Insulation Conference Chicago October 3-6 1983 C. Piscataway IEEE 2016. 2007 35 4 14. J. 2001 29 4 45. WANG Jingyu. Gas protection malfunction caused by low temperature and its preventive measures J. Jilin Electric Power 2001 29 4 45. 11 AKBARI A DEHPAHLEVAN S BORSI H. Analyzing dynamic 9. of moisture equilibrium in oil-paper insulation in power transformers for efficient drying C. CEIDP 2006 Proceedings of 2006 IEEE Conference on Electrical Insulation and Dielectric Phenomena Kansas City October 3-6 2006. Piscataway IEEE 2007.