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Research Article |

Development of an Improved Model for Assessment of Hot Spot Temperature of Current Transformers

Author(s): Ganiyu Adedayo Ajenikoko* and Emmanuel Babatunde Badmus

Published In : International Journal of Electrical and Electronics Research (IJEER)        Volume 6, issue 2

Publisher : FOREX Publication

Published : 25 may 2018

e-ISSN : 2347-470X

Page(s) : 12-16

DOI: https://doi.org/10.37391/IJEER.060202

Abstract

Current transformers form important components that make up a large portion of capital investments. Failure of a current transformer results in an adverse effect in the operation of transmission networks which causes an increase in the power system operation cost and inability to deliver electricity with absolute reliability. The age of a transformer is the life of its insulation, majorly, paper insulation. Transformer aging can be evaluated using the hot spot temperature which has the effect of reducing the insulation life of transformers. Previous researchers have developed models for assessment of top-oil temperature of current transformers. Such models have the limitation that they do not accurately account for the variation effect in ambient temperature and hence not applicable for an on-line monitoring system. This research paper develops an improved model for assessment of hot spot temperature from the IEEE top-oil rise temperature model by considering the ambient temperature at the first-order characterization using appropriate mathematical notations. The ambient temperature, top oil rise over temperature and winding hot spot rise over temperature were used as input parameters for the development of the improved hot spot temperature model by considering the final temperature state since the time-rate-of change in top-oil temperature is driven by the difference between the exits top-oil temperature for ambient temperature variation. The improved model was then implemented in MATLAB to compute the hot spot temperature for 24-hour load cycle. The result of the improved model shows that the least and highest value of the hot spot temperature are 630C and 105.40C respectively indicating a retardation in the aging process of the transformers. The improved model helps to minimize the risk of failure and to extend the life span of transformers thereby controlling the hot spot temperature rise and top oil temperature.

Keywords: Current Transformers, Hot Spot Temperature, Top-Oil Temperature, Ambient Temperature, Insulation Failure, Aging Effect and Aging Process.




Ganiyu Adedayo Ajenikoko*, Department of Electronic & Electrical Engineering, Ladoke Akintola University of Technology, P.M.B. 4000, Ogbomoso, Nigeria; Email: Nigeria, ajeedollar@gmail.com

Emmanuel Babatunde Badmus, Department of Electronic & Electrical Engineering, Ladoke Akintola University of Technology, P.M.B. 4000, Ogbomoso, Nigeria

    [1] Akbari M, Khazacc P, Sabetghadam I and Karimifard P. (2013): “Failure modes and effects analysis (FMEA) for power transformers”, No. E-13-MNG-1990, 28th International Power System Conference, Iran, Pp. 1-7.
    [2] Jalbert J, Gilbert R, Denos Y and Gervais P. (2012): “Methanol: a novel approach to power transformer asset management”, IEEE Transactions on Power Delivery, Vol. 27, Pp. 514-520.
    [3] Gouda O.E, Amer G.M and Salem W.A.A. (2012): “Predicting transformer temperature rise and loss of cycle in the presence of harmonic load current”, Open Journal of Applied Sciences, Vol. 3, Pp. 24-29.
    [4] Dong-Jin K, Kyo-Sun K, Jung-Wook W and Joo-Sik K. (2012): “A study on the Hot spot temperature in 154 kV power transformers”, Journal of Electrical Engineering and Technology, Vol. 7, No. 3, Pp. 312-319.
    [5] Cheim L, Platts D, Prevost T and Xu S. (2012): “Furan analysis for liquid power transformers”, IEEE Electrical Insulation, Vol. 28, Pp. 8- 21.
    [6] Swift G, Molinak T.S and Lehn W. (2011): “A fundamental approach to transformer thermal modelling- Part 1: theory and equivalent circuit”, IEEE Trans. Power Del., Vol. 16, No. 3, Pp. 174-179.
    [7] Anuradha K and Satish M.M. (2011): “Time domain spectroscopy measurement for the insulation diagnosis of a dielectric transformer”, IEEE Trans. on Dielectric and Electrical Insulation, Vol. 8, No. 5, Pp. 59-71.
    [8] Satish M.M and Diego M.R. (2010): “Thermal modelling of an inverted-type oil immersed current transformer”, IEEE Transactions on Power Delivery, Vol. 25, No. 4, Pp. 31-38.
    [9] Mohammed Y, Mohammed M and Amir A.S.A. (2010): “Investigation on impact of current harmonic currents on the distribution transformer losses and remaining life”, IEEE International Conference on Power Energy, PP. 22-46.
    [10] Jauregui R.L and Tylavsky D.J. (2008): “Acceptability of four transformers top oil thermal models – Part 1: defining metrics”, IEEE Trans. Power Delivery, Vol. 23, No. 2, Pp. 860-865.
    [11] Elmoudi A. (2008): “Transformer winding: hot spot temperature modeling and simulation”, IEEE Trans. on Power Systems, Vol. 7, No. 5, Pp. 33-46.
    [12] Diego M, Robalino V and Saish M.M. (2008b): “Correlation between hot-spot temperature and aging factor of oil-immersed current transformers”, IEEE Trans. on Power Del., Vol. 6, No. 8, Pp. 156-171.
    [13] Diego M, Robalino V and Satish M.M. (2008a): “Effect of thermal accelerated aging on a medium transformers”, IEEE Trans. on Power Systems, Vol. 6, No, 8, Pp. 114-127.
    [14] Karisson S (2007): “A review of lifetime assessment of transformers and the use of dissolved gas analysis”, An Unpublished M.sc Thesis, KTH School of Electrical Engineering, Pp. 1-51.
    [15] Srinvasan M and Krishnan A. (2005): “Prediction of transformer insulation life with an effect of environmental variations”, International Journal of Computer Applications, Vol. 56, No. 3, Pp. 33-48.

Ganiyu Adedayo Ajenikoko and Emmanuel Babatunde Badmus (2018), Development of an Improved Model for Assessment of Hot Spot Temperature of Current Transformers. IJEER 6(2), 12-16. DOI: 10.37391/IJEER.060202.