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Research – Development – Innovation

Séminaire Equipe OMN, 15 Fév. 2018

Le Jeudi 15 février 2018, RuoHan GONG, doctorant en fin de thèse à l’Université de Wuhan effectuera un séminaire sur le thème :

Study on Hot-spot Temperature Calculation and Inversion Detection Method of Oil-immersed Transformer
suivi d’une discussion scientifique.

Date : Jeudi 15 février 2018 à 13h30
Lieu : Salle 2S53 à Lilliad

Le résumé de sa présentation est ci-dessous :

Power transformers are one of the most important equipment of the electrical  power system. The operating reliability of transformers has a close influence on security  and stability of power systems. The end of the life span of power transformers is most  due to the loss of their normal insulation, which is very much dependent on the highest temperature occurred in any part of a winding insulation system, as known as hot spot temperature (HST). Thus, getting the values and location of HST is significant to meet the goals of maximizing the load ability, improving the effective lifetime and lowering the total cost associated with transformer operation and maintenance. Some works focused on this topic has been developed as follows:
(1) Considering the complicated and special solid-liquid-gas structure of oil-immersed transformer, the heat dissipation process inside transformer including heat conduction and convection is investigated by multi-physics coupling analysis. The validity and accuracy of calculation model is verified by temperature rise test.
(2) According to the temperature and velocity distribution analysis of inner transformer, an inverse detection method of HST based on support vector regression(SVR) is put forward. This method takes load and tank temperatures as input characteristics. The relative error of HST steady state temperature inversion is less than 3%.
(3) On the basis of steady inversion, an improved HST transient calculation method based on thermal-electrical analogy and IEC standard is proposed. The thermodynamic parameters of this model are estimated by Levenberg-Marquardt(LM) method. This model has been successfully applied to transformers with different voltage classes, capacities and structures. The maximum temperature difference is less than 3℃.