2020 | vol. 68 | nr. 1 | art. 6

The Influence of Solar Radiation on the Lifetimes of Power Transformers

Maaya Isseydou BEY, Petru V. NOŢINGHER, Cristina STANCU
In order to avoid the uncontrolled removal of the power transformers, a special importance is the accurate knowledge of the estimated, consumed and remaining service life of the insulation systems of these equipment taking into account the real loads during their operation. In this paper a method of calculating the lifetimes based on the recommendations of IEEE and IEC loading guides using the values of the hot spot temperature is presented. These are calculated based on the daily load curves of the transformers, as well as the variable temperatures of the environment and the solar radiation. To highlight the effect of ambient temperature and solar radiation, a case study of three transformers operating in different geographical areas, respectively in Romania (Craiova, Suceava, Constanta) and Mauritania (Noukchatt) is presented. It is found that the values of the hot spot temperature calculated in the presence of solar radiation are approx. 3 oC higher than those calculated in its absence and, for the same daily load regime, the lifetime consumed in one year has higher values for the transformer in Nouakchott, than for those in Craiova (with 231 days) and Suceava (with 256 days).
Keywords: power transformers, oil-paper insulation, solar radiation, hot spot temperature, estimated, consumed and remaining lifetimes
To cite this article: BEY M.I., NOTINGHER P.V., STANCU C., "The Influence of Solar Radiation on the Lifetimes of Power Transformers”, in Electrotehnica, Electronica, Automatica (EEA), 2020, vol. 68, no. 1. pp 45-58, lSSN 1582-51751582-5175.