Method for lifetime estimation of power transformer mineral oil

Lifetime estimation of vegetable oil for transformers

“…This method requires however high material and human efforts and takes a long time. A more rapid method, based on the activation energy corresponding to oxidation, was proposed in references [17][18] for mineral oils. In [19] a rapid method, coupling the infrared spectroscopy and chemometrics methods is proposed.…”

“…It is observed that vegetable oil has a higher stability, but lower activation energy. The activation energy (E a ) corresponding to vegetable oil oxidation was calculated with the Kissinger method using OOT, T 0.6 si T max parameters [17][18] (Table I). In case of T 0.6 parameter, the E a value, proportional to the curve's slope ln(β/T 0.6 ) vs f(1/T 0.6 ), was 91.2 kJ/mole (Fig.…”

Thermal degradation assessment of Kraft paper in power transformers insulated with natural esters

“…Electricity distribution and transmission require the use of power transformers, so they are vital and strategic components of any electric power system [1][2][3][4]. It is known that the failure of power transformers can produce significant economic losses related to its reparation or replacement as well as financial losses compensations required by consumers [4][5].…”

“…In the case of a 150 MVA transformer it may contain as much as 80 tons of oil and up to 30 tons of paper. This insulation system under operational conditions suffers electrical, thermal, environmental and mechanical stress due to the presence of traces of air and water which worsen electrical properties of paper and oil [5,11]. Although, oil can be easily reclaimed or substituted this will not extend the cellulose's life [2].…”

Development of a Hybridized Model for Predicting the Life Span of Power Transformers

“…Petru et al (Notingher et al, 2017) further proposed a novel model to estimate the remaining lifetime of an in-service power transformer based on monitoring of its oil resistivity. Laurentiu et al (Dumitran, Setnescu, Notingher, Badicu, & Setnescu, 2014) also developed a simpler model for a single ageing test that involve the usage of high temperature and the activation energy which are determined from non-isothermal Differential Scanning measurement. Furthermore, Dan Zhou (Zhou, Li, & Wang, 2012) proposed a baseline model integrated with Bayesian model in order to sequentially updating the model whenever new failure occurs , this allows the existing lifetime model to be improved.…”