Ocena življenjske dobe varistorja z weibullovo porazdelitvijo

PLOT, NIKA (author), Rudež, Urban (mentor)

V diplomskem delu je opisan postopek uporabe Weibullove verjetnostne porazdelitve na primeru določevanja življenjske dobe varistorja. Podane so potrebne informacije o nelinearnih elementih, ki se uporabljajo na področju zaščite elementov elektroenergetskega sistema. Dalje je v splošnem opisan varistor, natančneje pa so podani podatki o tipu varistorja podjetja Varsi, ki smo ga uporabili pri meritvah. Opisan je postopek določevanja standarda meritev in sam potek izvajanja meritev. Za interpretacijo rezultatov smo si izbrali dvoparametrično Weibullovo porazdelitev ter iskali parametra α in β. Pri tem življenjske dobe nismo merili glede na čas, ampak glede na število udarov, ki jih varistor prenese pri različnih obremenitvah z udarnim generatorjem. Obdelava podatkov je potekala na tri načine: z grafično metodo, metodo linearne regresije najmanjših kvadratov in z na svetovnem spletu prosto dostopnim programom EasyFit. Kot rezultat smo dobili enačbo, na podlagi katere lahko informativno sklepamo, pri katerem udaru bo pri določeni obremenitvi varistor odpovedal.

• Language: Slovenian
• Keywords: nelinearni elementi, varistor, Weibullova porazdelitev, življenjska doba
• Work type: Undergraduate thesis
• Organization: FE - Faculty of Electrical Engineering
• Year: 2016
• PID: 20.500.12556/RUL-83787
• Publication date in RUL: 30.06.2016

PLOT, NIKA, 2016, Ocena življenjske dobe varistorja z weibullovo porazdelitvijo [online]. Bachelor’s thesis. [Accessed 18 April 2025]. Retrieved from: https://repozitorij.uni-lj.si/IzpisGradiva.php?lang=eng&id=83787

Secondary language

• Language: English
• Title: Lifetime estimation of varistor using the Weibull distribution

Abstract

The thesis is based on the process of Weibull probability distribution to determine a lifetime expectancy of a varistor. Necessary information about nonlinear elements which are used in the field of surge protection is provided. Further we also have a description of a varistor and a more detailed overview of the type of varistor manufactured by the company Varsi, which was used for our measurements. It describes the procedure on how we determined the standard for the measurements and the whole process of measurements. Results were interpreted using two-parameter Weibull distribution and we were looking for parameters α and β. Lifetime expectancy wasn't measured in full product lifetime, but considering the number of strikes that varistor can take when exposed to different current loads, which we produced with a strike generator. Data was processed in three ways: with grapf method, linear regression – least squares estimation and with use of the program EasyFit, which is available as a free program on the internet. As a result we got an equasion, based on which we can informatively assume after how many strikes will varistor degrade when exposed to a particular current load.

• Keywords: non-linear elements, varistor, Weibull distribution, lifetime expectancy