توجه: محتویات این صفحه به صورت خودکار پردازش شده و مقاله‌های نویسندگانی با تشابه اسمی، همگی در بخش یکسان نمایش داده می‌شوند.
۱FAILURE ANALYSIS AND RELIABILITY EVALUATION of POWER TRANSFORMERS
نویسنده(ها): ، ، ،
اطلاعات انتشار: بیست و یکمین کنفرانس بین المللی برق، سال
تعداد صفحات: ۷
Failures of transformers in subtransmission systems not only reduce reliability of power system but also have significant effect on power system performance since one of the important components of any system quality is reliability of that system. To enhance utility reliability, failure analysis and rates, failure origin and physical damage causes must be study. This paper describes a case study of the reliability of subtransmission transformers (63\20 kV) installed in Mazandaran province, operated in subtransmission system. The information obtained from Mazandaran Regional Electric Company. The results of study and analysis on 60 substation including more than 110 transformers installed in
subtransmission system show that the failure modes of transformers can be represented by Weibull distribution. Weibull statistics have been widely used and accepted as a successful mathematical method to predict the remaining life time of any equipment. Useful conclusions are presented both for power systems operators and manufactures for improving the reliability of transformers.<\div>

۲Prediction of Chemical Characteristics of the Transformer Oil by Neural Networks
نویسنده(ها): ، ،
اطلاعات انتشار: بیست و یکمین کنفرانس بین المللی برق، سال
تعداد صفحات: ۷
This paper presents the prediction of chemical characteristics of the transformer oil by neural networks. The aim of this work is to reduce the aging experiments time, with obtaining the same results as in the case of long duration tests, by using neural networks. This model is composed of some characteristics of the transformer oil such as viscosity, acidity, flash point, water content, gravity and colour that have been predicted by service period. This list of evidences indicates the beginning of the oil degradation process. In this paper we show the power of NN to predict those characteristics according to some mathematical models such as polynomial and multiple linear regression. Also we compare two different softwares as NN1 (Neuro Solution) and NN2 (Matlab) for predicting some of theses characteristics, to show the accuracy of the proposed NN.<\div>

۳Initial Condition Effect on Ferroresonance Behavior in a Nonlinear Circuit
نویسنده(ها): ،
اطلاعات انتشار: بیست و دومین کنفرانس بین المللی برق، سال
تعداد صفحات: ۹
One of the main features of ferroresonance behavior is its different responses with the same parameter values depending on initial conditions. In this paper a simple ferroresonance circuit has been studied via mathema tic software Matlab. Different parameter effects on ferroresonance behavior especially different initial conditions have been studied. Core losses are nonlinear so it has been represented with a nonlinear equation and implemented in calculations. Domains of period–1 ferroresonance occurrence has been obtained in a space of parameters.<\div>

۴Range extension of Barbus sublimus Coad and Najafpour, 1997 (Actinopterygii: Cyprinidae) and its sympatric species in Southwest of Iran
نویسنده(ها): ، ، ،
اطلاعات انتشار: Iranian journal of animal biosystematics، دوم،شماره۱، ۲۰۰۶، سال
تعداد صفحات: ۶
Barbus sublimus, described by Coad and Najafpour (1997) as a new species, was retrieved first from the Aala Rood, a river in Khuzestan province, southwestern Iran. In our latest sampling a population of this species was found, for the first time, in Fahlian Rood, a river in a different water basin, in Fars province, Southwest of Iran, where no specimen of the species was collected in previous samplings at this location. The detail of taxonomic workdone on the specimens captured, species phylogeny, and the possibilities of its previous absence and then presence are described and discussed.
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