Wyniki 1-2 spośród 2 dla zapytania: authorDesc:"Tomasz KOLTUNOWICZ"

Diagnostics of transformer with insulation oil-paper DOI:10.15199/48.2015.08.18

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Artykuł omawia metody opisujące stan izolacji transformatorów. Przez określenie jej stanu jest poznanie pomiarów napięcia powrotnego oraz pomiarów rezystancji izolacji uzwojeń. Metoda pomiaru napięcia powrotnego jest metodą szeroko opisującą stan, która nie jest objęta normami ale w wielu przypadkach umożliwia uzyskanie jasnych i dokładnych wyników. Wyniki przede wszystkim pokazują zawartość wilgoci, zawartość przewodzących zanieczyszczeń w oleju oraz wpływ stopnia starzenia na papier izolacyjny. (Diagnostyka transformatorów z izolacją papierowo-olejową). Abstract. The article deals with method describing the state of transformer insulation. By the determining its state is acquainted return voltage measurement and measurement the insulation resistance of windings. Return measurement voltage method is wide state specifying method which is not set in standards but in many cases is a method which is determining a clear and exact result. The results have mainly shows moisture content, content of conductive impurities in oil and degree of aging of paper insulation impact. Słowa kluczowe: napięcie powrotne, rezystancja izolacji, wskaźnik polaryzacji, transformator. Keywords: return voltage, insulation resistance, polarization index, transformer. Introduction Influence of operating conditions leads to aging of individual parts of transformer, and also to changes of the major electrical and mechanical properties. To the check of the condition greatly contributes electro-technical diagnosis, whose main task is to find a clear relation between the change in functional characteristics of the machine and some measurable values. The assessment of these measured values must be visible not only the rate of change, but also whether it is a permanent or reversible state. The aim of diagnostics of transformers is to verify that the machine complies with the determined conditions in accordance with standards [1]. Economically reliable and effective po[...]

Analysis of transformer condition by frequency and time methods DOI:10.15199/48.2019.09.08

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Maintenance diagnostics of transformers considering to the influence of short-circuit currents during the operation should be carried out to increase the reliability in real trouble-free process. The short-circuits in operation are commonly created by different line faults, etc. in mechanical damage of insulation, an electric insulation, an electric insulation breakdown on over voltage, wrong operation and in the next case row [1]. The short-circuit currents cause a progressive serious disrepair of the transformer, because there are high currents in it which are awfully rising winding temperature, what it can cause damage their insulation. Much more danger is high electro-magnetic forces, which can be the reason for the devastation of transformer. Considering a significance of power three-phase transformers in the electric system, their price and possible damages arising in accidents, it is necessary to pay attention to higher prevention of these devices. Windings of the transformers should be designed to avoid various mechanical or thermal deteriorations caused by short-circuit currents occurring in operation. Besides the permanent deformation effects of shortcircuit currents, there are also gradual aging process of the electrical device, which can worsen its mechanical properties. Heat shocks can cause decrease of mechanical strength of transformer and consequent unexpected damage of transformer during the operation. To prevent a damage state of transformers, it is performed different types of the measurements that should illustrate an actual condition of the measured equipment. It is therefore important to choose a suitable diagnostics for the right prediction of such conditions. The theory of mechanical forces effect on transformer winding during short-circuit For a better comprehension this relation between transformer damage and short-circuits currents effects, it is needed focused on mechanical forces effect on tr[...]

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