سال انتشار: ۱۳۸۱

محل انتشار: هفدهمین کنفرانس بین المللی برق

تعداد صفحات: ۷

نویسنده(ها):

Georg Daemisch – Industriedienstleistungen Alte Nurberger, Regensburg Germany
DIDEE Daemisch – Industriedienstleistungen Alte Nurberger, Regensburg Germany

چکیده:

"During the 60s and 70s of the previous century, when the majority of the transformers was installed, they were intended to last for a life span of about 30 years. In the meantime, and due to a change in overall conditions brought about by liberalization combined with a variety of political and economic reasons, users have become keenly interested not only in keeping these transformers in service for an indefinite length of time, but in exploiting them up to maximum loading or – even worse – overloading them, something which usually wasn’t done at all, particularly for transformers in network applications. The question now is to figure out how to afford the prolonged and higher demand on transformers. The classic tools and test procedures normally at the hands of the transformer user are all based on the behaviour of new transformers. Applying these tools to transformers with oil-cellulose insulation systems which have been in use for more than 30 years creates more questions than can
be answered at the moment. It is quite common that moisture content, dielectric strength, DGA and other key data will show inconsistent results. These results make it impossible to get a clear picture in order to decide whether a particular transformer can be kept in service, to what degree it can be loaded or even overloaded, or what action is necessary to improve the operational safety level in order to cope with the required load pattern. For this reason, the new "science" Geriatrics of Transformers – is, at present, not capable of providing immediate satisfactory answers since a number of additional questions must be dealt with regarding additional new tools, data sampling, diagnosing and the establishing of suitable solutions prior to final approval. This paper is aimed primarily at presenting the new questions arising from the practice of evaluation and treating aged transformers, in order to promote discussions and draw the attention of transformer experts to this issue which will be one of the most important innovations in the world of transformers".