Problems related to the so called "loss of life", or isolation aging of distribution transformers [7], have been interesting over a long period of time. Since the beginning of the last century various concepts have been used to explain the transformers loss of life and as usual those are interpreted incorrectly. In fact, "loss of life" has always been understood as "reducing the isolation's loss of life".There are existing therminological differencess in IEEE and IEC standards, that are used in the methods for determination of ageing in distribution transformers. This paper is comparative analysis between the variables, defined in those standards. The presented analysis relates to a transformer with the following parameters: 630 kVA, 10/0,4 kV, Dy5. Index Terms-hot spot temperature, loss of life, transformer1-4244-1298-6/07/$25.00 ©2007 IEEE.

No abstract

The paper explains latest developments considering exploration of Macedonian wind resources. Problems of choice of location, measurement of wind energy potential, choice of type and unit size of wind turbine generators for the sites, are considered.

No abstract

This paper aims to determine the electromagnetic forces acting in a power transformer, when a current corresponding to the first peak of a three-phase circuit flows in the windings. The finite element method for the evaluation of the field's values is applied, and the electromagnetic forces acting in a power transformer windings are calculated. Finally the results of a computation test by a personal computer for the exposed method are graphically presented and some conclusions about the behavior of the calculated electromagnetic forces are derived.