Firouzifar - Dept. of public technology, MALARDALEN University, MDH Vasteras, Sweden، MAZANDARAN R.E.C
Firouzifar - MAZANDARAN R.E.C
Mahmoudi - Dept. of public technology, MALARDALEN University, MDH Vasteras, Sweden

This paper presents the evaluation of power transformers overloading in transmission and over distribution substations, supervised by MAZANDARAN which is a regional electrical company in Iran. It was found that ambient temperature rise and overload are two important factors in performance of these substations. Rise in electric power consumption increased the power transformer loads by %16.3 during year 2006 in provinces of MAZANDARN. Over loading generates high temperature within the power transformers. The changes in ambient temperature in a single day increase; they follow a sinusoidal pattern in MAZANDARN province. With the increase in climate temperature and overloading, the process of insulation aging accelerates in power transformers. Using IEC-60354 standards, a r emedy must be found for the climate temperature increase and the overloading of power transformer in MAZANDARAN province. Using FEMLAB a novel cooling system was developed to help reduce the aging rate of power transformer insulation [9, 19, 20, and 21].

Transformer, Overload, temperature, Ambient, cooling, FEMLAB