Alireza Bakhshinejad - Department of Electrical engineering, sowmesara Branch, Islamic Azad University, sowmesara, Iran
S.Mohammad Bagher Sadati - Department of Electrical and Computer Engineering, University of Kurdistan, Sanandaj, Kurdistan, Iran
Saeed Ahmadi - Department of Electrical engineering, sowmesara Branch, Islamic Azad University, sowmesara, Iran
Mehdi Tabasi - Department of Electrical engineering, sowmesara Branch, Islamic Azad University, sowmesara, Iran

According to validity of available statistics on total losses in power system including generation, transmission and distribution system, distribution system has the highest amount of total losses. On the one hand, expansion of electricity network and on the other hand, using nonlinear loads in distribution system will result in losses growth. In addition, transformers are one of the most important and populous equipments in distribution systems and have significant role in network losses. So, evaluation of their losses based on the harmonics produced by nonlinear loads is essential. In this paper, by measuring a 500 KVA oil-filled transformer loading, its losses are calculated. Then, by using a dry-type transformer instead of mentioned oil-filled transformer, losses are calculated again under the same distorted condition. Also, according to programs written in MATLAB environment, the load ability of two transformers has been investigated. In addition, the cost of energy losses has been calculated, too, and finally, results have been compared

Harmonic, Losse and Load Ability, Oil-Filed and Dry-Type transformer