A Calculation Method of Distribution Power Transmission Equipment Hot Spot Temperature Based on Relative Load Coefficient

Abstract

With the increase of power load year by year, the number of low-voltage users is increasing. Affected by factors such as uneven distribution of power load, three-phase unbalance is becoming more and more serious. Three-phase unbalance can easily lead to single-phase overload of distribution transformer, thus increasing the hot-spot temperature of winding. Especially in the peak period of power consumption, it is easy to cause burnout of heavy overload distribution transformer. According to the relative load factor, the calculation model of winding hot spot temperature of distribution transformer under three-phase unbalanced operation is constructed in this paper. Based on this model, the relationship between winding hot spot temperature and three-phase unbalance is analyzed. The results show that the three-phase unbalance has a great influence on the winding hot spot temperature. With the increase of unbalance, the hot spot temperature of transformer rises sharply.