Multi-objective optimization of ATCTr considering optimum placement and weather conditions in distribution systems

Distributed Generators (DGs) using Renewable Energy Sources (RESs) have a huge economical and environmental potential. However, high penetration of DGs in distribution systems cause voltage deviations beyond the statutory range, and can cause reverse power flow toward the substation transformer. It is essential to control and maintain the distribution voltage within proper range to ensure both a stable power supply and good power quality. To accomplish this, an auto-tap-changer pole transformer (ATCTr) is introduced to solve this problem. However, the ATCTr is more expensive than ordinary pole transformers. Minimizing the voltage deviation as well as minimizing the introduction cost of an ATCTr have a trade-off relationship. Accordingly, this paper presents the application of multi-objective optimization methods in order to minimize the voltage deviation while simultaneously minimizing the number of introduced ATCTrs and finding an optimum placement of the ATCTrs to attain optimum operation of the distribution system.