Effect of unbalance voltage on the operation and performance of a three phase distribution transformers

Abstract EN

Three phase supply system is found to be quite balanced in both magnitude and displacement at the generation levels but it is not so at distribution end.

Voltage unbalance which is a common and global phenomenon is found to be very effective in deteriorating the operation and performance of electrical apparatus.

Present paper is an attempt to analyze the operation of three phase distribution transformers with unbalance voltage conditions.

MATLAB programming based upon symmetrical component approach is adopted to estimate the performance of a three-phase transformer under unbalanced condition.

Both under voltage unbalance as well as over voltage unbalance have been considered for analysis purpose.

Numerical details study in case of distribution transformer with primary delta connection and secondary star connection with solidly grounded neutral is presented in this paper.

The degree of voltage unbalance is represented by the voltage unbalance factor (VUF) derived from symmetrical component.