Which of the following connections is used as distribution transformer?

Delta-star connection is used in the distribution transformer. The primary side is connected in delta while the secondary side of the transformer is connected in star.

The primary side of the main transformer is connected to the transmission line. To eliminate the third harmonics, the primary side of the distribution transformer is connected in a delta connection. Since in delta connection, the current reduces by a factor of √3, this reduces the current flowing through the transmission lines, minimizing losses and improving overall efficiency.

The star connection on the secondary side provides a neutral point, which is essential for connecting three-phase loads that require a neutral connection. It also helps in balancing the load across the three phases.

The star connection on the secondary side allows for easy grounding of the neutral point, which is important for safety and protection against faults.