Which transformer connection is common for three-phase systems?

In three-phase systems, both wye (Y) and delta (Δ) connections are commonly used, and each serves specific applications and functions.

The wye connection provides a neutral point, which can help in balancing loads and allows for the connection of single-phase loads alongside three-phase loads. This configuration is beneficial in distributing power to different kinds of loads, providing versatility in electrical systems.

On the other hand, the delta connection is often utilized for its ability to handle higher currents and provide a robust design for industrial applications. It also allows for connections without a neutral wire, which can be advantageous in certain scenarios.

Both configurations are essential in three-phase systems, and their use depends on specific needs such as balancing loads or managing power requirements. Therefore, since both delta and wye connections are prevalent and serve essential roles in various electrical systems, the answer indicating their commonality is justified.