How is the secondary of a transformer bank connected that has "X" leads?

In a transformer bank that has "X" leads, the secondary is connected in a delta configuration. The delta connection is established by connecting the terminals of the transformers in a loop, where each transformer's secondary winding is connected between a pair of phase conductors. This configuration allows for the capability to handle three-phase loads effectively and provides a path for circulating currents that can help balance the load across the transformers.

In a delta connection, each phase distributes the load equally, which is especially beneficial for large motor applications and provides better performance in high current situations. Additionally, the delta connection does not require a neutral point, which can simplify the system design when a neutral conductor is not required.

Using the delta configuration can also help with voltage stability, provide better phase-to-phase voltage, and minimize the possibility of circulating ground faults affecting the system. Understanding the implications of using delta versus other configurations like wye (or star), is essential for the effective design and operation of three-phase transformer systems.