What should be done with the neutral on an open wye-open delta transformer?

In a three-phase system, the neutral is crucial for providing a return path for current and stabilizing voltage levels across the phases. In an open wye-open delta transformer configuration, the neutral is typically tied to the system neutral. This connection helps to maintain proper voltage relationships within the system and ensures that loads are balanced.

When the neutral is tied to the system neutral, it allows for effective phase-to-ground overcurrent protection and under-voltage conditions. It also helps limit the maximum phase-to-neutral voltage, thereby enhancing the safety and reliability of the system. Additionally, this ensures that faults can be effectively cleared and that the system operates under standard electrical performance criteria.

Floating the neutral would leave the system vulnerable to voltage imbalances, and grounding it could create unwanted ground loops or hazards. Connecting it to the load circuit would not apply as the neutral should be a reference point for voltage rather than carrying current directly from a load. Thus, tying the neutral to the system neutral is the appropriate action for maintaining the integrity and stability of the electrical system in an open wye-open delta transformer setup.