What is the recommended practice when sectionalizing a "floated" wye transformer bank under conditions of ferro-resonance?

When dealing with a "floated" wye transformer bank under conditions of ferro-resonance, placing temporary grounds on the floated neutral is the recommended practice. This approach helps to stabilize the system by providing a reference point for the voltage, mitigating the risk of ferro-resonance, which can lead to overvoltages and potential damage to the transformer and other equipment.

Ferro-resonance occurs when non-linear inductance and capacitance in the system cause erratic voltage levels that can exceed the transformer's ratings. By grounding the floated neutral, you create a path for excess voltage, which can help to dampen the oscillations and reduce the severity of the ferro-resonance condition.

Disabling the transformer is not advisable in this scenario, as it could disrupt service and may not address the underlying issue of ferro-resonance. Completely isolating the transformer may also lead to unnecessary downtime and potential complications in system operations. Similarly, adding more load to the system can complicate the situation further and may not effectively address the resonance challenge. Therefore, placing temporary grounds on the floated neutral provides a balanced approach to managing the risks associated with ferro-resonance in transformer banks.