If a faulted transformer is cleared and the remaining two transformers are connected in an open wye-open wye configuration, what percentage of the original bank's capacity does the new configuration have?

In an open wye-open wye configuration with two remaining transformers after one has been faulted and cleared, the system operates at half the capacity of the original transformer bank. This is because, in a three-phase transformer configuration, if one transformer fails, the capacity that can be utilized from the remaining transformers is significantly reduced.

In a typical three-phase transformer bank, each transformer contributes equally to the overall capacity, which means that each transformer represents one-third (approximately 33.33%) of the total capacity of the bank. When one transformer is out of service, the remaining two transformers can only operate at 66.66% of the original bank's capacity when connected in an open configuration. However, when connected in an open wye configuration, they effectively only provide half of the original bank's total capacity. Therefore, the correct answer reflects that the new configuration has 50% of the original bank’s capacity.