What are the advantages of open delta connection?

An open-delta connection is a method of providing a three-phase supply, using two single-phase transformers. It is particularly useful if , say, one single-phase transformer, part of a three single-phase transformers forming a three-phase transformer bank, becomes damaged -allowing the two remaining transformers to provide a temporary three-phase supply to the load.
The drawback with this connection is that the capacity of the transformer bank is reduced, and it can only provide a lower load current.