The classic solution is to use an open delta transformer bank.
In your case, when a single phase event results in one fuse blowing, don't replace the fuse.
Anecdote warning:
In Central America, where the grounded wye/delta was common, it was also common to see one fuse open on vrtually all the wye/delta banks, until the next election.
If the ruling party changed, then all the party favorites in the top engineering jobs in the Government owned utility would be replaced. The new guy at the top would typically send out an order to "Get with it" and replace all the blown fuses.
Single phase events were common, (weekly) and the fuses would typically be replaced with the next larger size.
Eventually over-fused transformers would start to fail.
Usually, within about a year after an election, inertia and appathy would take over and the system would revert to one blown fuse on every bank.
Anecdote #2.
I had left the country and was no longer working for the island utility. I was back in the country for a visit and the manager of the utility asked my to come out to the island and walk around the system to check for any possible problems.
Sure enough, after I had spent a few years getting rid of all the wye/delta banks, here was a new wye/delta bank.
"I thought that we had agreed that we would no longer allow that connection on our system?"
"Yes, I know, but that is the national phone company's telephone exchange and we have to give them what they want."
"Do you remember when we used to have all the refrigerator burn-outs blamed on our power company?"
"Yes. That was awful."
"When was the last time that you were accused of a refrigerator burn out?"
"Not for years."
"Do you want to go back to those days?"
"No way."
"Well then we have to do something about that transformer bank."
The solution:
As you know, a fused cutout has a toggle arrangement on the bottom.
The toggle is held in place by the fuse link.
When the fuse blows, the toggle spring pulls the fuse link apart to aid in clearing.
The toggle collapses and allows the fuse holder to drop free.
We had a toggle spot welded in place without a fuse link installed.
This was put in place for one of the transformers.
The transformer bank then functioned in open delta with one transformer connected on the secondary but disconnected from the primary.
The customer never knew and never saw a difference in service.
You do have to check the transformer loading.
In our case, The single phase load was only lights and office machines for a small office.
The three phas load was one 17 KVA bettery charger.
The battery bank was three 50 KVA transformers.
Bill
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"Why not the best?"
Jimmy Carter