Quote:
Originally Posted by Richard_FM
It's always interesting to learn about non-standard electricity supplies.
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Yes, and they are getting less common "every opportunity should be taken to replace legacy systems with standard 3 phase, 4 wire, at 230/400 volts"
"no significant expansion of legacy systems is permitted"
The main drawbacks of such systems is the risk of a relatively prolonged outage in the event of a transformer failure.
The failure of a "conventional" substation transformer is normally handled by backfeeding at LV from adjacent mains on different transformers.
This can be done within an hour by two men in a van inserting fuses or links into street link boxes.
If this can't be done, then a large transportable generator may be connected to the LV busbars in the substation. This can usually be done within three hours.
The odd legacy systems can't be paralleled, nor supplied from a large generator. The supply would remain off until the new transformer was delivered. A small stock is kept of both reverse polarity and diametric transformers. But transport from a distant stores department and crane hire is unlikely to be achieved in less than 12 hours.