It is not my area of expertise, except where I happen to have come across it in the course of other works, I cannot comment on 60 MVA - that to me is a very large genset and more than a typical 11k/400 transformer, or even more than the supply end to an 11kV line feeding a few . However, in the UK the loads on the secondary of an HV LV substation are normally limited with fuses, though there may also be breakers and these may be triggered by a variety of things as well, and can be interlocked to kill the primary side if a secondary side fault develops.
There may be expulsion fuses somewhere in the primary feeders, such things are sometimes seen on the pole tops of 11kV (and maybe 33kV) rural lines. However, at the feeder end of the HV lines protection is far more sophisticated, and will include current transformers to operate breakers with 'inverse time' characteristics, and also to trip fast on HV earth faults. On meandering rural networks there may be trips that include automatic or remote control re-connectors as well, to give a degree of restart with only the faulty branch permanently disconnected after 3 goes or whatever.
Realise it is not just small transformers that have thermal trips built in - the Buchholz Relay fulfils this purpose, and turns off a transformer if the oil pressurre build perhaps if it is boiling for any reason. In the crudest form these may just short the HV, and rely on something further back to do the disconnection, but this is old hat, and more often would be linked to a proper HV breaker.
Industrial sites with private transformers that take in HV directly, at least those that are relatively modern, generally see something similar to that described by OMS in the middle posts in this thread from a few years ago. older thread about 11kV overload and fault systems . Even so, a long way further back is generally something simple that will melt, vapourise or perhaps just blow up, but by design, if the clever stuff does not behave itself.
It is not my area of expertise, except where I happen to have come across it in the course of other works, I cannot comment on 60 MVA - that to me is a very large genset and more than a typical 11k/400 transformer, or even more than the supply end to an 11kV line feeding a few . However, in the UK the loads on the secondary of an HV LV substation are normally limited with fuses, though there may also be breakers and these may be triggered by a variety of things as well, and can be interlocked to kill the primary side if a secondary side fault develops.
There may be expulsion fuses somewhere in the primary feeders, such things are sometimes seen on the pole tops of 11kV (and maybe 33kV) rural lines. However, at the feeder end of the HV lines protection is far more sophisticated, and will include current transformers to operate breakers with 'inverse time' characteristics, and also to trip fast on HV earth faults. On meandering rural networks there may be trips that include automatic or remote control re-connectors as well, to give a degree of restart with only the faulty branch permanently disconnected after 3 goes or whatever.
Realise it is not just small transformers that have thermal trips built in - the Buchholz Relay fulfils this purpose, and turns off a transformer if the oil pressurre build perhaps if it is boiling for any reason. In the crudest form these may just short the HV, and rely on something further back to do the disconnection, but this is old hat, and more often would be linked to a proper HV breaker.
Industrial sites with private transformers that take in HV directly, at least those that are relatively modern, generally see something similar to that described by OMS in the middle posts in this thread from a few years ago. older thread about 11kV overload and fault systems . Even so, a long way further back is generally something simple that will melt, vapourise or perhaps just blow up, but by design, if the clever stuff does not behave itself.
