What is HIGHSET differential protection?

[I_am_learning]

I know biased differential protection system. But one differential relay I have at work here has a feature called "Differential instantaneous highset overcurrent protection". Does anyone knows anything about it?

 

[Simon Bridge]

properly "high-set":
http://books.google.co.nz/books?id=...CFEQ6AEwCA#v=onepage&q=high-set relay&f=false

 

[I_am_learning]

Thanks Simon.
it appears high-set relays are used for radial feeder protection. I don't see what it has got to do with differential protection of transformer.

 

[Simon Bridge]

Neither do I - but people will call things by whatever name they think will sell.
You should have a good idea what high-set" means now though.

 

[I_am_learning]

High set just isn't a feature provided by a relay, it is just a method of setting relays. (Relays at the near ends are progressively set at higher pickup current value)
So how can relays talk of having and not having high-set protection?
I don't think I fully understand high-set yet.