Phase-phase fault detection

[pavement]

Does any of the experts in the protection field, who have more experience than myself know of a scheme to detect phase-phase faults on a unearthed system?

Thanking yous

 

[mvcjr]

A plain overcurrent relay (50/51) will do if there is no regards for fault direction.

God bless!

 

[rbulsara]

If instantaneous pick up is set correctly, it will help discriminate between short and overload.

For directional discrimination use device 67 in conjunction with 51 device.

 

[davidbeach]

A perfect application for negative sequence sensing.