Why is the Network Protector phase relay tested at 60° angle?

[StoneyJ180]

Why is the phase relay tested at 60° angle, as opposed to the 0° master relay test, if I worded that correctly... What exactly is happening at 60°?

[ironshovel77]

Why is the phase relay tested at 60° angle, as opposed to the 0° master relay test, if I worded that correctly... What exactly is happening at 60°?

I believe what testing at a 60 degree angle does is simulate a reverse power condition, which will trip the network protector.

[Relay1]

Why is the phase relay tested at 60° angle, as opposed to the 0° master relay test, if I worded that correctly... What exactly is happening at 60°?

StoneyJ180,
I hope you have gotten an answer before now! At 0° this would look like normal load current on the system,
but the 60° shift would be an indication of a single-phase to ground fault. So this would be a fault condition qualifier for the relays response to trip or block operation.