Voltage phasors at the two terminals of a transmissi on

Voltage phasors at the two terminals of a transmissi on line of length 70 k m have a magnitude of 1.0 per unit but are 180 degrees out of phase. Assuming that the maximum load current in the line is 1 5 th of minimum 3-phase fault current, which one of the following transmission line protection schemes will NOT pick up for this condition?

1. Distance protection using mho relays with zone-1 set to 80% of the line impedance
2. Directional overcurrent protection set to pick up at 1.25 times the maximum load current
3. Pilot relaying system with directional comparison scheme
4. Pilot relaying system with segregated phase comparison scheme

Distance protection using mho relays with zone – 1 set to 80% of line impedance will not provide protection.