Please Explain your answer with steps Thank you ZAB j60 Ohm

Please Explain your answer with steps. Thank you!

Z_AB = j60 Ohms, Z_BC = j40 Ohms, Z_CD = j50 Ohms, Z_BE = j30 Olms, Z_EF = j40 Ohms. Three MHO relays at 1 are needed to protect sections AB, BC, CD, BE, and EF of a 230 kV power system. Determine the settings in ohms of the relays to obtain the following coverage with infeed (effect of I_2) included: Zone 1: 90% of AB, Zone 2: AB + 30% of BC, and Zone 3: AB + BC + 20% of CD. For all faults on section BC and CD I_1/I_2 = 1.6 and for all faults on section BE and EF I_1/I_3 = 1.8. Find percentage of lines BE and EF protected by zone 2 and zone 3 settings of Relay 1. How much of BC and CD will be protected by zone 2 and zone 3 relays at 1 with breaker 2 open? The maximum load on line AB is 1400 MVA (three-phase) at a power factor of 0.9 lagging. The diameter of the mho circle has an angle of 85 degree. Will the zone 3 relay operate under maximum load? The operating point on the mho circle characteristics can be determined by Z_P = Z_R cos(phi_R - phi_P) where Z_P is the impedance from the origin to any point on the circle at an angle phi_P, and Z_R is the diameter of the relay characteristics.

Solution

0.85%