The positive, negative and zero sequence impedances of a three phase generator are

Q. The positive, negative and zero sequence impedances of a three phase generator are 𝑍₁, 𝑍₂ and 𝑍₀ respectively. For a line-to-line fault with fault impedance 𝑍_𝑓, the fault current is 𝐼_𝑓1 = 𝑘𝐼_𝑓, where 𝐼_𝑓 is the fault current with zero fault impedance. The relation between 𝑍_𝑓 and 𝑘 is