Pilot wire impedance

[Cerkit]

Hi,

I am calculating the voltage and current flowing in pilot wires in a voltage balance protection system. The literature I am reading says that for an external fault the impedance seen is half the open circuit impedance of the pilots. Does this mean that no current flows for an external fault?

 

[7anoter4]

See:

https://www.philadelphia.edu.jo/academics/mlazim/uploads/Power System protection - Part 07.pdf