A question about this distance relay model MATLAB/Sumlink

Hello, Guys.

So, I've been looking into modeling and understanding the distance protection.
I checked many articals and stuff.
AND lately I decided to apply and test this distance relay model.
I got the most of the parts, excpet the part of SLG model
Capture.PNG
I couldn't understand the R(K) and the I(K) over there.
 
Am fumbling between the images trying to understand the circuitry. Could you share a clearer image so that I could try and see how well we can help out?
Thank you!
 
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