Automatic detection of disconnected cables 1

[visseh]

I am trying to find a way to automatically stop de current source in case there is an open circuit somewhere between de current source and the resistance R4.

R2 represents a simplified model of the resistance of the cable between I1 and R4.
My problem is that I couldn't find a way to detect the open circuit.
Also the current source generate a current with multiple harmonic from a few hertz to few hundred hertz that have the same amplitude. Wich makes it harder to detect a law current crossing R4.
Could you please help me to find a way to detect a cable disconnection that is reliable and fast?

 

[visseh]

Hi Mc5w,

Thank you very much for all this details.
This is going to be used for portable machinery. My system doesn't exceed 100A and 650 V.
As I could understand, this solution would not work if the system is not grounded. My supply has 1ph 1 Neutral and is not always grounded.