How to implement wire alarm?

Question

Arduino

Good hour.
I encountered such a problem, there are several wires from 3 to 8 km long, the diameter of the wire is also different from 8 to 15 cm.
How can I organize an alarm for a wire break, at the time of the alarm, a "deadly" electric current should not pass through the wire. Also, when it breaks, the siren at the guard should turn on and various notifications will fly away (to the system for monitoring incidents at the enterprise, SMS, and others).
I decided to implement the entire project based on arduino, almost everything has already been implemented except for the most important wire integrity check.
Tell me how to implement a wire continuity check based on arduino?

Answer 1

Here the question is not about signaling, but about the protection and defense of the cable. Well, the alarm goes off. While the guards run 5 km - 20 meters of cable spi#$#%&. Or don't sleep#$#%& but the cable has already been cut, they got scared and ran away.
The real option is not to remove the voltage from the cables. Make only a "visible break" from the side of the excavator for the duration of the repair.
And notify EVERYONE about this - the voltage from the cable is NEVER removed !!!
It will be removed for a few minutes - at the beginning of the repair and at the end.

Answer 2

The break control is quite simple to implement: just connect both ends of it to the Arduino in a similar way to connecting a button. It can be a little more complicated, and using an analog input, monitor the line resistance - in this case, you can see not only a break, but also a short circuit. - approximately how the control of fire alarm loops is implemented. The question remains: the cable is a power cable, and you are going to hang an arduino on it .... one "mistake" when turning on the circuit, and only smoke will remain from such an alarm. There are relays for monitoring leakage current and monitoring insulation (sort of like the Rules obliget their installation on a similar technique) - I think this should be enough. Although, it seems to me, on the wrong side, you are approaching the problem of theft - if "evil people" want to, they will bypass any alarm and voltage on the cable (I know a case when they stole 3.5 km of an operating overhead (!) Line with a voltage of 10 kV)

Answer 3

And what kind of wires and what is transmitted through them? Is it a multi-twin or mono-core? By phrase

"lethal" electric current

you can understand that this is something powerful, and such cables are heavily armored, their routes must be fenced off and registered in giprozem, and it is very difficult to break a cable with a diameter of 8-15 cm even with an excavator.

Answer 4

When an alternating current flows through the wire, then in the coil wound on this wire, as on a core, electrical oscillations occur.