Even without electric cable, wet tethers can conduct electricity from lightning strikes.
How to reliably protect wind turbines against lightning strikes
To avoid these damages and costs, reliable lightning protection is needed. Lightning protection systems are used to divert incoming electrical current into the ground, protecting rotor blades or nacelles from damage.
The complete lightning protection system of a wind turbine consists of the external lightning protection system and the surge protection system. The external lightning protection is realized by receptors as well as arresters, which conduct the lightning current into the ground via defined paths.
I used DC brushed motors as generators, because the installation was easier, but without being able to test with the kite in crosswind flight, because the wires were torn off too easily. And I measured the power (in W) by using a car, a multi-meter, and the DC motor with the propeller:
However brushless motors and AC are far more efficient (less weight, higher voltage) but required some additional material and are more complex for a first experiment.
Electrical wires can be found at any DIY store.