You’re attending a de-icing test with variable resistance conductor for distribution lines. Here you can see a single loop of that conductor which has an Ampacity of 200 amps. The current in both sides of the conductors is 120 amps. The conductor is constructed of 1/8 `` diameter aluminum strands twisted around the steel core in the center, like the one shown in the video. The conductor’s resistance can be electronically switched from the very low value, that is when the conductor is in normal operation, to resistance which can be 10, 25, or even 50 times greater, and this is used for rapid de-icing. The switching is done by control electronics placed at both sides of the conductor section. Such a section can be as short as one span between two conducting poles, or towers, and as long as 2 kilometers. In case of any failure or over-heating, the conductor automatically returns to normal operation’s mode. This test is being conducted at -10 C with dense wet snow frozen in and around the conductor.
The conductor further away from us, will be switched in the rapid de-icing mode,
while the conductor closer to us will remain in the normal operation mode.
Begin test. Turn on the power. Both sides are in normal operation mode. Let’s turn on the rapid de-icing mode for the further away side. (2:05)
End of test (3:20) (de-icing time is from 2:05 to 3:20)
As you can see, the conductor in rapid de-icing mode is free of ice while the one further away from us, which is the one in normal mode did not heat, and therefore, still has the ice attached to it.