I was interested in this question, live-line work can be done at 220-380 volts. At 10,000 volts, work is only done on a switched-off line. But I read that in other countries people also connect to high-voltage lines to steal electricity. Most likely, in this case, there were no transformers or other connection methods nearby.
11kv is meduim voltage not high, and as I said, it is very common to perform live-line work on medium voltage lines, not sure why is that not done that in Russia, have you confirmed that?