I asked around and Bill Lemieux knew ;-))
Bill writes....
Siberian Research Institute of Power Engineering.
Looks awfully defunct now, judging from those pictures. Not
surprising, given the state of the economy of there. I'll bet that
whole site is contaminated with PCB's.
I expect this is probably the "huge spark" picture you saw:
http://205.243.100.155/frames/longarc.htm#Longspark
However, it is not clear that the impulse generator (I only assume
that's what it is) in the new pictures is the same one as in the old
pictures - the scale would appear to be different, and the number of
field equalization / anti-corona rings is definitely different.