I don't know if you allow youtube links to be pasted on your message board, but if so, get a load of this one! It is an actual Jacob's ladder behind someone's house on a fallen line, probably going up one phase and a ground line. You can see and hear the arc as it climbs, extinguishes and restarts and climbs again, over and over. Finally it climbs a bit too high and hits another phase, there is a brighter arc and a much louder arc-sound and spark-shower before an upstream recloser does its thing. It then restarts a few seconds later. And if you don't allow these links, at least check it out yourself! I have never seen a super high-amperage ladder like this one.
I have been exploring youtube for utility disasters and have found lots! This is the neat thing about video cameras everywhere and youtube to show them! One was taken by Silverbrook Highschool students as a violent arcing fault destroys the substation behind the school. Another, taken from a highrise looking down on a large substation (looks like 230kV) There is a very large arc (like your 500kV video on this site) on what looks like one phase of an open disconnect. This looks to be a much brighter, hotter arc than the 500kV one. Another neat Jacob's ladder video is what looks to be a tall, pole mounted set of disconnects, on a 45kV line. The disconnects are open, however the bottom phase has a persistant arc between the open switch elements. It starts, is pushed out by the wind, and becomes long, maybe about ten to fifteen feet long, then extinguishes and starts again, over and over. Finally you see it rise straight up to the phase above it. There is a violent, blinding blue vertical arc as it comes in contact with the above phase, a super-loud, jagged arc sound and a shower of sparks. An upstream recloser extinguishes the arc and remains open, finishing the video. Yet another horrfying video is what looks to be a 440 volt cabinet. Two workers are working on something within the open doors of the cabinet, when suddenly, there is a violent arc which throws both the men back, and one of them is on fire!!! Happily the guy on fire is able to rip off the burning clothes and he appears to be shaken, but alright.
One of my favorites is a TV camera crew interviewing a policeman in an ice-covered neighborhood. While the cop is talking and just behind him, you can see an ice-covered treelimb slowly swing down, and suddenly there is an incredibly violent, bright blue-green, loud phase-to phase arc and he jumps like he was shot!! It is followed by three more faults down the line in quick succession. NEAT stuff!
I also found a video that looks to be another angle of your 230kV disconnects being open. The day is bright and sunny in this video. The switches are slowly opened until the three swing rods fall open and there are the three long arcs, which extend until one of them hits a neighboring phase and it pops out. There must have been a few cameras recording this event? I have found many other videos on youtube also, with other utility faults and explosions. You should post them on your site!