Our small stadium is feed from a 3 phase 208 volt Y system. During our last football game the TV crew had a voltage drop down to 101 from 120. We have a meter logging voltage at the transformer and it show around 120 and 119 RMS, not issues shown there. The transformer feeds a MPD which then feeds a subpanel and from the subpanel it feeds another subpanel. The TV crew was coming off an outlet from the furthest subpanel. The problem does get worse the further you go out from the MDP. Example as follows (at the 2nd subpanel I may read 114, and from the outlet 110 and at the TV truck 103. I check the neutral connections at the second subpanel and it looks fine. I check the neutral connection at the first subpanel and it looks fine. I check the neutral connections at the MDP and it looks fine from what I can see, no sign of over heating. But, over half of the neutrals are connected to a split-bolt, from the split bolt one wire goes to a small bar that was added at some point, on that bar is where the main neutral lands. I am thinking this problem is a neutral problem and it resides in the split-bolts. Any help would be greatly appriciated. Thank you