Looking at the pics there are a multitude of issues. Can't imagine what the poles look like. Arrestors can be an issue, slack glass bells also. The pins through the clevis can deteriorate form movement and can arc. We had some three cornered paper clip lookin things to put in between to bond the two. The real solution was a tight DE or pin DE's
They fixed a whole host of things, leaky insulators, loose tiewires, loose hardware on three poles. The noise is down considerably now. Still some intermittent here & there that may or may not be powerline-related.
More than six months to fix, OUCH!