Working space from power lines varies based on line voltage.
But since they can't expect you to know if it's a 5Kv or 12Kv they make it a blanket
10 feet rule.
We did one similar last year. The local utility was easy to work with, only cost about $1200
To have them de-energize the lines for one day.
The worst part was just waiting for them to respond and to get a look at the job...
If I recall it took about a month of waiting.
Let us know how this goes for ya.