Distance between electric fence and other ground rods

Hello permies! I am about to run a small electric fence.(.1 joules for maybe 150 feet of two wire fence) It will go around a couple of garden beds to stop the raccoons from excavating, as their ongoing search for the biggest earthworm has caused us much strife!

One problem with my plan is that the area is under power lines right behind my house. I hear i need three ground rods 10 feet apart from each other and 50 feet from utility poles and my house electrical system. This wouldnt be possible without going clear to the other end of the property, maybe 100 feet from the fence, which seems like it could cause other problems. Does anyone know how much of a problem it would be to have these ground rods only 20 or 30 feet from these other systems? I have read other sources simply say "far enough" rather than give specific distances. Any advice on this matter would be greatly appreciated.

I'd work with what you have. I have four electric fence energizers on my farm (cows, laying chickens, garden, and brooding chickens). Each one has it's own grounding rod(s) and they're all within 50 feet of my home and one is about 25 feet from a utility pole that has it's own ground rod. I have not experienced any problems with any of my fences.

Three ground rods sounds to me like it may be overkill for 0.1 joule output, unless perhaps they are short ground rods. I have a 1 joule energizer connected to one 8-foot ground rod, and it works great.

The only people who need 3 ground rods are ranchers with a lot more fence than you're working with. I also have a 0.1 joule charger on 170 feet of chicken run with 3 hot strands and it works just fine with 1 ground rod. And it's only about 6 feet from the charger.

I agree with James and Matt. Unless you're running miles of electric fence or your soil and subsoil are very dry, one good ground rod is enough.

Naturally you will test the fence directly to make sure it's energized. That's usually a "hold my beer" moment.

Please be careful - your grounding issues may be problematic depending on the voltage of the power line overhead.
I know that all active power lines will generate a magnetic field around them.  And that magnetic field will induce current (think electromagnet) in a long piece of conductive material if it is parallel with the power line itself.
I recall a conversation with an employee of the electric company - he took a 20 foot piece of conduit and while walking it to the construction area, followed the path that turned from perpendicular to parallel with the overhead 345kv lines.  When he turned in line with the overhead wires, he took one heck of a jolt from the induced current.

Agreed, high voltage long-distance transmission lines create an induction hazard. This is well known in industry.

If it's a local 15kV distribution line, it shouldn't cause problems.