It would appear marketing is doing its job, you've got plenty of feet through the door.

What you don't have is a price that makes at least one buyer overlook the power lines (assuming there are no other significant negatives that can be addressed).
You can't change the power lines, so unless you've got another characteristic of the home that can be changed to overcome the objection, it's either tweak price or be patient until the one buyer comes along that doesn't object.

"There is no defect that price cannot cure."

When it comes to wires, I would advise getting the latest report from the power company as part of the marketing package.  And price does come into play also.  A

It's not the power lines, it's your price.

I'm selling in the same situation with multiple offers. Lower your price.

You could call the power company and see if they will give you a report that measures electric/magnetic fields. I think many will do that for free. Then, assuming it indicates safe levels, attach document to listing.

And of course lower the price.

Liz and Bill Spear have a great answer for you.  Have you gotten feedback from the agents?  A sampling of the 75 should tell you if there is anything else that needs work, in case the power lines are not the only (or main) issue.

It's all about the price, and the perceived value given the wires. You've had plenty of traffic and the message is pretty clear.

As others have said, a price adjustment tends to cure the issue with power lines. Bill of Liz and Bill Spear nails this. 

All 75 potential buyers objected to power lines? Are power lines disclosed in your listing on MLS? I suspect the price point may be an issue.

Disclose the power lines in your MLS listing, both in the photos and narrative as well as seller's disclosure. If you've had that many showings with no offers, it makes me think that you have not disclosed that and people are scheduling showings but losing interest when they see that.

Assuming there are no other defects, you probably need a price reduction as well.

Power lines are a potential health issue primarily for children. At the right price, different age groups might bite.

       A neighborhood in northeast Tallahassee has cross-country powerlines running through the middle of it, and a cell phone tower and a water tank tower right in the middle of that subdivision.  Those houses sell at full price in a matter of days. 

     As others said, reconsider the asking price.  Bring in an appraiser if necessary.

No power lines for that price.

Reduce the price and call your investors.

Look for a Smoker ?

75 showings, no bites, adjust the price!

Are you planning to show this string of comments to your seller?

It's all about price.  Your marketing efforts have brought 75 potential buyers through the property, but they have voted with their feet and have not brought you an offer (apprently not even a lowball one).

You need to either a) remove the power lines, or b) reduce the price to a point where the price is attractive enough that the nearby power lines become less important.

Power line...

Condition?

How long has it been on the market?  I would wait unless this is over DOM for that area.  Power lines were an issue and still are for some folks but not all share that concern.  

Power line study

In conclusion, there are no known health risks that have been conclusively demonstrated to be caused by living near high-voltage power lines. But science is unable to prove a negative, including whether low-level EMFs are completely risk free. Most scientists believe that exposure to the low-level EMFs near power lines is safe, but some scientists continue research to look for possible health risks associated with these fields. If there are any risks such as cancer associated with living near power lines, then it is clear that those risks are small.

Find an electrician for a buyer. Juice is their life. No big deal. Anything will sell if fairly priced. Anything not matter what negatives. Attractive pricing hides a multitudes of sins.

You can't get rid of power lines... but you can adjust your price. At the right price someone won't care.

Alert and disclose the power lines. That should eliminate those 75 who objected.

Stay in curiosity.  What is the objection? Are they concerned about the insurance going up?  Are they concerned about their property value going down?  Are they thinking the home is prone to a fire?  You can pullout some statistics to ease their fears.

A little patience is necessary or a price reduction might get more interest.

Price cures all. Meaning that once the price hits a point, it will be worth it to someone to over look the powerlines to buy this home. 

Price overcomes all objections. 

I have had a couple of listings with the green monsters , everything will sell at a certain price point.

Those powerlines do seem to lower the value of properties, you likely need to lower your price until you find the buyer that is willing to overlook those hazards.

If it is a really big problem on the street, sometimes the nearby owners will get together and pay for power lines to be put underground.  That's the talk in one of mine.  If it's only yours, well, that would be a big burden. And, yes, that will make for a drop in the comps if the others don't have that.