First, my default "new person interested in the challenge" advice. It is based only on my own observations on what problems applicants seem to run into:
http://www.randi.org/research/index.html
1. Read and understand the challenge rules linked from that page before doing anything. This is actually the only step JREF requires before you apply (though note there are many steps to the application process after that). I note though that it may save you time, frustration, and resources if you look at my other suggestions listed below before applying.
2. Read the FAQs linked from the page I listed above. It will give you a better understanding of the entire process. If some part of the process is still unclear, people here may be able to help clarify things.
3. Attempt to form a simple test protocol for yourself to test whether you can consistently reproduce results. People here can be of assistance with that.
4. Locate people willing to give a few moments of their time that you feel can objectively judge if you are able to demonstrate your claim. Some people are uncomfortable revealing their belief in the paranormal out of fear of the reaction. Assuming you have completed suggestion 3, a good approach is probably to simply say that you've been experimenting with something and have surprising results. Then ask if they'd be willing to examine it with you to determine if they see what you see.
5. Read some of the challenge applications linked from the above page. That link isn't working right now since the server change, but will probably be fixed by the time you get to this step. Otherwise, folks here can help you find it pretty quick. Try looking at what problems other applicants have had to anticipate any you may run into yourself.
6. Create a brief statement of what ability it is you are going to demonstrate, and design a robust test protocol for you to demonstrate for the challenge. Such a protocol needs to be double-blind. You need not describe how you think your ability works, just the statement of what it is and how you will demonstrate it. Also, consider how less-honest persons might attempt to fake a display of this power and look for controls that will prove you are not using such means. Again, people here can help with this step if you ask, including understanding what it means for a test to be double-blind.
7. I would suggest you perform one or more of these double-blind tests so that you can be confident in their success when it comes time to take the preliminary test. If you were to fail the preliminary test due to unforeseen issues, it would prevent you from retesting for an entire year at least.
8. After all of the previous steps are complete, it is time to officially apply for the challenge. After you have applied, Kramer will contact you to continue the application process.
Note that failure at any given step should make you pause to consider why. It indicates a problem you may encounter later in the application process that would be easier to fix now than after you have begun the process.
Finally, JREF prefers to simplify protocols. Would you be able to simply identify if a visible, indoor powerline carried an electric current or not? If so, then a good suggestion for a protocol is to identify whether or not such a line is 'on' or 'off' for a number of trials, say 10, and that you'll be accurate for 90%.
If your power doesn't identify current, but instead the metal (or whatever) in the line itself, then perhaps haveing a number of long boxes would do. One of the boxes would contain a power line, and your job would then be to identify which one.
Either of these would make things easier, as they could be conducted indoors and wouldn't require digging for confirmation.