Actually just studied a case similar to this in class.
In a nutshell, if it is for the public good they "could" get the .gov involved and pull imminent domain, but also if it is way out of easement with no questions asked then you could put up a huge stink about it and make it not happen. It's hard to say without knowing all the details and seeing the setup. I'd call someone aside from the AEP workers there (supervisor, project manager, etc.) and see where they got their info and "permission" to dig from.
For example a few years back near Delaware I believe, A company was trying to push city water piping further out Into the country. The guys going to get permission missed a house, and the homeowner let them dig on their land and it became an expensive day for the company. Not trying to encourage a lawsuit, but you do have rights. An attorney IMO would be an "on down the road" thing. Check with AEP and see where they stand with all the legal stuff on their end.
You'd be amazed how much stuff is skipped over since they are well aware they are able to get away with It.