Probably answered elsewhere, but there are so many PA threads, it's simpler to just make my own thread.

I have a number of PA pieces that are now unusable. I've seen it mentioned that they can be repaired at the PA station. However, whenever I try to open the Craft (E) option, it doesn't say anything about repair. All I get are options to mod the non-damaged pieces.

Is there a Perk required to do repairs? Like with Gun Nut and Armorer to use their associated benches effectively.

You should get a repair option when you mouse over a damaged piece. Post a pic of your interface in the power armor craft menu.

If the PA isn't in exactly the right spot at the station the option to repair won't show up.

The first couple of times I needed to repair I had to exit and enter the PA a few times to get it in the right spot.

If you actually click on the armor item that's broken you go into the interface to mod that item, which isn't what you want. Instead, highlight the item you want to repair in the list, then hit T on the PC. I believe that on the XB1 Controller my sister uses when playing, it's the Y button, which would correspond to the Triangle button on the PS4, but I don't use a controller myself when playing, so I can't say for sure. Just look at the control interface at the bottom when the item you want to repair is highlighted in the list of all the Power Armor pieces you have, and it will tell you what to hit to repair the item.