Op Amp Supply Voltages

Hello,

I have an instrumentation amplifier that is powered by a +/-15V...since this is a 30V difference is it possible to put one rail at +30V and the other rail at ground?

You may want to review this:https://www.electro-tech-online.com/threads/basic-opamp-circuits.35258/

In theory, yes, unless there is anything strange about it, like one pin internally connected to ground. I would firstly look at the absolute maximum ratings of each pin and see if connecting it to +30V/0V will violate any of these ratings

You need to follow the input common-mode range and output swing limits of the amp. Chances are, with a single supply, your input and output signals will now have to ride on a DC pedestal. The usual reason for using plus and minus supples is so that you can amplify plus and minus signals (such as AC) that are centered at ground.