The easy, not so safe fix is to have your lights and your ventilation on the same power strip or relay. That way if the ventilation goes off for some reason, the lights probably will too. The better way to do it is to have your lights on a thermostat mounted on the wall of your grow area. You may have to do some searching to find thermostats rated for 1000 watts, but I know they are out there. Set the thermostat at something like 100 degrees, or whatever yoiu think your plants can take. If the ventilation goes off, the temps will soon soar and the thermostat will turn the lights off. And of course, if the power goes out your lights will turn off anyway.

As far as the plants, I use a spray setup where most of the roots are exposed to nothing but air untill the sprayers come on. If I knew I would have no issues with power outages, I would have all of the roots exposed to air. But in this non-perfect world, I keep about 15% of my roots in nutrients at all times. (Kind of like DWC.) So when the power goes out for 18 hours my plants won't die of thirst.

Nothing real technical. Just keep in mind there will be power outages at every stage of designing and building your setup, and plan accordingly.