At the Raspberry Pi birthday bash this weekend, I had a Pi3 running an OpenOffice Impress presentation continuously in a loop all day on the bar. I had a problem with the screen blanking after several minutes. I fixed this using these commands in a terminal:
$ xset s noblank $ xset s off $ xset -dpms
(I discovered this by reading this)
If you want a more permanent solution then this may help you: (link)