So when i was setup a Raspberry Pi on a TV to show a webpage i find that Raspbian haved some kind of timeout that was making the TV to go dark after 10 minutes.
After a while searching i find that there is differents way to fix this in differnt versions but i run Raspbian Buster in the beginning of february 2020 and i tested a lot of things before i got it to not be black screen after 10 minutes.
To fix this you need to edit the file named /etc/xdg/lxsession/LXDE-pi/autostart with your chose of text editor and i change it to look like:
@lxpanel --profile LXDE-pi@pcmanfm --desktop --profile LXDE-pi@xset s noblank@xset -dpms s off
The two first lines is default lines to get the desktop to start but the last two is to disable the black screen that shows up after 10 minutes.
In the default file there is a line about xscreensaver that i removed.
Reboot the Raspberry Pi and wait and now i should not be black screen anymore.