powercfg.
To change this behavior via the GUI method, take the following steps:
You can set the value to "Never", if you never wish to have the monitor turned off.
You can also change the value from a command line interface (CLI),
i.e., a command prompt, using the powercfg command. E.g., if
I wanted to change the setting so the screen never gets turned off by Windows,
I could use the command below:
C:\>powercfg -change -monitor-timeout-ac 0 C:\>
Setting monitor-timeout-ac to 0 sets the value to "Never".
The value is in minutes, so if I wanted to change the setting to 1 hour, I
could use powercfg -change -monitor-timeout-ac 60. A five hour
timeout period can be set by using a value of 300. You can even
use a value that is not one of those listed via the
GUI method described above. E.g., the time options shown through the GUI
for the number of hours to which I can set the value are shown below:
The options for hours go from one hour to five hours in one hour increments with the next option being "Never". Yet I can set the timeout period to six hours from the command line interface.
C:\>powercfg -change -monitor-timeout-ac 360 C:\>
If I then check the setting using the GUI method, I will see the period before the monitor goes to sleep is 6 hours.
Note: if you are changing the monitor sleep period from a command prompt using the powercfg utility, you will need to close the Power & sleep window, if it is open, and reopen it to see the change you've made from the command line.
References: