You need to configure
logind.conf - this would not disable the suspend, it would just to tell it to ignore the lid switch.
This will also override any of your user's power settings, and will work whether you are logged in or not.
You can configure it via running:
sudo nano /etc/systemd/logind.conf
it should like something like this:
HandleLidSwitch= line to:
Here is a qoute from a manual page - note it can take other values like
HandlePowerKey=, HandleSuspendKey=, HandleHibernateKey=,
Controls whether logind shall handle the system power and sleep keys and the lid switch to trigger actions such as system power-off or
suspend. Can be one of "ignore", "poweroff", "reboot", "halt",
"kexec", "suspend", "hibernate", "hybrid-sleep" and "lock". If
"ignore", logind will never handle these keys. If "lock", all running
sessions will be screen-locked; otherwise, the specified action will
be taken in the respective event. Only input devices with the
"power-switch" udev tag will be watched for key/lid switch events.
HandlePowerKey= defaults to "poweroff".
HandleLidSwitch= defaults to "suspend".
HandleHibernateKey= defaults to
The manual page is here