have you tried looking at this thread?
https://forum.synology.com/enu/viewtopic.php?f=83&t=13722&sid=8949a425b356c8792b4431be6538c8b4
I have been trying to track down why my machine wakes at exactly 30 minutes each time as well. Atleast you make it 1 hour! try this command
enable ssh and goto the prompt and try this out.
"syno_hibernate_debug_tool --enable 1", wait for hibernation time to pass, enter the CLI-command "syno_hibernate_debug_tool --disable"
have a look at /var/log/messages