That really depends on how you distribute software to and then run or schedule it on those 100+ PC's from your central management server(s).
Moreover, a .pst-file can't be copied when it's open, which complicates any automatic solution.
How do you do the backup of other files on those PC's?
Finally: note that backup isn't moving. It's copying. Any interruption, such as power loss or the user shutting down the PC won't damage the source.
Want to backup email archives on a LAN location for 100+ users. How best to tackle this situation using a Microsoft function. Is there any danger when moving the pst files incase of power loss?