Strange.
Which CPU do you have, when did you get your Surface Pro 2, and can you do the following:
-> Open the command prompt as Admin (Win+X, and select: Command Prompt (Admin))
-> type: cd c:\, and hit the Enter key
-> then type: powercfg -energy, then hit the Enter key
This will run a diagnosis. It will write a report called energy-report.html in your C:\ drive, when it will be done.
When done, open energy-report.html.
Do you see any errors listed?
Does the problem still happens when you remove the keyboard and restart the system?