Summary:  Use the Get-NetAdapter function to show physical network adapters that are connected.

Hey, Scripting Guy! Question How can I use Windows PowerShell to see which physical network adapters on my Windows 8.1 computer
          are up and connected?

Hey, Scripting Guy! Answer Use the –physical parameter with the Get-NetAdapter function, and filter for a status of Up:

Get-NetAdapter -physical | where status -eq 'up'