Here's a handy PowerShell function I used to determine if I'm currently running as an Administrator in PowerShell

# Determine if I am running as an Admin
function AmIAdmin()
{
 $ident = [Security.Principal.WindowsIdentity]::GetCurrent()
 
 foreach ( $groupIdent in $ident.Groups )
 {
  if ( $groupIdent.IsValidTargetType([Security.Principal.SecurityIdentifier]) )
  {
   $groupSid = $groupIdent.Translate([Security.Principal.SecurityIdentifier])
   if ( $groupSid.IsWellKnown("AccountAdministratorSid") -or $groupSid.IsWellKnown("BuiltinAdministratorsSid"))
   {
    return $true;
   }
  }
 }
 
 return $false;
}