source: http://www.routereflector.com/2016/07/syncing-microsoft-nps-servers/

Use the following powershell script to sync microsoft NPS (radius) servers.

Export-NpsConfiguration -Path C:\TEMP\LocalNPSExportedConfig.xml

$CurrentServerNPS = $env:computername

$NPServers = Get-ADGroupMember "RAS and IAS Servers"
$NPServers | ForEach-Object {

	$NPServerName = $_.Name

	if ($NPServerName -ne $CurrentServerNPS) {
		$NPServerName
		copy-item Export-NpsConfiguration -Path  \\$NPServerName\C$\TEMP\LocalNPSExportedConfig.xml
		Invoke-Command -ComputerName $NPServerName -ScriptBlock {Export-NPSConfiguration -Path C:\TEMP\BackupNPSExportedConfig.xml
		Invoke-Command -ComputerName $NPServerName -ScriptBlock {Import-NPSConfiguration -Path C:\TEMP\LocalNPSExportedConfig.xml
	}
}