Power supply status is 'Dummy' in 'cpstat' command output on 5100/5200/5400 Security appliance.
Example:
[Expert@Gateway:0]# cpstat os -f power_supply
Power Supply
--------------
'Index'Status'
--------------
' 1'Dummy '
' 2'Dummy '
--------------
Cause
As there is only one power supply in these appliances the value in this output should not be monitored as it will not work to query it when the appliance is down.