SMP Gateway User Manual • 181
19 Redundancy
The SMP Gateway is a critical component in a substation automation system. Hence, there are
circumstances in which losing an SMP Gateway can severely impact substation operations. With
the redundancy option, you can group 2 SMP Gateways together in a redundant configuration, to
ensure continued operation of the substation automation system in the event of a failure. If one
gateway fails, the other one takes over. There are different types of redundancies, as IEDs,
SMP Gateways and networks can be redundant in many combinations.
Redundant SMP Gateways are addressed by a SCADA center as if they were a single
SMP Gateway with a single IP address. In the event that one SMP Gateway fails, the second
SMP Gateway immediately becomes active and takes ownership of the logical IP address.
Failover from the active SMP Gateway to the standby SMP Gateway typically takes less than 5
seconds. Network connections from the control center are temporarily lost when the active
gateway goes offline. The control center simply needs to reconnect to the same group IP address
in order to re-establish a new connection and restore system operation.
An additional benefit is that you can update SMP Gateway settings with minimum down time, by
updating the settings of the standby SMP Gateway, which will take over the other SMP Gateway
during its own update.
Note: The redundancy function is not available on SMP 4.
19.1 Redundant Group Operation
In an SMP Gateway redundancy group, one SMP Gateway plays an active role while the other
stands by. The active gateway polls the substation devices and responds to requests from control
centers. The standby gateway initializes itself, places its serial links in a high-impedance state and
waits to become active.
The active SMP Gateway uses a special protocol to send regular heartbeat messages to the standby
SMP Gateway. If the standby SMP Gateway fails to receive these messages, it automatically
assumes that it should become active. 2 distinct communications channels are used for the
heartbeat messages, to minimize the chances of both SMP Gateways becoming active due to a
single faulty connection. These channels can be LAN connections, dedicated serial connections, or
a mixture of both.
The 2 SMP Gateways in a group must have identical configurations and be physically connected
to the same substation devices. The active SIOM, which comes as an option with the SMP 4-20
To Next Page
Loading...
