ABB SAM600-IO Protocol Manual page 38

Section 6
Data sets and control blocks
32
server to invoke a SendGOOSE service is a local application issue as defined in
IEC 61850-7-2. Each update may generate a message in order to minimize
throughput time.
Additional reliability is achieved by re-transmitting the same data (with gradually
increasing SqNum and retransmission time).
T0 retransmission in stable conditions (no event for a long time)
(T0) retransmission in stable conditions may be shortened by an event
T1 shortest retransmission time after the event
T2, T3 retransmission times until achieving the stable conditions time
T0
IEC09000152 V1 EN-US
Figure 11: Transmission time for events (IEC61850 part 8-1)
Each message in the retransmission sequence carries a timeAllowedToLive
parameter that informs the receiver of the maximum time to wait for the next re-
transmission. If a new message is not received within that time interval, the
receiver assumes that the association is lost. The specific intervals used by any
GOOSE publisher are a local issue. The timeAllowedtoLive parameter informs
subscribers of how long to wait. The detection time of lost GOOSE is 2*
timeAllowedToLive in the subscriber. This allows one lost GOOSE message and to
cope with possible transmission delays in the network.
The GOOSE message concept is used for all application functions where two or
more IEDs are involved. Typical example is the station-wide interlocking
procedure or breaker failure protection.
Figure 10 shows the GOOSE concept for three IEDs which interchange GOOSE
messages between each other.
To send GOOSE messages a GoCB must be defined and a data set is needed that
contains the data objects of single data attributes to be sent.
Time of transmission
(T0)
T1 T1 T2
event
Switchgear control unit SAM600-IO Version 2.2 IEC
1MRK 511 440-UEN A
T3 T0
IEC09000152-1-en.vsd
Communication protocol manual