ABB Relion 630 Series Communication Protocol Manual page 40

Section 6
Data sets and control blocks
34
The GOOSE service model of IEC 61850-7-2 provides the possibility for fast and
reliable system-wide distribution of input and output data values. This
implementation uses a specific scheme of retransmission to achieve the appropriate
level of reliability. When a GOOSE server generates a SendGOOSEMessage request,
the current data set values are encoded in a GOOSE message and transmitted on the
multicast association. The event that causes the 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 retransmitting the same data (with gradually
increasing SqNum and retransmission time).
Table 3: Retransmissions
Transmission time
T0
(T0)
T1
T2, T3
T0
IEC09000152 V1 EN
Figure 11: Transmission time for events
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. In 630 series, the detection time is 1.8*timeAllowedToLive to cope
with possible transmission delays.
Description
Retransmission in stable conditions (no event for a
long time)
Retransmission in stable conditions may be
shortened by an event
Shortest retransmission time after the event
Retransmission times until achieving the stable
conditions time
Time of transmission
(T0)
T1 T1 T2
event
1MRS756793 E
T3 T0
IEC09000152-1-en.vsd
Communication Protocol Manual
630 series