SVCB attribute
Description
NoAsdu
Number of ASDUs, which are concatenated into
one APDU.
IncludeRefreshTime
If selected SV buffer contains the attribute
“RefrTm”.
IncludeSampleRate
If selected SV buffer contains the attribute
“SmpRate”.
Modify only MAC address, VLAN ID and sampled value ID to keep
the 9-2 LE compliancy. Leave the others as default.
6.4.3
Angle and amplitude corrections
The TxTR instrument transformer amplitude correction factors also affect the scaling
in SMV frames. Thus, it is sufficient to configure these correction factors in the sender
only. The angle correction factors on the other hand affect only the fundamental
frequency phasor and they need to be set in both the SMV sender and the receiver
analog input configuration.
6.4.4
SMV delay
The
SMV Max Delay
parameter, found via menu path
Configuration/System
, defines
how long the receiver waits for the SMV frames before activating the TxTR
ALARM
output. This setting also delays the local measurements of the receiver to keep them
correctly time aligned. The
SMV Max Delay
values include sampling, processing and
network delay.
TxTR
ALARM
activates when two or more consecutive SMV frames are lost or late. A
single loss of frame is corrected with a zero-order hold scheme, the affect on
protection is considered negligible in this case and it does not activate the TxTR
WARNING
or ALARM outputs.
Table 9:
Topology-dependent SMV max delay setting
Number of
hops in
network
Internal
application
delay (µs)
(50Hz)
Internal
switch
delay (µs)
Store and
forward
latency (µs)
Queue
latency
(µs)
1)
Additional
tolerance
(µs)
2)
Theoretical
max delay
(µs)
Recommen
ded max
delay
setting (µs)
2
1746
20
24
240
80
2112
3150
5
1746
50
60
600
200
2656
3150
10
1746
100
120
1200
250
3416
3150
15
1746
150
180
1800
300
4176
3150
Table continues on next page
1MRS757809 C
Section 6
Process bus and IEEE 1588 time synchronization
REC615 and RER615
73
Engineering Guide
