ABB RELION 650 SERIES, Technical Manual

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the IED connects the Access Points via a boundary clock. If PTP is “On” on
redundant Access Points, the IED acts as a “Transparent Clock”.
In a network there may be variety of possible masters that are connected together
where the masters by selection, using the priority of PTP (also called the Best
Master Algorithm, or BMC) to determine which of them that is the best master.
Priority order according to PTP
1. Priority 1
setting for each device, default 128, set to a lower number if this device shall
be the Grand Master.
2. GM class
given from the type of device, for instance “6” for a GPS clock, “7” for a GPS
clock that has lost synch during a hold-over time, “187” for a clock that can
also be a slave.
3. GM Accuracy
how accurate the time is as a enumerated value
4. Offset Scaled Variance
calculated value that shows the oscillator quality
5. Priority 2
setting for each device, default 128, set to a lower number if this device is
preferred to be the Grand Master, if Priority 1, GM class, GM accuracy and
OffsetScaledVariance are the same for all devices.
6. Identity, that is the MAC-adress of the port.
MAC address of the access points can be seen in LHMI under
the settings of each access point.
To setup a PTP network with no obvious Grand Master, you simply connect the
IEDs to one network and configure PTP to be “on” on all IEDs. On one IED, the
one from which you want to set the time in the station, you set the Priority2 to 127,
instead of default 128. Now, this IED has higher priority than the rest of the IEDs
and will thereby act as “Grand Master”.
PTP is not set from TIMESYNCGEN:1General , as SNTP is. Instead PTP is set
via a parameter of each Access Point.
19.1.4 Technical data
IP9658-1 v1
M12331-1 v8
Table 600: Time synchronization, time tagging
Function Value
Time tagging resolution, events and sampled measurement values 1 ms
Time tagging error with synchronization once/min (minute pulse
synchronization), events and sampled measurement values
± 1.0 ms typically
Time tagging error with SNTP synchronization, sampled
measurement values
± 1.0 ms typically
1MRK 506 382-UEN A
Section 19
Basic IED functions
Line distance protection REL650 2.2 IEC 809
Technical manual