IEEE 1588 v2 parameters and status information - Arc protection - Auto synchronization - Bay control and measurement - Merging unit - Transformer protection - 2 winding - Feeder protection - Voltage regulation - Capacitor bank protection - Petersen Coil control - Grid automation - Busbar differential protection (high impedance) - Back-up protection - Motor protection - Busbar protection (voltage and frequency) - Transformer protection - 3 winding - Interconnection protection - Generator protection - Power management/Load shedding - IEC 61850 Engineering Guide - REX640 Protection and control - Relion Protection and Control - PCL6 - IEC

Time

The time parameters are found via menu path Configuration > Time.

Table 1. Time parameters
Parameter	Value	Range
Synch source	IEEE 1588
PTP Domain ID	0	0...255
PTP priority 1 ¹	128	0...255
PTP priority 2 ¹	128	0...255
PTP Profile	IEEE C37.238-2011	1 = IEEE C37.238-2011 2 = IEC 61850-9-3
PTP Slave-only	0=False	0=False 1=True
Time master mode	1=Master with finite holdover	1=Master with finite holdover 2=Master with infinite holdover
Clear clock list	False	False True

In IEEE 1588 v2, the PTP domain is a logical grouping of clocks that synchronize to each other using the protocol but that are not necessarily synchronized to clocks in another domain.

PTP profile is used to select the profile which affects PTP announce frame format. Possible selection are "IEEE C37.238-2011" which is often referred as old Power profile and "IEC 61850-9-3" which is a profile for power utility automation.

PTP priority 1 and PTP priority 2 are used in the execution of the best master clock algorithm in which lower values take precedence. Priority 1 is the first one used to decide the clock master.

Time master mode, grandmaster clock holdover mode, either finite or infinite.

PTP Slave-only when enabled, the relay cannot become a clock master.

Clear clock list is used to clear the stored master clock list. For more information, see time synchronization in the technical manual.

Best master clock algorithm

The best master clock algorithm compares data describing two clocks to determine which data describes the better clock. This algorithm is used to determine which of the described clocks in several announce messages received by the local clock port is the best clock. It is also used to determine whether a newly discovered clock is better than the local clock.

The comparison algorithm is based on pair-wise comparisons of attributes with the following precedence.

Priority 1
Clock class
Clock accuracy
Clock stability
Priority 2
Clock identity: A tie-breaker based on unique identifiers

The TxTR ALARM output activates in the SMV receiver if transfer is made to a IEEE 1588 v2 master that has 8 ms or more offset compared to the previous master. The ALARM output stays on for a period of 11...33 s.

Time synchronization monitoring values

The time synchronization monitoring values are found via menu path Monitoring > IED status > Time synchronization.

Table 2. Time synchronization monitoring values
Description	Value
Synch source	IEEE 1588 master
Synch source	IEEE 1588 slave
Synch status	Up
Synch status	Down
Synch accuracy	0...26 bits

Sync accuracy indicates the synchronization accuracy in number of fractional bits and can be calculated from the number of bits according to a formula.

Figure 1. Equation

Table 3. Synch accuracy values and corresponding accuracies
Bits	Accuracy
17	8 µs
18	4 µs
19	2 µs
20	1 µs
21	500 ns
22	250 ns
23	125 ns
24	62.5 ns
25	31.25 ns

Note: The time synchronization accuracy is rounded to the next worse accuracy, for example, if the accuracy is 2..3 ms, it is shown as 8 bits (4 ms).

IEEE 1588 v2 monitoring values

The IEEE 1588 v2 monitoring values are found via menu path Monitoring > IED status > Time synchronization.

IEEE 1588 v2 monitoring values

Table 4. IEEE 1588 v2 monitoring values
Description	Value
PTP gm identity
PTP gm time Src	Atomic clock
	GPS
	Terrestrial radio
	PTP
	NTP
	Hand set
	Other
	Internal oscil.
PTP gm accuracy

Within a domain, grandmaster is the clock that is the ultimate source of time for clock synchronization using the PTP protocol.

PTP gm identity indicates the identity of the master clock.

PTP gm time Src indicates the source of time announced by the grandmaster clock.

PTP gm accuracy indicates the accuracy announced by the grandmaster clock.

SMV accuracy monitoring values

The SMV accuracy monitoring values are found via menu path Monitoring > IED status > SMV accuracy.

Table 5. SMV accuracy monitoring values
Description	Value
SMV synch accuracy	No sync
	Local clock
	Global clock
Local synch accuracy
Max Dev Sync Acc

SMV synch accuracy value "No sync" indicates that the SMV is either not in use or it is not synchronized with IEEE 1588 v2. "Local clock" indicates that SMV is synchronized to a local area clock and "Global clock" indicates that SMV is synchronized to a global time reference such as GPS.

Local synch accuracy indicates the time synchronization accuracy in microseconds.

Max Dev Sync Acc indicates the maximum clock deviation when the clock accuracy was over 4 μs.