IEEE 61850-9-3-2016 pdf free download – Communication networks and systems for power utility automation – Part 9-3: Precision time protocol profile for power utility automation.
NOTE I Thi IC’s contribution to bme neccitrecy Ii measurable useg peer Clocks *IIh known Contnbution ID till. error in the peer delay measurement and using links wth known or negligible asymmetry, and subtrectmg those amounts from the obser’ed IC time error
7.6 RequIrements for BC.
7.61 BC time inaccuracy
The BC time Inaccuracy cumulates the time errors In local clock adjustment, measuring the peer delay in the port in the SLAVE state and responding to the peer delay measurement from the downstream clocks In the port(s) In the MASTER state, II does not Include time errors due to asymmetry in either link, nor introduced by the upstream or downstream peer devices involved in the peer delay measurements.
A BC shall introduce less than 200 ns of device time inaccuracy between the port in the SLAVE state and any port in the MASTER state, given it Is in steady state.
A BC should send Announce and Sync messages oven ii it is not yet in steady state.
NOTE I The BC’s c.ontnbuiion to time inaccuracy Is ma.asirabi. using pear clocks with known oontnbution ID Irma error of the peer delay measurement and using links with known or negligIble asymmetry, and subtracting those amounts from the observed BC tine error.
76.2 BC as free-.’unnlng grandmaster
In case the BC has no port in the SLAVE state and no time reference signal, IEC 61588:201)9 IEEE Std 1588-2008. J.4.4.1 shall apply.
7.6.3 BC as master In holdover
A BC shall remain within the time inaccuracy of 7.4.1 for a holdover time of at least 5 s after
losing its time reference signal or PTP synchrontzation, given that it was in steady state
7.7 Requirements for media converters
Media converters (e.g. fibre to copper) introduce a delay, considered in the peer-to-peer delay measurement. This delay suffers from a significant litter and could be different in both directions.
Media converters that support IEC 61588 are considered as TCs or BCs and are subject to the requirements of 7.5 and 7.6. respectively.
Media converters that do not support IEC 615.88 shall present a jitter of less than 50 ne and an asymmetry of less than 25 ns.
7.8 Requirements for links
Links present a predictable and nearly constant link propagation delay (about 5 its/km for fibre or copper). wtiose average value is regularly calculated by peer-to-peer delay measurement.
NOTE Radio links are not conedered.
Since delay asymmetry is not measurable, network engineering must know it to compensate for It.
Links shall present a propagation asymmetry of less than 25 ns or shall have a known propagation asymmetry with an asymmetry variation of less than 25 ns.IEEE 61850-9-3 pdf download.