CHAPTER 5: SETTINGS PRODUCT SETUPL90 LINE CURRENT DIFFERENTIAL SYSTEM – INSTRUCTION MANUAL 5-955• The real time clock changed from the front panel or via Modbus register. The relay always generates this eventregardless of the time difference.• The Daylight Saving Time (DST) setting gets enabled and the current relay time is already in the DST zone• The real time clock enters or leaves DSTTo enable IRIG-B synchronization, the input IRIG-B SIGNAL TYPE must be set to DC Shift or Amplitude Modulated. IRIG-Bsynchronization can be disabled by making this setting None.To configure and enable PTP and/or SNTP, or to set local time parameters (for example time zone, daylight savings), use thefollowing sections.5.3.6.2 Precision time protocol (1588)SETTINGS PRODUCT SETUP REAL TIME CLOCK PRECISION TIME PROTOCOL (1588)SETTINGS PRODUCT SETUP REAL TIME CLOCK PRECISION TIME PROTOCOL (1588) PTP PORT 1(3)The L90 supports the Precision Time Protocol (PTP) specified in IEEE Std 1588 2008 using the Power Profile (PP) specified inIEEE Std C37.238 2011. This enables the relay to synchronize to the international time standard over an Ethernet networkthat implements PP.The relay can be configured to operate on some PTP networks that are not strictly PP. Time accuracy can be less thanspecified for a PP network. Tolerated deviations from strict PP include 1) missing declaration of PP compliance in themessages, 2) connection to a network device that does not support the PTP peer delay mechanism, 3) jitter substantiallygreater than 1 μs in received event messages, and 4) certain non-compliant announce and sync message update rates.The relay implements PTP according to IEEE Std 1588 2008 and the equivalent IEC 61588:2009(E), sometimes referred to asversion 2 PTP. It does not support the previous version of the standard (version 1).PTP is a protocol that allows multiple clocks in a network to synchronize with one another. It permits synchronizationaccuracies better than 1 ns, but this requires that each and every component in the network achieve very high levels ofaccuracy and a very high baud rate, faster than normally used for relay communications. When operating over a genericEthernet network, time error can amount to 1 ms or more. PP is a profile of PTP which specifies a limited subset of PTPsuitable for use in power system protection, control, automation, and data communication applications, and therebyfacilitates interoperability between different vendor’s clocks and switches. PP specifies a worst-case delivered time error ofless than 1 μs over a 16-hop network. PRECISION TIME PROTOCOL (1588) STRICT POWERPROFILE: DisabledRange: Enabled, Disabled PTP DOMAIN NUMBER:0Range: 0 to 255 PTP VLAN PRIORITY:4Range: 0 to 7 PTP VLAN ID:0Range: 0 to 4095 PTP PORT 1See below PTP PORT 1 PORT 1 PTP FUNCTION:DisabledRange: Enabled, Disabled PORT 1 PATH DELAYADDER: 0 nsRange: 0 to 60000 ns in steps of 1 PORT 1 PATH DELAYASYMMETRY: 0 nsRange: –1000 to +1000 ns in steps of 1The L90 is provided with optional Precision Time Protocol capability. This feature is specified as the IEEE 1588software option at the time of ordering. See the Order Codes section in chapter 2 for details.
