GE L90 Instruction Manual page 175

5 SETTINGS
The REAL TIME CLOCK EVENTS setting allows changes to the date and/or time to be captured in the event record. The
event records the RTC time before the adjustment.
To enable IRIG-B synchronization, the input IRIG-B signal type must be set to DC Shift or Amplitude Modulated using the
Settings > Product Setup > Real Time Clock > IRIG-B > IRIG-B Signal Type setting. IRIG-B synchronization can be dis-
abled 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
the following sections.

PATH: SETTINGS PRODUCT SETUP
 REAL TIME
 CLOCK
MESSAGE
MESSAGE
EE
MESSAGE
MESSAGE
The relay contains a real time clock (RTC) to create timestamps for communications protocols as well as for historical data,
such as event records and oscillography. When the relay restarts, the RTC initializes from an onboard battery-backed
clock, which has the same accuracy as an electronic watch, approximately ±1 minute per month (~23 ppm). Once the RTC
is synchronized with the Precision Time Protocol (PTP), IRIG-B, or SNTP, its accuracy approaches that of the synchroniz-
ing time delivered to the relay. When the L30/L90 channel asymmetry function is used, the relay's real time clock must be
synchronized to an external time source using PTP or IRIG-B, typically from a global positioning system (GPS) receiver.
The SYNCHRONIZING SOURCE setting configures the priority sequence that the relay uses to determine which of the
available external time sources synchronizes the RTC and the synchrophasor clock. A setting of None causes the RTC and
the synchrophasor clock to free-run. A setting of PP/IRIGB/PTP/SNTP, IRIGB/PP/PTP/SNTP, or PP/PTP/IRIGB/SNTP
causes the relay to track the first source named that is enabled and operational, or free-run if none of these are available.
Here, PP means a time source that is strictly compliant with PP, PTP means a time source that is not strictly compliant with
PP. When a time source fails or recovers, the relay automatically transfers synchronization as required by this setting.
See the 
COMMANDS SET DATE AND TIME
The REAL TIME CLOCK EVENTS setting allows changes to the date and/or time to be captured in the event record. The
event records the RTC time before the adjustment.
To enable IRIG-B synchronization, the input IRIG-B signal type must be set to DC Shift or Amplitude Modulated using the
Settings > Product Setup > Real Time Clock > IRIG-B > IRIG-B Signal Type setting. IRIG-B synchronization can be dis-
abled 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
the following sections.
GE Multilin

REAL TIME CLOCK
SYNCRONIZING SOURCE:
None
REAL TIME CLOCK
EVENTS: Disabled
IRIG-B SIGNAL TYPE:
None
 PRECISION TIME
 PROTOCOL (1588)
 SNTP PROTOCOL

 LOCAL TIME

menu item section of this manual to manually set the RTC.
L90 Line Current Differential System
5.2 PRODUCT SETUP
Range: None, PP/IRIG-B/PTP/SNTP, IRIG-B/PP/PTP/
SNTP, PP/PTP/IRIG-B/SNTP
Range: Disabled, Enabled
Range: None, DC Shift, Amplitude Modulated
See below
See below
See below
5
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