11.9
Date Code 20171006 Instruction Manual SEL-400 Series Relays
Time and Date Management
Time-Synchronized Events
Adaptive Internal Clock Period Adjustment
The Internal Clock Period, as shown in the TIME Q command response in
Figure 11.4, is the internal relay timekeeping period. The relay adjusts this mas-
ter internal clock when you apply HIRIG or HPTP mode timekeeping, adapting
the internal relay clock for your installation temperature conditions. If you lose
the timing lock, the relay internal clock operates at this precisely adapted clock
period until HIRIG or HPTP mode is restored. Time tags for event reports during
a loss of high-accuracy timekeeping remain very accurate. Lower-accuracy time
sources do not adaptively adjust the internal relay clock period.
COM PTP Command
The COM PTP command provides a report of the PTP data sets maintained by
the device as well as statistics for the measured time offsets with the parent (mas-
ter) clock. The PTP data sets contain information about the state, identity, and
configuration of the local, parent, and grandmaster clocks in addition to proper-
ties of the time being distributed by the grandmaster clock. See COM PTP on
page 14.14 for more information on this command.
Daylight-Saving Time (DST)
The status of DST time can be determined by one of three possible high-priority
sources (BNC, SER, or PTP). The daylight-saving time pending Relay Word bit
(DSTP) is valid only when IRIG is the active source. When PTP is selected, it
sets the DSTP bit to zero at all times. If no high-priority source with daylight-
saving time information is available, the DST bit is determined based on the
BEG_DST and END_DST Global settings.
When using PTP as the Time Synchronization source, the PTP master may not
provide valid DST information as the relay powers up. To ensure the relay pow-
ers up with the correct time when synced to a PTP source, you must ensure that
the relay Time and Date Management settings and the PTP master configuration
are in agreement.
Time-Synchronized Events
Time-Synchronized Triggers
You can program the relay to perform data captures at specific times. Relays that
are time-locked using HIRIG mode provide high-accuracy time-synchronized
data captures. When you use this method on multiple relays, the actual trigger
times can differ by as much as 5 ms, but the information in the binary COM-
TRADE file outputs from each relay is time-stamped at very high accuracy. Do
not assume that the relay triggers are locked with high accuracy; rather, compare
corresponding time-stamped data points from each COMTRADE file.
Time Triggering the Relay
Perform the following steps to trigger an event data capture in the relay at a spe-
cific time. These settings cause the relay to initiate a data capture at 12:00:30 p.m.
Use other SEL
OGIC control equations in a similar manner to trigger relay event
recordings.
NOTE: The MET PM
time
command can
be used to capture synchrophasor data
at a specific time if synchrophasors are
enabled with Global setting EPMU := Y.
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