Schweitzer Engineering Laboratories, Inc.
SEL-451 Data Sheet
13
Monitoring and Metering
Complete Metering Capabilities
The SEL-451 provides extensive metering capabilities as
listed in
Event Reporting and Sequential
Events Recorder (SER)
Event Reports and Sequential Events Recorder features
simplify post-fault analysis and help improve your
understanding of both simple and complex protective
scheme operations. These features also aid in testing and
troubleshooting bay settings and control schemes. Oscil-
lograms are available in binary COMTRADE and ASCII
COMTRADE formats.
Oscillography and Event Reporting
In response to a user-selected internal or external trigger,
the voltage, current, and element status information con-
tained in each event report confirms relay, scheme, and
system performance for every fault. Decide how much
detail is necessary when an event report is triggered:
8 kHz, 4 kHz, 2 kHz, or 1 kHz resolution analog data.
The relay stores from 24 seconds of data per fault at
1 kHz resolution to 3 seconds per fault at 8 kHz resolu-
tion. Reports are stored in nonvolatile memory. Settings
operational in the relay at the time of the event are
appended to each event report.
Event Summary
Each time the SEL-451 generates a standard event report,
it also generates a corresponding Event Summary. This is
a concise description of an event that includes bay/termi-
nal identification, event date and time, fault location,
phase voltages, fault type at time of trip, and trip and
close times of day.
With an appropriate setting, the relay will automatically
send an Event Summary in ASCII text to one or more
relay communications ports each time an event report is
triggered.
Sequential Events Recorder (SER)
Use this feature to gain a broad perspective of relay ele-
ment operation. Items that trigger an SER entry are
selectable and can include input/output change of state,
element pickup/dropout, recloser state changes, etc. The
relay SER stores the latest 1,000 entries.
Voltage Sag, Swell, Interruption
Records
The SEL-451 can perform automatic voltage disturbance
monitoring for three-phase systems. The voltage
sag/swell/interruption (VSSI) recorder uses the VSSI
Relay Word bits to determine when to start (trigger) and
when to stop recording. The VSSI recorder uses nonvola-
tile memory, so de-energizing the relay will not erase any
stored VSSI data.
The recorded data are available through the VSSI report,
which includes date, time, current, voltage, and voltage
sag/swell/interruption (VSSI) element status during volt-
age disturbances, as determined by programmable set-
tings VINT, VSAG, and VSWELL. When the relay is
recording a disturbance, entries are automatically added
to the VSSI report at one of four rates, depending on the
length of the disturbance:
➤
Once per quarter cycle
➤
Once per cycle
➤
Once per 64 cycles
➤
Once per day
High-Accuracy Time Keeping
Using a combination of IRIG-B and a global positioning
satellite, the SEL-451 can time-tag oscillography to
within 10 µs accuracy. This high accuracy can be com-
bined with the high sampling rate of the relay to synchro-
nize data from across the system with an accuracy of
better than 1/4 electrical degree. This allows examination
of the power system state at given times, including load
angles, system swings, and other system-wide events.
Triggering can be via external signal (contact or commu-
nications port), set time, or system event. Optimal cali-
bration of this feature requires a knowledge of primary
input component (VT and CT) phase delay and error.
A single IRIG-B time-code input synchronizes the
SEL-451 time to within
1 ms of the time-source input.
A convenient source for this time code is the SEL-2032
Communications Processor (via Serial Port 1 on the
SEL-451).
Precision Time Protocol (PTP)
Time Synchronization
In addition to IRIG-B, the relay can be time-synchro-
nized through the Ethernet network by using IEEE 1588
Precision Time Protocol, version 2 (PTPv2). When con-
nected directly to a grandmaster clock providing PTP at
