Schweitzer Engineering Laboratories SEL-351-5, Instruction Manual

Page: 534 / 706

12.34
SEL-351-5, -6, -7 Relay Instruction Manual
Date Code 20070117
Standard Event Reports, Sag/Swell/Interruption Report, and SER
Sag/Swell/Interruption (SSI) Report (Available in Firmware Version 7)
Sag/Swell/Interruption (SSI) Report (Available in
Firmware Version 7)
See Figure 12.8 and Figure 12.9 for an example SSI report.
SSI Triggering and
Recording
The SEL-351-7 can perform automatic voltage disturbance monitoring for
three-phase systems. The SSI Recorder uses the SSI Relay Word bits to
determine when to start (trigger) and when to stop recording. The recorded
data is available through the SSI Report.
See Voltage Sag, Swell, and Interruption Elements (Available in Firmware
Version 7) on page 3.51 for details on the operation of the SSI Relay Word
bits.
The SSI recorder operates (adds new entries to the stored SSI report) only
when group setting ESSI = Y in the active setting group, although the SSI
report can be viewed at any time.
The SSI recorder uses nonvolatile memory, so any stored SSI data will not be
erased by de-energizing the relay. The relay needs some time to store new SSI
data in nonvolatile memory, so if a system power outage also causes the relay
power to fail, there may not be an SSI record of the disturbance. This is not a
concern in substations where the relay is powered by a substation battery.
The relay triggers (generates) entries in the SSI report on the assertion of any
sag, swell, or interruption relay element (Relay Word bits SAG
p , SW p , INT p ,
where p = A, B, or C {wye-connected}; p = AB, BC, or CA {delta-
connected}), or when manually triggered by the SSI T command.
SSI Report Entries
➤
Entry number (1 is the most recent entry)
➤
Date and time stamp of entry
➤
Phase current magnitudes (Ia,b,c) as a percentage of the
nominal current rating of the phase current inputs (5 A or 1 A)
➤
Calculated residual current magnitude (Ig) as a percentage of
the nominal current rating of the phase current inputs (5 A or
1 A)
➤
Neutral current magnitude (In) as a percentage of the nominal
current rating of the neutral current input (5 A, 1 A, 0.2 A, or
0.05 A)
➤
Phase-neutral voltage magnitudes (V
A
, V
B
, V
C
) as a percentage
of Vbase (wye-connected) or phase-to-phase voltage
magnitudes (V
AB
, V
BC
, V
CA
) as a percentage of Vbase (delta-
connected)
➤
Vs channel voltage magnitude as a percentage of Vbase;
displayed value,
VS
Vs (secondary) PTRS •
1000 Vbase •
----------------------------------------------------------
100% • =