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12.35
Date Code 20070117
Instruction Manual
SEL-351-5, -6, -7 Relay
Standard Event Reports, Sag/Swell/Interruption Report, and SER
Sag/Swell/Interruption (SSI) Report (Available in Firmware Version 7)
➤
Base voltage magnitude (Vbase) in kV primary
Vbase = memorized positive-sequence voltage, V
1
(wye-
connected) or
Vbase =
√
3 • (memorized positive-sequence voltage, V
1
)
(delta-connected)
➤
Phase A, B, and C SSI element status columns; see
➤
Trigger state, “
*
” if present (in the column marked “
S
”)
➤
SSI recorder status; see
See
for an example Sag/Swell/Interruption (SSI) report.
SSI Recorder
Operation: Overview
The SSI Recorder operation can be summarized as follows: When power is
first applied to the relay and setting ESSI = “Y”, (or setting ESSI is changed
from “N” to “Y”), the relay measures the voltage inputs to determine if a valid
three-phase signal is present. When the conditions are satisfied for at least
12 seconds, the positive-sequence voltage, V
1
, is memorized as the Vbase
reference voltage. When global setting PTCONN = DELTA, a factor of
√
3 is
applied so that Vbase is in the phase-to-phase scale. This causes a single “R”
entry to be placed in the SSI archive, which indicates that the recorder is
ready. The Vbase value is allowed to change on a gradual basis to follow
normal system voltage variations, but is “locked” when a disturbance occurs.
Table 12.4
SSI Element Status Columns
Symbol
Meaning (for Each Column A, B, or C)
Global Setting PTCONN = WYE
Column A represents
p
= A
Column B represents
p
= B
Column C represents
p
= C
Global Setting PTCONN = DELTA
Column A represents
pp
= AB
Column B represents
pp
= BC
Column C represents
pp
= CA
.
No SSI bits asserted for phase
p
No SSI bits asserted for phases
pp
O
Overvoltage (SW
p
asserted)
Overvoltage (SW
pp
asserted)
U
Undervoltage (SAG
p
asserted)
Undervoltage (SAG
pp
asserted)
I
Interruption (INT
p
asserted; SAG
p
asserted, unless setting VSAG = OFF)
Interruption (INT
pp
asserted; SAG
pp
asserted, unless setting VSAG = OFF)
Table 12.5
Status SSI Column
Symbol
Meaning (Action)
Duration
R
Ready (when the SSI logic
first acquires a valid V
BASE
value)
Single entry
P
Pre-disturbance (4 samples per cycle).
Always signifies a new disturbance.
12 samples (3 cycles)
F
Fast recording mode (4 samples per cycle)
Varies. At least one SSI
element must be asserted.
E
End (post-disturbance at 4 samples per cycle)
Up to 16 samples
(4 cycles). No SSI
elements asserted.
M
Medium recording mode (one sample per cycle)
Maximum of 176 cycles
S
Slow recording mode (one sample per 64 cycles)
Maximum of 4096 cycles
D
Daily recording mode
(one sample per day, just after midnight)
Indefinite
X
Data overflow (single entry that indicates
that data was lost prior to the present entry)
Single entry
NOTE:
Any current or voltage value
greater than 999 percent will be
replaced by “
$$$
” in the SSI report.
Содержание SEL-351-5
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