GE LPS-D, Инструкция по эксплуатации

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GE Power Management LPS-D Line Protection System 1-
41
1 PRODUCT DESCRIPTION 1.9 SINGLE PHASE TRIPPING
1
Figure 1–20: OPEN POLE DETECTION LOGIC
1.9.3 OPEN POLE OPERATION
The functional logic diagrams do not depict all the logical interactions that occur in the software algorithms dur-
ing the period that one pole is open. Two software flags and two associated masks control the operation during
an open-pole period. The single-phase-trip flag, SINGPTRIP, is set when the LPS-D issues a single-phase trip.
The open-pole flag, OPENPOLE, is set when the pole-disagreement logic detects that one pole is open.
A primary function of SINGPTRIP is to disable all the phase-distance function phase pairs that are involved
with the open pole. If pole A is open, then SINGPTRIP disables phase pairs A-B and C-A but allows phase-pair
B-C to remain in service for all zones of protection. This prevents inadvertent operation of the A-B and C-A dis-
tance functions during the time that pole A is open when line-side potential is used. The SINGPTRIP mask dis-
ables the ground-distance functions associated with the open pole.
The OPENPOLE flag is shown on all the functional logic diagrams as one input to OR30. This indicates that
once the OPENPOLE flag is set, any subsequent fault will cause a three-phase trip regardless of the fault type.
The Fault Detector (FD) measurement is modified when the OPENPOLE flag is set. With all poles closed, FD
operates on the magnitude of
I
2
and I
0
, as well as the change in I
1
, I
2
, and I
0
. When the OPENPOLE flag is set,
FD operates on the change in the three sequence currents but does not operate on the magnitude of I
2
and I
0
,
since an open pole will produce some steady-state level of I
2
and I
0
.
The Potential Transformer Fuse Failure Detection function (FFB on the logic diagrams). For a Hybrid scheme,
the weak-infeed logic is modified as shown in Figure 1–19: SINGLE PHASE TRIPPING LOGIC (HYBRID
SCHEME) on page 1–40 and described above. The operation of the Out-of-Step Blocking logic is modified as
explained below. If the ground directional overcurrent functions are used as part of a pilot scheme, they are
disabled. The ground backup overcurrent functions, 50G and 51G, are disabled.
As indicated on the logic diagrams, the Phase Selector function indicates the faulted phase for single-phase-
to-ground faults and produces a multi-phase output for all other fault types. Tripping for the initial fault is the
faulted phase for single-phase-to-ground faults and all three phases for multiphase faults. Subsequent faults
during the open-pole period are tripped three-phase regardless of fault type.
1.9.4 RECLOSE CONTROL
The LPS-D includes two Reclose Initiation outputs. RI-1P picks up when the LPS-D selects to trip only one of
the three phase trip outputs. RI-3P picks up whenever the LPS-D selects to trip all three poles of the breaker.
A n y
P h a s e
o p e n
Only 1
P h a s e
o p e n
All
P h a s e s
O p e n
All Phase
V o l t a g e s H i g h
P h a s e A O p e n
P h a s e B O p e n
P h a s e C O p e n
5 2 b P h a s e C
5 2 b P h a s e B
5 2 b P h a s e A
A n y V o l t a g e
U n d e r v o l t a g e
UVA
IbA
UVB
IbB
UVC
IbC
O U T P U T O F U V U N I T S I S H I G H
W H E N V O L T A G E I S L O W