poleTwoOpened from C.B.
+
C.B.
poleOneOpened from C.B.
poleThreeClosed from C.B.
poleTwoClosed from C.B.
poleOneClosed from C.B.
poleThreeOpened from C.B.
en05000288_ansi.vsd
52b
52b
52b
52a
52a
52a
ANSI05000288 V1 EN-US
Figure 286: Pole discrepancy signals for internal logic
In this case the logic is realized within the function. If the inputs are indicating pole discrepancy
the trip timer is started. This timer will give a trip signal after the set delay.
Pole discrepancy can also be detected by means of phase selective current measurement. The
sampled analog phase currents are pre-processed in a discrete Fourier filter (DFT) block. From the
fundamental frequency components of each phase current the RMS value of each phase current is
derived. The smallest and the largest phase current are derived. If the smallest phase current is
lower than the setting
CurrUnsymPU
times the largest phase current the settable trip timer (
tTrip
)
is started. The
tTrip
timer gives a trip signal after the set delay. The TRIP signal is a pulse 150 ms
long. The current based pole discrepancy function can be set to be active either continuously or
only directly in connection to breaker open or close command.
The function also has a binary input that can be configured from the autoreclosing function, so
that the pole discrepancy function can be blocked during sequences with a single pole open if
single pole autoreclosing is used.
Section 8 1MRK 502 066-UUS B
Current protection
540
Technical manual
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