ABB REG650 Technical Manual page 228

Section 8
Current protection
222
C.B.
52a
52a
52a
52b
52b
52b
ANSI05000287 V1 EN
Figure 102: Pole discrepancy external detection logic
This binary signal is connected to a binary input of the IED. The appearance of this
signal will start a timer that will give a trip signal after the set time 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.
+
poleDiscrepancy Signal from C.B.
1MRK 502 043-UUS B
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Technical Manual