ABB REB500 - Breaker Pole Discrepancy Protection; Mode of Operation

1MRK 505 350-UEN Section 5
Additional protection options
Technical Manual 49
Distributed busbar protection REB500
5.5 Breaker pole discrepancy protection
5.5.1 Mode of operation
The breaker pole discrepancy protection is a local protection function in the bay
unit which supervises the three phase currents to ensure that the three circuit-
breaker poles open and close simultaneously. The tripping condition is fulfilled
when at least one of the phase currents is higher than setting (I
mset
) and the
difference between the phase currents (discrepancy factor Dpd
set
) exceeds a given
minimum for the set time.
Figure 18 Block diagram of breaker pole discrepancy protection
Dpdset: Pole discrepancy factor e.g. 0.6 ´ Imax
Imset: Pole discrepancy setting e.g. 0.2 ´ IN
To verify a pole discrepancy, the current criteria and the condition of the circuit-
breaker auxiliary contacts must be taken into account (external plausibility check).
As can be seen from the Figure 18, the output signal of the function is enabled by
the binary input “17610_PDF ext release”.