Functions
6-2337SA6 Manual
C53000-G1176-C133-1
Figure 6-118 Breaker failure protection with phase segregated initiation — example for
initiation by an external protection device with release by a separate set of trip
contacts
Initiation of a single-phase, e.g. “Start L1 only” is valid when the starting input (= trip
command of any feeder protection) appears for only this phase and current flow is
detected in at least this phase. If current flow is not detected, the auxiliary contact
position can be interrogated according to Figure 6-114, dependent on the setting (&KN
%5.&217$&7 = <HV).
The auxiliary contact criterion is also processed for each individual breaker pole. If
however the breaker auxiliary contacts are not available for each individual breaker
pole, then a single-pole trip command is assumed to be executed only once the series
connection of the normally open (NO) auxiliary contacts is interrupted. This
information is provided to the breaker fail protection by the central function control of
the device (refer to Section 6.20.2).
The three-phase starting signal “Start L123” is generated if trip signals appear in more
than one pole (regardless from which protection function). Phase segregated initiation
is then blocked. The input “!%)6WDUWZR,” (e.g. from Buchholz protection)
operates in three-phase mode as well. The function is the same as with common
phase initiation.
The additional release-signal “!%)UHOHDVH” (if assigned to a binary input) affects all
starting conditions. Initiation can be blocked via the binary input “!%/2&.%UN)DLO”
(e.g. during test of the feeder protection relay). Additionally, an internal blocking option
is provided.
7SA6
Trip L1
L+
external
prot. device
L–
>BF Start L1
Trip L1
Trip L2 >BF Start L2
Trip L2
Trip L3 >BF Start L3
Trip L3
>BF release
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