Method of operation
7SV512
V1
31
C53000---G1176---C91
&
&
&
&
&
&
>
=1
>
=1
>
=1
Init L1
&
>B/F
block
internal
blocking
>Start
>Trip
L1
>Trip
L2
>Trip
L3
>Start N
Init L2
Init L3
&
Init
L123
>Trip 3pole
&
Figure 4.11 Initiation conditions with 2-out-of-4
logic
Initiation can be blocked via the binary input ”
>B/F
block
” (e.g. during test of the feeder protection
relay). Additionally, an internal blocking facility is
provided (refer also Section 4.2.7).
The logic of the start conditions for the delay times is
shown in Figure 4.12. In principle, it is designed like
that for common phase initiation, but, individual for
each of the three phases. Thus, current flow and ini-
tiation conditions are processed for each phase. In
case of single-pole interruption during an auto-re-
close cycle, current disappearance is reliably moni-
tored only for the tripped breaker pole.
The auxiliary contact criterion is processed for each
individual breaker pole, too. But, if the breaker auxil-
iary contacts are not available for each individual
breaker pole, then a single pole trip command is as-
sumed to be executed only when the series connec-
tion of the auxiliary contacts is interrupted (i.e. the
signal ”any pole open” according Figure 4.7 is pres-
ent, refer Section 4.2.3).
For the first breaker failure protection stage, a differ-
ent delay time T1---1POLE can be set for single-pole
trip by the feeder protection. In addition, a choice
can be made whether expiry of the time T1---1POLE
should result in a phase-true single-pole trip (param-
eter TRIP 1POLE =
YES,
command output ”
BFP
Trip L1
”) or in a three-pole trip (parameter TRIP 1
POLE =
NO
, command output ”
BFP CrossTrip
”)
by the breaker failure protection.
With the second stage, distinction can be made
again between start by means of the current criteri-
on (”L1>” according Figure 4.4) or by means of the
auxiliary contact criterion (”Aux L1” according to Fig-
ure 4.6, for the assigned phase).
&
T1---
1POLE
BFP
Trip L1
L1>
(acc.
Fig 4.4)
Aux L1
(acc.
Fig 4.6)
>1
&
&
&
>1
”1”
”1”
T---TRIP---BB
T2
T1+T2
T2---CB---
AUX
T2---
CURR.
BFP
Trip BB
BFP
CrossTrip
Init
L1
(acc.
Fig 4.11)
>1
>1
further
phases
NO
YES
TRIP 1POLE
further
phases
Figure 4.12 Two-stage breaker failure protection with phase segregated initiation --- one phase
www
. ElectricalPartManuals
. com