• Scheme2_INX "Closed or open if clear indication available otherwise last position
saved"
SEMOD127523-27 v4
As the name of the scheme suggests, only when the auxiliary contacts signal clean “open” or
clean “closed” position, disconnector is considered to be open respectively closed. However
this poses the stringent requirements on the auxiliary contacts that the
PSCLOSED
signal
must become active a certain time (>150 ms) before current starts flowing for example,
through arcing. Otherwise this current will not be taken into account in the busbar protection
and this can result in a maloperation. Therefore, good timing of two auxiliary contacts is
definitely required.
The time during which the
POSOPEN
and
POSCLOSED
signals disagree (that is, both binary
inputs are active or both are inactive) is monitored by the isolator supervision function for
both of the above two schemes. The maximum time allowed before an alarm is given can be
set according to the disconnector timing.
Table
13 and the following two figures summarize the properties of these two schemes.
Table 13: Treatment of primary object auxiliary contact status within BBP in REB670
Primary equipment Status in busbar
protection
Alarm facility
Normally
Open
auxiliary
contact
status
(“closed” or
“a” contact)
Normally
Closed
auxiliary
contact
status
(“open” or
“b” contact)
when
“Scheme 1
RADSS”
is selected
when
“Scheme 2
INX”
is selected
Alarm after
settable
time delay
Information visible
on local HMI
open open closed Last
position
saved
yes intermediate_00
open
closed open open no open
closed
open closed closed no closed
closed closed closed closed yes badState_11
BBP
input „closed“
input „open“
N.O.
N.C.
1
0
1
0
1
0
closed
open
arcing possible
current
assignment
1) 1)
1) disconnector supervision running
en06000084.vsd
IEC06000084 V1 EN-US
Figure 42: Scheme1_RADSS
1MRK 505 370-UEN D Section 6
Differential protection
Busbar protection REB670 99
Application manual
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