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2.38.1 Selection of breaker system
A single breaker arrangement (1CB) is applied and the protection function is required to
operate in the 1CB, the user should set 1CB for the scheme switch [CB-System]. When a single-
and-a-half breaker arrangement system (1.5CB) is applied, the user should set 2CB for the
scheme switch. (2.84.8)
2.38.2 Decision of CB open/close status
Circuit-breaker auxiliary-contact is used to state the CB status; a normal-open contact (N/O)
and a normal-close contact (N/C) can be furnished in the CB. Thus, as to the phase-A contact
of the CB, signals “CB1-A_NO_CONT” and “CB1-A_NC_CONT” can be used to represent the
CB status in phase-A (i.e., tripped or closed in phase-A). The PROT_COMM function can decide
the CB status using the both signals; the decision generated will be provided for other
protection functions so that the IED can operate in accordance with the CB status.
(i) Signal option
As the CB auxiliary-contacts (N/O and/or N/C) may generate the signals, the user should set
the rule for the decision. When the N/O signal is generated but the N/C signal is not generated,
set NO for the scheme switch [CB1-Contact] so that the PROT_COMMON function can decide
the CB state using only the N/O. Conversely, the decision should be made with only the N/C,
NC is set for this scheme switch. When both N/O and the N/C used, set Both for the scheme
switch [CB1-Contact]†.
†Note: When the IED operates for the 1.5CB arrangement (i.e., two CBs are connected
with the IED), the user should set the scheme switches [CB1-Contact] and [CB2-
Contact] both.
(ii) Contact supervision
Table 2.38-2 exemplifies the rules between the CB main-contact and the CB auxiliary-contact.
Given that the main-contact is open, the N/O is open and the N/C is closed; however if the both
are open when the main contact is open, we should decide the information generated in the
PROT_COMMON is not true (say, an incorrect signal is generated). The contact supervision
can find the inconsistency in the decisions using the rule of Table 2.38-2.
Table 2.38-2 Main and Auxiliary contacts within CB
The user should set On for the scheme switch [CB-SV] when the operation of the contact
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