ABB REB670 - SLCE 8;ASCT Characteristics for End-Connection

Functions Comment
DRPRDRE function Trip Value Recording feature will be connected to the
individual summated bay current. Therefore recorded trip
current values will not correspond to any actual primary
currents. However such records can still be used to evaluate
internal busbar protection, CCRBRF/CCSRBRF and
OC4PTOC/PHS4PTOC protections operation.
Communication All communication features in the IED can be used in the
exactly the same way as with phase segregated design
SMBRREC function Autoreclosing function in the IED can be used in the exactly
same way as with phase segregated design.
6.1.6.6 SLCE 8/ASCT characteristics for end-connection
M12141-3 v4
Typical ASCT end-connection is shown in Figure 85. For this ASCT connection type,
the ampere-turn balance equation has the form according to Equation 12:
4 1 2 ( ) 3 ( )
SUMM
N I N IA N IA IB N IA IB IC× = × + × + + × + +
EQUATION1785-ANSI V1 EN-US (Equation 12)
The relationships between number of turns for this SLCE 8, ASCT for REB670, is
shown in Equation 13, Equation 14 and Equation 15:
N1 N2 N;= =
EQUATION1108 V1 EN-US (Equation 13)
N3 2 N×=
EQUATION1109 V1 EN-US (Equation 14)
N4 k 3 N× ×=
EQUATION1110 V1 EN-US (Equation 15)
where:
k a constant, which depends on the type of ASCT
(that is, k=1, for 1/1A ASCT or k=5 for 5/1A ASCT or k=2 for 2/1A ASCT)
The well-known relationship, between positive, negative and zero sequence current
components and individual phase current quantities is shown in Equation
16:
Section 6 1MRK 505 370-UUS A
Differential protection
172 Busbar protection REB670 2.2 ANSI
Application manual