IEC15000459 V1 EN-US
Figure 31: Two-end power line with two CB and CT groups at one end
If there are two CB and CT groups at both ends of a two-end power line,
information on currents must be fed to all four current inputs of both IEDs. Current
values at the remote end are obtained via a communication channel as shown in
Figure
32. Summing up the CTs’ secondary currents at the end with two CB and
CT groups is not allowed. CBs at both ends can be included in the protected zone
depending on their positions relative to the CTs.
IEC15000460 V1 EN-US
Figure 32: Two-end power line with two CB and CT groups at each end
Figure 33 shows a three-end power line configuration where one end has two CB
and CT groups. All four current inputs to IEDs are used. Current from each CT is
fed to an IED, and currents from different CTs are processed separately by the
protection algorithm. Summing up the CTs’ secondary currents at the end with two
CB and CT groups is not allowed. CBs at all ends can be included in the protected
zone depending on their positions relative to the CTs.
IEC15000461 V1 EN-US
Figure 33: Three-end power line with two CB and CT groups at one end
1MRK 505 382-UEN B Section 4
Analog and binary signal transfer for line differential protection
Communication set-up 670/650 series 2.2 39
Application Guide
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