Function Block; Functionality; Analog Channel Configuration - ABB RELION REX640 Technical Manual

1MRS759142 C
4.3.1.2
4.3.1.3
4.3.1.4
REX640
Technical Manual

Function block

GUID-344CB768-7B5E-4BF4-B37D-0234E34D4A5A V1 EN
Figure 301: Function block

Functionality

The line differential protection with in-zone power transformer LNPLDF is used as
feeder differential protection for the distribution network lines and cables. LNPLDF
includes low, stabilized and high, non-stabilized stages. The line differential
protection can also be used when there is an in-zone transformer in the protected
feeder section.
The stabilized low stage provides a fast clearance of faults while remaining stable with
high currents passing through the protected zone increasing errors on current
measuring. Second harmonic restraint insures that the low stage does not operate due
to energizing of a tapped or in-zone transformer. The high stage provides a very fast
clearance of severe faults with a high differential current regardless of their
harmonics.
The operating time characteristic for the low stage can be selected to be either definite
time (DT) or inverse definite time (IDMT). The direct inter-trip ensures both ends are
always operated, even without local criteria.

Analog channel configuration

LNPLDF has one analog group input which must be properly configured.
Table 571: Analog signals
Input
I3P
See the preprocessing function blocks in this document for the
possible signal sources.
Improper analog channel configuration causes a validation error if the analog
channels are not completely configured or they do not match with certain settings. For
troubleshooting, check the contents of this chapter and also the preprocessing blocks
Protection functions
Description
Three-phase currents
Section 4
555