ABB RELION REX640, Technical Manual, Page: 1231 / 1960

DSTPLAL can be controlled either by the autorecloser (zone extension logic) or by
monitoring the loss of load currents (the loss of load logic). Both operation modes
are enabled independently.
5.9.4 Analog channel configuration
DSTPLAL has one analog group input which must be properly configured.
Table 1175: Analog inputs
Input Description
I3P Three-phase currents
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 in this document. The configuration can be written to the protection relay
once the mismatch is corrected.
5.9.5 Operation principle
The function can be enabled and disabled with the
Operation setting. The
corresponding parameter values are "on" and "off".
The operation of DSTPLAL can be described with a module diagram. All the modules
in the diagram are explained in the next sections.
Zone
extension
logic
Loss of
load logic
OPR_Z_EXTN
OPR_LOSSLOAD
NONDIR_ST
AR_READY
EX_ACC
BLOCK
CB_CL_CMD
LOSSLOAD_ACC
I_A
I_B
I_C
I3P
Figure 699: Functional module diagram
Zone extension logic
Zone extension logic is enabled with
Operation mode = "Zone extension".
When the zone extension operation mode is enabled, the autoreclosing function
DARREC enables a fast fault clearance that covers the entire length of the protected
1MRS759142 F Protection related functions
REX640
Technical Manual
1231