ABB RELION REX640 Technical Manual page 760

Protection functions
The function contains a blocking functionality. It is possible to block function
outputs, timers or the function itself.
4.3.5.4 Analog channel configuration
HREFPDIF has one analog group input which must be properly configured.
Table 688: Analog inputs
Input
IRES
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.
4.3.5.5 Operation principle
The function can be enabled and disabled with the
corresponding parameter values are "On" and "Off".
The operation of HREFPDIF can be described using a module diagram. All the
modules in the diagram are explained in the next sections.
Figure 432: Functional module diagram
Level detector
The level detector compares the differential neutral current IDo to the set value of
the
value setting, the level detector sends an enable signal to the timer module to start
the definite timer.
760
See the preprocessing function blocks in this document for the possible
signal sources.
Io
IRES
BLOCK
Operate value setting. If the differential neutral current exceeds the Operate
Description
Residual current (measured)
Timer
Level
t
detector
Blocking
logic
1MRS759142 F
Operation setting. The
OPERATE
START
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REX640