Weak-End Infeed Logic - ABB REL650 Applications Manual

Section 12
Scheme communication
12.2.3.2
12.3
12.3.1
12.3.2
12.3.2.1
402
Set the pick-up delay tPickUpRev to <80% of the minimum sum of breaker operate time
+ communication delay time, but with a minimum of 20 ms.

Weak-end infeed logic

Set WEI to Echo, to activate the weak-end infeed function with only echo function.
Set WEI to Echo&Trip to obtain echo with trip.
Set tPickUpWEI to 10 ms, a short delay is recommended to avoid that spurious carrier
received signals will activate WEI and cause unwanted communications.
Set the voltage criterion PU27PP and PU27PN for the weak-end trip to 70% of the system
base voltage VBase. The setting should be below the minimum operate voltage of the
system but above the voltage that occurs for fault on the protected line. The phase-to-
phase elements must be verified to not operate for phase to ground faults.
Current reversal and WEI logic for distance protection,
phase segregated ZCWSPSCH (85)
Identification
Function description
Current reversal and WEI logic for
distance protection phase segregated
Application
Current reversal logic
If parallel lines are connected to common buses at both terminals, overreaching
permissive communication schemes can trip unselectable due to current reversal. The
unwanted tripping affects the healthy line when a fault is cleared on the other line. This
lack of security results in a total loss of inter-connection between the two buses.
To avoid this kind of disturbances, fault current reversal logic (transient blocking logic)
can be used.
The unwanted operations that might occur can be explained by looking into figure
figure 198. Initially the protection A:2 at A side will detect a fault in forward direction and
IEC 61850 IEC 60617
identification identification
ZCWSPSCH -
1MRK 506 334-UUS A
ANSI/IEEE C37.2
device number
85
197 and
Application manual