Principles For Under-Reach Permissive Communication Logic - ABB REL650 Applications Manual

1MRK 506 334-UUS A
3.1.6.2
Application manual
A communication signal is sent (CS) if a fault is detected by zone 2 (overreach zone).
When a communication signal is received (CR) zone 2 operates instantaneously. The logic
is shown in figure 13.
ZQMPDIS (21)
Zone 1 PICKUP
Zone 2 PICKUP
Receive signal (CR)
ANSI11000076 V2 EN
Figure 13: Logic of over-reach communication scheme
This scheme is used for short lines where it can not be assured that the zone 1 reach from
both line ends overlap each other. The scheme should also be used for lines where the fault
current infeed from one of the line ends is small and the weak end infeed logic is used.

Principles for under-reach permissive communication logic

The principle of the logic can be explained as shown in figure 14.
Zone 2
Zone 1
A
REL 650
Y
ANSI11000111 V1 EN
Figure 14: Principle of under-reach communication scheme
Zone 1 TRIP
Zone 2 TRIP
Z 1 = R 1 + jX 1
Z 0 = R 0 + jX0
Communication
Zone 1
Zone 2
REL650 setting examples
Send signal (CS)
OR
AND
ANSI11000076_2_en.vsd
B
REL 650
Y
ANSI11000111_1_en.vsd
Section 3
Trip
C
59