Principle For Blocking Scheme - ABB REL650 Applications Manual

Section 3
REL650 setting examples
3.1.6.3
60
A communication signal is sent (CS) if a fault is detected by zone 1 (underreach zone).
When a communication signal is received (CR) zone 2 operates instantaneously. The logic
is shown in figure 15.
ZQMPDIS (21)
Zone 1 TRIP
Zone 1 PICKUP
Zone 2 TRIP
Zone 2 PICKUP
Receive signal (CR)
ANSI11000074 V2 EN
Figure 15: Logic of under-reach communication scheme
This scheme is used for long lines where it can be assured that the zone 1 reach from both
line ends overlap each other.

Principle for blocking scheme

The principle of the logic can be explained as shown in figure 16.
1MRK 506 334-UUS A
Send signal (CS)
OR
AND
ANSI11000074_2_en.vsd
Application manual
Trip