Blocking Scheme - ABB REL650 Applications Manual

Section 3
REL650 setting examples
3.1.11.3
78

Blocking scheme

The principle of the logic can be explained as shown in figure 29.
Step
4 ( reverse )
A
REL 650
Y
ANSI11000117 V1 EN
Figure 29: Principle for four step residual overcurrent protection blocking
communication scheme
A communication signal is sent (CS) if a fault is detected by step 4 (reverse direction).
When a communication signal is received (CR) the fast overreaching step 2 will be
blocked. The logic is shown in figure 30.
Step 2
Step
1
Z 1 = R 1 + jX 1
Z 0 = R 0 + jX0
Communication
Step
1MRK 506 334-UUS A
B
REL 650
Step 1
Y
2
Step 4 ( reverse )
ANSI11000117_1_en.vsd
Application manual
C