Over-Reach Permissive Logic - ABB REL650 Applications Manual

1MRK 506 334-UUS A
3.1.11.1
Application manual
• Power line carrier (PLC)
• Microwave link (radio)
• Optic fibre link
There are the following alternatives for communication scheme:
• Under-reach permissive logic
•

Over-reach permissive logic

• Blocking scheme
1. Set SchemeType to Permissive OR
This corresponds to over-reach permissive scheme. The choice is based on the
following:
Permissive over-reach scheme is chosen because it is considered as the weak end
infeed logic shall be used as there is a risk of small current infeed. Th WEI function
requires permissive over-reach communication scheme.
2. Set tCoord to 0.000 s
3. Set tSendMin to 0.100 s
Over-reach permissive logic
The principle of the logic can be explained as shown in figure 25.
Step 2- reach
Step 1- reach
A
REL 650
Y
ANSI11000115 V2 EN
Figure 25: Principle for four step residual overcurrent protection overreach
communication scheme
REL650 setting examples
B
Z 1 = R 1 + jX 1
Z 0 = R 0 + jX0
Communication
REL 650
Step 1- reach
Step 2- reach
Section 3
C
Y
ANSI11000115_2_en.vsd
75