Logic Diagram - ABB REL 501-C1 2.5 Technical Reference Manual

5.4
120
Current reversal and weak end infeed logic for
residual overcurrent protection (EFCA)

Logic diagram

EFCA-BLOCK
EFCA-IRV
EFCA-IRVBLK
Figure 62: Simplified logic diagram, current reversal logic
EFCA-BLOCK
EFCA-WEIBLK
EFCA-CRL
WEI = Echo
Figure 63: Simplified logic diagram, weak end infeed - Echo logic
EFCA-BLOCK
200 ms
EFCA-WEIBLK
EFCA-CRL
WEI = Trip
EFCA-ST3U0
EFCA-CBOPEN
Figure 64: Simplified logic diagram, weak end infeed - Trip logic
0-60 s 10 ms 0-60 s
t t t
tPickUp tPickUp
200 ms
50 ms
t
&
t
50 ms 200 ms
t
&
t
&
0-60 s
&
t
tDelay
EFCA-ECHO
200 ms
&
t
EFCA-ECHO
&
t
EFCA-TRWEI
&
99000056.vsd
Chapter 5
Current
EFCA-IRVL
99000053.vsd
99000055.vsd