![Schweitzer Engineering Laboratories SEL-421-4 Instruction Manual Download Page 498](http://html.mh-extra.com/html/schweitzer-engineering-laboratories/sel-421-4/sel-421-4_instruction-manual_1216726498.webp)
6.162
SEL-421 Relay
Instruction Manual
Date Code 20171021
Protection Applications Examples
Circuit Breaker Failure Application Examples
Relay Configuration
Enable Scheme 2 circuit breaker failure protection for two circuit breakers.
EBFL1 :=
2
.
Breaker 1 Failure Logic (N, 1, 2, Y1, Y2)
EBFL2 :=
2
.
Breaker 2 Failure Logic (N, 1, 2, Y1, Y2)
Circuit Breaker 1 Failure Logic
Phase Current Level Detector
Set the phase fault current pickup greater than maximum load and less than the
fault current that flows through Circuit Breaker BK1 (I
S(BK1)
). Maximum load
current, I
S
, is 3.25 A secondary.
Figure 6.45
500 kV Power System for Circuit Breaker Failure Scheme 2
Table 6.43
Secondary Quantities
Parameter
Value
Line impedances
Z
1L1
Z
0L1
3.98
87.6° secondary
14.48
82.1° secondary
Source S impedances
Z
1S
= Z
0S
4.4
88° secondary
Source R impedances
Z
1R
= Z
0R
1.78
88° secondary
Nominal frequency (f
NOM
)
60 Hz
Maximum operating current (I
load
)
3.25 A secondary
Line 1
Line 2
S (MOSCOW)
R (PULLMAN)
BK1
BK2
BUS 1
IW
IX
SEL-421
BUS 2
Summary of Contents for SEL-421-4
Page 6: ...This page intentionally left blank ...
Page 14: ...This page intentionally left blank ...
Page 30: ...This page intentionally left blank ...
Page 104: ...This page intentionally left blank ...
Page 128: ...This page intentionally left blank ...
Page 536: ...This page intentionally left blank ...
Page 584: ...This page intentionally left blank ...
Page 616: ...This page intentionally left blank ...
Page 696: ...This page intentionally left blank ...
Page 750: ...This page intentionally left blank ...
Page 755: ...Instruction Manual PM400 01 NB SEL 400 Series Relays Instruction Manual 20171006 ...
Page 776: ...This page intentionally left blank ...
Page 932: ...This page intentionally left blank ...
Page 976: ...This page intentionally left blank ...
Page 1024: ...This page intentionally left blank ...
Page 1038: ...This page intentionally left blank ...
Page 1064: ...This page intentionally left blank ...
Page 1128: ...This page intentionally left blank ...
Page 1206: ...This page intentionally left blank ...
Page 1316: ...This page intentionally left blank ...
Page 1350: ...This page intentionally left blank ...
Page 1464: ...This page intentionally left blank ...
Page 1468: ...This page intentionally left blank ...
Page 1492: ...This page intentionally left blank ...
Page 1518: ...This page intentionally left blank ...