Schweitzer Engineering Laboratories SEL-421-4 - Figure 5.19 LOP Logic

5.32
SEL-421 Relay Instruction Manual Date Code 20171021
Protection Functions
Loss-of-Potential Logic
Figure 5.19 LOP Logic
—
Δ
| V
1
| > 10%
| V
0
| / | V
1
| > 10%
3PO
SPO
Reset has
priority
LOP
ELOP := Y, Y1
ILOP
| V
1
| (last cycle) > 8% V
NOM
| V
1
| > 85% V
NOM
| I
G
| > 5% I
NOM
| I
1
| > 5% I
NOM
| I
1
| > 2% I
NOM
| V
0
| > 15% | V
1
|
| I
G
| > 15% | I
1
|
| V
1
| > 15% V
NOM
Δ| I
G
| > 6% I
NOM
Δ| I
1
| > 2% I
NOM
| I
G
| (last cycle) > 5% I
NOM
| I
1
| (last cycle) > 5% I
NOM
LOP (last interval)
15
CYC
0
0
CYC
30
3PO
SPOA + SPOB + SPOC
OOSDET
0
20
CYC
0
2
CYC
60
CYC
0
Δ
I
1
> 5°
Δ
I
G
> 5°
3POR
−Δ
| V
1
| > 10%
S
R
Q
3PO
Reset
Relay
Word
Bits
Setting
Relay Word Bits
Relay Word Bits