Schweitzer Engineering Laboratories SEL-351-5, Инструкция по эксплуатации, Страница: 145 / 706

Date Code 20070117
Instruction Manual SEL-351-5, -6, -7 Relay
Section 4
R.Instruction Manual
Loss-of-Potential, Load Encroachment,
and Directional Element Logic
Loss-of-Potential Logic
The loss-of-potential (LOP) logic operates as shown in Figure 4.1 .
q From Figure 5.3 ; w to Figure 4.6 , Figure 4.7 , Figure 4.8 , and Figure 4.21 ; e to
Figure 5.6 ; r to Figure 4.15 , Figure 4.16 , and Figure 4.22 .
Figure 4.1 Loss-of-Potential Logic
Inputs into the LOP logic are:
Inputs Description
3PO three-pole open condition
(indicates circuit breaker open condition see
Figure 5.3 )
V
1
positive-sequence voltage (V secondary)
I
1
positive-sequence current (A secondary)
I
0
zero-sequence current (A secondary)
V
0
zero-sequence voltage (V secondary) {wye-connected PTs}
LOP
ELOP = Y
ELOP = Y1
ELOP = Y or Y1
3PO
V1GOOD
Wye-Connected PTs
Delta-Connected PTs
VNOM
V
1
, I
1
, I
0
V
0
V
2
Loss-of-Potential
Logic
Relay
Word
Bits
Relay
Word
Bit
Settings
q
w
e
r