Schweitzer Engineering Laboratories SEL-311C - Figure 4.14 Negative-Sequence Voltage-Polarized Directional Element for Phase Distance and Negative-Sequence Elements

4.19
Date Code 20060320 Instruction Manual SEL-311C Relay
Loss-of-Potential, CCVT Transient Detection, Load-Encroachment, and Directional Element Logic
Directional Control for Phase Distance and Negative-Sequence Elements
q From Figure 4.1; w to Figure 3.4, Figure 3.5, Figure 3.6, and Figure 3.23.
Figure 4.14 Negative-Sequence Voltage-Polarized
Directional Element for Phase Distance and Negative-Sequence Elements
I
2
V
2
If Z2F Setting > 0, Forward Threshold = 1.25 • Z2F — 0.25 •
I
2
V
2
If Z2F Setting ≤ 0, Forward Threshold = 0.75 • Z2F — 0.25 •
Forward Threshold:
I
2
V
2
If Z2R Setting < 0, Reverse Threshold = 1.25 • Z2R + 0.25 •
I
2
V
2
If Z2R Setting ≥ 0, Reverse Threshold = 0.75 • Z2R + 0.25 •
Reverse Threshold:
Direction Element Characteristics
R2
X2
Forward Threshold
Reverse Threshold
Z2 PLANE
32QR
(Reverse)
R32Q
(Reverse)
32QF
(Forward)
F32Q
(Forward)
50QF
Enable
Forward
Threshold
Reverse
Threshold
50QR
Re[V
2
•(I
2
•1
∠
Z1L)*]
|I
2
|
2
Z2 =
I
2
V
2
Relay
Word
Bits
Relay
Word
Bit
32QE
q ILOP
Relay
Word
Bits
Relay
Word
Bit
LOP
Relay
Word
Bit
ELOP = Y
Setting
Loss-of-Potential
q
w
1
∠
Z1L = 1 ohm at the
positive-sequence line angle