Date Code 20011205
Distance and Overcurrent Elements
3-17
SEL-311A Instruction Manual
0
0.2
0.4
0.6
0.8
1
1.2
1.4
1.6
1.2
2
3
4
5
6
7
8
9
10
Applied Current (Multiples of Pickup Setting)
Pi
ckup T
ime (C
ycl
es)
Maximum
Minimum
Figure 3.11: SEL-311A Relay Nondirectional Instantaneous Overcurrent Element Pickup
Time Curve
0
0.2
0.4
0.6
0.8
1
1.2
1.4
1.6
1.8
1.2
2
3
4
5
6
7
8
9
10
Applied Current (Multiples of Pickup Setting)
Reset Time (Cycles)
Maximum
Minimum
Figure 3.12: SEL-311A Relay Nondirectional Instantaneous Overcurrent Element Reset
Time Curve
Residual Ground Instantaneous/Definite-Time Overcurrent Elements
One residual ground instantaneous/definite-time overcurrent element is available. It is enabled
with the E50G enable setting, as shown in Figure 3.13.
Residual ground instantaneous/definite-time overcurrent elements are available for use in any
user-defined tripping or control scheme.
To understand the operation of Figure 3.13, follow the explanation given for Figure 3.10 in the
preceding
Phase Instantaneous/Definite-Time Overcurrent Elements
subsection, substituting
residual ground current I
G
(I
G
= 3I
0
= I
A
+ I
B
+ I
C
) for phase currents and substituting like settings
and Relay Word bits.
In Figure 3.13 the 67G1 element has its directional control fixed forward. See Figure 4.12 in
Section 4: Loss-of-Potential, CCVT Transient Detection, Load-Encroachment, and
Directional Element Logic
for more information on directional control.
Summary of Contents for SEL-311A
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