Sel 751A - Relay Word Bit; Table 4.13 Equations Associated with U.S. Curves; Table 4.14 Equations Associated with IEC Curves

4.16
SEL-751A Relay Instruction Manual Date Code 20100129
Protection and Logic Functions
Basic Protection
Relay Word Bit
ORED51T
Relay Word bit ORED51T is asserted if any of the Relay Word bits 51AT,
51BT, 51CT, 51PIT, 51P2T, 51N1T, 51N2T, 51G1T, 51G2T, or 51QT are
asserted.
Table 4.13 Equations Associated With U.S. Curves
Curve Type Operating Time Reset Time Figure
U1 (Moderately Inverse) Figure 4.8
U2 (Inverse) Figure 4.9
U3 (Very Inverse) Figure 4.10
U4 (Extremely Inverse) Figure 4.11
U5 (Short-Time Inverse) Figure 4.12
Table 4.14 Equations Associated With IEC Curves
Curve Type Operating Time Reset Time Figure
C1 (Standard Inverse) Figure 4.13
C2 (Very Inverse) Figure 4.14
C3 (Extremely Inverse) Figure 4.15
C4 (Long-Time Inverse) Figure 4.16
C5 (Short-Time Inverse) Figure 4.17
t
p
TD 0.0226
0.0104
M
0.02
1–
----------------------+
⎝⎠
⎛⎞
• =
t
r
TD
1.08
1M
2
–
----------------
⎝⎠
⎛⎞
• =
t
p
TD 0.180
5.95
M
2
1–
----------------+
⎝⎠
⎛⎞
• =
t
r
TD
5.95
1M
2
–
----------------
⎝⎠
⎛⎞
• =
t
p
TD 0.0963
3.88
M
2
1–
----------------+
⎝⎠
⎛⎞
• =
t
r
TD
3.88
1M
2
–
----------------
⎝⎠
⎛⎞
• =
t
p
TD 0.0352
5.67
M
2
1–
----------------+
⎝⎠
⎛⎞
• =
t
r
TD
5.67
1M
2
–
----------------
⎝⎠
⎛⎞
• =
t
p
TD 0.00262
0.00342
M
0.02
1–
----------------------+
⎝⎠
⎛⎞
• =
t
r
TD
0.323
1M
2
–
----------------
⎝⎠
⎛⎞
• =
t
p
TD
0.14
M
0.02
1–
----------------------
⎝⎠
⎛⎞
• =
t
r
TD
13.5
1M
2
–
----------------
⎝⎠
⎛⎞
• =
t
p
TD
13.5
M1–
--------------
⎝⎠
⎛⎞
• =
t
r
TD
47.3
1M
2
–
----------------
⎝⎠
⎛⎞
• =
t
p
TD
80
M
2
1–
----------------
⎝⎠
⎛⎞
• =
t
r
TD
80
1M
2
–
----------------
⎝⎠
⎛⎞
• =
t
p
TD
120
M1–
--------------
⎝⎠
⎛⎞
• =
t
r
TD
120
1M–
--------------
⎝⎠
⎛⎞
• =
t
p
TD
0.05
M
0.04
1–
----------------------
⎝⎠
⎛⎞
• =
t
r
TD
4.85
1M
2
–
----------------
⎝⎠
⎛⎞
• =