Schweitzer Engineering Laboratories SEL-387E - Page 117

Date Code 20080110 Protection Functions 3-69
SEL-387E Instruction Manual
100
0.01
0.1
1
10
100
1000
24ITD = 5.0
120 140 160 180 200
24ITD = 7.5
24ITD = 10.0
24ITD = 0.5
24ITD = 1.0
24ITD = 0.1
24C2T Operating Time
(seconds)
Volts/Hertz (%)
(24IP = 100%)
DWG: M300G148
1
3
sec
p
1
%100
IP24
10VNOM
NFREQ
•
freq
PTR•V•3
ITD24
t
⎟
⎟
⎟
⎟
⎟
⎟
⎟
⎠
⎞
⎜
⎜
⎜
⎜
⎜
⎜
⎜
⎝
⎛
−
⎟
⎟
⎠
⎞
⎜
⎜
⎝
⎛
⋅
= seconds
Figure 3.42: Volts/Hertz Inverse-Time Characteristic, 24IC = 1