S&C Vista - Page 57

S&C Instruction Sheet 681-530 57
Overcurrent Control Settings
Table 13. IEEE Curves
Time Overcurrent Phase Protection
Inverse Segment
Standard Inverse (U1)
Very Inverse (U2)
Extremely Inverse
(U3)
Long-Time Inverse
(U4)
Short-Time Inverse
(U5)
Continuous Current
600
900/1200
Short Circuit, RMS Sym. Short Circuit, RMS Sym.
12.5 and 16 kA 25 kA 12.5 and 16 kA 25 kA
Minimum Trip Current,
A
14 to 12500 in steps
of 0.01
14 to 13200 in
steps of 0.01
28 to 12500 in steps
of 0.01
28 to 13200
in steps of
0.01
Low-Current Cutoff, A
●
14 to 12500 in steps
of 0.01
14 to 13200 in
steps of 0.01
28 to 12500 in steps
of 0.01
28 to 13200
in steps of
0.01
Time Multiplier 0.5 to 15 in steps of 0.01
Time Adder, s 0 to 1000 in steps of 0.01
Definite-Time Phase Protection Element #1
Definite-Time Current,
A
■
14 to 12500 in steps
of 0.01
14 to 13200 in
steps of 0.01
28 to 12500 in steps
of 0.01
28 to 13200
in steps of
0.01
Definite-Time Time, s 0 – 1000 in steps of 0.001
Definite-Time Phase Protection Element #2
Definite-Time Current,
A
▲
14 to 12500 in steps
of 0.01
14 to 13200 in
steps of 0.01
28 to 12500 in steps
of 0.01
28 to 13200
in steps of
0.01
Definite-Time Time, s
◆
0 – 1000 in steps of 0.001
Reset Time Parameters
Reset Type TIMED
Reset Time, s
▼
0 to 1000 in steps of 0.001
● Low-current cutoff must be equal to or greater than the minimum trip current.
■ Definite time current must be greater than or equal to low-current cutoff and/or the minimum trip current.
▲ Definite Time Current 2 should be greater than or equal to Definite Time Current 1.
◆ Time should be less than Definite-Time 1.
▼ Accumulated value will reset to zero after Reset Time has elapsed.