1MAC050144-MB C
Section 11
General function block features
615 series ANSI
671
Technical Manual
The
Minimum trip time
setting defines the minimum trip time possible for the IDMT mode.
For setting a value for this parameter, the user should carefully study the particular IDMT
curve.
11.3.2.1
Standard inverse-time characteristics for undervoltage protection
The trip times for the standard undervoltage IDMT curves are defined with the coefficients
A, B, C, D and E.
The inverse trip time can be calculated with the formula:
(Equation 87)
t [s] trip time in seconds
V
measured voltage
V< the set value of the
Pickup value
setting
k
the set value of the
Time multiplier
setting
Table 544: Curve coefficients for standard undervoltage IDMT curves
Curve name
A
B
C
D
E
(21) Inverse
Curve A
1
1
0
0
1
(22) Inverse
Curve B
480
32
0.5
0.055
2
t s
k A
B
V
V
V
C
D
E
⎡
⎣⎢
⎤
⎦⎥
=
⋅
× < −
<
−
⎛
⎝⎜
⎞
⎠⎟
+
Summary of Contents for 615 Series ANSI
Page 1: ...Relion Protection and Control 615 series ANSI Technical Manual ...
Page 2: ......
Page 29: ...1MAC050144 MB C Section 615 series ANSI 22 Technical Manual ...
Page 389: ...Section 4 1MAC050144 MB C Protection functions 382 615 series ANSI Technical Manual ...
Page 485: ...Section 6 1MAC050144 MB C Supervision functions 478 615 series ANSI Technical Manual ...
Page 635: ...Section 10 1MAC050144 MB C Other functions 628 615 series ANSI Technical Manual ...
Page 711: ...Section 16 1MAC050144 MB C Glossary 704 615 series ANSI Technical Manual ...
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