ABB RER620

1MAC309294-MB F Section 10
General function block features
RER620 537
Technical Manual
10.3.1.1 Standard inverse-time characteristics for overvoltage protection
The trip times for the standard overvoltage IDMT curves are defined with the coefficients
A, B, C, D and E.
The inverse trip time can be calculated with the formula:
(Equation 64)
t [s] trip time in seconds
V measured voltage
V> the set value of
Pickup value
k the set value of Time multiplier
Table 425: Curve coefficients for the standard overvoltage IDMT curves
Curve name A B C D E
(17) Inverse Curve A 1 1 0 0 1
(18) Inverse Curve B 480 32 0.5 0.035 2
(19) Inverse Curve C 480 32 0.5 0.035 3
ts
kA
B
VV
V
C
D
E
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