Figure 347: Operation timer characteristic of IFPTOC-function when Operation
principle = “EF-current based” and Operating curve type = “Inverse time IEEE80”.
Setting IEEE multiplier is 500,Maximum earthing Ris is 10 ohms, EF current Str Val =
0.02*In (2 A), IDMT stage Min Op Tm = 100 ms and IDMT stage Max Op Tm = 5000
ms. Reduction factor = 1.0. Characteristics are according to standard IEEE80.
Principle based on touch voltage estimate
The operation of IFPTOC based on touch voltage estimate is described next. In
case
Operation principle
= “Touch voltage based”, then operation is based on
the estimated touch voltage magnitude according to
Equation 119
. The harmonic
content of touch voltage can be included into estimate with setting
Enable
harmonics
= “Enable”.
1MRS759142 F
Protection functions
REX640
Technical Manual
611
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