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Table 2.5-2 Constants for inverse-time-reset characteristics
Curve Type
IEC 60255-151
A
IEC Normal Inverse (IEC-NI‡)
B
IEC Very Inverse (IEC-VI‡)
C
IEC Extremely Inverse (IEC-EI‡)
-
UK Long Time Inverse (UK-LTI‡)
D
IEEE Moderately Inverse (IEEE-MI)
E
IEEE Very Inverse (IEEE-VI)
F
IEEE Extremely Inverse (IEEE-EI)
-
US CO8 inverse (US-CO8)
-
US CO2 short time inverse (US-CO2)
†Note: To select the inverse-time-reset characteristic, set [OCN1-Rtimer]=DEP.
Conversely set [OCN1-Rtimer]=DEF to select definite-time-reset characteristic.
Note: For the setting [OCN1-Rtimer]=DEP (inverse-time-reset), the integrated value will
be reduced in accordance to the magnitude of an energized current, when the
energized current is smaller than the setting [OCN1]. The reducing degree will be
determined with the reset curve characteristics defined in the standards.
Note: For the setting [OCN1-Rtimer]=DEF (definite-time-reset), the integrated value
shall be zero when an energized current is smaller than the setting [OCN1], when
the small energized current is continued for timer setting [TOCN1R]. The
integrated value will not be zero when the energized current does not flow small
for the setting [TOCN1R]. DEF is allowed to set in the IEEE, US, and ORG. DEF is
set unconditionally in the IEC and UK (see Table 2.5-3).
Figure 2.5-4 Inverse-time-reset characteristics curves
Figure 2.5-5 illustrates that an integrating value will be influenced dependent on the
DEP or DEF setting. An energized quantity (I), where I is greater than a threshold setting
[OCN1], will make an integrating value, which can determine how the element operates. If the
Curve Description
- 96 -
6F2T0207 (0.01)
kr
β
(sec)
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
4.85
2
21.6
2
29.1
2
5.95
2
2.261
2
GRE200 (5,6)
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