IDMT curve operation are given as: Pickup value = 110%, Voltage Max Cont = 100%,
Time multiplier = 5, Maximum trip time = 3600 s, Constant delay = 0.8 s and Cooling time
= 100 s.
GUID-78B05F4B-3434-4DD5-89F6-17F099444C04 V1 EN
Figure 326: Tripping curve of “OvExt IDMT Crv4” based on the specified settings. The
two dots marked on the curve are referred to in the text.
If the excitation level stays at 1.25, the tripping occurs after 15.20 s. At the excitation level
of 1.42, the time to tripping would be 5.90 s as per the two dots in
Figure 326. In this case,
the setting Maximum trip time 3600 s does not limit the maximum trip time because the
trip time at Pickup value = 110% (1.1 pu) is approximately 75 s.
4.5.6.7 Signals
Table 558: 24 Input signals
Name
Type Default Description
I_A SIGNAL 0 Phase A current
I_B SIGNAL 0 Phase B current
I_C SIGNAL 0 Phase C current
I
1
SIGNAL 0 Positive-phase sequence current
Table continues on next page
1MAC059074-MB A Section 4
Protection functions
615 series ANSI 655
Technical Manual
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