7SR11 & 7SR12 Commissioning and Maintenance Guide
©2017 Siemens Protection Devices Limited Chapter 6 Page 27 of 72
Calculated Timing values in seconds for TM =1.0
Curve 2 xIs 5 xIs
IEC-NI
10.03 4.28
13.50 3.38
26.67 3.33
IEC-LTI
120.00 30.00
ANSI-MI
3.80 1.69
7.03 1.31
ANSI-EI
9.52 1.30
Note that the operate time may be subject to the Minimum op time setting for the element and/or may have a
Follower DTL applied.
2.7.3.1 Element Blocking
The Derived Earth Fault elements can be blocked by Binary Input Inhibit, VT Supervision and Inrush Detector
operation. The Characteristic can be made non-directional by VT Supervision. This functionality should be
checked.
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