7PG2113/4/5/6 Commissioning & Maintenance
©2012 Siemens Protection Devices Limited
Chapter 6 Page 31 of 77
Calculated Timing values in seconds for TM =1.0
Curve
2 xIs
5 xIs
IEC-NI
10.03 4.28
IEC-VI
13.50 3.38
IEC-EI
26.67 3.33
IEC-LTI
120.00 30.00
ANSI-MI
3.80 1.69
ANSI-VI
7.03 1.31
ANSI-EI
9.52 1.30
Table 2.5-2
Standard Curve Timing
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.
2.5.1.1
ANSI Reset
If the element is configured as an ANSI characteristic, it may have a reset delay applied. If ANSI reset is selected
for an IEC characteristic element, the reset will be instantaneous.
ANSI reset times from operated condition to fully reset are as follows for zero applied current and TM = 1.0. The
reset curve characteristic type and TM is defined by the operating characteristic.
Curve
Fully operated to reset with Zero current applied & TM=1 (secs)
ANSI-MI
4.85
ANSI-VI
21.6
ANSI-EI
29.1
Table 2.5-3
Standard ResetCurve Timing
Apply current in the following sequence, a) 2x setting for a time to ensure element operation, b) Zero current for
the reset time above (xTM), c) 2x setting for a time to ensure element operation. Check that the second operation
(c) is similar to the first (a) and in line with the expected operate time for the element at this current level.
Repeat the test with the reset time (b) reduced to 50% of the previous value. Ensure that the second operate time
(c) is 50% of the first (a) operate time.
Table 2.5-4
51c Reset Results
Check correct indication, trip output, alarm contacts, waveform record.
Operate
time
(expected)
Reset time
(calculated)
Operate time
(measured)
50% Reset
Time
(calculated)
50% operate
time
(calculated)
50% operate time
(measured)
First test (c)
Second Test (c)