Element Blocking; Ansi Reset - Siemens 7SR18 Solkor Manual

3.3.1
E B
LEMENT LOCKING
The Phase Overcurrent elements can be blocked by Binary Input Inhibit and Inrush Detector operation. The
Characteristic can be modified by Cold Load (51-n only). This functionality should be checked.
Element BI Inhibits
51-1
51-2
50-1
50-2
3.3.2
ANSI R
ESET
If the element is configured as an ANSI characteristic, it may have an ANSI (decaying) 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 Time multiplier
(TM) = 1.0. The reset curve characteristic type and TM is defined by the operating characteristic.
Curve
ANSI-MI
ANSI-VI
ANSI-EI
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.
Operate Reset time
time (calculated)
(expected)
Check correct indication, trip output, alarm contacts, waveform record.
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Inrush Detector
Fully operated to reset with Zero current applied & TM=1 (seconds)
Operate time 50 % Reset
(measured) Time
(calculated)
First test (c)
7SR18 Commissioning & Maintenance Guide
4.85
21.6
29.1
50 % operate 50 % operate time
time (measured)
(calculated)
Second Test (c)
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