Siemens 7SR21 Manual page 38

7SR21 & 7SR22 Argus Commissioning and Maintenance
Apply 2x setting current if possible and record operating time
Is DTL P.U. Current Operate Time
Phase Tolerance Tolerance
(Amps) (sec) Amps 2 x Is
REF
It is also desirable to check the operating voltage achieved with the setting resistor and all parallel CTs connected
but de-energised. A higher capacity test set will be required for this test. Adequate current must be supplied to
provide the magnetising current of all connected CTs. Precautions should be taken to ensure that no personnel
are at risk of contact with any of the energised secondary wiring during the test.
Settings Data Voltage Setting Measured
To complete testing of the REF requires primary injection through the phase and residual (REF) CT in series to
simulate an out of zone fault and ensure stability of the relay. The test can then be repeated with the REF CT
secondary connections reversed to prove operation.
2.9.1.1 Element Blocking
The Restricted Earth Fault element can be blocked by Binary Input Inhibit. This functionality should be checked.
Element BI Inhibits
64H
Check correct indication, trip output, alarm contacts, waveform record.
Check that any shorting links are removed after testing.
©2010 Siemens Protection Devices Limited Chapter 6 Page 38 of 69