7SR242 Duobias Commissioning & Maintenance Guide
©2010 Siemens Protection Devices Limited Chapter 6 Page 13 of 57
It should be considered that where several overlapping elements are used simultaneously, the overall protection
operate time may be dependent on the operation of different individual elements at the various levels of applied
current or voltage. The resulting composite characteristic may be tested by enabling all of the relevant applicable
elements or the element operations can be separated or disabled and tested individually.
All relay settings should be checked before testing begins. It is recommended that the relay settings are extracted
from the relay using ReyDisp Evolution software and a copy of these settings is stored for reference during and
after testing. It may be necessary to disable some protection functions during the testing of other functions to
allow unambiguous results to be obtained.
Care must be taken to reset or re-enable any settings that have been temporarily altered during the testing before
the relay can be put into service. At the end of testing the relay settings should be compared to the file extracted
at the start to ensure that errors have not been introduced.
An example ‘Test Sheet’ summary document is included at the end of this Guide.
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