Protective Elements
Commissioning: Overfrequency [f>]
Object to be tested
All configured overfrequency protection stages.
Necessary means
Three-phase voltage source with variable frequency and
Timer
Procedure
Testing the threshold values
Keep on increasing the frequency until the respective frequency element is activated;
Note the frequency value and
Disconnect the test voltage.
Testing the trip delay
Set the test voltage to nominal frequency and
Now connect a frequency jump (activation value) and then start a timer. Measure the tripping time at the
relay output.
Testing the fallback ratio
Reduce the measuring quantity to less than 99.95% of the trip value (or 0.05% fn). The relay must only fall back at
99.95% of the trip value at the earliest (or 0.05% fn).
Successful test result
Permissible deviations/tolerances can be taken from the Technical Data.
Commissioning: Underfrequency [f<]
For all configured underfrequency elements, this test can be carried out similar to the test for overfrequency
protection (by using the related underfrequency values).
Please consider the following deviations:
For testing the threshold values, the frequency has to be decreased until the protection element is activated.
For detection of the fallback ratio, the measuring quantity has to be increased to more than 100.05% of the
trip value (or 0.05% fn). At 100.05% of the trip value the relay is to fall back at the earliest
(or 0.05% fn).
922 MCDGV4 DOK-HB-MCDGV4-2E
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