Protective Elements
Commissioning: f< and DF/DT – Underfrequency and DF/DT
Object to be tested:
All frequency protection stages that are projected as f< and Df/Dt.
Necessary means:
Three-phase voltage source and
Frequency generator that can generate and measure a defined frequency change.
Procedure:
Testing the threshold values
Feed nominal voltage and nominal frequency to the device:
Decrease the frequency below the f< threshold and
Apply a defined frequency change (step change) that is above the setting value (example: apply a frequency
change of 1 Hz during the set time interval DT if the setting value DF is 0.8 Hz). The relay has to trip
immediately.
Successful test result
Permissible deviations/tolerances and dropout ratios can be taken from the Technical Data.
Commissioning: f> and DF/DT – Overfrequency and DF/DT
Object to be tested:
All frequency protection stages that are projected as f> and Df/Dt.
Necessary means:
Three-phase voltage source and.
Frequency generator that can generate and measure a defined frequency change.
Procedure:
Testing the threshold values
Feed nominal voltage and nominal frequency to the device:
Increase the frequency above the f> threshold and
Apply a defined frequency change (step change) that is above the setting value (example: apply a frequency
change of 1 Hz during the set time interval DT if the setting value DF is 0.8 Hz). The relay has to trip
immediately.
Successful test result:
Permissible deviations/tolerances and dropout ratios can be taken from the Technical Data.
925 MCDGV4 DOK-HB-MCDGV4-2E
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