Protective Elements
Commissioning: f< and -df/dt ā Underfrequency and ROCOF
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 linear, defined rate of change of frequency.
Procedure:
Testing the threshold values
Feed nominal voltage and nominal frequency to the device
Decrease the frequency below the f< threshold and
Apply a rate of change of frequency (step change) that is below the setting value (example apply -1 Hz per
second if the setting value is -0.8 Hz per second). After the tripping delay is expired the relay has to trip.
Successful test result
Permissible deviations/tolerances and dropout ratios can be taken from the Technical Data.
Commissioning: f> and df/dt ā Overfrequency and ROCOF
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 linear, defined rate of change of frequency.
Procedure
Testing the threshold values
Feed nominal voltage and nominal frequency to the device.
Increase the frequency above the f> threshold and.
Apply a rate of change of frequency (step change) that is above the setting value (example apply 1 Hz per
second if the setting value is 0.8 Hz per second). After the tripping delay is expired the relay has to trip.
Successful test result:
Permissible deviations/tolerances and dropout ratios can be taken from the Technical Data.
924 MCDGV4 DOK-HB-MCDGV4-2E
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