Areva MiCOM P921 - Page 343

Technical Guide P92x/EN CM/E11
Commissioning Guide
MiCOM P921-P922-P923 Page 21/28
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Stage (f1>) check:
1. If time delay (tf1>) is short, gradually increase the frequency from the nominal
frequency fn to the value of the stage (f1>): tripping should occur for a
frequency in the range [(f1>) – 10mHz, (f1>) + 10mHz].
2. If time delay (tf1>) is long, adjust the frequency to [(f1>) – 50mHz] and check
that tripping does not occur. Increase the frequency to 1.2x(f1>) and check that
tripping occurs.
3. Gradually reduce the frequency and measure the value of the drop-off stage
(f1>): the function must reset for a frequency less than or equal to [(f1>) –
50mHz].
Stage (f1<) check:
1. If time delay (tf1<) is short, gradually reduce the frequency from the nominal
frequency fn to the value of the stage (f1<): tripping should occur for a
frequency in the range [(f1<) – 10mHz, (f1<) + 10mHz].
2. If time delay (tf1<) is long, adjust the frequency to [(f1<) + 50mHz] and check
that tripping does not occur. Reduce the frequency to 0.8x(f1<) and check that
tripping occurs.
3. Gradually increase the frequency and measure the value of the drop-off stage
(f1<): the function must reset for a frequency greater than or equal to [(f1<)
+50mHz].
Action check:
1. appearance of an alarm message on the display
2. flashing of the “Alarm” LED
3. illumination of the “Trip” LED if tripping is programmed
4. illumination of the LEDs associated with instantaneous information (f1>) and
(f1<) and time-delayed information (tf1>) and (tf1<) if programmed
5. trip relay operation (RL1) if programmed
6. operation of output relay associated with stages (f1>) and (f1<) if programmed
5.5 "Rate of change of frequency" function tests
5.5.1 Wiring diagram
Refer to the diagram used for "Phase over/under voltage protection" functions tests.
5.5.2 MiCOM P923 relay parameters
Only configure the rate of change of frequency for 2 of the 6 stages available (one
with positive sign and the other with negative sign).