Micom P721, Техническое руководство

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Commissioning and Maintenance P72x/EN CM/C21
MiCOM P721/P723 Page 11/28
4.3.2 MiCOM settings
4.3.2.1 MiCOM P723 Settings
Note that the setting cell Protection line select under Configuration/Connection should be set
as Phase.
Protection Menu
[87] PHASE DIFF. PROTECTION
[87] Phase diff. Prot. YES
[87] Threshold I Diff 2.00 In
[87] Fault Timer t diff 0.00 s
[87] Check Zone? No
[87] Measurement Filter Fourier, Sample, Fast sample modes
[87] Reset Timer tReset 0.00 s
AUTOMAT. CTRL/Trip commands Menu
TRIP [87] tDiff YES
4.3.3 [87] Threshold I Diff with Fourier mode
The Fourier mode is based on the module of the fundamental of the differential current. If
, the relay trips. Diff I Threshold [87] Idiff
>
Values to be recorded:
[87] Threshold I Diff for each phase
Time delay tDiff> for each phase.
[87] Threshold I Diff check:
If the time delay [87] Fault Timer tdiff is short, gradually increase the injection current up to
the value of the [87] Threshold I Diff.
If the time delay [87] Fault Timer tdiff is long, inject 0.95 x [87] Threshold I Diff and check that
there is no tripping. Then inject 1.1 x [87] Threshold I Diff and check the trip.
Gradually decrease the injected current and record the value of the drop out.
Checks:
Alarm message on the LCD.
Alarm LED flashes.
Trip LED on
[87] tDiff LED on (if programmed).
Trip output closes.
[87] tDiff output closes (if programmed).
[87] Fault Timer tdiff check:
Apply a current onto phase A and measure the time delay [87] tDiff by pre-setting the current
above the [87] Threshold I Diff (I injected > 2 x [87] Threshold I Diff). Repeat the same test
for phases B and C.