Areva MiCOM P125, Technical Manual

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P12y/EN CM/C22 Commissioning and Maintenance
Page 16/24 MiCOM P125/P126 & P127
IEC curves
Type of curve Tripping time (in seconds) for TMS =1
IEC 2 x I threshold 10 x I threshold
Nominal Min - Max Nominal Min - Max
STI 1.78 1.62 - 1.98 0.5 0.45 - 0.55
SI 10.1 9.1 - 11.1 3 2.7 - 3.3
VI 13.5 12.2 - 14.9 1.5 1.35 - 1.65
EI 26.7 24 - 29.5 0.8 0.72 - 0.88
LTI 120 108 - 132 13.3 12 - 14.6
IEEE/ANSI curves
Type of curve Tripping time (in seconds) for TMS =1
IEEE/ANSI 2 x I threshold 10 x I threshold
Nominal Min - Max Nominal Min - Max
STI 0.25 0.22 - 0.28 0.08 0.07- 0.09
MI 3.8 3.4 - 4.2 1.2 1.08 - 1.32
I 2.2 1.9 - 2.4 0.3 0.27 - 0.33
VI 7.2 6.5 - 8 0.7 0.63 - 0.77
EI 9.5 8.5 - 10.5 0.4 0.36 - 0.44
Checks:
•
Ie> Alarm message on the LCD display.
•
Alarm LED flashes.
•
Trip LED on
•
Ie> threshold LED on (if programmed).
•
Trip output closes.
•
Ie> threshold output closes (if programmed).
4.3.5.2 Phase overcurrent I> threshold test (P126 & P127)
Phase overcurrent threshold check:
•
If the time delay tI> is short, gradually increase the injection current up to the value of
the I> threshold.
•
If the time delay tI> is long, inject 0.95 x I threshold and check that there is no tripping.
Then inject 1,1 x I threshold and check the trip.
•
Gradually decrease the injected current and record the value of the drop out off (I>
threshold).