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4.7 Function 51N. Inverse time calculated neutral overcurrent
This protection function can be set by using the following parameters:
Function
Description
Minimum
Maximum
Step
Unit
Default
51N_1 (*)
51N_2 (*)
Inverse time calculated neutral overcurrent
Function
Enable
-
-
No/Alarm/Trip/SHB Trip
-
No
Curve Type
-
-
(1)
-
IEC
Standard
Inverse
Time Dial (TMS)
0.05
25.00
0.01
(2)
1.00
Current Tap
0.050
20.000
0.001
xIn
5.000
Time Delay
0.000
300.000
0.001
s
0.200
(*) Optional depending on model
(1)
Definite time and 8 curves are included to be selected by the user:
TYPE
NAME
DT
Definite Time
IEC
Standard Inverse
Very Inverse
Extremely Inverse
Long Time Inverse
Short time Inverse
IEEE
Moderately Inverse
Very Inverse
Extremely Inverse
(2)
The range of the time Multiplier setting will depend on the curve. The range of this setting for each
curve family is as follows:
TIME DIAL (TMS)
Description
Minimum Maximum Step Unit Default
IEC
Time Multiplier
0.05
1.00
0.01
-
1.00
IEEE
Time Multiplier
0.10
25.00
0.01
-
1.00
If the option
‘Defined
time
’
is selected for the curve setting, the unit behaves like an instantaneous
directional overcurrent unit. In this case, the unit time delay is adjusted by using the parameter
‘Time
delay’
. If a curve is selected for the curve setting, the time delay depends on the curve, dial (TMS) and
tap settings.
If the unit operates as defined time, the function is activated at 100% of the set tap value, and it
deactivates at 95%. If the unit operates with a curve, the function is activated at 110% of the set tap
value, and it deactivates at 100%. The reset is instantaneous in both cases.
If the unit operates as defined time, the accuracy of the Time Delay is equal to the set time delay ±35ms
or ±0.5% (whichever is greater).If a curve is selected for the curve setting, the accuracy of the time delay
is equal to the theoretical time ±30ms or ±5% (whichever is greater).
The curves used are IEC 60255-151 and IEEE, which are described in the corresponding section.
Summary of Contents for SIL-A A Series
Page 8: ...www fanox com Rev 04 8 112 2 1 2 Case dimensions The dimensions are in mm...
Page 9: ...www fanox com Rev 04 9 112 2 1 3 Connection diagrams 2 1 3 1 Analog connections...
Page 12: ...www fanox com Rev 04 12 112 2 2 SILA with short circuitable current terminals 2 2 1 Front view...
Page 13: ...www fanox com Rev 04 13 112 2 2 2 Case dimensions The dimensions are in mm...
Page 14: ...www fanox com Rev 04 14 112 2 2 3 Connection diagrams 2 2 3 1 Analogic connections...
Page 22: ...www fanox com Rev 04 22 112 3 3 Functional diagram...
Page 61: ...www fanox com Rev 04 61 112...
Page 63: ...www fanox com Rev 04 63 112...
Page 64: ...www fanox com Rev 04 64 112...
Page 65: ...www fanox com Rev 04 65 112...
Page 111: ...www fanox com Rev 04 111 112 11 APPENDIX NOTES...
