Siemens Reyrolle 7SR46 - Page 51

The following characteristic curves are supported by 51N-n:
•
DTL
•
IEC-NI
•
IEC-VI
•
IEC-EI
•
IEC-LTI
•
ANSI-MI
•
ANSI-VI
•
ANSI-EI
Operating time for IEC
Operating time for IEEE/ANSI
Reset time for IEC/IEEE/ANSI
Table 3-2 Constants for Operating-Curve and Reset-Curve Characteristics
Operating Curve Reset Curve
Curve type K α P A B R n
IEC-NI 0.14 0.02 – – – 9.7 2
IEC-VI 13.5 1.0 – – – 43.2 2
IEC-EI 80 2.0 – – – 58.2 2
IEC-LTI 120 1.0 – – – 80 2
IEEE/ANSI-MI – – 0.02 0.0515 0.114 4.85 2
IEEE/ANSI-VI – – 2.0 19.61 0.491 21.6 2
IEEE/ANSI-EI – – 2.0 28.2 0.1217 29.1 2
Where,
I - Fault-current Magnitude
I
S
- Pickup setting
T
m
- Time multiplier
Application and Settings Notes
Gn 51N-n Element
Default setting: Disabled
This setting is used to allow the element to be switched on and off if it is not required. A separate setting is
provided for each element. These settings can be used to select the number of elements required.
Parameter State
Description
Disabled
The element is inactive.
Enabled
The element is active.
Functions
3.5 51N Time-Delayed Earth Fault – Derived
Reyrolle, 7SR46 Device, Manual 51
C53000-G7040-C103-1, Edition 10.2022