hager hw+, Руководство пользователя

Страница: 14 / 120

14
6LE007331A
The types of protection device
3.1 List of protection devices
The Sentinel electronic trip unit protects against overcurrent and ground faults for all types
of electrical distribution in accordance with the requirements of standards IEC 60947-1 and
60947-2.
List of protection devices
- Long Time Delay protection - L : Overload protection
- Short Time Delay protection - S : Protection against low current short circuits
- Instantaneous protection - I : Protection against high current short circuits
- Ground fault protection - G : Phase-to-ground fault protection
- Neutral protection - N : Protection against overloads and short circuits which may flow
through and damage the neutral conductors.
I (A)
t (s) L S I
tr
lr lg li lsd
tsd
tg
l²t
l²t
L
Ir Long Time Delay protection threshold
tr Long Time Delay
S
Isd Short Time Delay protection threshold
tsd Short Time Delay
I²t ON/OFF I²t curve on Short Time Delay protection activated or not
I Ii Instantaneous protection threshold
G
Ig Ground protection threshold
tg Ground protection time delay
I²t ON/OFF I²t curve on ground protection activated or not
N N
% of the adjustment value of the Ir and Isd thresholds for
the phases
Protection ANSI code
L 49
S i²t OFF: 50TD
i²t ON: 51
I 50
G i²t OFF: 50N-TD
i²t ON: 51N
In addition to Instantaneous protection, Sentinel trip units have MCR (Making Current Release)
protection, which is operational if a short circuit fault occurs during a closing operation.
Protection setting adjustment device
The settings of the protection device can be modified using the adjustment dials and the
display.
All protection functions are based on the root-mean-square value (RMS) of the current to take
into account the presence of current harmonics.
The extensive choice of protection curve settings facilitates coordination in terms of selectivity.