hager h3+ - Neutral Protection

38 6LE005550A
Function of the Energy trip unit
3.2 Protection function
Ground protection is a protection against high strength insulation faults. It is similar
to short time delay protection. It also has an inverse time I²t function, which can be
activated or deactivated when adjusting this protection.
This i²t function makes it possible to improve selectivity of ground faults with
downstream devices. It is activated from the Ig threshold and functions up to In.
3.2.5
Neutral protection
Neutral protection is available on Energy 4P circuit breakers. It is particularly useful
when the cross-section of the neutral conductor is reduced in relation to the phase
conductors.
It uses the long time delay, short time delay and instantaneous protection
parameters.
Neutral protection curve
In (A)
t (s)
tsd
N=100%N=50%
lr lilsd
Neutral protection
Adjusting the Ir and Isd thresholds for neutral protection
N coecient adjustment range (%) Parameters impacted
OFF – 50 - 100
The coecient is applied to the adjustment
value of the Ir and Isd thresholds for the phases.
The instantaneous current threshold remains identical to that of the phases.
The N coecient can be adjusted from the embedded display, the panel display or
the h3+ configuration tool.
Neutral protection time delay
The time delays for neutral protection remain identical to the phase time delay
adjustment values.