NHP TemBreak PRO, User Manual

Page: 35 / 105

Protection Settings
35
TemBreak PRO
B_BE-UM-001-EN
– V1.1.0
Neutral Protection (NP)
Neutral protection is available with 4P B_BE MCCBs with Neutral trip unit option added. It is particularly useful when the cross-section of the neutral
conductor is reduced in relation to the phase conductors.
Neutral protection is based off the standard LTD and STD protection parameter of the main phases. The I
r
and I
sd
parameters for the Neutral pole are
adjusted according to the set Neutral Coefficient percentage. For example, If the Neutral conductor is sized at 50% of the main phases, and the N
Coefficient Adjustment parameter is set to 50%, then I
r
and I
sd
of the Neutral pole will be 50% of I
r
and I
sd
of main phase poles.
The time delays for the Neutral pole remain identical to the t
r
and t
sd
time delay adjustment values for the main phases and cannot be independently
changed.
INST protection of the Neutral pole is not affected by the N Coefficient adjustment setting and is identical to the I
i
trip threshold of the main phases.
The Neutral Coefficient percentage can be adjusted using the DIP switches on the MCCB by setting the two NP switches (positions 2 and 3).
DIP switch 2:
-
OFF: NP disabled
-
ON: NP enabled
DIP switch 3:
-
OFF: N% = 50% x I
r
-
ON: N% = 100% x I
r
N Coefficient Adjustment Settings (%) Parameters Impacted
50 – 100 – OFF The coefficient is applied to the adjustment value of the phase I
r
and I
sd
thresholds