NHP Terasaki TemBreak PRO P SE Series, User Manual

Page: 45 / 122

Protection Settings
45
TemBreak PRO
P_SE-UM-001-EN
– V1.2.0
Neutral Protection (NP)
Neutral protection is available with 4P P_SE MCCBs as standard. 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.
Adjusting I
r
and I
sd
for Neutral Protection (Current)
Adjustments to Ir and Isd for the Neutral pole are made by adjuring the N Coefficient setting, which can be made using one or a combination of the below
methods:
-
P_SE OCR embedded display
-
TPED
-
TPCM
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
50
%
N
Notice : If the I 2 t function for STD is enabled, I 2 t will also be included in the Neutral Protection curve as
calculated from the Neutral pole I
r
parameter.