ERL F-PRO 116, User Manual

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5-4 F-PRO 116 User Manual D05125R01.20
If the Derived Neutral current is greater than the set current the enabled function will go for the
operation after the set delay (51N) or as per the set Inverse curve (51N) or instantaneous (50N).
The function has an additional feature of “Inrush Blocking”. This is provided to block the function
from operation when second harmonic current is present over the fundamental. Each element
(50N-1, 50N-2) can be independently inhibited via external input status which can be configured
from input matrix. This will help in achieving comprehensive blocking schemes.
50N - Derived Neutral Overcurrent Logic diagram
Figure 5.3: Logic Diagram of 50N Function
Table 5.4: 50N Neutral Overcurrent Settings (No. of Stages – 2)
Setting Description Range
Function Activation Enable/disable
Pickup
0.05 to 25 A (1 A) / 0.25 to 125 A (5 A)
Pickup Delay 0.00 to 999.99 seconds
Inrush Blocking Enable/disable
51N – IDMTL Derived Neutral Overcurrent Logic diagram
Figure 5.4: Logic Diagram of 51N Function
Functional Block Via External Input
Function Enable
I
N
> 50N Pickup
Inrush Block
50N Operated
51N Operated
I
N
> 51N Pickup
Function Enable
Inrush Block
Functional Block Via External Input