FUNCTION CHARACTERISTICS
26
NG10 - Manual - 04 - 2022
4.3 I/O DESCRIPTION
Metering inputs
The following inputs are provided:
• Three phase current inputs for side H
• Three phase current inputs for side L
• One residual current input
The nominal currents are independently adjustable at 1 A or 5 A through DIP-switches
The input circuits are appropriately dimensioned in order to withstand the currents which arise
when a fault occurs, both in transient and steady state condition.
Signal processing
Various processing levels are involved:
• Acquisition (base level).
• Direct measures of physical channels (first level).
• Calculated measures (second level).
• Derived (third level).
The measures concerning a level are based on data worked out in the previous level.
For each level the required resources concerning the priority for tasks (conditioning circuits, DSP
and CPU) are on hand.
ACQUISITION (base level)
The input signals are sampled 16 times per period:
- i
L1H
...i
L3H
Phase current instantaneous values - side H
- i
L1L
...i
L3L
Phase current instantaneous values - side L
- i
E
Residual current instantaneous value
From the sampled quantities, several measures are computed for protection, monitoring and meter-
ing purposes.
• Direct
• Calculated
• Phase
• Sequence
• Harmonic
• Demand
sensori.ai
NG10
side H
side L
52
G
Three phase current inputs - side H
Three phase current inputs - side L
One residual current input IE
acquisizione.ai
ACQUISITION
instantaneous values
≈
To Next Page
Loading...
