46
NVA100X-D - Manual - 02 - 2016
FUNCTION CHARACTERISTICS
4.3 I/0
Metering inputs
The following inputs are provided:
Six phase current inputs
Two residual current input
The rated currents are independently adjustable at 1 A or 5 A through sw setting
Three phase voltage inputs with programmable nominal voltages within range 50...130 V (
U
R
=100 V)
or 200...520 V (
U
R
=400 V) to be select on order. The nominal voltages is user adjustable inside a
wide setting range, so the relays can be employed on plants with TV different secondary voltages
(50...130 V for versions with
U
R
=100 V and 200...520 V for versions with
U
R
= 400 V). The version with
U
R
=400V allows a direct measure without interposing VTs for low voltage applications (200...520 V
nominal voltage). The voltage inputs must be connected for measuring phase-to-neutral voltages.
From the
U
L1
,
U
L2
,
U
L3
measures
the phase-to-phase voltages
U
L12
,
U
L23
,
U
L31
are calculated.
One residual voltage input, with programmable nominal voltage within range 50...130 V (
U
ER
=100 V )
Signal processing
Various processing levels are involved:
Acquisition (base level).
Direct measures of physical channels (fi rst 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 64 times per period:
-
i
L1H
...
i
L3H
Phase current instantaneous values - side H
-
i
L1L
...
i
L3L
Phase current instantaneous values - side L
-
i
E1
Residual current instantaneous value - side 1
-
i
E2
Residual current instantaneous value - side 2
-
u
L1
...
u
L3
Phase voltage instantaneous values
-
u
E
Residual voltage instantaneous value (traditional VT inputs only)
From the sampled quantities, several measures are computed for protection, monitoring and meter-
ing purposes.
Direct
Calculated
Phase
Sequence
Power
Harmonic
Impedance
Demand
Energy.
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Three phase voltage inputs
One residual current input side 2
One residual current input side 1
One residual voltage input
sensori.ai
NVA100X-D
Three phase current inputs side H
Three phase current inputs side L
G
Three phase voltage inputs
One residual current input side 2
One residual current input side 1
One residual voltage input
sensori.ai
NVA100X-D
Three phase current inputs side H
Three phase current inputs side L
G
acquisizione.ai
≈
ACQUISITION
instantaneous measures
acquisizione.ai
≈
ACQUISITION
instantaneous measures
