FUNCTION CHARACTERISTICS
71
NVA100X-D - Manual - 02 - 2016
4.4 PROTECTIVE
ELEMENTS
Rated values
Inside the
Base
menu the following parameters can be set:
Relay reference name
The the reference for the settings of relay rated currents (phase and residual)
Primary nominal values, employed for to return measures in the primary values
Measurements reading mode (primary or relative values)
Reset delay for Cold Load Pickup
[1]
Information for settings:
Relay reference name.
Alphanumeric mnemonic string (max 16 characters) useful for identifi cation of protected plant.
Relay nominal frequency
f
n
This nominal value must be set same as the frequency of the grid.
Example: grid frequency
f
n
= 50 Hz
Relay nominal frequency
f
n
= 50 Hz
Relay phase rated current for side H and side L
I
nH
,
I
nL
This rated value must be set to 1 A or 5 A
[2]
, same as the secondary CTs rated current.
Rated primary phase current chosen as reference (
I
nref
)
CT’s primary current chosen by relay for amplitude compensation.
Rated primary phase current chosen as reference (
RefSide
)
Choice of the reference side for the phase compensation currents
Number of sides for differential protection (
NumSides
)
Setting the number of sides on which the differential protection operates (fi xed to 2)
Current matching type (
MatchType
)
Setting the current compensation type (INT-internal, EXT-external CTs)
Protected object (
ProtObj
)
Setting the type of protecting object (fi xed to TRANSF)
Relay residual current - side 1 and side 2 (
I
En1
and
I
En2
)
This rated values must be set by means dip-switch to 1 A or 5 A
[3]
, same as the secondary residual
CT rated current.
Relay phase-to-phase voltage
U
n
Two reference voltage are available:
U
R
=100 V and
U
R
=400V
For the fi rst instance the
U
n
relay nominal voltage must be set to the phase-to-phase voltage of the
secondary VTs voltages at grid nominal voltage.
The
U
n
value must calculated as:
If VTs with primary rated voltage is equal to the grid voltage divided by √3, the following streamlined
calculus may be used:
U
n
= VTs secondary rated voltage [V] x √3
Example 1
The relay rated voltage may be set to:
U
n
=
U
ng
/
K
VT
= 6900 / 100 = 69 V
Note 1 Parameter available at level 1 only
Nota 2 Per rendere attiva la modifi ca della regolazione, dopo il comando “Fine tarature“ è necessario RIAVVIARE IL DISPOSITIVO
Nota 3 Per rendere attiva la modifi ca della regolazione, dopo il comando “Fine tarature“ è necessario RIAVVIARE IL DISPOSITIVO
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Voltage transformer ratio
K
VT
Grid nominal voltage
U
ng
where the VTs are included [V]
U
n
=
Voltage transformer ratio
K
VT
Grid nominal voltage
U
ng
where the VTs are included [V]
U
n
=
Es1-Un.ai
K
VT
=
/
/
V
V
10000
3
100
3
= 100
/
/
V
V
10000
3
100
3
= 100
Grid rated voltage
U
ng
= 6.9 kV
VTs ratio
K
VT
=
U
ng
= 6.9 kV
U
n
52
NVA100X-D
Es1-Un.ai
K
VT
=
/
/
V
V
10000
3
100
3
= 100
/
/
V
V
10000
3
100
3
= 100
Grid rated voltage
U
ng
= 6.9 kV
VTs ratio
K
VT
=
U
ng
= 6.9 kV
U
n
52
NVA100X-D
