Thytronic NV10B - Protective Elements - Rated Values

CHARACTERISTICS
37
NV10B - Manual - 04 - 2022
4.4 PROTECTIVE ELEMENTS
Rated values
Inside the Base menu the following parameters may be set:
• Relay reference name.
• Relay nominal voltages (phase and residual), to which the regulation are related.
• Primary nominal values, employed for measures relative to primary values.
• Measurements reading mode.
Information for settings:
• Relay reference name.
Alphanumeric mnemonic string (max 16 characters) useful for identification 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 nominal voltage U
n
Two reference voltage are available: U
R
=100 V and U
R
=400V
The U
n
relay nominal voltage must be set to the value of relay input voltages at grid nominal volt-
age.
The U
n
value must calculated as:
If VTs with primary nominal voltage is equal to the grid voltage divided by √3, the following stream-
lined calculus may be used:
U
n
= VTs secondary nominal voltage [V] x √3
Example 1
The relay nominal voltage may be set to:
U
n
= U
ng
/ √3 · K
TV
= 6000 /√3 · 60 = 100 /√3 = 58 V
Voltage transformer ratio K
TV
Grid nominal voltage U
ng
where the VTs are included [V]
U
n
=
Es1-Un.ai
K
TV
=
/
/
V
V
6000
3
100 3
= 60
U
ng
= 6.0 kV
NV10B
U
L1
U
L2
U
L3
VOLTAGE INPUTS
n
a
N
A
L1
L2
L3
Phase to ground VTs connection
B5
B6
B3
B4
B1
B2