Thytronic NA11, Manual

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45 NA11 - Manual - 02 - 2009 FUNCTION CHARACTERISTICS
4.4 PROTECTIVE ELEMENTS
Rated values
Inside the Base menu the following parameters can be set:
Relay reference name.
Relay nominal currents (phase and residual), to which the regulation are related.
Primary nominal values, employed for measures relative to primary values.
Measurements reading mode.
Language.
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 nominal current I
n
This nominal value must be set by means dip-switch to 1 A or 5 A, same as the secondary CTs
nominal current.
Dip-switches are located on board of the CPU module; the exhaustive treatment of Dip setup is
described in the “6.5 SETTING NOMINAL CURRENTS
I
n
AND I
En
” paragraph.
Relay residual nominal current I
En
[1]
This nominal value must be set by means dip-switch to 1 A or 5 A, same as the secondary CT nomi-
nal current.
Dip-switch is located on board of the CPU module; the exhaustive treatment of Dip setup is de-
scribed in the “6.5 SETTING NOMINAL CURRENTS
I
n
AND I
En
” paragraph.
Phase CT primary current I
np
This parameter affects the measure of the phase currents when the primary measurement read-
ing mode is selected. It must be programmed to the same value of the phase CT primary nominal
current.
Example
The phase CT primary current I
np
must be set as: I
np
= 500 A
Residual CT primary current I
Enp
This parameter affects the measure of the residual current when the primary measurement reading
mode is selected. It must be programmed to the same value of the residual CT(s) primary nominal
current.
Example 1
The residual CT primary current I
Enp
must be set as: I
Enp
= 100 A
Note 1 The computed residual current is available for NA11 protection relays equipped with LPCT sensor inputs
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Es-In.ai
K
TA
= 500A/5A=100
52
I
n
NA11
Es-In.ai
K
TA
= 500A/5A=100
52
I
n
NA11
Es1-IEn.ai
1x
K
TA
= 100 A /1 A
52
I
En
= 1 A
NA11
Es1-IEn.ai
1x
K
TA
= 100 A /1 A
52
I
En
= 1 A
NA11