140
NVA100X-D - Manual - 02 - 2016
FUNCTION CHARACTERISTICS
The second element may be blocked by means of the Cold Load Pickup (CLP)
[1]
function.
If the CLP function is enabled the element is blocked for an adjustable time interval, starting from the
starting control criterion (circuit breaker closure or
I
RUN
threshold).
The CLP Activation time parameter (
tLRCLP>>
) may be adjusted inside the
Set \ Profi le A(or B) \
Locked rotor - 50S/ 51LR/14\
ILR>> Element \ Setpoints
menu.
Starting control
If the
CLP Source
parameter is set to
IRUN
and the maximum value of phase currents is lower than
0.1
I
B
, the protection is blocked off.
If the
CLP Source
parameter is set to
CB
and the circuit breaker is open, the protection is blocked
off.
The
CLP Source
parameter, common for profi les
A
and
B
, is available inside the
Set \ Starting
control set
menu.
Note 1 The inverse time threshold, unlike the defi nite time, is not in any way conditioned by the CLP activation time
Setting example: I
MOT-ST
= 5
I
LR>inv
With input current I
=
I
MOT-ST
and setting t
LR>inv
=10 s
the operate time is t
= 10 s
Operating characteristic concerning the locked rotor element (50S/51LR(48)/14)
F_48-Char.ai
t
=
t
LR
>
inv
·
(
I
MOT-ST
/
I
)
2
I
MOT-ST
I/
I
LR>inv
t
[s]
1
2
3
4
5
6
7
8 9 10
20
50
0.01
0.1
1
10
100
250
1000
10 000
t
LR>inv
= 1 s
t
LR>inv
= 10 s
t
LR>inv
= 200 s
t
LR>inv
= 100 s
