Siemens SENTRON 3WL10, Руководство пользователя

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Description
2.4 Electronic trip unit ETU
Air circuit breaker 3WL10
Manual, 11/2017, L1V30499596002-01
49
Basic rules of parameterization and basic protection functions
Parameter Effect on char-
acteristic curve
Description Cause Example
L I
r
Current setting value of
the overload protection:
I
r
=0.4…1.0 × I
n
absolute values in A
Setting of the over-
load protection to the
load current of the
circuit to be protected
I
r
= 0.9 x I
n
(where I
n
=1000A)
Overload range as of I
r
= 900 A
t
r
Delay time in the over-
load range The set time
is the tripping time at
6 × I
r
.
Use for current and
time selectivity
The set delay time t
r
of, for exam-
ple, 10 s always applies at the
reference point 6 x I
r
.
In this case, it is therefore
6 x 900 A = 5400 A
The tripping characteristic in
the overload range can be plotted
in the same way as for I²t
dependency.
S I
sd
Operating current of the
short-time-delayed short-
circuit protection
I
sd
= 1.0 … 10 x I
n
Limitation of the
short-circuit range in
which the current has
to be interrupted as
quickly as possible,
but with a defined
time delay
I
sd
= 8 x I
n
= 8000 A
(at I
n
= 1000 A)
Range of the short-time delay as
of 8000 A
t
sd
Delay time of the
short-time-delayed
short-circuit protection
Use for time selectivi-
ty. Time delay of t
sd
can be definite-time
or inverse-time in
relation to I²t
For example, at t
sd
= 0.4 s (con-
stant): Tripping after 400 m for
short-circuit values above 8000 A
and below a value of I
i
I I
i
Current setting value
of the instantaneous
short-circuit protection
I
i
= 1.5 … 15 x I
n
Limitation of the
short-circuit range in
which the impermis-
sibly high current has
to be interrupted as
quickly as possible
I
sd
= 12 x I
n
= 12000 A
(at I
n
= 1000 A)
Range of the instantaneous
tripping on short-circuits as of
12000 A
G I
g
Current setting value of
the ground-fault protec-
tion
Line protection On ground-fault current
as of 0.1 x I
n
= 100 A
(at I
n
= 1000 A)
Tripping, for example, after a time
of t
g
= 0.1 s
t
g
Delay time until
disconnection
Line protection Tripping after a time of t
g
= 0.1 s