Siemens SIPROTEC 7UT613 series Manual page 175

Dynamic Cold Load
Pickup
User-Defined
Curves
Inrush Restraint
7UT613/63x Manual
C53000-G1176-C160-2
2.4 Time Overcurrent Protection for Phase and Residual Currents
This means that a pickup will only occur if a current of about 1.1 times the setting value
is present.
The current value is set in address 2221 or 2222 3I0p. The most relevant for this
setting is the minimum appearing earth fault current. Please consider that measuring
tolerances may be higher with multiple measuring locations due to summation errors.
The corresponding time multiplier is set in address 2224 D 3I0p. This has to be co-
ordinated with the grading coordination chart of the network. For earth currents with
earthed network, you can mostly set up a separate grading coordination chart with
shorter delay times.
If you set a very small pickup value, consider that the inrush restraint function cannot
operate below 10 % nominal current (lower limit of harmonic filtering). An adequate
time delay could be reasonable if inrush restraint is used.
The time multiplier can also be set to ∞. If set to infinity, the pickup of this function will
be indicated but the stage will not trip after pickup. If the 3I0p stage is not required at
all, select address 122 DMT/IDMT 3I0 = Definite Time during configuration of
the protection function.
If under address 2225 TOC DROP-OUT the Disk Emulation is set, a dropout in ac-
cordance with the dropout characteristic occurs, as described in section „Dropout Be-
haviour"
An alternative set of pickup values can be set for each stage. It may be selected au-
tomatically in a dynamic manner during operation. The following alternative values are
set for the stages here (section 2.6).
for definite time overcurrent protection 3I0:
• address 2311 or 2312 for pickup value 3I0>>,
• address 2313 for delay time T 3I0>>,
• address 2314 or 2315 for pickup value 3I0>,
• address 2316 for delay time T 3I0>,
for inverse time overcurrent protection 3I0 acc. to IEC characteristics:
• address 2321 or 2322 for pickup value 3I0p,
• address 2323 for time multiplier T 3I0p;
for inverse time overcurrent protection 3I0 acc. to ANSI characteristics:
• address 2321 or 2322 for pickup value 3I0p,
• address 2324 for time multiplier D 3I0p;
For inverse time overcurrent protection the user may define his own tripping and
dropout characteristic. For configuration in DIGSI a dialogue box appears. Enter up
to 20 pairs of current and tripping time values.
The procedure is the same as for „Phase Current Stages" under „User-specific Char-
acteristics" (see section 2.4.2.1).
To create a user defined tripping characteristic, the following must have been set for
configuration of the scope of functions: address 122 DMT/IDMT 3I0 the option User
Defined PU. Should you also wish to specify the dropout characteristic, select option
User def. Reset.
At address 2202 InRushRest. 3I0 of the general settings, the inrush restraint can
be enabled (ON) or disabled (OFF). Especially for transformers and if overcurrent time
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