Time Overcurrent Protection For Residual Current; Setting Notes - Siemens SIPROTEC 4 7UT6 Series Manual

No. Information
023.2552 I> TRIP
023.2553 Ip TRIP

Time Overcurrent Protection for Residual Current

2.4.3
The function and operation of the definite-time overcurrent protection and of the inverse-time overcurrent
protection for residual current is discussed in detail in the section "Time Overcurrent Protection - General"
above (see Section
overcurrent protection for residual current 3I0 O/C.
2.4.3.1

Setting Notes

General
NOTE
i
i
The first time overcurrent protection for residual current is described in the setting instructions. The param-
eter addresses and message numbers of the second and third time overcurrent protection are described at
the end of the setting instructions under "Additional Time Overcurrent Protection Functions for Residual
Current".
During configuration of the functional scope (Section
residual current stages is determined under address 122 DMT/IDMT 3I0. Only the settings for the character-
istic selected can be performed here. The definite time stages 3Ι0>> and 3Ι0> are available in all cases.
If a second or third residual overcurrent protection is used, this must be configured accordingly in addresses
134 DMT/IDMT 3I0 2 and 136 DMT/IDMT 3I0 3.
Each protection function must be assigned to a side of the main protected object or another 3-phase current
measuring location. This can be carried out separately from the phase overcurrent protection (Section
2.1.4 Power System Data 1
assignment of the measured current inputs of the device against the measuring locations (current transformer
sets) of the power plant (Section
Measuring Locations").
NOTE
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If the time overcurrent protection is assigned to a side of the main protected object, the current values are
set referred to the rated current of that side Ι/Ι
In address 2201 3I0 O/C, the time overcurrent protection for residual current can be set to ON or OFF. The
option Block relay allows to operate the protection but the trip output relay is blocked.
Address 2208A 3I0 MAN. CLOSE determines which of the zero sequence current stages must be activated
instantaneously with a detected manual close. Settings 3I0>> instant. and 3I0> instant. can be set
independently from the selected type characteristics; 3I0p instant. is only possible if one of the inverse
time stages has been configured. The stabilisation does not affect 3I0>>. This parameter can only be set with
DIGSI at Additional Settings. For this setting, similar considerations apply as for the phase current stages.
In address 2202 InRushRest. 3I0 inrush restraint (inrush restraint with 2nd harmonic) is enabled or disa-
bled. Set ON if the residual current stage of the time overcurrent protection is applied at the supply side of a
transformer whose starpoint is earthed. Otherwise, retain setting OFF. 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).
SIPROTEC 4, 7UT6x, Manual
C53000-G1176-C230-5, Edition 09.2016
Type of
Informa-
tion
OUT
OUT
2.4.1 General). The following paragraphs contain the specific information for setting the
under margin heading "Further 3-phase Protection Functions"). Consider also the
2.1.4 Power System Data 1
2.4 Time Overcurrent Protection for Phase and Residual Currents
Comments
I> TRIP
Ip TRIP
2.1.3 Functional Scope) the characteristic type for the
under margin heading "Assignment of 3-phase
. In other cases, current values are set in amps.
NS
Functions
155