[logikdia-ueberstromstufen-3i0-fuer-nullstrom-121102-st, 1, en_GB]
Figure 2-70
Logic diagram for the overcurrent stage 3I0> for residual current (simplified)
The pickup values of all stages
I>
(phases),
3I0>
(zero sequence current),
I>>
(phases),
3I0>>
(zero
sequence current) and the time delays associated for each stage can be set individually.
Inverse Time Overcurrent Protection
The inverse-time overcurrent protection stages always operate with a characteristic either according to the IEC
or the ANSI standards or according to a user-defined characteristic. The characteristics and their equations are
displayed in the Technical Data. When configuring one of the inverse time characteristics, definite time stages
I>>
and
I>
are also enabled.
Pickup, Tripping
Each phase current and the zero sequence current (sum of phase currents) are compared individually to a
common setting value
Ip
or
3I0p
. If a current exceeds the setting value by 1.1 times, the corresponding
stage picks up and is signalled selectively. If inrush restraint is used, a frequency analysis is performed first.
Depending on the detection of inrush currents, either normal pickup annunciations or relevant inrush
messages are issued. For pickup, the RMS values of the fundamental harmonics are used. During the pickup of
an
Ip
stage, the tripping time is calculated from the flowing fault current by means of an integrating meas-
uring procedure, depending on the selected tripping characteristic. After expiration of this time period, a trip
command is output as long as no inrush current is detected or inrush restraint is disabled. If inrush restraint is
enabled and inrush current is detected, there will be no tripping. Nevertheless, an annunciation is generated
indicating that the time expired.
2.4.1.2
Functions
2.4 Time Overcurrent Protection for Phase and Residual Currents
140
SIPROTEC 4, 7UT6x, Manual
C53000-G1176-C230-5, Edition 09.2016
Содержание SIPROTEC 4 7UT6 Series
Страница 394: ...394 SIPROTEC 4 7UT6x Manual C53000 G1176 C230 5 Edition 09 2016 ...
Страница 482: ...482 SIPROTEC 4 7UT6x Manual C53000 G1176 C230 5 Edition 09 2016 ...
Страница 504: ...504 SIPROTEC 4 7UT6x Manual C53000 G1176 C230 5 Edition 09 2016 ...
Страница 522: ...522 SIPROTEC 4 7UT6x Manual C53000 G1176 C230 5 Edition 09 2016 ...
Страница 528: ...528 SIPROTEC 4 7UT6x Manual C53000 G1176 C230 5 Edition 09 2016 ...
Страница 538: ...538 SIPROTEC 4 7UT6x Manual C53000 G1176 C230 5 Edition 09 2016 ...
Страница 664: ...664 SIPROTEC 4 7UT6x Manual C53000 G1176 C230 5 Edition 09 2016 ...
Страница 666: ...666 SIPROTEC 4 7UT6x Manual C53000 G1176 C230 5 Edition 09 2016 ...
Страница 683: ...Z Zero sequence currents 109 Index SIPROTEC 4 7UT6x Manual 683 C53000 G1176 C230 5 Edition 09 2016 ...
Страница 684: ...684 SIPROTEC 4 7UT6x Manual C53000 G1176 C230 5 Edition 09 2016 ...