Overcurrent Protection in the Bay Unit
191
7SS52 V4 Manual
C53000-G1176-C182-3
TI>>
The parameter TI>>
(1203/BU) is used to set the trip time delay for tripping of the
high-set current stage (definite-time). The delay time is started when the threshold for
the phase currents is exceeded. This threshold is set with the parameter I>> (1202/
BU).
MEAS.REPET The parameter MEAS.REPET
(1206/BU) is used to select whether a repetition of the
measurement will be performed for the phase currents in the high-set stage.
With setting YES the measurement of the phase currents in the high-set stage will be
repeated.
With setting NO the measurement of the phase currents in the high-set stage will not
be repeated.
CHARACTER. The parameter CHARACTER. (1211/BU) is used to select the characteristic of the in-
verse-time O/C protection for the phase currents.
This parameter is only displayed if the parameter CHARAC. PH
(7812/BU) is set to IN-
VERSE TIME.
With setting NORMAL INVERSE, a characteristic according to IEC 255-3 (type A) will
be used.
With setting VERY INVERSE, a characteristic according to IEC 255-3 (type B) will be
used.
With setting EXTREMELY INVERSE, a characteristic according to IEC 255-3 (type C)
will be used.
I> I> (1212/BU) and TI> (1213/BU) are only relevant for the definite time mode
(CHARAC. PH = DEFINITE TIME (7812/BU), Chapter 5.14, page 184). For the set-
ting of the overcurrent stage I> the most relevant factor to be considered is the maxi-
mum operating current that can occur. A pick-up caused by overload must be exclud-
ed, since, in this mode, the device operates as fault protection with correspondingly
short tripping times and not as overload protection.
If the I> stage is not required, the time TI> (1213/BU) is set to infinite.
The parameter I> (1212/BU) is used to set the threshold for the phase currents in the
overcurrent stage.
This parameter is only displayed if the parameter CHARAC. PH
(7812/BU) is set to
DEFINITE TIME.
TI> The parameter TI> (1213/BU) is used to set the trip time delay for tripping of the over-
current stage. The delay time is started when the threshold for the phase currents is
exceeded. This threshold is set with the parameter I> (1212/BU).
This parameter is only displayed if the parameter CHARAC. PH
(7812/BU) is set to
DEFINITE TIME.
Ip Ip (1214/BU) and TIp (1215/BU) are only relevant for the inverse-time characteris-
tics (CHARAC. PH = DEFINITE TIME (7812/BU), (Chapter 5.14, page 184). Please
note that in accordance to IEC regulations a safety factor of about 1.1 has been in-
cluded between the pick-up value and the setting value. This means that a pickup will
only occur if a current of about 1.1 times of the setting value is present.
If the Ip stage is not needed, the time TIp is set to infinite. With setting 0 the protection
trips after the inherent operating time.
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