Overcurrent Protection in the Bay Unit
193
7SS52 V4 Manual
C53000-G1176-C182-3
MEAS.REPET
The parameter
MEAS.REPET
(
1506/BU
) is used to select whether a repetition of the
measurement will be performed for the earth current in the high-set stage.
With setting
YES
the measurement of the earth current in the high-set current stage
will be repeated.
With setting
NO
the measurement of the earth current in the high-set current stage will
not be repeated.
CHARACTER
.
The parameter
CHARACTER.
(
1511/BU
) is used to select the characteristic of the in-
verse-time O/C protection for the earth current.
This parameter is only displayed if the parameter
CHARAC. E
(
7815/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 INVERS
, a characteristic according to IEC 255-3 (type C)
will be used.
IE>
For earth faults the pickup values and delay times can be set individually. This allows
to use a different grading with shorter delays for earth faults.
IE>
(
1512/BU
) and
TIE>
(
1513/BU
) are only relevant for the definite-time mode (
CHARAC. E
=
DEFI-
NITE TIME
(
7815/BU
), Chapter 5.14, page 184). For setting the overcurrent stage
IE>
the most relevant factor to be considered is the lowest earth fault current that can
occur.
If the
IE>
stage for earth faults is not to be active at all, the delay time
TIE>
(
1513/
BU
) can be set to infinite.
The parameter
IE>
(
1512/BU
) is used to the threshold for the earth current in the
overcurrent stage.
This parameter is only displayed if the parameter
CHARAC. E
(
7815/BU
) is set to
DEF-
INITE TIME
.
TIE>
The parameter
TIE>
(
1513/BU
) is used to set the trip time delay for tripping of the
overcurrent stage. The delay time is started when the threshold for the earth current
is exceeded. This threshold is set with the parameter
IE>
(
1512/BU
).
This parameter is only displayed if the parameter
CHARAC. E
(
7815/BU
) is set to
DEF-
INITE TIME
.
IEp
IEp
(
1514/
BU
) and
TIEp
(
1515
/
BU
) are only relevant for the inverse-time characteris-
tics (
CHARAC. E = DEFINITE TIME
(
7815/BU
), Chapter 5.14, page 184). This al-
lows to use a different grading with shorter delays for earth faults. Please note that in
accordance to IEC regulations a safety factor of about 1.1 has been included 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
IEp
stage for earth is
not to be active at all, the delay time
TIEp
can be set to
infinite.
If the I
Ep
stage is not needed at all, the time
TIEp
is set to infinite. With setting
0
the
protection trips after the inherent operating time.
The parameter
IEp
(
1514/BU
) is used to set the threshold for the earth current in the
overcurrent stage of the inverse-time O/C protection.
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