Ι/Ι
p
= 1 bis 0.86 Ι/Ι
p
= 0.84 bis 0.67 Ι/Ι
p
= 0.66 bis 0.38 Ι/Ι
p
= 0.34 bis 0.00
0.98 0.91 0.81 0.72 0.63 0.47 0.28 0.09
0.97 0.90 0.80 0.70 0.61 0.44 0.25 0.06
0.96 0.89 0.78 0.69 0.59 0.41 0.22 0.03
0.95 0.88 0.77 0.67 0.56 0.38 0.19 0.00
0.94 0.86
Inrush Restraint
At address 2002 InRushRest. Ph of the general settings, the inrush restraint can be enabled (ON) or disa-
bled (OFF). Especially for transformers and if overcurrent time protection is used on the supply side, this
inrush restraint is required. Function parameters of the inrush restraint are set in “Inrush”.
The inrush restraint is based on an evaluation of the 2nd harmonic present in the inrush current. The ratio of
2nd harmonics to the fundamental component 2.HARM. Phase (address 2041) is set to Ι
2fN
/Ι
fN
= 15 % as
default setting. It can be used without being changed. To provide more restraint in exceptional cases, where
energising conditions are particularly unfavourable, a smaller value can be set in the afore-mentioned address.
If the current exceeds the value indicated in address 2042 or 2043 I Max InRr. Ph., no restraint will be
provoked by the 2nd harmonic.
The inrush restraint can be extended by the so-called crossblock function. This means that on harmonic
content overshoot in only one phase, all three phases of the Ι> or Ι
p
stage are blocked. At address 2044 CROSS
BLK.Phase the crossblock function is set to YES or to NO.
The time period for which the crossblock function is active after detection of inrushes is set in address 2045 T
CROSS BLK.Ph.
Further time overcurrent protection functions for phase currents
In the aforementioned description, the first overcurrent protection for phase currents is described. The differ-
ences in the parameter addresses and message numbers of the first, second and third overcurrent protection
are illustrated in the following table. The positions marked by x are identical.
Addresses of the
parameters
Addresses of the
dynamic
parameters
Message no.
1. Overcurrent protection for phase currents 20xx 21xx 023.xxxx(.01)
2. Overcurrent protection for phase currents 30xx 31xx 207.xxxx(.01)
3. Overcurrent protection for phase currents 32xx 33xx 209.xxxx(.01)
NOTE
If the overcurrent protection is assigned to a side of the main protected object, the respective values apply
to the setting of the current values Ι/Ι
NS
, i.e. with reference to the rated current of the side of the main
protected object.
Settings
Addresses which have an appended “A” can only be changed with DIGSI, under “Additional Settings”.
The table indicates region-specific presettings. Column C (configuration) indicates the corresponding secon-
dary nominal current of the current transformer.
Addr.
Parameter C Setting Options Default Setting Comments
2001 PHASE O/C ON
OFF
Block relay
OFF Phase Time Overcurrent
2.4.2.2
Functions
2.4 Time Overcurrent Protection for Phase and Residual Currents
152 SIPROTEC 4, 7UT6x, Manual
C53000-G1176-C230-5, Edition 09.2016
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