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Making of I>> Phase Overcurrent Protection Settings
c. To prevent pickup current reach the I>> threshold and cause an unwanted instantaneous
trip, I>> can be set to 7 I
rTR
practically.
d. According to the calculation above, do the following settings:
Making of Ie> Earth Overcurrent Protection Settings
e. It is assumed that earth current up to 0.25 I
rTR
is considered to be normal. Over this
value, the primary circuit will be broken in 1.0 s. Presuming those, I
e
> threshold value is
calculated as follows:
f. According to the calculation above, do the following settings:
Making of Ie>> Earth Overcurrent Protection Settings
g. Presuming earth current equal to or higher than 0.75 I
rTR
is considered as earth fault,
I
e
>> threshold value is calculated as below:
h. According to the calculation above, do the following settings:
6. All needed settings are done by now. Check all the settings and note them. CPM 310 G is ready
for commissioning. □
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