Omicron Lab CT Analyzer, User Manual

Page: 236 / 254

CT SB2 User Manual
42
VA
cos ϕ
Use this column to set the nominal burden for each tap
combination.
To obtain correct measurement results, the nominal
burdens for the inner tap combinations (e.g. X1-X2 etc.)
should be smaller than the nominal burden for the full tap
combination according to the winding ratios of the tap
combinations (e.g. 25VA for X1-X5, 12.5VA for X1-X4 etc.).
The
CT Analyzer supports this with an automatic function.
As soon as the primary current I
pn
is specified for a tap
combination, the CT Analyzer automatically calculates and
sets the corresponding nominal burden and cos
ϕ
for this
tap combination. For this, the CT Analyzer automatically
scales down the nominal burden for the full tap combination
according to the ratio of the specific tap combination and
rounds it to the next value stated in the standard (see Figure
6-3 on page 38).
The nominal burden (VA) automatically assigned by the
CT Analyzer can be changed manually by the user for all
tap and intertap combinations except the full tap
combination. The cos
ϕ
cannot be changed by the user.
Note: The "VA" column is displayed by default when
opening the MR-Config. card the first time after initializing a
new multi-ratio test. If the "Burden" column is displayed
instead, use the
Nom. Burden soft key to display the "VA"
column with the nominal burdens again.
Burden
cos
ϕ
The "Burden" column is displayed if you selected to display
the operating burden in the
MR-Config. card using the Op.
Burden soft key.
This column displays the operating burden for the tap
combination. The operating burden is taken from the
CT-Object card and cannot be changed in the MR-Config.
card. The same value is used for all tap combinations to test
the behavior of the CT with the connected burden.
Parameter Description