Omicron Lab CT Analyzer, User Manual

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37
CT Analyzer Test Cards for Multi-Ratio CT Testing
Note: Depending on the selected standard and CT type, other or further CT data
may be necessary for a correct assessment. If the "Check "*" settings before
start" option is enabled in the default test settings of the
CT Analyzer , all
parameters that are required for assessment are marked by a star "*" in the CT-
Object card. For more detailed information, please refer to the CT Analyzer
User Manual.
Figure 6-2 CT-Object card with soft keys for predefined CT ratios if the
number of taps is 5
VA (or Vb)
cos ϕ
Nominal burden for the full tap combination of the CT.
For protection CTs of the IEEE C57.13 classes C, K and T,
enter the rated secondary terminal voltage V
b
instead of VA.
The CT Analyzer then automatically calculates the value for
VA.
The cos
ϕ
for the nominal burden is automatically selected
according to the standard.
Note: The CT Analyzer automatically scales down the
nominal burden specified here for the individual tap
combinations available in the
MR-Config. card according to
their ratios (see ”VA” on page 42).
Burden
cos
ϕ
Operating burden and cos
ϕ
of the tap in use .
Enter the burden manually or measure the burden using the
Burden card.
Note: The operating burden specified here is used for all tap
combinations specified in the MR-Config. card. In contrast to
the nominal burden (VA), the operating burden is not scaled
down according to the ratios (see ”Burden” on page 42).
You could use these fields for example to simulate the CT
behavior at different load conditions after the test. Enter the
value of your choice and view the measurement results of the
multi-ratio CT test for the new operating burden in the
MR-Results card (see section 6.3.2 on page 45).