CPC 100 V 3.20
Transformer - 1
Use the TRRatio test card to measure a power transformer’s ratio by injecting AC voltage with
up to 2 kV from AC OUTPUT into the transformer’s primary side (refer to the following figure).
Setup for testing a power transformer ratio: Yy0 transformer, primary and secondary side star
connection.
Note: The Settings page opens automatically if the Auto-tap operation mode is activated.
The Settings page allows adding the transformer’s ratio per tap as follows. After pressing the
Add Tap menu key first enter the Tap Number, V prim and V sec. Add the next tap by pressing
the Add Tap menu key and enter the corresponding V prim and V sec values. After this,
pressing the Add Tap menu key repeatedly adds more taps with a step calculated from the
values of the preceeding taps. The tap entries apply equally to all phases. After adding all taps,
press the Main Page menu key to transfer the data to the main page.
Use the Automatic Tap Fill function to automatically fill in the nominal ratio table of the TRRatio
test card for symmetric tap changers.
Performing a TRRatio Test (per Tap)
DANGER
Death or severe injury caused by high voltage or current
► Do not connect the CPC 100 output to the secondary side of the transformer. This
will cause hazardous voltages on the primary side
V sec Actual voltage measured at V1 AC
° Phase angle of the primary current relative to Vprim nominal.
:1 Calculated ratio value from the measured values Vprim / Vsec
% Deviation of the actual ratio from the nominal ratio
Transformer tap
identifier and tap
number for the
measurements in
the respective line
of the table
Actual voltage
injected from
AC OUTPUT into
the transformer’s
high-voltage side
Primary current
from 2kV AC
output;
changes
depending on
the line
selected in
table below
Output frequency
Nominal primary injection voltage
Nominal ratio, calculated from Vprim nom /
Vsec nom
Vector group;
selection depending
on the settings
Operation mode
Pressing the Settings menu key opens the Settings page. The Settings page of
the TRRatio test card has another functionality as on other test cards.
While passing through the power transformer’s tap changer positions, press
Keep Result for each single position.
Note: This procedure is only required for manual wiring. Otherwise, the test runs
fully automatically.
TRRatio (per Tap) Settings Page
Transformer