Transformer
6 - 3
TRRatio (per Tap)
Use the TRRatio test card to measure a power transformer’s ratio by injecting
AC voltage with up to 2kV from AC OUTPUT into the transformer’s primary side
(refer to Figures 2 and 3).
CPC 100 measures both the voltage it applies to AC OUTPUT and the
transformer’s secondary voltage at V1 AC. From these values it calculates the
ratio and its deviation from the nominal ratio in percent.
In addition, the exciting current is measured as well as the phase angles of both
the secondary voltage and the exciting current.
Furthermore, the TRRatio test card is used to measure a power transformer’s
ratio for each single tap changer position (see Figure 4).
Figure 2:
Setup for testing a
power transformer ratio:
Yy0 transformer,
primary and secondary
side star connection