doble SFRA, User Manual, Page: 51 / 126

3. Setting Up and Running a Test
72A-2570-01 Rev. K 07/2011 3-27
HV Wye (Star) Response
Figure 3.42 shows a typical HV wye (star) winding response. All three phases
show similar responses at low frequencies, with the following characteristics:
• The center phase has a slightly increased impedance (more negative
dB) at low frequencies.
• The center phase has one resonance and the outer phases two. The
outer phases are similar at low frequencies.
• The three phases come back together as frequencies approach 10 kHz.
• The three phases show regions of similarity and regions of
dissimilarity across the frequency range.
Figure 3.42 HV Wye Winding Trace
Short-Circuit Test Response
Figure 3.43 on page 3-28 shows the three short-circuit responses from the HV
side of a transformer. As expected, the responses are similar.