High Precision $500/\surd{}\ 3\ \mathrm{kV}$ Two-Stage Voltage Transformer with High-Voltage Excitation

To develop a two-stage voltage transformer (VT) with high-voltage excitation above 10 kV, this paper designed a new structure. Excitation winding and precision ratio winding are vertically symmetrical distribution. This makes it works at a higher voltage possible. A compensation circuit is added to the secondary of this two-stage VT to acquire higher accuracy. A 500/√3 kV two-stage VT has been developed successfully based on this principle. Measurements indicate that the error is (-6 to+1) μV/V for the ratio error and (-6 to -1) μrad for the phase displacement at (20%-120%) rated voltage.