The development of a two-stage voltage transformer of 110/√3 kV and class 0.001

This paper presents a new structure of a two-stage voltage transformer(TSVT) with low voltage excitation, which can be used to design a TSVT as toroidal wound cores with high voltage and high accuracy. It just needs to wind one high voltage coil around the cores instead of two high voltage coils in the traditional TSVT with high voltage excitation, which reduces the difficulty in insulation design and makes the fabrication of TSVT with higher voltage possible. A (110/√(3)) kV/(100 /√(3)) V TSVT has been developed with this scheme. Both of the error in low voltage and voltage coefficient in (20%-120%)U_n are less than 3×10^-6.