In the power system

the traditional voltage transformer has a large size and a high level of insulation. In view of the above questions

we researched a new non-contact voltage transformer

which could reduce difficulty in voltage transformer insulation design and expand the application of voltage transformer. On the basis of the electric field coupling principle

we designed a new voltage transformer. The design of unipolar structure has solved problems of traditional voltage transformer such as great difficulty in insulation design and high cost caused by grounding electrode. Differential signal input structure is adopted for the detection circuit

which has effectively restrained the influence of common-mode interference signal. The voltage transformer is applied to the single-phasevoltage class of 10 k V for test. According to the test results

the designed transformer can meet the requirements of accurate and real-time measurement for voltage of the charged conductor as well as provide a new method for electricity larceny prevention and on-line monitoring of power grid in electric system.