External Excitation of Axial Magnetic Field for Intermediate-Frequency Vacuum Arc Research

In order to the make the magnetic field synchronous with the actual current in the current interruption experiment, an external excitation of axial magnetic field for intermediate-frequency vacuum arc experiment and research is designed and tested in this paper. The excitation system is consisted of intermediate-frequency current transformers (CTs) and Helmholtz coil. CTs are used to induct current in main circuit and the Helmholtz coil can be excited by the secondary current. Thus the axial magnetic field (AMF), which is synchronous with the primary current, is generated inside the Helmholtz coil. And different from traditional magnetic field excitation system, the magnetic field generated by commercial AMF contact can be simulated. The test is implemented to test the excitation system. The phase difference between the primary side and secondary side of the CT is less than 10'. The steady state error of B is within 1% and the dynamic error of B/I is within 1.5% as well. The results turn out to be consistent with the theoretical value, which proves the effectiveness of this external excitation system.