Location of partial discharge occurring in ground coil of superconducting Maglev system under noise environment using radio interferometer system

Superconducting magnetically levitated vehicle (Maglev) system needs a large number of ground coils installed on the guideway, which corresponds to the rails of a conventional railway. Main insulating material of ground coil is epoxy resin; it is required to develop the insulation diagnostic technique for the ground coils installed along the entire length of the guideway in order to increase the reliability of the Maglev system. We apply the radio interferometer system, which has been originally designed, to the location of a partial discharge (PD) occurring in the ground coil attached to the sidewall of a mock-up of concrete guideway constructed outside. In consideration of radio noise, a finite-duration impulse response (FIR) filter and the short-term-average to long-term average (STA/LTA) ratio method are installed in the radio interferometer system. The FIR filter removes radio noise from received signals, and the STA/LTA ratio method determines arrival time of electromagnetic (EM) waves emitted from PD.