Detection of Partial Discharges Occurring in Propulsion Coils of Superconducting Maglev Systems Using a Radio Interferometer System with a Vector-Antenna Mounted on a Test Bogie

摘要

We have been studying radio sensing techniques to detect partial discharges (PDs) occurring in propulsion coils used in superconducting magnetic levitation (Maglev) systems. In this study, preliminary experiments were carried out for setting an objective of detecting PDs occurring in the propulsion coils by using a radio interferometer system with a vector-antenna mounted on a test bogie, which can be run at the speed of 200 km/h by remote control. In the experiments, the radio interferometer system with the vector-antenna was mounted on the test bogie that was kept stopped; PD sources occurring in a propulsion coil were located. The vector-antenna composed of vertical and horizontal dipole-antennas was set to the center of the antenna-array of the on-board radio interferometer system. An antenna-module contains the antenna-array composed of three dipole-antennas and the vector-antenna. Three sets of mock-ups of the propulsion coil and the levitation-guidance coil were arranged in a row on the side of the test bogie. One of the propulsion coils has eight cylinder-shaped holes penetrating through the insulating material to the inner conductor for attaching a needle-electrode; one or some of the holes can be voluntarily chosen to generate PDs. Experimental results show that a PD source generated at a voluntary position of the propulsion coil could be roughly located by using the antenna-array; the vertical and horizontal components (electric fields) of electromagnetic (EM) waves emitted from the PD source could be separately received by using the vector-antenna.