Parameter Extraction for the Degradation of On-Board Arrester in High-Speed Railway Under Effects of Multiple Strokes

On-board arrester (OBA) is an essential equipment of electric multiple units (EMUs), and its working condition will directly affect the reliable operation of EMU. Simultaneously, due to frequent multiple strokes (MSs), OBA suffers from accelerated impulse deterioration and serious life threatening. Thus, this article extracts the feature parameters for degraded OBA under effects of MS. First, an experiment platform is established to perform the MS experiment. The dc parameters and frequency-domain dielectric spectroscopy (FDS) parameters of OBA are then measured. Subsequently, the measured data and the reliability of experimental results are discussed. Finally, microscopic feature parameters [i.e., barrier height (BH) and depletion layer width (DLW)] and dielectric feature parameters of OBA are extracted, and their effectiveness is verified (the maximum and mean of absolute relative error are merely 5.14% and 2.76%, respectively). The results demonstrate that: 1) with increasing MS aging, DLW and BH descend gradually, and after 30 MSs, the maximum decreases are 64.5% and 82.28%, respectively; 2) the geometric capacitance and third polarized branch capacitance ascends exponentially with the deepening of impulse aging, while the insulation resistance and relaxation time constants drop exponentially; and 3) several microscopic and dielectric feature parameters are extracted to effectively evaluate the degradation state of OBA.