  Accurate measurement circuit and high-frequency sensors with sufficient
bandwidth are necessary for the analysis of individual partial discharge (PD)
pulses. In this paper, a testbed is designed and constructed for the
investigation of DC PD pulses. The testbed is equipped with a 50 ohm
transmission line (TL) that terminate to an oscilloscope for measuring the
charge displacement current generated by PD pulses. Besides the oscilloscope
measurements, two types of electromagnetic field sensors (D-dot and B-dot) were
developed to capture the EM fields of the PD pulses propagating through the TL.
The main goal of this paper is to investigate the DC PD pulses through the EM
fields and the corresponding discharge current pulses that are considered as
calibrating signals for the developed D-dot and B-dot sensors. The results of
DC cavity discharge measured by the constructed testbed and the EM field
sensors demonstrate close agreement with the reference PD pulses measured via
oscilloscope.
