An Investigation into Electromagnetic Radiation due to Partial Discharges in High Voltage Equipment Based on Non-Contact Measurements

The non-contact PD measurement is based on wideband radiometry to detect the radiated electromagnetic waves. This paper studies the propagation characteristics of the radiation by considering a current transformer (CT) as an example in both modeling simulation and experimental tests. A three-dimensional model is established for finite element analysis of the radiated emissions from a current transformer, incorporating two kinds of insulation materials, air and transformer oil. Studies are made of the effects of the insulation material properties and the structure of the CT tank, for which frequency response and resonance are also analyzed by the finite element method. Simulation results obtained are evaluated and used together to inform the design of practical experiments. This paper describes these experiments and draws its conclusions based on their comparison, and indicates the effect of resonant frequencies on the receiving frequency spectra.