Development of a Setup for High-Field Dielectric Frequency Response Characterization

Modern power system capacitors operate under extreme electrical stresses, necessitating advanced diagnostic techniques to assess their performance. While commercial instruments for measurements of dielectric frequency response (DFR) provide valuable insights into materials performance, they can be limited in their voltage range, restricting their applicability to high-field conditions. This paper presents the development of a high-voltage DFR measurement system designed for high-field dielectric characterization of polymeric materials. The proposed system overcomes the limitations of existing instruments by extending the measurable electric field range, enabling the study of nonlinear dielectric effects. The system's performance is validated through comparative measurements of a vacuum capacitor, a low-loss ceramic capacitor, and a polyethylene terephthalate (PET) film sample with gold-deposited electrodes. Results demonstrate the system’s ability to measure dielectric loss factors down to the 10⁻⁵ range, exceeding the resolution of the commercial instrument used for comparison in this study. Furthermore, field-dependent variations in dielectric properties are successfully captured, highlighting the system's capability for studying nonlinear dielectric behavior under high electric fields. The developed methodology contributes to the optimization of dielectric materials for next-generation power system capacitors.