Breakdown Characteristics of Propylene Carbonate and Deionized Water Under Nanosecond Pulsed Voltages

Propylene carbonate (PC) has several advantages, including a high dielectric constant, high resistivity, and excellent environmental adaptability, making it a promising candidate as a novel energy storage medium for pulse forming lines (PFL). In this study, an experimental platform for liquid insulation that is capable of delivering a maximum output voltage of 700 kV and a pulse rise time of approximately 100 ns is employed to examine the breakdown characteristics of PC under different electrode gaps. For comparison, the breakdown characteristics of deionized (DI) water are also investigated. The experiment utilizes a sphere-to-plate electrode configuration with a hemispherical electrode diameter of 5 cm, plate electrode diameter of 9 cm, and an adjustable electrode gap ranging from 0 to 1.5 cm. The results indicate that the breakdown voltages of both PC and DI water increase almost linearly with the electrode gap, whereas the average breakdown field strength decreases exponentially as the electrode gap widens. Unlike DI water, PC does not exhibit polarity effects under the test conditions. However, the insulation performance exhibits a measurable decline after the first breakdown. These findings highlight the advantages and limitations of PC as an energy storage medium and offer valuable insights into its potential applications in related fields.