Fundamental Analysis of Interfacial Signal in Double-Layer with Different Permittivity Using PEA Method

This paper deals with the interfacial signal in the double-layer. In the insulating systems in power electric devices, multi-layered insulation structures are usually used. For example, a joint of a power transmission cable has a double-layer of a cross-linked polyethylene (XLPE) and a rubber material, and a high voltage is applied to the doble layer. In such case, precise analysis of interfacial charge is required because accumulated charge at the interface has a critical impact on the overall stress distribution. The space charge distribution was measured in the double-layer using the PEA method, and the PEA signal generated at the interface was investigated. After voltage is applied to the specimen, initially the DC and pulse electric fields are shared depending on the dielectric constant of each material. Acoustic waves are observed at the interface due to the difference in electric fields of the pulses. To investigate the interfacial signal, the charge distribution in the double-layer was calculated based on the charge distribution measured in the single-layer and compared with the measured signal. The calculated results and measured signals were very similar. Information about this phenomenon can help with signal processing and lead to a more precise interpretation of the space charge distribution in the double-layer.