Calibration of pulsed electroacoustic method considering electrode–dielectric interface status and porosity

Abstract

Pulsed electroacoustic (PEA) method is widely used, but measurement conditions not always agree with the underlying PEA assumptions. This necessitates space charge recovery; however, existing research only addresses the attenuation and dispersion in lossy media. The effects of electrode-dielectric interface contact status and porosity on the accuracy of space charge distribution are discussed in the present article. It is shown that the presence of nonlinear interface and porosity can introduce severe error. However, because the properties of acoustic propagation of waves (which are generated from charge on the electrode and in the bulk) are different, the conventional recovery algorithm is no longer suitable for calibrating the charge density. To obtain accurate space charge profiles, it is necessary to eliminate these effects. A method has been proposed which is based on the original measurement process. The validity of the proposed method was tested by reasonable post-recovery electric field distributions.

Space charge behavior evolution with thermal aging of oil-paper insulation

“…While space charge distribution profiles were not calibrated, just to avoid confusion and leave the data original. Details of calibration can be found in [22]. According to [22], the calibration depends on A rp , f 0 and σ 0 , where A rp is relevant to fast wave's transmission, f 0 is the corner frequency caused by surface roughness and σ 0 is the charge density at the anode.…”

“…Details of calibration can be found in [22]. According to [22], the calibration depends on A rp , f 0 and σ 0 , where A rp is relevant to fast wave's transmission, f 0 is the corner frequency caused by surface roughness and σ 0 is the charge density at the anode. The parameters for recovery were listed in Table I, neglecting the effect of thermal ageing on surface roughness and porosity.…”

A Calibration Method for Acoustic Space Charge Measurements Using Multilayer Samples

“…The transfer function for attenuation and dispersions factors of Equations (26)–(28) was presented in [22,28]; By applying the proposed calibration sample, the transfer function can be calculated using the measuring external electrode and the internal electrode, avoiding the acoustic discontinuity at the external top electrode [19]. …”

“…The post-processing involves deconvolution methods whose calibration is obtained by measurement of known surface charge values at the electrodes when a known voltage is applied at a space charge free sample. Following this procedure, the existence of acoustic discontinuities for the generation and the propagation of the acoustic signals at the electrodes are not fully taken into account, which may affect the calibration [17,18,19]. …”

Interface Charge Characteristics in Polymer Dielectric Contacts: Analysis of Acoustic Approach and Probe Microscopy

“…Furthermore, changing the electrode material and surface conditions can be useful in detecting interface charges at various electrode/dielectric structures. [69][70][71][72] However, acoustic methods have limitations for measuring interface charges at a submicron scale, such as less than 1 µm, due to the low resolution of the sensor. [56,73,74] In recent years, the probe microscopy method has enabled atomic-level resolution imaging, making it possible to study charge behaviors at the submicron scale.…”