A Review and Functional Analysis of Space Charge Measurement Deconvolution Techniques for HVDC Cables

Abstract

As High Voltage Direct Current (HVDC) technology becomes increasingly important for the integration of large-scale renewable energy sources and to ensure efficient long-distance power transmission, an accurate assessment of insulation performance is necessary to maintain system reliability and minimize fault risks. In this scenario, the measurement of space charge in dielectric materials is useful for optimizing insulation systems for HVDC equipments. The Pulsed Electro-Acoustic (PEA) method is one of the most widely used techniques for space charge analysis, but distortions introduced by the measurement system significantly affect the accuracy of the acquired signals. Among the various factors influencing the acquisition of the space charge profile is the convolution process between the signal and the measuring cell, which is characterized by its own transfer function. Therefore, signal deconvolution is essential for accurately reconstructing the space charge distribution. This paper presents a comparative review of the deconvolution techniques suggested by researchers in the field of PEA measurement. Theoretical principles, advantages, and limitations of methods such as Fourier and Wiener deconvolution are analyzed, along with advanced solutions based on Laplace and Short Time Fourier Transforms. Furthermore, the techniques have been implemented and tested in a MATLAB environment for practical comparison. The results demonstrate how the choice of technique influences the quality of the reconstructed signal, providing optimal selection criteria for different experimental conditions.