Interaction Between Electric Field Profile and Partial Discharges Simultaneously Detected in a Loaded HVDC Cable: PDs Analysis

This study aims to examine the relationship between electric field distribution and the initiation of partial discharge (PD). The test subject is a DC model cable with an air void defect, exposed to both electrical stress and a thermal gradient. Electric field distributions were determined based on space charge measurements using an innovative Pulsed Electroacoustic (PEA) cell, while PD activity was tracked using a PryCam sensor. By acquiring data on space charge and PD phenomena simultaneously, the interaction between these phenomena is clarified. The results indicate that the electric field distribution along the cable's radial direction changes over time. Initially, the electric field has a Laplacian distribution, but this inverts after 20 minutes of voltage application. This inversion increases the electric field at the cable's outer radius, where the air void defect is located, causing the partial discharge inception electric field within the defect to reach 17.8 kV/mm in the unaffected section of the cable. This paper represents the second part of a single work. In the first part, the PEA measurement aspect is described in detail. In this second part, the analysis of the PDs, their separation by means of a clustering algorithm and comparison with the electric field distributions obtained are examined in detail.