High‐voltage frequency domain spectroscopy analysis of a thermally aged XLPE submarine cable under continuous and cyclic voltage based on carrier transport and polarisation characteristics

Abstract

In order to ensure the safe operation of submarine cables, it is of great significance to analyse the insulation state of submarine cables from the perspectives of microstructure, carrier transport characteristics and macroscopic dielectric properties. In this study, based on the high-voltage frequency domain spectroscopy (HV-FDS) measurement system, HV-FDS experiments of fresh and thermally aged submarine cables were carried out under continuous (0.5, 2, 4 and 10 kV) and cyclic (2-10-2 kV) applied alternating voltages. Then, combining the changes of the microstructure structure of cross-linked polyethylene (XLPE) insulation, the aggregate structure deterioration model of XLPE was proposed to discuss the physical mechanism of HV-FDS characteristics of submarine cables under different voltages and insulation states. Results show that the HV-FDS characteristics of submarine cables have significant voltage dependence under continuous voltage excitation. The HV-FDS of submarine cables show memory characteristics under cyclic voltage excitation. Compared with the fresh submarine cable, the thermally aged submarine cable shows more significant voltage dependence and memory characteristics of HV-FDS. The memory characteristics of HV-FDS are mainly determined by the carriers transport and the interfacial polarisation caused by the accumulation of polar particles at the electrode/dielectric interface. This study covers the correlation mechanism among the microstructure, carrier transport and macroscopic HV-FDS properties of submarine cable insulation, which lays a foundation for further research and condition evaluation of submarine cables.This is an open access article under the terms of the Creative Commons Attribution-NonCommercial-NoDerivs License, which permits use and distribution in any medium, provided the original work is properly cited, the use is non-commercial and no modifications or adaptations are made.

Influence of thermal ageing on high‐field polarisation characteristics and conductivity behaviour of submarine polymeric cables insulation

“…The oxidation reaction is inhibited and the crystal structure keeps relatively complete. Accompanying with antioxidant consuming, some small molecules are in contact with each other, which can lead to the recrystallisation [18,30]. Moreover, antioxidant reactions also produce polar by-products that act as carriers.…”

“…The cable insulation XLPE, cross-linked polyethylene, is a capacitive load, which can be represented by the resistivecapacitive circuit of Figure 1, which can be used to investigate the leakage current behaviour and support the investigation of dielectric frequency response [17]. When the alternating voltage U(ω) is applied to the copper conductor of high voltage submarine cable, as shown in Equation (1), the leakage current I will flow through insulation to lead sheath, Equation (2) [18,19]. -139…”

“…The cable insulation XLPE, cross‐linked polyethylene, is a capacitive load, which can be represented by the resistive–capacitive circuit of Figure 1, which can be used to investigate the leakage current behaviour and support the investigation of dielectric frequency response [17]. When the alternating voltage U ( ω ) is applied to the copper conductor of high voltage submarine cable, as shown in Equation (), the leakage current I will flow through insulation to lead sheath, Equation () [18, 19]. $$$U(\omega )={U}_{m}{\mathrm{e}}^{\mathrm{j}\alpha }$$$ $$$I(\omega )={I}_{m}{\mathrm{e}}^{\mathrm{j}\beta }$$$ where U m is the amplitude of the applied alternating voltage, α is the initial phase angle, I m is the amplitude of the response current and β is its phase.…”

High-Voltage Cable Condition Assessment Method Based on Multi-Source Data Analysis

“…It applies D-S evidence theory to the state assessment of cables [11], uses multiple monitoring indicators, and proposes a comprehensive evaluation model for cable insulation that integrates evidence theory and fuzzy theory. It also established a comprehensive indicator system for cables [12], and obtained the weight values of various indicators based on the improved analytic hierarchy process [13]. On this basis, a comprehensive evaluation model of cable operating status with improved radar chart theory was established [14].…”

Invariant electrical conductivity upon thermal ageing of a crosslinked copolymer blend for high voltage insulation

“…5,6 It is of paramount importance that the excellent dielectric properties of click chemistry-cured copolymer blends do not deteriorate with time. Ageing of polyethylene-based insulation materials can introduce chemical defects as well as structural changes, which can negatively affect their dielectric and thermo-mechanical properties 22–26 and hence may cause electrical treeing as well as a decrease in the dielectric breakdown strength. 27–30…”