Plasma Interface Modification Endows Bilayered Polypropylene Insulation with Suppressed Space Charge and Enhanced...

Area of Science:

• Materials Science
• Electrical Engineering
• Plasma Physics

Background:

• High-voltage direct current (HVDC) submarine cables are crucial for clean energy transmission but require cable joints for splicing due to length limitations.
• The interface between cable insulation (CI) and reinforcing insulation in joints is prone to charge accumulation, leading to insulation failure.
• Existing cable joint designs face challenges in managing interfacial charge behavior and ensuring long-term reliability.

Purpose of the Study:

• To develop an interface modification strategy for polymer (PP) bilayered insulation in HVDC submarine cable joints.
• To investigate the effect of Ar-driven dielectric barrier discharge with H2O on interfacial properties and performance.
• To elucidate the mechanisms behind improved insulation performance through surface modification and functional group incorporation.

Main Methods:

• Construction of an Ar-driven dielectric barrier discharge system to treat the insulation interface.
• Optimization of treatment parameters: treatment time and H2O precursor concentration.
• Characterization of interfacial morphology, charge accumulation, breakdown strength, and trap properties using experimental and Density Functional Theory (DFT) methods.

Main Results:

• Optimal treatment (7 min, 1.0% H2O) etched surface spikes, reduced microdefects, suppressed heterocharge accumulation by 66%, and increased breakdown strength by 8.2%.
• H2O incorporation introduced oxygen-containing groups (-OH, -OCH3), increasing trap depth (1.06 to 1.15 eV) and deep trap density.
• DFT calculations confirmed uniform interfaces reduce electric-field distortion and charge injection; oxygen groups act as charge-capture centers, hindering charge migration.

Conclusions:

• The proposed interface modification strategy effectively improves the performance of PP bilayered insulation for HVDC submarine cable joints.
• Surface etching and functional group incorporation synergistically reduce interfacial charge accumulation and enhance dielectric strength.
• This approach offers a valuable reference for manufacturing high-performance, long-lasting submarine cable joints.