Enhancement of Partial Discharge Resistance and Breakdown Strength Characteristics of Low-Density Polyethylene Nanocomposites Using Plasma Treatment Method

Abstract

: Insulations in the power cable system are prone to ageing and degradation, eventually leading to a complete breakdown. One of the solutions to reduce insulation breakdown in polymeric insulation is by adding nanofillers into the polymer matrices of the insulation to form polymer nanocomposites. However, the addition of the nanofiller into the polymer usually results in agglomeration inside the nanocomposites. Recently, atmospheric pressure plasma (APP) has been introduced by adopting the nanofiller's surface modification method to hinder agglomeration formation. The aims of using APP are to enhance the nanofiller-polymer interfaces and improve the dielectric properties, emphasizing partial discharge (PD) resistance and AC breakdown strength. In this study, APP has been used to treat boron nitride (BN) and silicon dioxide (SiO 2 ) nanoparticle surfaces for the purpose of enhancing the compatibility with low-density polyethylene (LDPE) matrices. Untreated and plasma-treated nanoparticles have been added into LDPE with different filler loading of 1 wt%, 3 wt% and 5 wt% via the direct compounding method. Compared with untreated nanocomposites, the 30-minutes plasma-treated nanocomposites could improve the PD resistance by reducing the PD magnitude up to 513 pC and reducing the PD number to 11661. Moreover, the AC breakdown strength of the plasma-treated nanocomposites had increased from 0.53 kV/mm to 26.65 kV/mm. If compared to LDPE/BN nanocomposites, it was discovered that the LDPE/SiO 2 nanocomposites displayed significantly better dielectric characteristics. In addition, plasma treatment of the nanoparticles could produce nanocomposites with better formulation stability and promising dielectric performance, which can prolong the insulation's lifetime and ensure the reliability of the power supply.