International Journal of Electrical and Computer Engineering (IJECE) Vol. 7, No. 2, April 2017, pp. 568~575 ISSN: 2088-8708, DOI: 10.11591/ijece.v7i2.pp568-575  568 Journal homepage: http://iaesjournal.com/online/index.php/IJECE The Effect of Plasma-Treated Boron Nitride on Partial Discharge Characteristics of LDPE N.A. Awang, M.H. Ahmad, Y.Z. Arief, I. H. Zakaria, N.A. Ahmad Institute of High Voltage & High Current (IVAT), Faculty of Electrical Engineering, UniversitiTeknologi Malaysia, 81310 Johor Bahru, Malaysia Article Info ABSTRACT Article history: Received Jun 9, 2016 Revised Nov 20, 2016 Accepted Dec 11, 2016 Power supply reliability is a key factor in a country economic stability. It is contributed by the reliable power distributor via transmission lines, overhead or underground cables. However, the power cables and accessories are always exposed to pre-breakdown phenomena known as partial discharges (PD) which commonly occur in microvoids, defects or protrusions inside the insulation.To improve the performance of the cable insulation against PD, nanofillers are added into the insulating materials. However, to achieve superior performance of PD resistance, the nanofillers must be homogeneously dispersed into the polymer matrices withtightly bonded interfacial zones. Therefore, this could be achieved by employing method of surface functionalization by using cold atmospheric plasma to strengthen the filler/polymer interfaces. In view of foregoing, this study investigated the effects of surface treated boron nitride (BN) nanoparticles in Low Density Polyethylene (LDPE) on the PD characteristics by following CIGRE Method II at 7 kVrmsapplied voltage. The phase resolved PD characteristics were performed. The results revealed that by treating the nanofillers with cold plasma, the PD resistance of LDPE were highly achieved compared with the untreated BN nanofillers. Keyword: Atmospheric pressure plasma Boron nitride CIGRE method II Low density polyethylene Partial discharge Copyright © 2017 Institute of Advanced Engineering and Science. All rights reserved. Corresponding Author: M.H. Ahmad, Institute of High Voltage & High Current, Faculty of Electrical Engineering, Universiti Teknologi Malaysia Email: mohdhafizi@fke.utm.my 1. INTRODUCTION Polymeric insulating materials are widely used in high voltage equipment, especially in power cables. However, under long period, polymeric cables which exposed to the ageing and degradation will eventually lead to electrical failure. One of the main causes of electrical failure in insulation cables is partial discharge. Partial discharge (PD) is defined as a localized dielectric breakdown of a small portion of an insulation solid or fluid that partially bridge the insulation between the conductors which may or may not occur adjacent to a conductor [1]. Thus, PD phenomenon needs to be considered in insulation diagnostics and performance assessment measurement. Since this phenomenon only occurs within the defect in the insulation, it does not cause a direct breakdown of the insulation immediately [2]. Failures in high voltage components due to insulation breakdown can result in costly and time consuming maintenance as the whole component may need to be replaced. Therefore, one of the methods against PD is by adding nanofillers into the polymer to reduce the PD activities in polymeric insulation. However, the nanofillers tend to agglomerate in polymer matrices due to their incompability. The homogeneous dispersion and good adhesion of the nanoparticles cannot be achieved thereby leading to properties degradation of the power cable insulation. As a solution, coupling agent was used to modify the surface of the nanoparticles chemically. This method has shown some promising results by improving the interfacial bonding [3], but this technique still has some