Comparative Study of SiR/EPDM Containing Nano-alumina and Titanium Dioxides in Electrical Surface Tracking M. Fairus, M. Hafiz, Noor Syazwani Mansor, M. Kamarol School of Electrical and Electronic Engineering, Universiti Sains Malaysia, Engineering Campus, 14300 Nibong Tebal, Pulau Pinang, Malaysia and M. Jaafar School of Materials and Mineral Resources, Universiti Sains Malaysia, Engineering Campus, 14300 Nibong Tebal, Pulau Pinang, Malaysia ABSTRACT The combination of polymer materials, such as silicone rubber (SiR) and ethylene propylene diene monomer (EPDM), has become one of the potential developments of new polymer insulator with superior characteristics. SiR/EPDM with a ratio of 50:50 weight percentages had produced the optimal electrical and mechanical properties of polymer composites. However, the study of these balanced blends with inclusion nanofillers remains limited and has yet to be completely explored. In the current research, SiR/EPDM blends were prepared with two types of nanofillers, namely, Al 2 O 3 and TiO 2 . The loading concentrations of the nanofillers for each specimen were 1, 2, 3, 4, and 5 Vol%. The effects of the Al 2 O 3 and TiO 2 nanofillers with different loading concentrations on the surface-tracking characteristics were investigated. Experimental results revealed that the addition of nanofillers to the SiR/EPDM composite significantly improved the performance of the electrical surface-tracking resistance, thereby decelerating the aging process or minimizing damage to the surface. Moreover, experimental results showed that SiR/EPDM filled with 1 Vol% of the Al 2 O 3 nanofiller had an improved tracking time performance than the SiR/EPDM filled with 2 Vol% of the TiO 2 nanofiller had. The tracking time and thermal conductivity characteristics of both nanocomposites were higher than those of the unfilled SiR/EPDM. Index Terms — surface discharge, silicone rubber (SiR), ethylene propylene diene monomer (EPDM), nano-alumina (Al 2 0 3 ), nano-titanium (TiO 2 ), tracking time, thermal conductivity, leakage current (LC), dry band arcing (DBA). 1 INTRODUCTION HIGH voltage transmission line insulator is one of the most significant components in an electrical power system. Several types of outdoor insulators are available, such as pin, suspension, and strain insulator; however, their main functions are identical, thereby preventing electrical current from flowing directly to the ground through the tower or poles [1]. Traditional insulator is made of Teflon® (an organic material) and ceramic and glass materials (inorganic materials). Inorganic materials have been replaced recently with polymer materials due to several advantages, such as good dielectric characteristic, low installation cost, light weight, and good vandalism resistance. Polymer materials also have higher tensile strength and less cleaning maintenance than inorganic materials because of the hydrophobic nature of insulators [2]. Polymer insulators have been manufactured with varied types of polymer materials, such as silicone rubber (SiR), epoxy resin, ethylene propylene diene monomer (EPDM), ethylene propylene rubber, high-density polyethylene, and an alloy of SiR/EPDM. Polymer insulator materials, such as SiR, have been extensively used because of their excellent electrical characteristics, such as high dielectric strength and volume resistivity. However, these materials have poor mechanical strength and low tracking resistance, as well as expensive. EPDM has excellent resistance to tracking and erosion and higher mechanical strength than SiR; however, the former suffers from low volume and surface resistivity compared with SiR [3–8]. Polymer composite with another type of polymer material has become one of the major research subjects in developing new Manuscript received on 24 October 2016, in final form1 April 2017, accepted 24 May 2017. Corresponding author: M. Kamarol. IEEE Transactions on Dielectrics and Electrical Insulation Vol. 24, No. 5; October 2017 2901 DOI: 10.1109/TDEI.2017.006414