In this research, the leakage current (LC) and applied voltage waveforms on samples of installed outdoor porcelain and silicone rubber (SIR) insulators were measured by using a storage digital oscilloscope concurrent with humidity, temperature, and illuminance measurements. Essentially, the measurements were conducted daily, every three hours, for thirty days, and the data were analyzed using exponential regressions, box plots, and correlation coefficients. The porcelain and SIR insulator leakage currents varied from 23.7 A to 28.8 A and 8.4 A to 10.35 A for median values, respectively, while for outlier excluded values, they varied from 20.3 A to 40.0 A and 5.1 A to 17.1 A, respectively. Both leakage currents slightly increased as the exposure duration of the insulator rose, while the ratio decreased very slightly. Additionally, the leakage currents decreased moderately and slightly as the temperature and illuminance increased, respectively. However, the parabolic leakage currents increased as the humidity rose, especially at high humidity. Therefore, the porcelain insulator was more susceptible than the daily SIR, while the SIR insulator was more highly influenced by aging of the exposure duration. The rainy condition contributed to the highest leakage currents on both insulators, whereas the drizzle condition contributed to the highest leakage current on the SIR insulator. The total harmonic distortion (THD) and phase angle of the porcelain insulator leakage currents experienced differences of 5.8% and 7.8 degrees in the minimum and maximum humidity, respectively, but both quantities were less for the SIR insulator. INDEX TERMS humidity, leakage current, porcelain, silicone rubber I. INTRODUCTION High voltage outdoor insulators have an important role in electrical power transmission and distribution systems, including operational reliability, safety, and efficiency [1]. However, their functions are mostly influenced by environmental conditions [2-3]. Common insulator materials include glass and porcelain, which are ceramic materials that have been used for hundreds of years. Moreover, composite and cast cycloaliphatic epoxy resin (epoxy resin, ER), as a polymeric category, has been used in the last few decades [3-4]. These insulators have sheds for reducing the electric field stress and tolerating the accumulation of pollution [5]. Currently, research conducted on insulator leakage currents based on daily time functions is limited. Vosloo et al. [6] illustrated the average peak leakage currents on some insulators, and Roman et al. [7] monitored the insitu dc leakage current magnitudes, namely, rain, humidity, and temperature, on composite and glass insulators. According to Castillo-Sierra et al. [8], the ceramic insulator leakage currents were measured using a clamp meter, as were the temperature and humidity, followed by a regression analysis. Further research by Vosloo and Holtzhausen [9] showed that the peak leakage current of porcelain insulators, including precipitation, relative humidity (RH), ul...

ABSTRAK Isolator merupakan komponen yang penting dijaga keandalannya dalam sistem transmisi dan distribusi tenaga listrik. Isolator rentan mengalami kegagalan akibat lingkungan, karena terpapar langsung kondisi dimana isolator tersebut terpasang. Salah satu jenis isolator yang sering digunakan adalah bahan keramik, dimana memiliki kelebihan diantaranya kekuatan mekanik yang cukup handal. Namun kekurangan isolator jenis ini adalah sifat permukaannya yang hidrofilik, yaitu mudah menyerap air sehingga bila digunakan pada kelembaban tinggi cenderung memicu timbulnya arus bocor. Arus bocor merupakan parameter penting pada isolator karena sering menjadi penyebab kegagalan isolator. Untuk mengetahui seberapa besar pengaruh kondisi lingkungan terhadap arus bocor, dilakukan pengujian terhadap isolator keramik dalam waktu 24 jam. Data arus bocor diambil setiap 3 jam untuk melihat perubahannya berdasarkan perubahan kelembaban, dan suhu lingkungan. Hasilnya didapat bahwa semakin tinggi kelembaban udara, dan semakin rendah suhu lingkungan maka arus bocor semakin tinggi. Hasil penelitian ini dapat dijadikan acuan untuk mengantisipasi kegagalan isolator keramik akibat arus bocor sehingga keandalan sistem tenaga listrik dapat terjaga. Kata kunci: Isolator keramik, Lingkungan, Kelembaban, Suhu. ABSTRACT Isolator is an important component that must be maintained to keep electric power transmission and distribution system reliability. Isolators are susceptible to failure due to the environment, because they are directly exposed to conditions where the insulator installed. Ceramic insulator is one type of isolator that is often used, which has advantages including mechanical strength that is quite reliable. However, the lack of this type of isolator is its hydrophilic surface, which is easy to absorb water so that when used at high humidity tends to trigger a leakage current. Leakage current is an important parameter in an insulator because it can be a cause due to insulator failure. To find out how environmental conditions impact on leakage currents along day, a ceramic isolator is tested within 24 hours. Leakage current data is taken every 3 hours to see the changes based on changes in humidity, and ambient temperature. The result is the higher humidity of the air, and the lower ambient temperature, can make insulator leakage current rise up. The results of this study can be used as a reference to anticipate the failure of ceramic insulators due to leakage currents so that the reliability of the electric power system can be maintained. Keywords: ceramic insulator, environtment, humidity, temperature.