Study on Leakage Current Characteristics and Electrical Equivalent Circuit Properties of Aged Polymer Insulator under Artificial Environmental Condition

The most common kind of insulators that is currently used as outdoor insulators is ceramic insulator, for their advantageous characteristics such as high resistance against thermal and corrosion as well as good mechanical strength. However, especially in areas with high humidity and high pollutant level, the replacement frequency of ceramic or glass insulators are quite often due to the pollutant that easily stick on the insulators surface can decrease the insulator performance, causing flashover to occur sooner than it is supposed to. Polymer insulator is then introduced to solve this problem since it has better hydrophobicity which allows it to repel pollutants and light in weight. There have been many research conducted regarding polymer insulator, but until now the field implementation is still limited, especially in Indonesia. The effect of the tropical climate and high pollution level still has to be continuously studied on the polymer insulator performance. One of the parameters that determine the performance quality of an insulator is leakage current (LC). This paper discusses the leakage current characteristics of a polymer insulator when it is artificially aged and affected by different environmental condition. Additionally, electrical equivalent circuit parameters of polymer insulator in each environmental conditions are also studied through simulation of outdoor insulator using ATPDraw software. There are eight different LC waveforms consisting of new and aged polymer insulator from each experimental conditions (4 different conditions) that are compared and taken into simulation to analyze the electrical equivalent circuit parameters such as capacitance, nonlinear resistance, and number of arc models of each polymer insulator condition. The key parameters that determine the similarity between the measured and simulated LC waveforms include the LC magnitude, Total Harmonic Distortion (THD) and dominant harmonic number.