One important component in the high voltage overhead lines placed on the transmission tower is the insulator. When polymer insulators are installed in tropical climates, there will be two conditions occurs, such as: i) the changes from wet to dry will cause the pollutant particles in the air will attach to the surface of the insulator. This condition will cause the sedimentation on the surface of the insulator; ii) the changes from dry to wet will form a conductive layer that leads to the leakage current flow. The flow of leakage current leads to the formation of dry-band on the surface. The formation of a dry band creates an electric arc or PD and can eventually cause a flashover insulator. Laboratory experiments were carried out at different levels of pollution and RH. PD signals in the form of leakage current flowing to the ground are transformed by HFCT. PD patterns are collected through an innovative PD detection system. PD signals measured in the form of PRPD patterns are evaluated using the concept of equivalent band-width and time-length equivalent to understand the pollution performance of polymer insulators. The width of the frequency field produced from the experiment can be the basic of analysing the severity of the surface pollution of outdoor polymer insulators.

One of the important components in the high voltage overhead lines placed on the transmission tower is an insulator. Insulators that are installed outdoor will be exposed to the environment directly. Due to environmental conditions and pollutants attached to the surface, leakage currents can flow on the surface of the insulator. Large leakage currents can damage the surface of the insulator and cause losses in the form of heat and even cause flashover. This paper provides an alternative way to prevent early flashover by detecting the severity of the insulator surface based on harmonic measurements of leakage currents. Insulator performance mainly depends on the conductivity of the surface layer being polluted or by generating pollutants via the equivalent salt deposit density (ESDD). The leakage currents were evaluated at different ESDD levels as deposits of very light, light, moderate, and heavy NaCl salt pollution on a 20 kV outdoor polymer insulators. From the experiments, it can be concluded that: i. The leakage current that occurs when the surface of the insulator is very lightly polluted has an unsymmetrical waveform that is distorted and leads to a positive with a large THD; ii. The magnitude of the leakage current with the surface of the insulator is polluted, which leads to greater weight, but the harmonic distortion and THD are getting smaller with the waveform of the leakage current signal leading to a sinusoidal waveform.

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The dielectric properties of LDPE-NR biopolymeric insulating materials can be improved by adding the silica nanoparticles in a certain percentage of weight into the composite. In the present study, four types of bionanopolymeric samples were prepared. To each sample, the nanosilica particles with a weight percentage of 1.5%, 3%, 4.5% and 6% a were added. To see the electrical characteristics, the four samples were placed under the AC high voltage for 1 hour and the partial discharge (PD) signals were recorded continouesly in that period of time. The results show that the number of positive and negative PD pulses for each silica sample after 60 minutes of testing was not the same for all samples. The that samples with a higher percentage of nano silica had fewer PD pulses. This indicates that nanosilica particles can improve the PD resistance of LDPE-NR insulation materials.