Feasibility Study on Electrical Properties of 20 kV Polymeric Insulator Dry Test and Rainwater Test

Insulator is a very important equipment in an electric power system. Ceramic insulators have been widely used to support conductors in 20 kV power lines. The problem of ceramic insulators is that they are heavy, easily contaminated on the surface and require a lot of energy in the manufacturing process. Therefore, polymer insulators were developed. This paper presents the design of an epoxy resin polymer insulator with Titanium Dioxide (TiO2) as a nanofiller. The leakage current test was carried out in a high voltage laboratory by applying an AC high voltage of 50 Hz to the insulator dry conditions and the insulator wetted by rainwater contaminants. The results of the leakage current test in dry conditions are 487.6 μA, rainwater contaminated conditions are 594.93 μA, insulation resistance in dry conditions is 2.07 G-Ohms, and contaminated conditions are 1.41 G-Ohms. Based on the test results show that the insulator leakage current increases up to 22% when the surface of the insulator is contaminated with rainwater. Meanwhile, the insulation resistance decreased by up to 32% in conditions contaminated with rainwater. The value of leakage current and insulation resistance indicates that the epoxy resin insulator with TiO2 as filler is electrically feasible to use.

Effects of Flash Sintering Parameters on Performance of Ceramic Insulator

Ceramic outdoor insulators play an important role in electrical insulation and mechanical support because of good chemical and thermal stability, which have been widely used in power systems. However, the brittleness and surface discharge of ceramic material greatly limit the application of ceramic insulators. From the perspective of sintering technology, flash sintering technology is used to improve the performance of ceramic insulators. In this paper, the simulation model of producing the ceramic insulator by the flash sintering technology was set up. Material Studio was used to study the influence of electric field intensity and temperature on the alumina unit cell. COMSOL was used to study the influence of electric field intensity and current density on sintering speed, density and grain size. Obtained results showed that under high temperature and high voltage, the volume of the unit cell becomes smaller and the atoms are arranged more closely. The increase of current density can result in higher ceramic density and larger grain size. With the electric field intensity increasing, incubation time shows a decreasing tendency and energy consumption is reduced. Ceramic insulators with a higher uniform structure and a smaller grain size can show better dielectric performance and higher flashover voltage.

A Study of Multilayer Perceptron Networks Applied to Classification of Ceramic Insulators Using Ultrasound

Interruptions in the supply of electricity cause numerous losses to consumers, whether residential or industrial and may result in fines being imposed on the regulatory agency’s concessionaire. In Brazil, the electrical transmission and distribution systems cover a large territorial area, and because they are usually outdoors, they are exposed to environmental variations. In this context, periodic inspections are carried out on the electrical networks, and ultrasound equipment is widely used, due to non-destructive analysis characteristics. Ultrasonic inspection allows the identification of defective insulators based on the signal interpreted by an operator. This task fundamentally depends on the operator’s experience in this interpretation. In this way, it is intended to test machine learning applications to interpret ultrasound signals obtained from electrical grid insulators, distribution, class 25 kV. Currently, research in the area uses several models of artificial intelligence for various types of evaluation. This paper studies Multilayer Perceptron networks’ application to the classification of the different conditions of ceramic insulators based on a restricted database of ultrasonic signals recorded in the laboratory.

Global experience of HVDC composite insulators in outdoor and indoor environment

High-voltage direct current (HVDC) transmission is known as green-energy transfer technology and has recently become an attractive alternative of high-voltage alternating current (HVAC) due to its high-power transmission capability and lower power loss. Use of composite insulators on direct current (DC) transmission lines experienced rapid growth in recent years due to their high hydrophobicity and better performance in contaminated environment than conventional ceramic insulators. During their service operation on DC lines, insulators are prone to more accumulation of contaminants due to unidirectional electric field. The contaminants under wet conditions allow leakage current to flow on the insulator surface. Being organic in nature, polymeric insulators have a tendency to age under the combined effects of electrical and environmental stresses. To fully understand the long-term aging performance of DC composite insulators, a detailed survey was considered necessary. Towards that end, this paper critically summarizes worldwide experience of aging performance of composite insulators in the field as well as in laboratory conditions.

Visualizing Polymer Damage Using Hyperspectral Imaging

Silicone rubbers (SIRs) are common industrial materials which are often used for electrical insulation including weather sheds on non-ceramic insulators (NCIs). While SIRs are typically resilient to outside environments, aging can damage SIRs’ favorable properties such as hydrophobicity and electrical resistance. Detecting SIR aging and damage, however, can be difficult, especially in service. In this study we used hyperspectral imaging (HSI) and previously investigated aging methods as a proof of concept to show how HSI may be used to detect various types of aging damage in different SIR materials. The spectral signature changes in four different SIRs subjected to four different in-service aging environments all occurred between 400––650 nm. Therefore, remote sensing of NCIs using HSI could concentrate on bands below 700 nm to successfully detect in service SIR damage.