Surface Of Outdoor Insulators Research Articles

Accurate Sensing of Insulator Surface Contamination Using Customized Convolutional Neural Network

Accurate sensing of contamination on the insulator surface is vital for the reliable operation of transmission lines. Hence, the present work aims to develop a deep learning framework for remote and accurate contamination sensing on the surface of outdoor insulators. The experiment is conducted on an 11-kV porcelain disc insulator to generate an extensive database of images representing different insulator surface conditions, i.e., clean surface and surface with sand, mud, and ash contaminations. The captured images were fed to a customized convolutional neural network (CNN) architecture for automated feature extraction and recognition. The proposed CNN model delivers appreciably high recognition accuracy at significantly reduced training time for sensing various insulator contaminations compared with other benchmark CNN models (AlexNet, VGGNet16, and ResNet50). Moreover, the proposed framework delivers an excellent recognition performance in sensing surface contamination under different lighting conditions. Therefore, the proposed methodology can be implemented for the condition monitoring of real-life insulators.

Stacked Ensemble Deep Learning for Outdoor Insulator Surface Condition Classification: A Profound Study on Water Droplets

Stacked Ensemble Deep Learning for Outdoor Insulator Surface Condition Classification: A Profound Study on Water Droplets

Research Progress of Self-Cleaning, Anti-Icing, and Aging Test Technology of Composite Insulators

Composite insulators are widely used in power systems because of their advantages of light weight, good pollution resistance, and high mechanical strength. With the increasingly serious environmental pollution problem, especially in winter at high latitudes, composite insulators are easily affected by fog, bird droppings, algae, and icing. Long-term exposure to the outdoor insulator surface will cause aging, which will then pose ae potential safety hazard to the stable operation of insulators. Therefore, the self-cleaning, anti-icing, and aging test technologies of composite insulators are particularly important. This paper introduces the research progress and current situation of self-cleaning, anti-icing surface preparation, and aging test technology of composite insulators, and looks forward to the future development of composite insulators.

Synthesis and characterization of hydrophobic nano-silica thin coatings for outdoor insulators

The hydrophobic characteristics of outdoor insulator surface have significant influence on the lifetime and performance of the power transmission lines. In this research, a textured silica layer was dip-coated on the surface using a tetraethyl-orthosilicate (TEOS) containing solution in order to create a hydrophobic surface. Subsequently, the created coating was modified by dipping it in an octadecyl-trichloro-silane/ethanol solution to decrease its surface energy. The coating was characterized by field emission scanning electron microscopy, X-ray diffraction method, Fourier-transform infrared spectroscopy and atomic force microscopy. The microstructural studies confirmed the formation of a uniform microstructure with the mean particle size of 19 nm and roughness of less than 80 nm. The results demonstrated that by creating the hydrophobic coating, the contact angle increased from 14 to 120?. The result of leakage current test at 10 kV showed that the leakage current of the coated insulator was about 24.4 ?A, while that of the non-coated one was about 32 ?A. The adhesion strength of the coating was 1.7MPa.

Numerical Simulation of Leakage Current on Conductive Insulator Surface

The outdoor insulator is commonly exposed to environmental pollution. The presence of water like raindrops and dew on the contaminant surface can lead to surface degradation due to leakage current. However, the physical process of this phenomenon is not well understood. Hence, in this study we develop a mathematical model of leakage current on the outdoor insulator surface using the Nernst Planck theory which accounts for the charge transport between the electrodes (negative and positive electrode) and charge generation mechanism. Meanwhile the electric field obeys Poisson’s equation. Method of Lines technique is used to solve the model numerically in which it converts the PDE into a system of ODEs by Finite Difference Approximations. The numerical simulation compares reasonably well with the experimental conduction current. The findings from the simulation shows that the conduction current is affected by the electric field distribution and charge concentration. The rise of the conduction current is due to the distribution of positive ion while the dominancy of electron attachment with neutral molecule and recombination with positive ions has caused a significant reduction of electron and increment of negative ions.

High voltage outdoor insulator surface condition evaluation using aerial insulator images

High voltage insulator detection and monitoring via drone-based aerial images is a cost-effective alternative in extreme winter conditions and complex terrains. The authors examine different surface conditions of the outdoor electrical insulator that generally occur under winter condition using image processing techniques and state-of-the-art classification methods. Two different types of classification approaches are compared: one method is based on neural networks (e.g. CNN, InceptionV3, MobileNet, VGG16, and ResNet50) and the other method is based on traditional machine learning classifiers (e.g. Bayes Net, Decision Tree, Lazy, Rules, and Meta classifiers). They are evaluated to discriminate the images of insulator surface exposed to freezing, wet, and snowing conditions. The results indicate that traditional machine learning methods with proper selection of features can show high classification accuracy. The classification of the insulator surfaces will assist in determining the insulator conditions, and take preventive measures for its protection.

Influence of Single and Multiple Dry Bands on Critical Flashover Voltage of Silicone Rubber Outdoor Insulators: Simulation and Experimental Study

Dry band formation on the surface of outdoor insulators is one of the main reasons leading to flashover and power outages. In this paper, a dynamic arc model is proposed for single and multiple dry bands configuration to predict the critical flashover voltage for silicone rubber outdoor insulators. An arc is modelled as a time dependent impedance consisting of a Resistor Inductor Capacitor (RLC) circuit. The effect of dry band location and existence of multiple dry bands on critical flashover voltage is investigated. To validate the proposed model, experiments were conducted in a climate chamber under controlled environmental conditions on rectangular silicone rubber sheets polluted using improved solid layer method based on IEC 60,507. Tests were conducted at different dry band configurations and pollution severity levels. A good correlation was found between experimental results and simulation results. This model can provide a good foundation for the development of mathematical models for station post insulators having multiple dry and clean bands and can be used in the design and selection of outdoor insulators for polluted conditions.

Properties and applications of superhydrophobic coatings in high voltage outdoor insulation: A review

The deposition of ice, snow, pollution or their mixtures on the surface of outdoor insulators may severely affect their performance, resulting in electrical and or mechanical failures. Various preventative methods are used to minimize the problems of ice and pollution build up on the surface of outdoor insulators. In the last few decades, advanced coatings have been developed for better performance of outdoor insulators in contaminated and freezing environments. These advanced coatings offer the advantage of low wettability, high thermal and ultraviolet resistance, self-cleaning, self-healing, low ice adhesion strength and delayed freezing time. It is believed that these benefits will not only increase the reliability of transmission systems but may also reduce the capital cost of transmission infrastructure. This paper presents a detailed review on the properties and applications of superhydrophobic coatings in outdoor high voltage insulation. This review can be beneficial to scientists and engineers in evaluating the performance and durability of superhydrophobic coatings in polluted and freezing conditions. It also highlights the need for standardized tests and procedures for better understanding the behavior of superhydrophobic coatings in different environments and their long-term durability.

An Experimental Study on Surface Discharge Characteristics of Different Types of Polymeric Material under AC Voltage

Surface discharge is a common electrical discharge that normally occurs on the surface of outdoor insulators and also causes the failure in the electrical insulation system. One of the causes of surface discharge is the presence of high voltage stress. Experimental works had been carried out to examine the surface discharge characteristics on polymeric samples as insulation material. The IEC (b) electrode configuration had been used to investigate the surface discharges phenomena of different types of polymeric materials with controlled of air relative humidity (RH). In these experimental works, three types of polymeric sample were selected, namely high-density polyethylene (HDPE), ethylene-vinyl acetate (EVA), and polystyrene (PS), respectively. The characteristics of the discharge are critically depending on the types of polymer. Surface discharges intensity, number of discharge occurrence, and surface morphology of each polymeric material were also investigated. Comparisons of these electrical characteristics were conducted among the samples. Results from the experiment showed that the EVA samples experienced severe degradation as compared to HDPE and PS samples.

Electroquasistatic Field Simulation for the Layout Improvement of Outdoor Insulators Using Microvaristor Material

A possible solution to locally reduce the high electric-field stress along the surface of outdoor insulators is to use the resistive field grading materials such as zinc–oxide microvaristor polymer compounds. This material is nonlinearly semiconductive and its conductivity depends on the electric-field intensity. In this paper, the field control effect of this material is demonstrated. Different configurations in order to optimize the layout of this material are compared. A case study is carried out for a 765-kV outdoor large-scale long rod polymeric insulator using different layouts of the microvaristor material. Electroquasistatic simulations are performed to evaluate the tangential electric-field distributions along the surface of the insulator for the dry clean surface condition and with a few single water droplets on the surface.

Prediction of equivalent salt deposit density of contaminated glass plates using artificial neural networks

Contaminants are deposited on the outdoor insulator surface due to environmental conditions. Conductivity or Equivalent Salt Deposit Density (ESDD) normally expresses this contamination on the insulator surface. In the laboratory, NaCl, tap water and distilled water are used for measuring conductivity and ESDD. In addition, different sizes of glass plates are used as an insulating medium. A conductivity-measuring instrument (Cond 300i) is used to measure the conductivity of the salt-solution. Based on the experimental data, the relationship between the different variables (temperature, salinity, salt, type of water, plate size and sigma) and the ESDD are modeled using artificial neural networks. The developed model showed a good predictive success with R 2 value above 0.98. This value indicates high accuracy for both model development and the model generalization capability. The meteorological variables (temperature, salinity, salt, type of water, plate size, etc.) with the greatest influence on ESDD are also identified using the weight partitioning method. It is found that glass plate size is the variable that has the greatest effect on the prediction of the ESDD since it has a contribution of 47%. The volume conductivity at different degrees had a contribution between 12.38% and 12.87%, while the type of water, the salt quantity, the salinity, and the temperature used had a contribution percentage of 7.92, 7.92, 7.43, and 4.46, respectively. The investigation indicated that the ANN models are well-suited for predicting the contamination level to prevent flashover on the insulator surface and for analyzing the contribution of the different factors affecting this contamination level that are represented either by the ESDD or the conductivity. Additionally, the ANN models can be extended for other applications in which nonlinear relationships are observed.

Evaluation methods on polymer materials for surface of outdoor insulators

Performance of nonceramic insulators is strongly related to hydrophobicity of the surface. Therefore, it is useful to evaluate the characteristics of the surface of organic insulating materials. To characterize the methods for the evaluation, some measurements were conducted on silicon rubber (SR), EPDM, PMMA and polyethylene (PE). The influence of irradiation with a mercury lamp was detected through measurements of contact angle, formation time of water film, and mass analysis of released gases under irradiation of electron beam. Measurement of the contact angle by using polar and nonpolar liquids revealed that silicon rubber (SR) was the most resistant against UV radiation. SR also showed recovery of hydrophobicity after UV irradiation. Measurement of the current flowing across the surface of materials exposed to artificial fog showed good agreement to the measurement of contact angle. Infrared absorption spectroscopic analysis enabled the intensity of oxidation of highly UV-deteriorated organic insulating materials to be detected. Radicals on the surface of specimens were specified from the result of mass analysis of released gases. From these results, the nature of deterioration of organic insulating materials irradiated by UV is discussed.

屋外用高分子材料表面の評価法の検討

屋外用高分子材料表面の評価法の検討

Continuous Recording of Outdoor Insulator Surface Conductance

Surface conductance of outdoor insulators exposed to pollution and moisture from rain or fog is related to two aspects of insulator application: 1) possibility of insulator flashover and 2) duration and severity of surface arc discharges. This paper will discuss some of the experience with monitoring the surface conductance of porcelain and synthetic insulation under voltage stress and exposed to outdoor weathering in various locations in the U. S. Simple flat surfaces mounted at a 30° angle from the horizontal and some shed-type insulators have been followed in this study. Recordings have been made over periods of several years, comparing results with low and high voltage stress. Results of these outdoor tests are also compared with results of tests of similar surfaces in a synthetic salt-fog chamber.

Insulator surface contamination

ONE OF THE major unsolved problems in the insulation of electric power lines is that of obtaining trouble-free operation under conditions of severe atmospheric contamination. The presence of conducting film on the surface of outdoor insulators subjected to high voltage leads to a number of serious results. This may be summarized briefly as follows:

Insulator Surface Contamination

ONE OF THE major unsolved problems in the insulation of electric power lines is that of obtaining trouble-free operation under conditions of severe atmospheric contamination. The presence of conducting film on the surface of outdoor insulators subjected to high voltage leads to a number of serious results. This may be summarized briefly as follows: