Search results

The purpose of this paper is to introduce an efficient model for analysis of the voltage distribution along the long ceramic insulator strings in a high‐voltage tower window, especially when the structure and parameters of the ceramic insulator are unknown. The effect of the grading ring on the voltage distribution is also investigated.

A circuit model composed of capacitors is used to analyze the voltage distribution along the ceramic insulator strings in a transmission tower window. The capacitances of the disk insulators, line conductors, and tower are obtained by using the finite element method, charge simulation method, boundary element method, and measurement according to their characteristics.

The model is very efficient. The voltage distribution along insulator strings can be optimized by adjusting the parameters of the grading ring. The maximum amount of voltage applied to a single insulator disk can be reduced effectively by increasing either the diameter of the grading ring or the distance from the upper surface of the grading ring to the high‐voltage end of the insulator string.

The model is very efficient for analysis of the voltage distribution along the long ceramic insulator strings, especially when the structure and parameters of the ceramic insulator are unknown.

The purpose of this paper is to propose an optimum design of a corona ring for insulator strings using optimisation techniques, which are gravitational search algorithm (GSA) and imperialist competitive algorithm (ICA).

An insulator string model geometry with a corona ring was modelled in a finite element analysis software, and it was used to obtain the electric field distribution in the model. The design was optimised using GSA and ICA. The variables were the corona ring diameter, ring tube diameter and vertical position of the ring along the insulator string.

Using optimisation method, the minimum electric field magnitude on the insulator string with a corona ring design is lower than without using optimisation method. GSA yields better results than ICA in terms of the optimised corona ring design.

The proposed methods can help in improvement of corona ring design in reducing the electric field magnitude on the energised end of insulator strings.

A new method to design an optimum corona ring for insulator strings, which is using optimisation methods, has been developed in this work.

This study aims to the three major problems of low cleaning efficiency, high labor intensity and difficult to evaluate the cleaning effect for manual insulators cleaning in ultra high voltage (UHV) converter station, the purpose of this paper is to propose a basic configuration of UHV vertical insulator cleaning robot with multi-freedom-degree mechanical arm system on mobile airborne platform and its innovation cleaning operation motion planning.

The main factors affecting the insulators cleaning effect in the operation process have been analyzed. Because of the complex coupling relationship between the influencing factors and the insulators cleaning effect, it is difficult to establish its analytical mathematical model. Combining the non-linear mapping and approximation characteristics of back propagation (BP) neural network, the insulator cleaning effect evaluation can be abstracted as a non-linear approximation process from actual cleaning effect to ideal cleaning effect. An evaluation method of robot insulator cleaning effect based on BP neural network has been proposed.

Through the BP neural network training, the robot cleaning control parameters can be obtained and used in the robot online operation control, so that the better cleaning effect can be also obtained. Finally, a physical prototype of UHV vertical insulator cleaning robot has been developed, and the effectiveness and engineering practicability of the proposed robot configuration, cleaning effect evaluation method are all verified by simulation experiments and field operation experiments. At the same time, this method has the remarkable characteristics of sound versatility, strong adaptability, easy expansion and popularization.

An UHV vertical insulator cleaning robot operation system platform with multi-arm system on airborne platform has been proposed. Through the coordinated movement of the manipulator each joint, the manipulator can be positioned to the insulator strings, and the insulator can be cleaned by two pairs high-pressure nozzles located at the double manipulator. The influence factors of robot insulator cleaning effect have been analyzed. The BP neural network model of insulator cleaning effect evaluation has been established. The evaluation method of robot insulator cleaning effect based on BP neural network has also been proposed, and the corresponding evaluation result can be obtained through the network training. Through the system integration design, the robot physical prototype has been developed. For the evaluation of other operation effects of power system, the validity and engineering practicability of the robot mechanism, motion planning and the method for evaluating the effect of robot insulator cleaning have been verified by simulation and field operation experiments.

A gas insulated substation (GIS) barrier with conical insulators from a cast epoxy resin is optimized to withstand AC and DC stresses. The field distribution across insulators with long creepage path and field distortion due to the deposition of charge on the insulator surface is calculated on a parametric geometry model by finite element techniques. The shape of the insulator and surrounding electrodes was improved fairly quickly using a direct search method with constraints. The results of optimization were verified by standard measurements on high voltage insulators in SF₆ gas.

This paper aims to present simulation studies on voltage and electric field characteristics for imperfect ceramic insulators using QuickField^TM software. Based on previous studies, it is accepted that string insulator can still serve the transmission line although imperfect of certain insulator exist in a string. However, different materials of porcelain and glass type had made these insulators own different abilities to carry electricity to be transferred to the consumers.

Cap and pin type of porcelain and glass insulators are used as the main subject for comparison. The simulation works begins with modeling a single insulator, followed by string of ten insulators with their respective applied voltage, that is, 11 and 132 kV. The insulator was modeled in alternate current conduction analysis problem type using QuickField Professional Software. Technical parameters for porcelain and glass insulator were manually inserted in the modeling.

This paper presents an investigation on the influence of broken porcelain and glass insulators in string for voltage and electric field characteristics. For single insulator, the voltage distribution may literally reduce when experiencing external damages; whereby the broken porcelain insulator condition is worse than the glass insulator. In terms of electric field distribution, the glass insulator is badly affected compared with the porcelain insulator, as it is pulverized comprehensively.

Further work needs to be done to establish whether the experiments of these simulations study will present coequal outcomes. This study endeavors in promoting a good example of voltage and electric field characteristics across high voltage (HV) insulator with the presence of broken insulator in the string.

This study is beneficial to future researchers and manufacturing companies in strategic management and research planning when they involve in the field of HV insulators. It will also serve as a future reference for academic and study purposes. This research will also educate many people on how HV insulators work.

This study will be helpful to the industry and business practitioners in training for the additional results and knowledge to be updated in the area of HV insulators.

This paper presents the analysis of porcelain and glass insulators according to their respective logic conditions when broken. Consequently, the existence of a damage insulator in a string may alter the distribution of voltage and electric field which may ultimately lead to the insulation breakdown after some time. This is because the broken insulator may cause other insulators to withstand the remaining voltage allocated for that particular insulator and may affect the insulators in terms of the life span. Therefore, the distribution of voltage and electrical field characteristics in the presence of broken insulators had been studied in this project.

Detection of deformation of devices in high voltage electricity transmission line systems is an important issue in terms of economy and reuse. This study is aimed to detect devices that are deformed or thought to have suffered due to environmental and electrical reasons.

In this experimental study, it was ensured that the sound and deformed insulators used in energy transmission lines were determined by the analysis of the sounds obtained by using the impact method. Equal intensity impact was applied to the isolator using the pendulum and the resulting sound noise signal analyses were made using power spectral density (PSD), magnitude scalogram (MS), multitape power spectrum density (MPSD) and continuous wavelet transform (CWT) methods in the study. In the analysis results, the isolators that are not visible to the eye and have certain damage were successfully separated from the intact insulators. Especially, MPSD and CWT analysis results are quite satisfactory.

Damage analysis of insulators used in electricity transmission lines has been made. A total of 40 insulators were examined in two categories in their group, both damaged and not damaged. Data collection system was established. The data obtained from the data collection system were analysed and compared using four analysis methods. PSD, MS, MPSD and CWT analyses were made in the study. All the analyses carried out generally contain features that distinguish damaged and undamaged insulators from each other, the most successful results are MS and CWT results. CWT results are very successful in terms of time and amplitude, and it has been proposed as a method that can be used to separate damaged and undamaged insulators.

It can be suggested as a result of experimental tests that the results of CWT analysis can be used in the pulse noise method in isolators to be tested for reuse in electrical power transmission lines.

The purpose of this paper is to introduce the realizing process of the fuzzy logical reasoning method in relation to the insulation detection of insulator strings, especially about the establishment of the fuzzy relation matrix.

Utilizing fuzzy logical reasoning method, the online fault diagnosis of the transmission line insulator strings can be realized efficiently, although the insulation status of the insulator strings is influenced by many factors and the relation between the measured electric parameters about the insulator with the degree of the deterioration is ambiguous.

Utilizing the pattern recognition method to build the fuzzy relation matrix after choosing the probability of the corona current, the root‐mean‐square value and the peak value and the pulse frequency of the leakage current as the fuzzy operating input variables, using the fuzzy reasoning method to estimate the insulation status proves to be a practical approach.

The experiments verify the correctness of this method by simulating work conditions of insulator strings on an 110 kV transmission line.

This paper proves that using the fuzzy reasoning method to estimate the insulation status of the online insulator strings is a practical approach. The results of the laboratory and the field tests verify the correctness of this approach and the validity of the identification method to build the fuzzy relation matrix.

The purpose of this paper is to compare environmental performance of two shackle insulator manufacturing enterprises in India by evaluating and quantifying the life cycle environmental impacts in these enterprises using ISO 14040 guidelines.

All relevant life cycle phases – raw material, manufacturing, transportation and disposal – are considered. Primary inventory data for the two enterprises are collected through observations of processes at the sites. Ecoinvent 3.0 database is used as secondary data source. Process flow models are developed using Umberto software. ReCiPe impact assessment methodology is adopted to calculate environmental impacts in terms of endpoint categories of ecosystem quality, human health and resource availability; and midpoint categories of climate change, fossil depletion, human toxicity, metal depletion, ozone depletion, terrestrial acidification and water depletion.

This study has found that manufacturing phase followed by raw material extraction and transportation phases are responsible for most of the environmental impacts. This study also found that raw materials used in glaze preparation (manganese and ferrite), electricity, heavy fuel oil (C-9) and cotton have high environmental impacts in the manufacturing phase.

The limitation of this study is that most of the inventory data are collected from only two manufacturing plants.

The researchers/enterprises can use the knowledge body for modelling and result comparison under different conditions. The enterprises can do the micro analysis of environmental effects of processes to improve environmental as well as economic performance. The government agencies can use the data for policy development and deployment.

The main contribution of the research is the creation of a knowledge body in the area of ceramic product environmental impacts. The paper provides inventory for the life cycle assessment (LCA) of shackle insulators using primary source (measured values) as no secondary data source is available for the shackle insulators. The inventory and results of this study can be used as reference for the future LCA studies in ceramic industry.

The term “partial discharges” (PD) is a common term for various phenomena: discharges at points or edges of cylindrical conductors, in gases and gas insulated devices, liquid insulation materials, at borders between different insulation materials and, of course, in solid dielectrics. These phenomena result in insulation breakdowns, various disturbances to the environment, and after longer periods, some large‐scale failures. This paper presents the results of theoretical research of the behavior of a system of medium voltage covered conductors. This research work has been elaborated by the use of computer aided electric field calculations. For the confirmation of theoretical findings, practical measurements of partial discharges have been made.

The paper first discusses the question of which objectives may be meaningful for the optimization of high‐voltage insulators, and exhaustively analyses the relationship between field strength and the geometrical properties of the boundary surfaces of a Boundary Value Problem (BVP). Afterwards a theoretical formulation of the optimization task is presented. In order to seek the parameters that may play a role in the optimization task, a formula for the global field derivative for shaping boundaries is derived. The parameters which can be determined by means of the numerical field calculation are discussed. These can be used as a point of reference for the development of an optimization procedure.