Reliability Of Transmission Lines Research Articles

Extreme Wind Speed Estimation for Wind-Resistance Design of a Transmission Line Situated in a Typhoon-Prone and Hilly Area

The southeastern coast of China is annually threatened by typhoons originating from the northwestern Pacific Ocean, posing a risk of severe damage to coastal transmission lines. This study employs the random forest-based typhoon full-track simulation method and YM wind field to assess the wind-resistance reliability of transmission lines. The obtained extreme wind speeds of a transmission line site in Wenzhou are 33.7m/s and 35.8m/s under the 50-year and 100-year return periods, respectively. The effects of micro-topography on the extreme typhoon wind speed are further analyzed, and the extreme wind speed distribution maps of Wenzhou City and Yueqing City are plotted, respectively. The results indicate a decreasing trend in typhoon wind speed within inland regions, while micro-topography displays a substantial effect on enhancing the typhoon wind speed.

Age Estimation of Transmission Line Using Statistical Health Index and Failure Probability Curve-Fitting Method

The aging process of transmission lines has a direct impact on the reliability and safety of the power grid. Therefore, an accurate age estimation method is imperative for effective maintenance planning and infrastructure investment. This paper introduces a systematic methodology for estimating the age of overhead transmission lines, utilizing the percentage statistical health index (%SHI) and the failure probability curve-fitting (FPCF) method. The %SHI, employing a scoring and weighting approach derived from test results and inspections, is used to assess the actual condition of transmission line equipment. Additionally, the FPCF approach is applied to illustrate the connection between the SHI and the likelihood of failure, facilitating the assessment of transmission line age by fitting failure probability curves to the SHI data. This age is directly associated with the probability of experiencing a failure. The evaluation was conducted on 924 towers situated along four transmission lines connecting the 115 kV substations S1–S2, S3–S4, S5–S6, and S7–S8. These transmission lines are in four regions with diverse terrain and environments such as mountains, rice fields, and more. In the SHI calculation, practical testing results and historical failure data were applied. The results clearly indicate that there were notable disparities in the age estimations for transmission lines in diverse geographical regions of Thailand when compared to their actual ages. These discrepancies can be attributed to various factors, including the local environment, such as rainfall, flooding, and salt-laden air as well as specific geographical features like mountainous and coastal terrain. To mitigate the deterioration of transmission lines in all regions, it is essential to implement a proactive maintenance strategy. This strategy should involve more frequent inspections, the use of advanced monitoring technologies, and the establishment of robust maintenance procedures, with which it would become possible to enhance the accuracy of equipment condition assessments, ultimately resulting in an overall improvement in the reliability of transmission lines.

Analysis and Suggestions for the Self-blast Problem of Glass Insulators on Transmission Lines

By virtue of many advantages such as good self-cleaning ability, outstanding mechanical performance, and excellent anti-vibration-fatigue ability, the glass insulators have been widely used in various alternating-current and direct-current transmission lines. However, the self-blast incidents of glass insulators have frequently occurred in transmission lines with various voltage levels, seriously affecting the safe operation of transmission lines. Herein, the main causes of self-blast problem of glass insulators are summarized and analysed from different perspectives, and some corresponding suggestions have been proposed to reduce the self-blast of glass insulators. In addition, the relevant prospects are provided for the future research work about the glass insulators. The viewpoints in this article have important theoretical and practical significance for improving the safety and reliability of transmission lines and ensuring the stable operation of electrical power systems.

Reliability models of overhead power lines in the calculation algorithm based on network topological analysis

The article proposes an approach to the analysis of the reliability of high-voltage transmission lines developed using topological concepts of analyzing the structure of networks in the electric power industry. The study used practical power distribution schemes used at hydroelectric power plants in the East Siberian region. On the basis of the probabilistic model, a computational algorithm has been formed, software for assessing reliability has been developed. Using the described tools, a numerical assessment of the reliability indicators of outgoing high-voltage power lines 220 kV was carried out.

Energy Saving Transmission Line Evaluation Based on Mechanical and Electrical Characteristics Analysis

In order to improve the safety and reliability of transmission lines in certain areas, an energy-saving line selection scheme based on mechanical and electrical characteristics analysis is proposed. We determine the structural technical parameters and system conditions of the new energy-saving conductor through specific cases. In the mechanical characteristics, the dynamic stress, safety factor and the maximum sag of four different types of conductors during galloping are compared; In electrical characteristics, the current carrying capacity and resistance loss are mainly calculated. Finally, the economic and social benefits of energy-saving conductor are analyzed in combination with the specific project situation, and the specific precautions in the conductor selection process are analyzed, which provides a technical reference for the design, selection and application of energy-saving conductor.

Insulator image autonomous recognition and defect intelligent detection based on multispectral image

Insulator determines the insulation level and power supply reliability of transmission lines. The traditional operation and maintenance method of insulators has a large workload. This paper presents an insulator recognition and fault diagnosis system based on image recognition and machine learning. Firstly, the composite insulators in complex backgrounds have been identified by Faster RCNN algorithm, which helps to extract the image of insulators by drone shot. Then, the cracking of umbrella skirts has been carried out by means of image processing. Also, the contamination of composite insulator umbrella skirts is also identified. The appropriate feature quantity by Fisher’s discrimination is recommended, and the insulator contamination level has been identified by S component. Lastly, analyzing the infrared image of the insulator provides the basis for the normalization of insulator temperature rise detection results in different environments. Insulator image autonomous recognition and defect intelligent detection, which is based on deep reinforcement learning, is helpful for the operation, maintenance and repair of line insulators.

Fault Identification of Double-circuit Transmission Lines on The Same Tower Based on CEEMDAN-SSA-SVM

In order to improve the reliability of double-circuit transmission lines on the same tower, by analyzing the variation law of inverse wave of fault voltage inside and outside the area, a support vector machine (SVM) method for internal and external fault identification of double-circuit transmission lines on the same tower based on adaptive noise complete ensemble empirical mode decomposition and sparrow search algorithm optimization is proposed. This method carries on the phase mode transformation of the current and voltage after the fault. The inverse wave current in the time window after the fault is adaptively decomposed by CEEMDAN, and the corresponding energy entropy is extracted to form the feature vector. The SMOTE algorithm is used to balance the fault samples outside the region. Finally, the feature vector set is input to the SSA-SVM classifier for training and testing. Through theoretical and simulation analysis, the following results are obtained: the algorithm in this paper is not affected by fault initial angle, transition resistance and fault distance.

Stretchable and self-healable spoof plasmonic meta-waveguide for wearable wireless communication system

Microwave transmission lines in wearable systems are easily damaged after frequent mechanical deformation, posing a severe threat to wireless communication. Here, we report a new strategy to achieve stretchable microwave transmission lines with superior reliability and durability by integrating a self-healable elastomer with serpentine-geometry plasmonic meta-waveguide to support the spoof surface plasmon polariton (SSPP). After mechanical damage, the self-healable elastomer can autonomously repair itself to maintain the electromagnetic performance and mechanical strength. Meanwhile, the specially designed SSPP structure exhibits excellent stability and damage resistance. Even if the self-healing process has not been completed or the eventual repair effect is not ideal, the spoof plasmonic meta-waveguide can still maintain reliable performance. Self-healing material enhances strength and durability, while the SSPP improves stability and gives more tolerance to the self-healing process. Our design coordinates the structural design with material synthesis to maximize the advantages of the SSPP and self-healing material, significantly improving the reliability and durability of stretchable microwave transmission lines. We also perform communication quality experiments to demonstrate the potential of the proposed meta-waveguide as interconnects in future body area network systems.

Analysis of 3-Phase Symmetrical and Unsymmetrical Fault on Transmission Line using Fortescue Theorem

This paper investigates the major faults affecting the transmission of electrical energy after power has been generated from the power generating station. In a 3-phase transmission line, faults arise due to numerous causes such as aircraft, line breaks due to the excessive loading, heavy winds, trees falling across the lines etc. The faults faced in a 3-phase transmission line are broadly categorized into two main parts, namely: unsymmetrical faults and symmetrical faults. Furthermore, there is another classification of faults in 3-phase transmission lines such as: shunt type of faults and series type of faults, but this paper discusses the shunt type of faults which create short circuit on single line to ground (L-G) faults between two conductors or line to line (L-L) faults, or double line to ground (LL-G) or (triple) three line to ground (LLL-G) faults. This was achieved using the Fortescue Theorem on MATLAB software. The results show that the single L-G faults occur more frequently followed by the L-L faults, LL-G faults, and LLL-G faults. This study is essential to evaluate the power reliability and stability of power transmission lines.

Impact of Changing Wind Loads on the Reliability of Power Transmission Lines in Different Regions of Russia

Impact of Changing Wind Loads on the Reliability of Power Transmission Lines in Different Regions of Russia

Lightning Performance of Unshielded 220 kV Transmission Lines Equipped With Metal Oxide Arresters

Overhead ground wires installed on transmission lines have been proved to be effective to protect conductors from direct lightning strokes, but ground wire breakouts due to icing are frequently reported. In order to prevent electric failure accidents caused by ground wire breakouts under icing conditions, unshielded transmission lines equipped with metal oxide arresters (MOAs) whole line have been proposed in high mountainous areas. Compared with ordinary transmission lines, lightning stroke risk of unshielded lines is much higher. In order to improve the lightning performance of unshielded lines, it is necessary to obtain the essential lightning energy absorption ability of the MOAs installed on unshielded lines. In this article, simulation model of unshielded 220 kV transmission lines equipped with MOAs is built, the influences of lightning parameters, striking occurrence point and grounding resistance on the absorbed energy of MOAs are analyzed. Based on Monte Carlo method, lightning trip-out rate of unshielded transmission lines are calculated, and suggested energy absorption ability of MOAs is proposed, which can give references for the improvement of power supply reliability of transmission lines.

Study on influencing factors and laws of infrared temperature measurement of silicone rubber composite insulator

Silicon rubber composite insulator is favoured by power system because of its excellent anti-pollution flashover performance. Among them, the core rod is an important structural component to bear the mechanical load of composite insulator. In recent years, there have been many brittle fracture faults of composite insulators in China, which directly affect the reliability of transmission lines. The composite insulator is usually accompanied by abnormal heating during the aging process. As an effective live detection method, infrared temperature measurement can find the defects of composite insulator in time and reduce the occurrence of string breaking accidents. In this paper, by artificially simulating the abnormal temperature rise of composite insulator, infrared temperature measurement was carried out under the conditions of different observation distance, different observation angle, different sheath thickness and different heat source temperature, so as to explore the influencing factors and laws of infrared temperature measurement of composite insulator. The results show that due to the difference of heat loss, sheath barrier and radiation ratio in thermal radiation propagation, the measured temperature decreases and the absolute temperature difference increases with the increase of observation distance, sheath thickness and observation angle. The built-in heat source temperature increases the total internal heat, which can partially weaken the influence of sheath thickness on the measured temperature and significantly expand the difference caused by observation angle.

Simulation and Analysis on Motion Behavior of Metal Particles in AC GIL

Metal particle contamination can seriously affect the reliability of gas-insulated metal enclose transmission line (GIL) and cause insulation failure. In this article, we investigate the metal particle motion patterns based on the entity model of GIL by using finite element simulation. Analysis of motion characteristics of metal particles at different GIL locations is presented based on the charged mechanism and dynamic equation. The impacts of particle attributes, applied voltage, and shielding electrode on motion characteristics are studied. It is found that under ac voltage, the metal particles on the concave and convex sides basically move toward the insulation components. When the metal attributes are different, the size and density of particles dominate the motion pattern under the same voltage. The research observations also indicate that a higher value of applied voltage facilitates the particle to reach the insulator surface while a higher frequency inhibits the particle movement and increases the number of collisions at the ground electrode. Furthermore, the shielding shape affects the electric field distribution, which in turn changes the motion characteristics of particles. Accordingly, the strategy of voltage withstand test and the improved scheme of particle collector are discussed and suggested. This work provides a valuable basis and reference for metal particle control and will guide the design of particle collectors in ac GIL.

The Effect of Soil-Structure Interaction on Vibration Reliability of Transmission Line

Since the main material of the plug-in foundation transmission tower legs is directly connected to the foundation, the traditional reliability calculation method is no longer accurate. For this reason, this paper considers the soil-structure interaction between the foundation soil and the tower legs, replaces the upper limit of the natural circular frequency and frequency ratio of the original iron tower with the corresponding value after considering the SSI (Soil-Structure Interaction), and proposes a SSI-based insertion Analysis method of vibration reliability of type foundation iron tower. First, perform modal analysis to obtain the natural circular frequency of the tower considering SSI; then, according to the external load of the tower under the icing of the wire and the vibration displacement equation of the tower considering SSI, the expression of the comprehensive amplitude amplification factor of the tower is derived, and then the consideration is obtained. The upper limit value of the frequency ratio of SSI and the functional function; finally combined with the normal distribution to solve the problem, the vibration reliability of the plug-in foundation tower considering SSI is obtained. The proposed method has been applied in the analysis of a galloping accident on a line in Guangdong Province. The maximum reliability of the damaged 6-base plug-in foundation tower obtained by this method is 0.9713, which is less than the target reliability of 0.9993.

An insulator self-blast detection method based on YOLOv4 with aerial images

Due to long-term exposure to the natural environment, insulators are prone to self-blast, threatening the safety and reliability of transmission lines. Because of the different sizes of the insulator self-blast area and the complicated background, it is inevitable that the missed and false detections occur. To solve this problem, this paper proposes a deep neural network called Mina-Net (Multi-Layer INformation Fusion and Attention Mechanism Network). Mina-Net is based on YOLOv4. First, the shallow feature map with more detailed texture information is fused into the feature pyramid. Then, an improved SENet is applied to recalibrate the features of different levels in the channel direction. The experimental results on the actual dataset show that Mina-Net has increased the average precision by 4.78% compared with the YOLOv4.

Improvement of energy efficiency of agricultural enterprises through the survey of high-voltage transmission lines using unmanned aerial vehicles

The paper studies the reliability of transmission lines of Michurinsk district electric lines in Tambov Region. It evaluates the quality of overhead power transmission lines in the support-insulator-wire system and determines the reliability factor of overhead lines. The paper proposes methodological approaches to the survey of power transmission lines using unmanned aerial vehicles. Their use seems quite promising and profitable, since the cost of such work is an order of magnitude lower.

Comparing policy conflict on electricity transmission line sitings

Maintaining the quality and reliability of electricity transmission lines is central to effective energy governance. However, transmission line siting is often a contentious policy decision since permitting and constructing lines may involve private and public property, residents and communities, and localized and national concerns. Yet, policy conflict in transmission siting across cases and over time has remained largely understudied. This article derives and tests hypotheses about policy conflict in the context of transmission lines completed or constructed between 2017 and 2018 in the United States. In exploring the full population of transmission lines, we find that a majority exhibit relatively low and moderate levels of conflict and attention rather than high levels. We further examine a subset of six of these cases that represent a range of conflict and attention intensity. We describe variation in the diversity of actors and frames, advocacy coalitions, and the volume of discourse associated with transmission line siting over time. As problems related to energy governance have become more complex, energy siting disputes are likely to remain a fruitful area for research on policy conflict.

On damage rate of overhead power transmission lines in power supply systems

The purpose of the article is to analyze the damage rate of overhead power transmission lines (OPL) in medium-voltage electrical distribution networks of the Irkutsk region. The established International Indices that determine the level of reliability of the functioning of electric networks are considered, and information on the compliance of the condition of electric networks in Russia with these indices is analyzed. Analytical information on the damage rate of elements of these networks and their causes in Europe, America, and Russia is presented. The emphasis is placed on the fact that the most common damage is characteristic of overhead power lines, especially 6–10 kV lines. As an object of research, two branches of the Irkutsk electric grid company (IEC) were taken, one of which provides electricity to rural consumers, the other — mainly to consumers residing in the territory of the city Irkutsk. The characteristics of these electric networks, their territorial location and basic technical data are presented. To conduct analytical monitoring of the level of reliability of overhead power transmission lines, logs of disconnection of the Eastern and Southern electric networks of the IEC over a long-term period were used. On the basis of this information, tables of failures and their consequences in the studied electrical networks were compiled for monthly average data over the period under examination for various causes of damage. To plot time diagrams of the parameters under examination, computer programs were compiled in the Matlab system, the use of which made it possible to obtain visualization of changes in failures for various reasons for the electrical networks under consideration. The information on the time of power supply interruptions in these networks, as well as the amount of electricity underutilized by consumers during these interruptions and its cost are analyzed. It is shown that in the electric networks under consideration, most of the power failures are related to the territorial dispersion of these networks, and the low level of equipment controls and insufficient qualification of operating personnel, as evidenced by the significant number of failures for unknown reasons. Besides, a significant part of the failures is due to damage to the overhead line wires, switching equipment and the effect of wind load. Recommendations for improving the condition of power transmission lines and a number of measures aimed at improving the level of reliability of power supply are presented.

Prediction of The High Voltage Insulators Service Life Based on The Effective Values of Leakage Currents

The insulation condition of overhead lines is one of the main factors affecting reliability of overhead power transmission lines. It is known that the process of insulation lapping or rupture is mainly affected by environmental conditions and the degree of pollution of the insulators surface. This paper substantiates the possibility of using the leakage current values of insulators for monitoring the state of insulation and predicting its resource. The results of experimental studies of leakage currents of high-voltage insulators depending on their service life are given, on the basis of which forecasting the possible resource of insulators is carried out. The results obtained can be used to develop more effective diagnostics for detecting insulator failures at an early stage to take appropriate measures to coordinate the insulation.

Transient switching analysis of a nonconventional rural generation system

This paper introduces a nonconventional rural generation system that extracts energy from high-voltage transmission line surroundings. The system was designed for a 230-kV transmission line and consists of a special 20-km collector line and an innovative substation. The energy is coupled to the collector line and supplied through a resonant circuit. There is no physical contact with the transmission line. A detailed electromagnetic study is described, assuring there is no disturbance at the transmission line and that the rural system delivers high-quality energy. Spark gaps were used to avoid overvoltage along the rural feeder. Transmission line reliability is not compromised.