Transmission Line Corridor Research Articles

Fast Detection of Hidden Dangers in Transmission Line Corridors Based on Region Partitioning and Feature Extraction

Hidden dangers like large-scale construction machinery are the main causes of line trips. In this paper, we propose a fast detection algorithm for hidden dangers in transmission line corridors based on region partitioning and feature extraction. Since the scenes in the sky are simple and stable compared with the scenes on the ground, we detect hidden dangers in the sky and those on the ground separately. For hidden dangers in the sky, we firstly designed an algorithm to calculate the mask image for sky area. After dividing the sky area, we extracted features including colors and shapes of the difference areas in order to eliminate the interference factors. The targets left are the hidden dangers we truly cared about. For hidden dangers on the ground, firstly we design a pre-processing algorithm to eliminate the influence of uneven illumination on subsequent matching. Secondly, we propose a multi-scale gray-weighted average method to fuse multiple channels of multiple color spaces, by which we can effectively suppress noise caused by camera shake and maximize the area that cannot be matched. Thirdly, we use the Haar feature density map to filter the photo to remove discrete pixel points caused by small disturbances. Finally, we extract multiple features and fuse those features on decision level to obtain the final matching result. When deployed on intelligent monitoring devices and tested with massive scene photos, our algorithm has achieved the expected running efficiency and detection accuracy.

Study on Tree-wire Critical Breakdown Distance of 500kV Transmission Lines

Flashover fault is an important cause of trip or even outage of transmission lines. In order to reduce the occurrence of tree flashover failure and strengthen the management of tree growth in the transmission line corridor, it is necessary to study electric field and potential distribution characteristics of trees below transmission lines. Firstly, the influence of tree dielectric constant and conductivity on 3D modelling is analysed. Then the actual 3D simulation model is established. The spatial electric field and potential variation of trees with different shape crowns and different heights and horizontal distances are studied. The starting field strength of flow is used as the gap breakdown criterion, and the critical breakdown distance under different power supply phase angles is calculated. Conclusion shows that the critical distance of tree flashover of 500kV transmission line is 1.76m. In practical applications, trees should be avoided too close to the wire.

Importance of transmission line corridors for conservation of native bees and other wildlife

In forested regions, electric transmission line corridors often provide large linear expanses of managed early successional habitats for sun-loving plants, invertebrates, and vertebrates, many of which are legislatively protected or otherwise targets of conservation efforts. We sampled the bee fauna at 27 randomly selected sites along a 140-km (89-mile) segment of a transmission line that extends from Connecticut to New Hampshire. Each site contained two plots, one within the powerline corridor and another in a closely adjacent forest. Data were collected over a 12-week study period (late May to early August) with corridor plots yielding more than twice as many bee species and more than ten times the number of individuals than the forest plots. The aggregate richness for the 54 plots (=205 species) represents nearly half the bee fauna of New England with species estimation curves suggesting that many additional species were resident but went unsampled. Two globally rare species, Epeoloides pilosulus and Macropis ciliata, were documented from the powerline plots. The time-extended (five-year) vegetation management cycles currently used by many utility companies in New England result in a dynamic array of vegetation composition and structure that supports a multitude of bees as well as other insects, reptiles and amphibians, shrubland birds, small mammals, and other early successional taxa.

Effects of spatial proximity to proposed electric power lines on residents' expectations, attitudes, and protest behavior: A replication study

Governments and energy operators are frequently confronted with opposition to the construction of new high-voltage transmission lines. In this context, a recent experiment by Mueller et al. (2017) tested the so-called proximity hypothesis and found that spatial proximity to proposed transmission line corridor route alternatives significantly affected residents' likelihood of having negative risk expectations, showing low levels of support, and engaging in protest against the planned facility. Moreover, their findings suggest that the relationship between spatial proximity and the dependent variables is appropriately modeled by a distance decay function, showing that effects attenuate with increasing distance from the infrastructure site. Unfortunately, because of the fact that the study is the only one that has tested the proximity hypothesis in the context of planning new transmission lines so far, the existing evidence cannot be considered as a solid knowledge base. Therefore, to strengthen the reliability of the existing evidence, the natural experiment of Mueller et al. (2017) has to be replicated, which is the purpose of the present study. The findings of the replication clearly support the results provided by Mueller and colleagues and provide further empirical evidence that strengthens the proximity hypothesis in the context of power grid expansion.

Electric Field Exposure Assessments and a Novel Control Method for Buildings Installed Nearby High-Voltage Lines.

This essay presents a review of new methods for electric field value assessment in high-voltage areas. For buildings that are placed near high-voltage transmission line corridor, two main scenarios are modeled using finite element method. A new approach to reduce electric field value is also simulated and the results are discussed in detail. The results are compared to related standards values. In some cases the improvement rate exceeds 65%.

Surface Coverage Classification of UAV High Resolution Image Transmission Lines Corridor based on Total Convolution Neural Network

In recent years, UAV imagery has been applied more and more to the work of power line inspection. Surface coverage classification is a key step. Because of the size and amount of data of UAV high-resolution images, the accuracy requirements of traditional classification algorithms can no longer meet the practical needs. In this paper, a pixel level classification algorithm based on full convolution neural network is proposed. The total convolution neural network model reduces the error caused by other forms of deformation such as image translation, scaling, tilting and so on. In the application of UAV image, the total convolution neural network is used to classify the image, and the high dimensional information extracted from the coiling layer is used to learn the feature of the image fully, and the accuracy of the classification is improved. By comparing with the random forest algorithm, the advantages of the full convolution neural network in the classification of the surface coverage of the UAV transmission line corridor are verified, and the reference value is provided for the electric patrol line and the image classification of unmanned aerial vehicles.

Characteristics of C3F7CN/CO2 as an alternative to SF6 in HVDC-GIL systems

The application of environmentally friendly gases to insulated transmission pipelines could potentially improve the flexibility of transmission line corridors and reduce the environmental impact of such lines. Recently, C 3 F 7 CN has been considered as a potential replacement for SF 6 . The present work assesses the feasibility of applying C 3 F 7 CN to high voltage DC transmission lines to attain a lower global warming potential (GWP). The GWP is estimated through calculation of C 3 F 7 CN mixtures with other gases and based on the weighted average method. The liquefaction temperature of these mixtures is between 0.4 and 1.2 MPa as determined by combining the Peng- Robinson equation of state with the van der Waals mixing rule. The insulating characteristics of C 3 F 7 CN/CO 2 mixtures in conjunction with DC voltage in a uniform electric field was also studied. Based on the present research, the viability of C 3 F 7 CN/CO 2 mixtures was evaluated by examining their heat transfer properties. The results show that, at operating temperatures of -20 and -30 °C, and at a pressure of 0.7 MPa, the maximum allowable mole fractions of C 3 F 7 CN in the mixture to avoid condensation is 7.8 and 5.1%, respectively. The insulation characteristics of 4% C 3 F 7 CN/96% CO 2 and 8% C 3 F 7 CN/92% CO 2 mixtures at 0.7 MPa is equivalent to that of SF 6 gas at 0.5 MPa. The heat-transfer capabilities of 4% C 3 F 7 CN/96% CO 2 and 8% C 3 F 7 CN/92% CO 2 mixtures meet the requirements of the GIL temperature rise standard. It is concluded that C 3 F 7 CN/CO 2 represents an environmentally friendly insulation gas suitable for use in HVDC-GIL equipment.

Automatic Clearance Anomaly Detection for Transmission Line Corridors Utilizing UAV-Borne LIDAR Data

Transmission line corridor (i.e., Right-of-Ways (ROW)) clearance management plays a critically important role in power line risk management and is an important task of the routine power line inspection of the grid company. The clearance anomaly detection measures the distance between the power lines and the surrounding non-power-facility objects in the corridor such as trees, and buildings, to judge whether the clearance is within the safe range. To find the clearance hazards efficiently and flexibly, this study thus proposed an automatic clearance anomaly detection method utilizing LiDAR point clouds collected by unmanned aerial vehicle (UAV). Firstly, the terrain points were filtered out using two-step adaptive terrain filter and the pylons were detected in the non-terrain points following a feature map method. After dividing the ROW point clouds into spans based on the pylon detection results, the power line point clouds were extracted according to their geometric distribution in local span point clouds slices, and were further segmented into clusters by applying conditional Euclidean clustering with linear feature constraints. Secondly, the power line point clouds segments were iteratively fitted with 3D catenary curve model that is represented by a horizontal line and a vertical catenary curve defined by a hyperbolic cosine function, resulting in a continuous mathematical model of the discretely sampled points of the power line. Finally, a piecewise clearance calculation method which converts the point-to-catenary curve distance measurements to minimal distance calculation based on differential geometry was used to calculate the distance between the power line and the non-power-facility objects in the ROW. The clearance measurements were compared with the standard safe threshold to find the clearance anomalies in the ROWs. Multiple LiDAR point clouds datasets collected by a large-scale UAV power line inspection system were used to validate the effectiveness and accuracy of the proposed method. The detected results were validated through qualitatively visual inspection, quantitatively manual measurements in raw point clouds and on-site field survey. The experiments show that the automatic clearance anomaly detection method proposed in this paper effectively detects the clearance hazards such as tree encroachment, and the clearance measurement accuracy is decimeter level for the LiDAR point clouds collected by our UAV inspection system.

A Novel Method of Autonomous Inspection for Transmission Line based on Cable Inspection Robot LiDAR Data

With the growth of the national economy, there is increasing demand for electricity, which forces transmission line corridors to become structurally complicated and extend to complex environments (e.g., mountains, forests). It is a great challenge to inspect transmission line in these regions. To address these difficulties, a novel method of autonomous inspection for transmission line is proposed based on cable inspection robot (CIR) LiDAR data, which mainly includes two steps: preliminary inspection and autonomous inspection. In preliminary inspection, the position and orientation system (POS) data is used for original point cloud dividing, ground point filtering, and structured partition. A hierarchical classification strategy is established to identify the classes and positions of the abnormal points. In autonomous inspection, CIR can autonomously reach the specified points through inspection planning. These inspection targets are imaged with PTZ (pan, tilt, zoom) cameras by coordinate transformation. The feasibility and effectiveness of the proposed method are verified by test site experiments and actual line experiments, respectively. The proposed method greatly reduces manpower and improves inspection accuracy, providing a theoretical basis for intelligent inspection of transmission lines in the future.

直升机3D激光扫描技术在架空输电线路巡检中的应用

本文介绍了直升机3D激光扫描技术，并将其应用到国网北京公司某500kV架空输电线路巡检中，通过获取的输电线路走廊的高密度、高精度激光点云和光学影像数据，实现输电线路本体及周围环境的三维建模、线路瞬时工况安全距离检测、线路不同工况安全距离分析以及平断面图输出，进而给出实时工况安全距离危险点分析报告，为线路安全维护提供可靠信息。 This paper introduces the technology of helicopter 3D laser scanning and the application to the inspection of a 500kV overhead transmission line in Beijing. By obtaining high density, high precision laser point clouds and optical image data in the transmission line corridor, it can realize3D modeling, safety test of line instantaneous under working condition, safety distance analysis under different working conditions and output of plane section, of transmission line and surrounding environment. Then the risk point report of the safety distance analysis under real time working condition is given, which provides reliable information for the maintenance of line safety.

Construction and application research of Three-dimensional digital power grid in Southwest China

With the rapid development of Three-dimensional (3D) digital design technology in the field of power grid construction, the data foundation and technical means of 3D digital power grid construction approaches perfection. 3D digital power grid has gradually developed into an important part of power grid construction and management. In view of the complicated geological conditions in Southwest China and the difficulty in power grid construction and management, this paper is based on the data assets of Southwest power grid, and it aims at establishing a 3D digital power grid in Southwest China to provide effective support for power grid construction and operation management. This paper discusses the data architecture, technical architecture and system design and implementation process of the 3D digital power grid construction through teasing the key technology of 3D digital power grid. The application of power grid data assets management, transmission line corridor planning, geological hazards risk assessment, environmental impact assessment in 3D digital power grid are also discussed and analysed.

Assessment of the electromagnetic coupling between lines of different voltages sharing the same structures

With the increasing demand in densely populated areas and the consequent lack of space for exclusive transmission line corridors, sharing structures between transmission and distribution lines has become a commonly used solution, especially in emerging countries. This practice causes the electromagnetic interaction between these lines. This study evaluates the effect of the electromagnetic coupling between a conventional 69 kV line and a compact overhead distribution line (spacer cable system) rated 11.4 kV sharing the same structures. Simulations were performed using the software ATPDraw (Alternative Transient Program) considering steady-state conditions, the occurrence of faults on the high-voltage line and transmission line energisation.

Effects of spatial proximity to proposed high-voltage transmission lines: Evidence from a natural experiment in Lower Saxony

Governments and energy operators are frequently confronted with opposition to the construction of new energy infrastructure and a lack of public support. This is also true for the planning of new high-voltage overhead transmission lines. In this context, a question of interest for policy makers and energy operators is how residents react when they realize that they may be affected by future transmission lines in close proximity to their homes. This study provides evidence of how local residents respond to the announcement of transmission line corridor route alternatives (TLCRAs). By means of a natural experiment, it estimates the causal effects of spatial proximity to proposed TLCRAs during the planning phase of an energy project. The results reveal that proximity significantly enhanced residents’ risk perceptions with respect to landscape deterioration, property/house value reduction, and damages to human health. We also found that increasing proximity decreased residents’ support for grid expansion and increased the likelihood of performing information seeking behavior and becoming a member of a local citizens’ initiative. Finally, our findings suggest that the relationship between spatial proximity and the dependent variables are appropriately modeled by a distance decay function, showing that effects attenuate with increasing distance from the infrastructure site.

Windbreaks working as barriers to high speed winds for protection of electric power transmission lines and towers

The effects of bad weather conditions on transmission lines associated with high speed wind events have concerned not only industry players, but also the government and consumers of electricity. Recently in Brazil, events of this nature have caused large-scale disruptions in the supply of electricity, resulting in direct economic losses throughout the chain of production and consumption. This paper aimed to propose a methodology for reduction of the occurrence of faults in transmission lines and towers related to high speed wind events and gusts, including a safety analysis and recommendation for corrective maintenance. Results are based on a R&D project, with its development including: a) the identification of transmission line faults occurred in Brazil, with wind events as the main underlying cause; b) the description of wind tunnel tests and computational fluid dynamics (CFD) modeling results aiming at exploring the effectiveness of windbreaks (tree rows alongside the transmission line corridors) as a mean to reduce wind impacts against towers and transmission lines; c) recommendations to reduce the risks of collapse of the transmission infrastructure of large-scale electric power systems which are exposed to extreme weather events. The research development was supported by State Grid Brazil, as a part of their R&D investment in its subsidiary company, Porto Primavera Transmissora de Energia (PPTE) during the years of 2014 and 2015.

Simultaneous Lever-Arm Compensation and Disturbance Attenuation of POS for a UAV Surveying System

This paper deals with the problem of lever-arm compensation encountered in an unmanned aerial vehicle surveying system, which is composed of several surveying sensors, a position and orientation system (POS), and an electrooptical pod. As an integration of an inertial navigation system and a global positioning system (GPS), the POS is used to provide the position and attitude of the surveying sensors for motion compensation. However, the lever arm between the inertial measurement unit and the GPS antenna is uncertain and time-varying, and therefore, its influence on the estimation accuracy of POS is serious. In order to improve the measurement accuracy of the POS, a new scheme of dynamic lever-arm compensation is proposed in this paper. The main contribution of this paper is twofold. First, by using the encoder data of the electrooptical pod, a dynamic lever-arm compensation method is derived to compensate the caused lever-arm effect. Second, an $H_{\infty }$ a posteriori filter is designed for POS to attenuate the influence of a lever-arm compensation error and noise uncertainty. Finally, an actual flight experiment for the transmission line corridor surveying is carried out, and it is validated that the proposed method outperforms the existing methods.

The Risk of Wildfire Evaluation System for Transmission Lines Based on Remote Sensing Technology

研发了输电线路走廊山火风险实时监测与分析系统，提出结合国内外卫星遥感影像数据分析的山火风险评估模型。将该系统成功的应用于湖北电网输电线路山火风险评估，实现了湖北电网范围内的输电线路不同区域的风险分级，应用结果表明，本系统通过互联网技术和卫星遥感，专家系统，大数据挖掘等多重手段，有效的获取了山火风险高发区段，指导了冬春季节的山火预防工作。 In this paper, a real-time monitoring and analysis system for risk of wildfire in transmission line corridor is presented, which has been combined with wildfire risk assessment model based on domestic and international satellite image data. This system has been successfully applied in wild-fire risk assessment for transmission line power grid of Hubei province, which has also realized the classification of risk for different areas in transmission line. The final results have shown that, combined with multiple methods, such as, internet technology, remote sensing technology, expert system and data mining, areas in transmission line with high wildfire risk can be effectively ob-tained by the proposed system, which could be regarded as a guide for fire prevention in the sea-sons of spring and winter.

Research on Rib Stiffener Distribution and Ultimate Strength of Steel Tubular Tower’s K-Joint

The method of calculating K-joint’s ultimate strength given by “Code for design of steel structures” GB 50017-2003 requires that, the angle θ between K-joint’s chord and brace is no less than 30°. While, due to the request of electric gap or transmission line corridor, the angle of steel tubular tower’ K-joint in power transmission line have to be designed less than 30° sometimes. In order to solve the engineer problem, rib stiffener were usually added to K-joint structure. 3 kinds of new rib stiffener to directly-welded K-joint of steel tubular tower were designed, and numerical simulation was made to study the structures’ performance under load and ultimate bearing capacity. With new-designed rib stiffener, K-joint’s stress distribution in weld jointing area, where usually bear stress badly, is improved obviously. Stress concentration is eliminated, and maximum stress is lowered. It is suggested that, in the case of exceeding code’s suggest range, k-joint structure must be reinforced to increase intensity, and the 3 format of rib stiffeners can improve the structure’s stress distribution and ensure the security of the structure.

Factors Contributing to Haze and the Influence on External Insulation of Power Equipments

Haze-fog has been a severe pollution weather phenomenon in China due to a large number of emissions of pollutants with the rapid development of economy. The areas burst haze are usually coincidence with high density of electricity transmission line corridor or power load areas, and so the pollution flashover accidents happen frequently. In this paper the haze pollution situations and factors contributing to haze are introduced, and the mechanisms of haze inducing and aggravating the pollution flashover accidents are explained by analyzing the temporal and spatial distribution of PM2.5 and size characteristics of dust deposited transmission. Moreover, the influences of haze on power transmission and transformation equipment external insulation are discussed with combining the simulation pollution flashover experiments of high conductivity fog.

Common raven occurrence in relation to energy transmission line corridors transiting human-altered sagebrush steppe

Energy-related infrastructure and other human enterprises within sagebrush steppe of the American West often results in changes that promote common raven (Corvus corax; hereafter, raven) populations. Ravens, a generalist predator capable of behavioral innovation, present a threat to many species of conservation concern. We evaluate the effects of detailed features of an altered landscape on the probability of raven occurrence using extensive raven survey (n = 1045) and mapping data from southern Idaho, USA. We found nonlinear relationships between raven occurrence and distances to transmission lines, roads, and facilities. Most importantly, raven occurrence was greater with presence of transmission lines up to 2.2 km from the corridor. We further explain variation in raven occurrence along anthropogenic features based on the amount of non-native vegetation and cover type edge, such that ravens select fragmented sagebrush stands with patchy, exotic vegetative introgression. Raven occurrence also increased with greater length of edge formed by the contact of big sagebrush (Artemisia tridentata spp.) with non-native vegetation cover types. In consideration of increasing alteration of sagebrush steppe, these findings will be useful for planning energy transmission corridor placement and other management activities where conservation of sagebrush obligate species is a priority.

Research on Transmission Line Corridors Moving Target Video Detection Device

The utility model provides a transmission line corridors video moving target detection apparatus for transmission line corridors fireworks warning judge, vehicle intrusion detection, construction machinery construction early warning detection and fires. Including: video detection module, embedded modules, communication modules and power supply modules. Video detection module will monitor video information transmitted via the communication module to the analysis and processing ARM-based embedded module, embedded module after the results after the data were processed packaged, transmitted to the communication module, is sent to the control center via 3G wireless communication network master. The utility model is the role: a moving target for the transmission line corridor monitoring, eliminating the presence of various risks and improve the operation and management level and intelligence transmission lines.