Crane movement limiting device design for safe operation near power lines

1998 ◽  
Vol 1 (2) ◽  
pp. 95-105
Author(s):  
Daniel Imbeau ◽  
Joseph-Jean Paques ◽  
Sylvie Bergeron ◽  
Réal Bourbonnière
Keyword(s):  
Power Line ◽  
Operating Conditions ◽  
Power Lines ◽  
Control Input ◽  
Safe Operation ◽  
Motion Response ◽  
Braking System ◽  
Fixed Length ◽  
Lifting Capacity ◽  
Hard Ball

Performance of experienced crane operators in stopping rotational movements of a crane platform was compared with that of an automatic braking system. Sixteen certified crane operators performed boom movements towards a segment of a typical power line using a 100 tons lifting capacity crane equipped with a fixed-length 18 m long boom, a single lifting cable, and hard ball hook. The 18 m boom was later replaced with a 49 m boom to vary crane geometry and motion response. In all trials, a 1500 kg (3500 lb) load was hooked to the lifting cable. In critical operating conditions, the control input strategy used by the experienced crane operators could yield a stopping angle comparable to that of the automatic braking system. However, when compared with the automatic braking system, the operators had a better control on the oscillations of the load during the stopping maneuver. The data collected in this experiment were used to specify two key parameters in the design of a crane movement limiting device.

scholarly journals Modeling the reliability of electrical power lines of the seaport in conditions forced electricity consumption

2021 ◽  
pp. 121-127
Author(s):  
А.П. Лицкевич ◽  
С.А. Лицкевич ◽  
О.Н. Лицкевич
Keyword(s):  
Mathematical Model ◽  
Technological Process ◽  
Operating Time ◽  
Electricity Consumption ◽  
Arbitrary Point ◽  
Power Line ◽  
Operating Conditions ◽  
Power Lines ◽  
Power Cable ◽  
Cable Line

В работе рассматривается задача оценки времени наработки силовой кабельной линии морского порта, с учетом форсирования технологического процесса в морском порту (погрузочно-разгрузочных работ) и, в связи с этим, повышения величины токовой нагрузки в силовой линии, превышающей допустимый предел, что ведет к повреждению линии. Для оценки влияния форсированного технологического процесса, на наработку силовых линий, вводятся основные факторы влияния: время длительности форсированного режима; величина тока в линии; температура окружающей среды. С их помощью вводится функция сокращающегося временного ресурса наработки силовой линии, которая отображает повреждения в силовой линии. Общая математическая модель наработки силовой кабельной линии включает повреждения в кабельной линии как основной фактор. Решение задач осуществляется с помощь разработанных программных средств и применения нечеткой математики, в среде Mathcad. Представленная математическая модель позволяет количественно оценить время наработки при использовании форсированных технологических режимов и повышенного потребления энергии, а также оценить степень снижения времени наработки, в результате суммарного действия повреждающих факторов, для произвольного момента времени в условиях эксплуатации. The paper considers the problem of estimating the operating time of the power, cable line of the seaport, taking into account the acceleration of the technological process in the seaport (loading and unloading operations) and, in this regard, the increase in the current load in the power line exceeding the permissible limit, which leads to damage lines. To assess the influence of the forced technological process on the operating time of the power lines, the main factors of influence are introduced: the duration of the forced mode; line current value; ambient temperature. With their help, the function of reducing the time resource of the operating time of the power line is introduced, which displays the damage in the power line). The general mathematical model of the power cable line operating time includes damage in the cable line as the main factor. The solution of problems is carried out with the help of the developed software and the use of fuzzy mathematics, in the Mathcad environment. The presented mathematical model makes it possible to quantitatively evaluate the operating time when using forced technological modes and increased energy consumption, as well as to assess the degree of reduction in the operating time, as a result of the total action of damaging factors, for an arbitrary point in time under operating conditions.

scholarly journals Comparison of Screening Configurations for the Mitigation of Voltages and Currents Induced on Pipelines by HVAC Power Lines

Energies ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 3855
Author(s):  
Arturo Popoli ◽  
Leonardo Sandrolini ◽  
Andrea Cristofolini
Keyword(s):  
Finite Element Analysis ◽  
Cross Sections ◽  
Detrimental Effect ◽  
Power Line ◽  
Skin Depth ◽  
Power Lines ◽  
Element Analysis ◽  
3D Finite Element ◽  
Different Shapes ◽  
High Magnetic Permeability

In this paper, a strategy for reducing the electromagnetic interferences induced by power lines on metallic pipelines is proposed and numerically investigated. The study considers a set of steel conductors interposed between the power line and the pipeline. Different shapes of conductor cross sections and different magnetic permeabilities are considered, to identify the solution exhibiting the greatest mitigation efficiency for the same amount of material. The investigation is carried out by means of a quasi-3D finite element analysis. Results show that the main mechanism responsible for the mitigation is constituted by the currents induced in the screening conductors by the power line. Hence, a high magnetic permeability can have a detrimental effect since it reduces the skin depth to values below the size of the screening conductor. In this case, a reduction of the screening current and in the mitigation efficiency is observed. Nevertheless, the study shows that the use of strip-shaped screening conductors allows the employment of cheaper magnetic materials without compromising the mitigation efficacy of the screening conductors.

“These Power Lines Make Me Ill”: A Typology of Residents’ Health Responses to a New High-Voltage Power Line

Risk Analysis ◽  
2017 ◽  
Vol 37 (12) ◽  
pp. 2276-2288 ◽  
Author(s):  
Jarry T. Porsius ◽  
Liesbeth Claassen ◽  
Fred Woudenberg ◽  
Tjabe Smid ◽  
Danielle R. M. Timmermans
Keyword(s):  
High Voltage ◽  
Power Line ◽  
Power Lines

scholarly journals Dynamic Line Rating—An Effective Method to Increase the Safety of Power Lines

2021 ◽  
Vol 11 (2) ◽  
pp. 492
Author(s):  
Levente Rácz ◽  
Bálint Németh
Keyword(s):  
Expert System ◽  
Electric Field ◽  
High Voltage ◽  
Low Frequency ◽  
Power Line ◽  
Power Lines ◽  
Design Parameters ◽  
Monitoring Methods ◽  
Limit Value ◽  
Potential Applications

Exceeding the electric field’s limit value is not allowed in the vicinity of high-voltage power lines because of both legal and safety aspects. The design parameters of the line must be chosen so that such cases do not occur. However, analysis of several operating power lines in Europe found that the electric field strength in many cases exceeds the legally prescribed limit for the general public. To illustrate this issue and its importance, field measurement and finite element simulation results of the low-frequency electric field are presented for an active 400 kV power line. The purpose of this paper is to offer a new, economical expert system based on dynamic line rating (DLR) that utilizes the potential of real-time power line monitoring methods. The article describes the expert system’s strengths and benefits from both technical and financial points of view, highlighting DLR’s potential for application. With our proposed expert system, it is possible to increase a power line’s safety and security by ensuring that the electric field does not exceed its limit value. In this way, the authors demonstrate that DLR has other potential applications in addition to its capacity-increasing effect in the high voltage grid.

Overview of Path-Planning and Obstacle Avoidance Algorithms for UAVs: A Comparative Study

2018 ◽  
Vol 06 (02) ◽  
pp. 95-118 ◽  
Author(s):  
Mohammadreza Radmanesh ◽  
Manish Kumar ◽  
Paul H. Guentert ◽  
Mohammad Sarim
Keyword(s):  
Path Planning ◽  
Comparative Study ◽  
Operating Conditions ◽  
Computational Time ◽  
Safe Operation ◽  
Sense And Avoid ◽  
Planning Algorithms ◽  
And Control ◽  
Global And Local ◽  
Further Development

Unmanned aerial vehicles (UAVs) have recently attracted the attention of researchers due to their numerous potential civilian applications. However, current robot navigation technologies need further development for efficient application to various scenarios. One key issue is the “Sense and Avoid” capability, currently of immense interest to researchers. Such a capability is required for safe operation of UAVs in civilian domain. For autonomous decision making and control of UAVs, several path-planning and navigation algorithms have been proposed. This is a challenging task to be carried out in a 3D environment, especially while accounting for sensor noise, uncertainties in operating conditions, and real-time applicability. Heuristic and non-heuristic or exact techniques are the two solution methodologies that categorize path-planning algorithms. The aim of this paper is to carry out a comprehensive and comparative study of existing UAV path-planning algorithms for both methods. Three different obstacle scenarios test the performance of each algorithm. We have compared the computational time and solution optimality, and tested each algorithm with variations in the availability of global and local obstacle information.

scholarly journals Power line routing and configuration as major drivers of collision risk in two bustard species

Oryx ◽  
2020 ◽  
pp. 1-10 ◽  
Author(s):  
Ana Teresa Marques ◽  
Ricardo C. Martins ◽  
João Paulo Silva ◽  
Jorge M. Palmeirim ◽  
Francisco Moreira
Keyword(s):  
Abiotic Factors ◽  
Bird Species ◽  
Power Line ◽  
Power Lines ◽  
Mitigation Measures ◽  
Suitable Habitat ◽  
Collision Risk ◽  
Great Bustard ◽  
Line Configuration ◽  
Tetrax Tetrax

Abstract Collision with power lines is a major cause of mortality for many bird species. Understanding the biotic and abiotic factors that increase collision risk is therefore important for implementing mitigation measures to minimize mortality, such as power line rerouting or wire marking. Here, we used collision events registered during 2003–2015 along 280 km of transmission power lines in southern Portugal to analyse spatio-temporal patterns and collision risk factors in two sympatric, threatened, and collision-prone species: the great bustard Otis tarda and the little bustard Tetrax tetrax. The occurrence of collisions was not uniform across space and time, and variations could be explained by the species' ecological requirements, distribution patterns and behaviour. Although both species fly considerable distances between areas of suitable habitat, collisions were far more likely in power line sections with > 20% (for the little bustard) or > 50% (for the great bustard) of open farmland habitat in the surroundings. Power line configuration was also important: taller pylons and those with a higher number of wire levels posed a higher risk for both species. Wire marking had a small but significant effect for the little bustard, reducing collisions risk. There was, however, no similar effect for the great bustard, possibly a result of limited data. Mitigation measures should be implemented to prevent bustard collisions, including adequate route planning, ideally avoiding areas with > 20% of open habitat. Line configuration and wire marking are particularly important where such localities cannot be avoided and power lines cross areas with a high proportion of bustard habitat, including outside protected areas.

scholarly journals CONTROL OF ACTIONS OF STEEL TANK IN WORKING

2018 ◽  
Vol 22 (4) ◽  
pp. 66-74 ◽  
Author(s):  
A. A. Vasilkin
Keyword(s):  
Strain State ◽  
Low Cycle Fatigue ◽  
Operating Conditions ◽  
Maximum Effect ◽  
Safe Operation ◽  
Stress Strain ◽  
Load Bearing ◽  
Stress Strain State ◽  
Steel Tank ◽  
Steel Tanks

In steel tanks made by the method of rolling, defects of a geometric shape often occur in the area of the welded welded joint of the wall. Subsequently, in these areas, as a result of low cycle fatigue, an unacceptable defect appears in the form of a crack, which makes it necessary to remove the reservoir from operation and carry out a set of measures for its repair. To determine the terms of safe operation of vertical steel tanks with geometric defects, it is proposed to use the methodology control of the actions of structures of load-bearing structures, one of the directions of which is the regulation of the stress-strain state of steel structures. To implement the possibility of regulating construction, it is necessary to identify such parameters, the change of which will give the maximum effect in achieving the set goals. As the indicated parameters, the design characteristics (material properties, design scheme, geometric characteristics) and factors of external influences (load, operating conditions) can act. To regulate the stress-strain state design of vertical steel tanks, the following regulators are proposed: product loading height, wall deflection arrow and permissible number of tank loading cycles. By numerical calculation of the VAT of the vertical steel tank design with geometric defects, the necessary values and values of the stress state are determined. Further, using known analytical dependencies from the field of fracture mechanics, it is possible to determine the permissible number of loading cycles of the reservoir before the appearance of a crack-like defect. The application of the methodology control of the actions of structures load-bearing structures, by means of a certain change in the established control parameters, allows increasing the number of loading cycles of the reservoir, thereby increasing the period of safe operation of the defective reservoir and thereby increasing the economic efficiency of the tank farm.

scholarly journals Simulation Study of the Process of Friction in the Working Elements of a Car Braking System at Different Degrees of Wear

2018 ◽  
Vol 12 (3) ◽  
pp. 221-226 ◽  
Author(s):  
Andrzej Borawski
Keyword(s):  
Simulation Study ◽  
Friction Pair ◽  
Experimental Studies ◽  
Real Life ◽  
Operating Conditions ◽  
Heating Process ◽  
Passenger Cars ◽  
The Road ◽  
Emergency Braking ◽  
Braking System

Abstract Among the many elements of a modern vehicle, the braking system is definitely among the most important ones. Health, and, frequently, life, may rest upon the design and reliability of brakes. The most common friction pair used in passenger cars today is a disc which rotates with the road wheel and a cooperating pair of brake pads. The composite material of the pad results in changing tribological properties as the pad wears, which was demonstrated in experimental studies. The change is also facilitated by the harsh operating conditions of brakes (high and rapid temperature changes, water, etc.). This paper looks into how changing tribology reflects on the heating process of disc and pads during braking. And so a simulation study was conducted, as this method makes it possible to measure temperature in any given point and at any time, which is either impossible or extremely difficult in real life conditions. Finite element method analyses were performed for emergency braking events at various initial speeds of the vehicle reflecting the current road speed limits.

scholarly journals Wind: generating power and cooling the power lines

2020 ◽  
Vol 17 ◽  
pp. 105-108
Author(s):  
Marko Kaasik ◽  
Sander Mirme
Keyword(s):  
Wind Speed ◽  
Electric Power ◽  
High Voltage ◽  
Transmission Lines ◽  
Power Transmission ◽  
Mixed Forest ◽  
Wind Farms ◽  
Power Line ◽  
Power Lines ◽  
Local Wind

Abstract. The electric power that can be transmitted via high-voltage transmission lines is limited by the Joule heating of the conductors. In the case of coastal wind farms, the wind that produces power simultaneously contributes to the cooling of high-voltage overhead conductors. Ideally this would allow for increased power transmission or decreased dimensions and cost of the conductor wires. In this study we investigate how well the wind speed in coastal wind farms is correlated with wind along a 75 km long 330 kW power line towards inland. It is found that correlations between wind speed in coastal wind farms at turbine height and conductor-level (10 m) are remarkably lower (R=0.39–0.64) than between wind farms at distances up to 100 km from each other (R=0.76–0.97). Dense mixed forest surrounding the power line reduces both local wind speed and the correlations with coastal higher-level wind, thus making the cooling effect less reliable.

scholarly journals Collision with power lines and electrocutions in birds — an analysis based on Swedish ringing recoveries 1990–2017

Ornis Svecica ◽  
2019 ◽  
Vol 29 ◽  
pp. 37-52
Author(s):  
Thord Fransson ◽  
Lina Jansson ◽  
Tuomo Kolehmainen ◽  
Thomas Wenninger
Keyword(s):  
At Risk ◽  
Natural History ◽  
Power Line ◽  
Power Lines ◽  
Local Power ◽  
Line System ◽  
Underground Cables ◽  
Number Of Species ◽  
History Information ◽  
Over Time

Recoveries of birds ringed in Sweden from the period 1990–2017 were used to analyse the occurrence of collisions with power lines and electrocutions. Out of more than 10,000 recoveries of birds found dead with finding circumstances mentioned, 8.6% was associated with power line constructions. The number of species involved was 51 and high proportions were especially evident in some species of owls and raptors. The overall proportion of recoveries caused by collision / electrocution shows a significant decrease over time. A decrease over time in the proportions of electrocution and collision was also evident when analysing finding circumstances in four species where corpses were sent to the Swedish Museum of Natural History. Information about the power line system in Sweden during the period 2007–2016 shows that the length of local power lines has decreased with about 21% during a ten-year period and that underground cables have increased with 28% during the same period. The results show that collisions with power lines have decreased more than electrocutions and this may imply that there are still many places where birds are at risk of being electrocuted.

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