Conductor Motion Research Articles

Equation of motion of split conductor of anchor section at icing in wind flow

The relevance of the examined problem is connected with the necessity to develop measures to combat conductor galloping and the design of power transmission lines (ETL). The purpose of the research – to analyse statistical observation data on conductor galloping and apply a mathematical model to determine the parameters of galloping, to develop effective measures to combat conductor galloping and to improve the design of power lines. A sophisticated mathematical model was developed using Mathcad software to analyze conductor galloping in overhead power lines. This model, based on the equations of motion, predicts various galloping parameters under different conditions such as wind speed, span length, and initial mechanical stress. Time diagrams were constructed to represent linear and torsional motions, revealing correlations between amplitudes and frequencies. A comprehensive statistical analysis was performed on wire characteristics and split phase parameters to evaluate their impact on galloping patterns. Numerical methods, including the Runge-Kutta method, were employed to solve the equations and compute time-dependent behaviors. Results were visualized through graphs and diagrams to facilitate interpretation. The results revealed that conductor galloping occurs at wind speeds between 5 to 18 m/s, with significant occurrences at temperatures from 0°C to -10°C. The study identified that conductor galloping occurs within a wind velocity range of 5 to 13 m/s, predominantly with wind orientations between 30˚ and 90˚. The analysis showed that the frequency of galloping closely matches the natural oscillation frequency at low wind speeds but diverges with increasing wind speed and span length. These findings provide insights into the conditions under which conductor galloping is likely to occur and can inform design and operational strategies for overhead power lines.

A dynamic method for online measurement and calibrating with Lorentz force velocimetry

Our previous study (Zheng et al 2020 Metall. Mater. Trans. B 51 558–69; Zheng et al 2020 Acta Metall. Sin. 56 929–36) reports a non-invasive in-situ measurement technology using Lorentz force velocimetry (LFV) to quantitatively measure the meniscus velocity of molten steel online. However, effective signal recognition from complex environment noise and determination of zero-point calibration in harsh metallurgical processing is an essentially challenging task and indeed needs further exploration. In this paper, a method of combining double probe arrangement with real-time differential processing technology was proposed, the twin design structure not only enables the measurement of ∼mN Lorentz forces, but also has significant characteristics of environmental tolerance. The Lorentz force signal caused by conductor motion can be accurately calculated through a differential method, meaning that the problem of zero compensation in industrial online measurement can be effectively overcome. Moreover, based on the functional correlation between the Lorentz force and the parameter of the conductor to be measured, a method of the probes moving variably and actively and their data difference ratio processing was adopted, so as to achieve dynamic calibration during online measurement. This measurement strategy provides a new approach for LFV to achieve online dynamic measurement and online calibration, and provides technical support for electromagnetic measurement technology towards engineering applications.

Taming Diffusion Models for Music-Driven Conducting Motion Generation

Generating the motion of orchestral conductors from a given piece of symphony music is a challenging task since it requires a model to learn semantic music features and capture the underlying distribution of real conducting motion. Prior works have applied Generative Adversarial Networks (GAN) to this task, but the promising diffusion model, which recently showed its advantages in terms of both training stability and output quality, has not been exploited in this context. This paper presents Diffusion-Conductor, a novel DDIM-based approach for music-driven conducting motion generation, which integrates the diffusion model to a two-stage learning framework. We further propose a random masking strategy to improve the feature robustness, and use a pair of geometric loss functions to impose additional regularizations and increase motion diversity. We also design several novel metrics, including Frechet Gesture Distance (FGD) and Beat Consistency Score (BC) for a more comprehensive evaluation of the generated motion. Experimental results demonstrate the advantages of our model. The code is released at https://github.com/viiika/Diffusion-Conductor.

Production and Study of Electrical Characteristics for one of the Dual Estelline Polymers

This study involved the development of a poly-2,4-hexamine-1,5 diol. Conductivity mechanics were investigated by tracking voltage-current characteristics, conductivity (time-current), and conductor motion as a function of temperature between 313 and 353 ok. The principal slopes of (I-t) curves reveal that an increase in temperature results in a rise in conductivity and conductor-carrier mobility (mobility µ). In addition, the activation energy was determined to be 0.897 via a calculation based on the curve formed by (-1/T). Also, the hysteresis of electrical conductivity at different temperatures was studied while the voltage stayed the same.

Numerical and experimental investigation of a floating overhead power transmission system

A promising concept of floating offshore overhead power transmission system (FOPTS), in which the power transmission tower is installed on a TLP-type floating foundation, is investigated experimentally and numerically to study its feasibility. A numerical method is proposed in which the potential flow theory is used to evaluate the floating foundation hydrodynamics. The lumped-parameter method with a wake oscillator model is applied to the aerodynamic modelling of the overhead in order to determine the wind-induced motion and the corresponding internal force of the conductors. Multi-body simulations are performed in Simscape® by coupling the floating foundation hydrodynamics and the conductor aerodynamics. Wind-tunnel experiments on a simplified FOPTS model are carried out to study the coupled motion of the TLP tower and the overhead conductor. The proposed numerical method is validated by comparison of the conductor tension and motion to the experiment. Numerical simulations have been performed under realistic offshore environments based on the meteorological data of the Sea of Japan. Wind-wave misalignment effects on the structure of the FOPTS are investigated, and the safety of the conductors, the mooring lines, and the sea navigation are discussed.

Buckling of interphase spacers during vibration following ice shedding

The axial load and buckling of interphase spacers (IPSs) in power transmission lines are investigated during vibration following ice shedding. IPSs are used to maintain the clearance between different phases of transmission line conductors. Axial forces act on the IPSs during conductor motion, potentially leading to buckling. Two numerical approaches are proposed to study this phenomenon. The first one involves a dynamic model that simulates ice shedding from conductors separated by spacers and provides the axial load that acts on the spacers during the vibration. The material properties are obtained from material tests on fiber-reinforced plastic (FRP) samples, which is the material used to manufacture modern IPSs. The other numerical approach simulates the buckling behavior of IPSs under the axial load obtained from the previous model and provides the deformed shape of the IPS together with the stresses that develop during buckling. An experimental set-up is designed for buckling tests on small-scale FRP samples, and it is applied to validate the buckling model. Buckling may damage the spacer, but it is not necessarily harmful if stresses are small enough and the deformation is elastic during buckling. By understanding the behavior of IPSs under dynamic forces and obtaining the maximum deformation and stress during buckling, it may be possible to improve the design and performance of these components in power transmission lines.

Cycling of Induced Magnets (CIM) – Principle: A New Discovery

Cycling of Induced Magnets (CIM) within the interruption of repulsion is a new discovered phenomenon that utilizes the inherent induction and repulsion properties of magnetic materials. The cyclic motion of magnetic conductors, the effect of CIM, is utilized to facilitate the prime mover action for generation of electrical energy as per Faraday’s law. This CIM may leads to the innovation and development of new technology in the area of electrical power generation. In this paper the foundation stage, which can be referred as ‘Zero Base’ stage of the new discovered principle of CIM, is stated and detailed cause effect and orientation prospects for the justification of the principle is discussed. The application of the outcome of CIM for electrical power generation possibility is also presented.

Glaze icing process of moveable overhead conductor and its aerodynamic characteristics with numerical method

There have been theoretical and experimental reports of glaze icing process which limited to fixed overhead power lines or cables, but very few are related to conductor motions, not to mention its effects on the conductor's aerodynamic characteristics. Thus, a preliminary study is conducted to demonstrate glaze icing process on a moveable overhead conductor and to discuss the effects of the conductor motions on water films, ice shapes and its corresponding aerodynamic characteristics. Based on lubrication theory, an analytical glaze accretion model on upwind side of the overhead conductor is established by considering water film thickness, ice thickness, conductor motions and joule heats. Wind pressures and frictions, and aerodynamic coefficients are computed with computational fluid dynamics(CFD) method. Comparison between the fixed conductors and the moveable conductors on water films and the ice shapes are carried out, and the effects of upper rivulets on aerodynamic vibrations of the iced conductors are discussed accordingly. The results shown that the conductor motion has obviously effect on the water films and upper rivulet positions, and further affected ice shapes. Moreover, in the glaze icing process, the conductor motion presented a kind of wind velocity and amplitude-restricted vibrations. It turns out proposed models can capture main features of glaze icing on the moveable overhead conductor and shed light on more actual glaze icing analysis.

Features of Nondissipative Channeling of Moving Particles Near a Conductor with Current

The specific features of free (outside a conductor) motion of charged particles in the field of a vector potential produced by a direct current flowing in a cylindrical or a flat conductor are considered. It is shown that when particles with negative charge move along the current direction (as well as when positively charged particles move in the opposite direction), the process of interaction of charges with the vector potential of the current corresponds to the presence of a very deep potential well whose minimum lies outside the conductor. This position of the minimum of the potential well corresponds to the flow of a current whose strength does not exceed several kiloamperes for electrons and positrons and several tens of kiloamperes for protons. When these values are exceeded, the minimum shifts into the bulk of the conductor. When the current decreases or the longitudinal energy of a particle increases, the position of the minimum varies in the range from near the surface of the conductor to values that are many tens of times greater than the thickness (diameter) of the conductor. The depth of the potential well increases with increasing energy of a particle and may reach tens and hundreds of kiloelectronvolts even for nonrelativistic particles. The structure of the potential well near the surface of a flat conductor with current corresponds to a harmonic oscillator whose frequency depends on the current strength, the thickness of the flat conductor, and the particle energy. The presence of such features makes it possible to implement a nondissipative channeling regime outside the conductor and the transportation of particles over a long distance.

Effects of Time-Varying Mass on Stability of High-Voltage Conductor in Rain–Wind Condition

Abstract Although unanticipated low-frequency vibrations frequently happen on high-voltage conductors under the simultaneous occurrence of wind and rain, the source of these vibrations is not well known. Many studies focus on the impact of rain loads on the high-voltage conductor but very few examine the effects of time-varying mass. Raindrops hitting high-voltage conductors may partially stay on their surface and form rivulets or ridges. As the adhered raindrops may be blown or shaken off, the mass of the rivulets will vary with time. In order to investigate how the time-varying mass of the rivulets affects conductor motion, an analytical model with time-varying mass is established, which leads to the statement of an instability criterion. The vibration characteristics and instability of a high-voltage conductor with fixed and movable rivulet are discussed. The results show that the time-varying mass ratio may affect the peak vibration amplitude, and the unstable zone of the conductor with moveable upper rivulet is much wider than that with fixed upper rivulet, and the rain–wind-induced vibration occurs more easily than Den Hartog galloping. Such comparative studies may prove valuable as they enhance the understanding of the mechanism of the rain–wind induced instability of the high-voltage conductors.

Galloping Stability Criterion for 3-DOF Coupled Motion of an Ice-Accreted Conductor

AbstractThis study presents an analytical galloping stability criterion for a three-degree-of-freedom (3-DOF) coupled motion of an ice-accreted conductor by using the eigenvalue perturbation method...

Power Line Simulation for Safety Distance Detection Using Point Clouds

Airborne LiDAR has been adopted as a powerful survey tool for overhead power transmission line (TL) cruising so that the operator can quickly search for, locate and eliminate the risk objects at the power line corridor scene. However, the TLs are moving objects, which positions are dynamically affected by working conditions (e.g. temperature variation, wind-induced conductor motion) while they are acquired by airborne LiDAR. The point clouds data acquired by airborne LiDAR only reflect the geometric relationship between the TL and its surrounding objects at the transient moment of the data acquisition. In order to overcome the shortcomings of the instantaneously acquired laser scanning data, this article presents an approach for simulating the dynamic TL shape under different working conditions based on mechanical computation of the overhead line. The proposed approach considers the tension variation of TL resulting from weather conditions, such as temperature, wind and ice, while simulates TL sag curve using the parabolic catenary equation combined with the tension. A performance evaluation was conducted over the TLs data with multiple voltage levels. Experiments results show that the proposed approach is effective for simulating the 3D shape of TL under different working conditions. The simulation error achieved was less than 0.65m and the maximum Diff-Ratio was about 1.57%. This provides a scientifically sound predicting and modeling approach for TL risk assessment and warning along the corridor.

Power Line Simulation for Safety Distance Detection Using Point Clouds

Airborne LiDAR has been adopted as a powerful survey tool for overhead power transmission line (TL) cruising so that the operator can quickly search for, locate and eliminate the risk objects at the power line corridor scene. However, the TLs are moving objects, which positions are dynamically affected by working conditions (e.g. temperature variation, wind-induced conductor motion) while they are acquired by airborne LiDAR. The point clouds data acquired by airborne LiDAR only reflect the geometric relationship between the TL and its surrounding objects at the transient moment of the data acquisition. In order to overcome the shortcomings of the instantaneously acquired laser scanning data, this article presents an approach for simulating the dynamic TL shape under different working conditions based on mechanical computation of the overhead line. The proposed approach considers the tension variation of TL resulting from weather conditions, such as temperature, wind and ice, while simulates TL sag curve using the parabolic catenary equation combined with the tension. A performance evaluation was conducted over the TLs data with multiple voltage levels. Experiments results show that the proposed approach is effective for simulating the 3D shape of TL under different working conditions. The simulation error achieved was less than 0.65m and the maximum Diff-Ratio was about 1.57%. This provides a scientifically sound predicting and modeling approach for TL risk assessment and warning along the corridor.

Aerodynamic Characteristics of Iced 8-bundle Conductors under Different Turbulence Intensities

Iced conductor motion is induced by the aerodynamic instability. The aerodynamic characteristics of iced bundle conductors in turbulent flow are significantly different from that in uniform flow. The aerodynamic coefficients of iced 8-bundle conductors’ segment models under different turbulence intensities flow are measured by the wind tunnel experiment. Furthermore, the aerodynamic coefficients of each crescent- and sector-shape iced 8-bundle conductors under different turbulence intensities flow and ice thicknesses are obtained. The wind tunnel test results indicate there have obvious difference between aerodynamic characteristics of bundle conductors in turbulent flow and that in uniform flow. Then, key parameters, such as turbulence intensity, ice thickness and ice shape have significant influences on aerodynamic coefficients of each sub-conductors. Differences exist among aerodynamic coefficients of crescent-shape and sector-shape iced 8-bundle conductors. Finally, the galloping coefficients of iced 8-bundle conductors are discussed. The wind tunnel experiment results can offer useful reference resources for the comprehensive analysis of galloping of iced bundle conductors and their prevention techniques.

Wind-induced conductor response considering the nonproportionality of generalized aerodynamic damping

Aerodynamic damping is a key factor that influences the wind-induced responses of transmission conductors. The inaccurate estimation of aerodynamic damping leads to misunderstanding of conductor response to wind actions. For dynamic response analysis in the frequency domain, the generalized aerodynamic damping matrix used to solve conductor motion is diagonal. This study reanalyzed the conductor generalized aerodynamic damping matrix by considering its horizontal and vertical motions and the coupling effects of different modes. The derived generalized aerodynamic damping was a nondiagonal matrix, and we defined it as nonproportional generalized aerodynamic damping. Variations in the aerodynamic damping ratio and the nonproportionality of generalized aerodynamic damping with wind speed were investigated through numerical studies of single- and triple-span conductors. Triple-span conductors with different span lengths, hanging heights, and initial pretension forces were adopted to discuss the effects of the nonproportionality of generalized aerodynamic damping on estimating the dynamic responses of conductors. Results showed that neglecting the vertical motion of a conductor leads to an overestimation of the aerodynamic damping ratio, especially under high wind speed conditions. The nonproportionality of generalized aerodynamic damping is highest when the incoming wind speed at 10 m is 25 m/s. Ignoring such nonproportionality leads to an overestimation of the resonant responses of conductors but exerts minimal effects on total fluctuating responses mainly contributed by background components. Therefore, for a transmission conductor with a significant resonant response, the nonproportionality effect of generalized aerodynamic damping must be considered. Increasing span length and conductor height or reducing initial pretension force seems to enhance nonproportionality effects on conductor responses.

Effects of wind and rain on the motion of the high-voltage conductor in a simplified valley terrain

Due to the funneling effects of valley terrain, intensified wind and rain may cause conductor galloping, line breaking, insulator flashover and even tower collapses. Researchers are mainly concerned about the distribution of wind velocities within valley terrains, and very few of them studied the characteristics of wind-driven rain and its effects the motion of the suspended high-voltage conductor. The objective of this paper is to investigate the characteristics of wind and rain in a simplified valley and their effects on the motion of the high-voltage conductor. The distribution of wind velocities in the simplified valley is computed by computational fluid dynamics method (CFD), of which the results demonstrate that the valley length has a stronger effect on wind velocity compared to flat terrain, and the maximum speed-up amplitude of wind velocity reaches 67% which apparently higher than 10% specified in Codes of GB 50545-2010. Meanwhile, the velocities and the trajectories of raindrops are calculated with finite difference method, and the results show that raindrops’ velocities in the valley terrain increase rapidly than that of in the flat terrain. Then an analytical model based on the finite element method is proposed to study the effects of wind and rain on the motion of the high-voltage conductor suspended over the simplified valley, and the results show that the maximum percentage of vibration amplitude by rain-wind loads relative to wind loads can reach to 8% (in-plane) and 19% (out-of-plane). Therefore, wind and rain in the valley terrain obviously different from that of in the flat terrain and should be give more attention in the design and operation of transmission lines.

Wind Tunnel Test Investigation on Unsteady Aerodynamic Coefficients of Iced 4‐Bundle Conductors

Iced conductor motion is induced by the aerodynamic instability of these conductors. The unsteady aerodynamic characteristics are different from the steady aerodynamic characteristics. The unsteady aerodynamic coefficients of typical iced conductors’ models under torsional motion are measured by the unsteady wind tunnel test. The unsteady aerodynamic coefficients of crescent‐shape and sector‐shape iced 4‐bundle conductors under different torsional motion frequencies, wind velocities, and ice thicknesses are obtained. Wind test results show that there are significant differences between the unsteady and steady aerodynamic coefficients. The unsteady aerodynamic coefficients curve is a loop which is different from the steady aerodynamic coefficients. In addition, the obvious differences exist between unsteady aerodynamic coefficients of crescent‐shape and sector‐shape iced bundle conductors. Critical parameters, including torsional motion frequencies, wind velocity, ice shape, and ice thickness, have significant influences on unsteady aerodynamic coefficients. It shows that the wind tunnel experiment results are able to provide necessary data for the investigation of iced bundle conductor motion and their prevention techniques.

Characteristics of magnetic field distribution on the dual-cross layout cylinder PM type linear Halbach array

A strong magnetic field forming by Halbach PM array is an effective technical element for the developing of industrial magnetically actuators. In a brand new layout Halbach array using cylinder-shaped PMs, by synchronized rotation in the same direction with of all magnets, the slide of the magnetic field distribution has been confirmed. The proposal dual-cross layout Halbach array model using cylinder-shaped PMs, it can be expected multidimensional motion of the secondary conductor. However, the slide performance of magnetic field seems to depend on the forming of the magnetic flux density distribution. And, its magnetic flux density distribution is clearly dependent on the arrangement parameters of the cylinder-shaped PM of the array. In this paper, we would like to report that the forming of the magnetic field depending on arranged and layout parameters of the brand new dual-cross layout cylinder-shaped PM type linear Halbach arrays, by magnetic field simulation and measurement.

Estimating Sag and Wind-Induced Motion of Overhead Power Lines With Current and Magnetic-Flux Density Measurements

Overhead high-voltage transmission lines (HVTLs) extend over diverse geographic regions under uneven weather conditions, where sag and wind-induced conductor motion poses serious issues for uninterrupted power distribution by HVTLs. Sag reduces the ground clearance of the line, whereas conductor motion may result in phase to phase short circuit, and damage to support structure. A real-time estimate of these factors is deemed important to develop requisite prevention measures. In this paper, we present a novel method to cater for sag and motion estimation in real-world scenarios. Our method can detect a change in sag and conductor motion, whether it is symmetrical or unsymmetrical to one or more conductors. We require uniaxial magnetic-field (MF) sensors mounted at support tower, equal to conductors, and synchronized with current-transformer (CT) data at substation. The sensors provide noncontact MF measurements, which are time stamped and transmitted to the substation. The data are then simultaneously processed along with electric current readings from the CT. For processing, we developed a unified algorithm that first distinguishes variation in sag from motion in conductor. Then, it estimates the corresponding sag or motion in any of the conductors. The method is verified first by numerical simulations, and then with a scaled setup in laboratory. Different test cases were identified by the algorithm. Error remains $\leq 1$ % for unsymmetrical sag estimation. In addition, trajectory of a conductor in motion is retrieved. Where the root mean square error between actual and retrieved conductor amplitude was only 0.0833 for the observation window of 200 ms.

Wind adaptive modeling of transmission lines using minimum description length

The transmission lines are moving objects, which positions are dynamically affected by wind-induced conductor motion while they are acquired by airborne laser scanners. This wind effect results in a noisy distribution of laser points, which often hinders accurate representation of transmission lines and thus, leads to various types of modeling errors. This paper presents a new method for complete 3D transmission line model reconstruction in the framework of inner and across span analysis. The highlighted fact is that the proposed method is capable of indirectly estimating noise scales, which corrupts the quality of laser observations affected by different wind speeds through a linear regression analysis. In the inner span analysis, individual transmission line models of each span are evaluated based on the Minimum Description Length theory and erroneous transmission line segments are subsequently replaced by precise transmission line models with wind-adaptive noise scale estimated. In the subsequent step of across span analysis, detecting the precise start and end positions of the transmission line models, known as the Point of Attachment, is the key issue for correcting partial modeling errors, as well as refining transmission line models. Finally, the geometric and topological completion of transmission line models are achieved over the entire network. A performance evaluation was conducted over 138.5km long corridor data. In a modest wind condition, the results demonstrates that the proposed method can improve the accuracy of non-wind-adaptive initial models on an average of 48% success rate to produce complete transmission line models in the range between 85% and 99.5% with the positional accuracy of 9.55cm transmission line models and 28cm Point of Attachment in the root-mean-square error.