Characteristics Of Transmission Lines Research Articles

Evaluating the Influence of Thin Film of Water on the Frequency Dependences of Transmission Line S-Parameters at Positive and Negative Temperatures

Relevance. Provision of reliable and uninterrupted radio communication is critically important under changing climatic conditions of its operation. The combined effect of temperature and humidity can lead to changes in the electrical characteristics of transceiving devices and thereby disrupt the communication channel. In difficult climatic conditions of operation, due to constant temperature changes on the surface of the printed circuit boards, which are part of them, condensation can form, affecting the performance of the entire device. In this regard, the electrical characteristics change, which must be taken into account when designing critical REE. When designing transmission lines on printed circuit boards, it is reasonable to evaluate climatic impacts on it in a wide frequency range, which requires the development of new models and methods that allow taking into account these impacts.Goal of the work: to evaluate the influence of the temperature of a thin film of water on the surface of a microstrip transmission line on its frequency dependences of S-parameters. Finite element methods and laboratory experiment were used.Results. A methodology to account for the effects of ambient temperature and humidity on the electrical characteristics of a microstrip transmission line (MTL) is presented, which allows evaluating the variation of the S-parameters of the line over wide ranges of frequencies, air temperature and humidity, as well as the chemical composition of the environment. The S-parameters of water in a container placed inside a coaxial chamber are measured over the frequency and temperature ranges of 10 MHz to 12 GHz and minus 50 to 100℃, respectively. Using the presented model, the frequency dependences of the electrical conductivity of water at different temperatures are calculated. It is shown that at positive temperature, the electrical conductivity can reach 6.5 Sm/m and at negative temperature it can reach 1.3 Sm/m. Using the developed methodology, the influence of different water electrical conductivity on the S-parameters of MTLs is evaluated. The influence of water and ice layer thickness on the S-parameters of MTLs was shown. It is found that models describing the electrical conductivity of water have an excellent influence on the electrical parameters of the transmission line. Novelty. A method of accounting for the influence of ambient temperature and humidity on the S-parameters of the transmission line is presented, which is characterized by the use of a model of water conductivity based on insertion losses calculated from the measured S-parameters of a coaxial chamber with water in the container when its temperature is changed. Practical significance: a model and a methodology for taking into account the impact of temperature and humidity of the environment on the MTL characteristics are presented, allowing estimating the S-parameters of the line in a wide range of frequencies, air temperature and humidity, as well as the chemical composition of the environment.

A microwave permittivity sensor on a Mach–Zehnder Interferometer of: Spoof surface plasmon polariton waveguides

A microwave Mach–Zehnder Interferometer (MZI) sensor for the permittivity characterization of liquids is presented in this paper. Two spoof surface plasmon polariton (SSPP) waveguide transmission lines (TLs) composed of compact spiral units is utilized in a differential architecture. Loading a dielectric material on the sensing arm induces a phase difference between the two arms, leading to periodic interference dips on the transmission curve. The spectral positions and magnitudes of these dips change with different dielectric materials. Due to the nonlinear dispersion characteristics of the SSPP TL, the proposed SSPP-based MZI sensor achieves improved sensitivity compared with microstrip-based MZI sensor. To validate the sensor’s performance, six different oil samples and a set of adulterated oils were measured, incorporating a polydimethylsiloxane (PDMS) channel on the sensing arm. The variations in the spectral position and magnitude of the interference dip centered at 3.2 GHz are employed to determine the dielectric constants and loss tangents of the tested oils. The sensitivity in measuring the dielectric constant is 3.61 %. The maximum errors for measuring the dielectric constant and the loss tangent are 4.3 % and 6.7 %, respectively. Compared to other sensors for liquid oil detection, the proposed sensor provides a relatively high sensitivity while maintaining a low liquid volume, making it a promising candidate for permittivity measurements of liquid analytes and solid materials with similar dielectric constants.

Harvesting Broadband Breeze Vibration Energy via Elastic Bistable Triboelectric Nanogenerator for In Situ, Self‐Powered Monitoring of Power Transmission Lines

AbstractTriboelectric nanogenerator (TENG), as a new technique for energy capture, has unique advantages in harvesting high‐entropy energy. In view of the wind‐induced vibration characteristics of power transmission lines, the symmetric elastic bistable triboelectric nanogenerator (EB‐TENG) is introduced in this work. The core component of the EB‐TENG is the elastic bistable cantilever beam structure, which is designed by introducing an elastic perturbation structure to the conventional cantilever beam. This beam results in several sub‐resonance frequencies in addition to the natural frequencies, which broadens the frequency band of the EB‐TENG. In addition, the EB‐TENG adopts a symmetrical cantilever beam to ensure effective harvesting of vibration energy, even in situations of self‐tilting and external tilting vibration. The experimental outcomes confirm that the EB‐TENG can significantly harvest vibration energy in the 7–60 Hz frequency range and delivers the maximum peak power of 2.846 mW, which meets the major vibration frequency range of power transmission lines under the action of breeze. Finally, self‐powered strategy based on EB‐TENG online monitoring devices (such as tower obstruction lights, temperature and humidity sensors, and line high temperature wireless alarms) is constructed. This work helps promote the application of in‐situ self‐powered monitoring based on TENG in smart transmission lines.

Research on monitoring method for ice-covered state of transmission lines based on conductor end displacement

To efficiently and economically monitor the status of transmission lines in frozen rain areas, we propose a method, which can monitor the status of ice- covered transmission lines based on conductor end displacement. Firstly, we delve into the factors that contribute to icing on transmission lines and the subsequent mechanical implications. Subsequently, we propose an equal-height double-node conductor model that aptly captures the stress characteristics of transmission lines in frozen rain environments. This model utilizes the horizontal displacement of the mid-span endpoint and the wire's load as proxies for the variations in horizontal tension and sag. Furthermore, we establish the overall static balance equation for continuous overhead conductors, grounded in the principle of nodal force equilibrium. We then elaborate on the operational framework of our monitoring model. A comparative analysis with existing models reveals the superior accuracy and computational efficiency of our proposed model. To validate our approach, we construct a real-world transmission line setup and assess the economic viability of various monitoring strategies. Additionally, we examine the impact of varying icing thicknesses and locations on the transmission line's status. Our findings indicate that our model outperforms traditional counterparts in terms of accuracy, computational speed, and cost-effectiveness. Specifically, at ice-covered sections, the maximum sag and tension of the conductor exhibit a direct correlation with the ice thickness. Conversely, in non-ice-covered areas, the maximum sag inversely correlates with ice thickness, while the tension maintains a direct relationship.

Two-terminal traveling wave fault location approach based on frequency dependent electrical parameters of HVAC cable transmission lines

With the expansion of high-voltage alternating current transmission networks, the widely used two-terminal traveling wave method faces several challenges in cable fault location. On one hand, the frequency dependent characteristics of longer cable transmission lines can significantly impact the accuracy of traveling wave propagation velocity. On the other hand, the processing of traveling wave signals obtained synchronously is also a crucial factor that requires attention. To enhance the performance of cable fault location, the principles of two-terminal traveling wave method need to be updated. Firstly, the cable model derived from the theory of wave propagation in multi-conductor systems is presented, which reflects the frequency dependent characteristics of the electrical parameters. Whereupon, an innovative cable traveling wave fault location scheme primarily composed of arrival time identification and instantaneous frequency calculation is proposed. Eventually, based on electromagnetic transient simulation software PSCAD/EMTDC, the robustness of the innovative cable fault location method against fault type, fault location, fault resistance, fault initial angle and earth resistivity issues is demonstrated.

Smart line planning method for power transmission based on D3QN‐PER algorithm

AbstractThe planning of power transmission line projects encompasses vast and complex geographical terrains. To address the complexity of transmission line planning and achieve lower line costs, this study proposes a novel intelligent line planning method. For the first time, it combines the Dueling Double Deep Q Network (D3QN) with the prioritized experience replay (PER) mechanism. First, correlate the reward function with metrics such as line length, number of corner points, and geographical environmental data, which are pertinent to the construction costs of power transmission line. Second, the D3QN algorithm is formulated by integrating Double DQN and Dueling DQN. The network's input information is divided into two components during training, aligning with the characteristics of power transmission line planning projects. Finally, the convergence efficiency of the algorithm is improved by using the PER mechanism for the problem of cost difference due to the different number of corner points in the planning path. In order to test the feasibility of the algorithm, we conducted experiments using real maps. Compared with the traditional ant colony optimization (ACO) algorithm, the D3QN‐PER deep reinforcement learning algorithm reduces the line length by more than 4% and the number of corner points by more than 60%.

Параметрическая оптимизация асимметричных многопроводных линий передачи с учетом комбинационных импульсов

Transmission lines are significant elements and play an important role in determining the performance, reliability and functionality of radio electronics. A number of factors appearing in the use of transmission lines can lead to problems in the field of electromagnetic compatibility. One such factor is the appearance of asymmetry due to inhomogeneities, PCB manufacturing errors, dense tracing, mismatch, etc. The paper considers the effect of asymmetry on the characteristics of transmission lines with inhomogeneous dielectric filling. It is found that asymmetry of cross section and/or boundary conditions leads to the appearance of combinational pulses. Combination pulses are of interest because their arrival times do not correspond to the per-unit-length delays of the modes propagating in the transmission lines, but consist of their combinations. Their level may be comparable to the level of information signals, which may result in distortion or loss of useful information. Meanwhile, asymmetry and the resulting combinational pulses represent a new resource for improving the performance of devices based on transmission lines, which can be used to protect radio electronics from electromagnetic interference of picosecond and nanosecond duration. For the first time the optimization of parameters taking into account combinational pulses is carried out on the example of three diagrams of symmetric multiconductor transmission lines with asymmetry of termination loads: reflection symmetric and with a reference conductor in the form of side polygons. Using the genetic algorithm, the optimal parameters are obtained, which allow to reduce the value of the maximum amplitude by 1.5 times, as well as the parameters allowing to increase in 2 times the minimum value of the time interval between the decomposition pulses, on which depends the possibility of complete decomposition of the interference pulse, compared to the value obtained in the initial diagram with optimized parameters, where there are no combinational pulses at the same device dimensions. The optimization results demonstrate the efficiency of using the resource of combinational pulses to improve protective structures based on transmission lines with inhomogeneous dielectric filling.

A novel trading optimization strategy of source-load bilateral thermoelectric spot based on industrial parks interior

With the continuous reform of the electricity market in the whole world, internal trading models in parks are generally studied in terms of load peaking, load flexibility and energy management. In this paper, the regional differential trading method is adopted for industrial users with different energy needs, and the interests of all parties within the industrial park are considered. Spot transactions involving surplus energy on both the supply side and the demand side are considered, and the weight allocation of transactions in each park is coordinated. Firstly, the way of circulating waste heat and power within the industrial park is analyzed from the composition of the trading system of the industrial park. The demand side is transported heat and electricity while the energy storage device is considered. The contact line is modeled on the basis of the energy transmission line characteristics. Secondly, the industrial park is disaggregated regionally using cascade analysis within the target area to decide load regulation mode between systems and modules. Thirdly, regional differences in trading are adopted for industrial users with different energy needs while the interests of all parties within the park are considered. Both sides of the supply side and the demand side participate in spot trading of surplus energy. The allocation of weights is coordinated for trading in the various industrial parks. Finally, The DICOPT solver optimizes operating costs and takes into account energy abandonment penalties. In the waste heat power transaction in the industrial park, the remaining power can be saved by 9.78 %, and the waste heat can be saved by 4.35 %. Numerical results from instances indicate that this method surpasses traditional trading approaches, aligning with the rigorous standards of scientific research.

Influence of Various Biomass Smoldering Flue Gas on Physical Characteristics of High Voltage Transmission Line

Through intelligent resistivity tester and universal tensile testing machine, the physical properties of steel-cored aluminum strand above smoldering biomass fuel were analyzed. The results show that compared with the original aluminum single wire, the resistivity of each aluminum single wire under each biomass smoldering condition increases, and the increase amplitude increases with the decrease of the height of the aluminum single wire. The height of the steel core aluminum strand has no obvious effect on the tensile strength before and after smoldering. When the height of the steel-cored aluminum strand from the combustible surface is 5 cm, the Young 's modulus of all aluminum single wires decreases, among which the Young 's modulus of aluminum single wires after smoldering Eucalyptus leaves and poplar sawdust decreases the most. When the height of the steel-cored aluminum strand from the fuel surface is 15 cm and 25 cm, the Young 's modulus of the aluminum single wire after smoldering of different fuels varies (224.4-821.9 MPa). When the height of the steel-cored aluminum strand from the combustible surface is 5cm, the flue gas temperature is high, and the outer aluminum strand of the steel-cored aluminum strand can absorb a certain amount of heat, thereby causing a small shape change occurrence.

Front Cover: Equivalent transmission line characterization and multi‐layer material measurement analysis of the signal conversion process in the pulsed electro‐acoustic method

Front Cover: Equivalent transmission line characterization and multi‐layer material measurement analysis of the signal conversion process in the pulsed electro‐acoustic method

Prediction method for response characteristics parameters of isolated-span overhead lines after ice-shedding based on finite element simulation and machine learning

In response to the problem of insufficient research on the prediction for response characteristics parameters of isolated-span transmission lines under various ice-shedding modes, study on the prediction for ice-shedding response parameters of isolated-span overhead lines is conducted in this paper based on finite element simulation and machine learning. Firstly, the finite element simulation model of isolated-span overhead line is established and verified. Seven model input parameters are determined by considering 12 typical ice-shedding modes and ice-shedding labels are introduced. Six key output parameters reflecting the electrical and mechanical characteristics of the ice-shedding transmission line are obtained by feature extraction. Secondly, the output parameters of the ice-shedding transmission line under different input parameter conditions are obtained by using the finite element simulation method. A total of 1400 sets sample data are constructed. Then, four typical regression prediction models of BP (Back Propagation Algorithm), RBF (Radial Basis Function Algorithm), SVM (Support Vector Machine Algorithm) and RF (Random Forest Algorithm) are established to predict the key output parameters of ice-shedding transmission lines. Finally, the optimal prediction model for ice-shedding response characteristics parameters of isolated-span transmission lines is selected and the application effect is analyzed by actual ice-shedding case. It is found that the RF prediction model is the optimal prediction model among the four regression prediction models. The prediction method for ice-shedding response characteristics parameters of isolated-span transmission line proposed in this paper can accurately predict the response characteristics parameters of ice-shedding transmission lines which can provide some references for the safe operation of isolated-span transmission lines in heavy ice areas.

Control Method for Up and Down Lines of Transmission Line Operation Robots

The current transmission line robot up and down the line relies on manual lifting, and this method is labor-intensive, dangerous, and requires the assistance of many people. To address this problem, the paper proposes a control method based on UAV-assisted transmission line power line operation robot up and down the line. Aiming at the characteristics of transmission lines, in order to solve the problem of uneven posture and even side-turning when the robot is on line, the robot adopts the way of lifting with four traction ropes driven by the reel, and analyzes the tilting situation that the robot may encounter when it is on line, and puts forward a BP fuzzy neural network PID-based leveling control method, which compares the rapidity and stability of the leveling of the different control methods in the case of perturbation, and solves the problem of uneven posture and side-turning of the robot when it is on line. the problem of uneven attitude. Finally, a robot lifting attitude leveling experiment is carried out in a simulated field to prove the feasibility of the proposed automatic robot up and down line method in practical applications.

Research on fault localization method of transmission line based on distributed monitoring

Abstract Transmission lines are the arteries of power system operation, carrying the important task of conveying electric energy, which is the most fragile and fault-prone place in the power system. This paper first analyzes the traveling wave propagation characteristics of transmission lines. It builds a mathematical model for the refraction and reflection phenomena of traveling waves that occur in the process of readjustment and distribution of transmission lines. The three traveling wave monitoring points nearest to the fault point are used to localize the fault, and the principle of the phase difference of split-phase current is explored based on the fault component. By means of experimental analysis, the phase currents of the three measurement points are detected, and for the transient current waveforms at the time of lightning strikes and short-circuits, the lightning fault localization method of the transmission line based on wavelet transforms is proposed and analyzed for fault localization of the technique. The results of simulation experiments show that when a ground fault occurs in the L1 phase of the line, the current fault components of measurement point 2 and measurement point 3 increase rapidly, and the element between measurement points is more than 10kA. The phase difference of the components is 180°, so the fault interval of the transmission line is from measurement point 2 to measurement point 3, and the fault phase is the L1 phase. Upon analysis, it is apparent that the actual fault distance error of 0.838km is the measurement of the fault distance of the transmission line, and the method proposed in this paper has a high level of measurement accuracy.

Characteristics of multi-span transmission lines following ice-shedding

Numerical simulation method for dynamic responses of multi-span transmission lines with evenly and unevenly distributed ice following ice-shedding from full and partial span in the cases without and with wind loads, is presented and verified by reduced-scale modeling tests. Jump envelop, dynamic swing parameters, maximum reactions on tower and tensions in conductors are defined to depict the dynamic response characteristics of transmission lines following ice-shedding. The characteristics of multi-span lines with various parameters following ice-shedding are numerically studied, meanwhile a dataset is built. Using the dataset and the back-propagation (BP) neural network algorithm, prediction models for the dynamic response characteristics providing instructions for the design of electric insulation clearance and strength of transmission lines in ice zones are established and the software is developed.. The suitability of the prediction model and existing methods are discussed.

On the Features of Calculating Linear Parameters and Characteristics of Multi-Wire Transmission Lines

The features of calculating the matrices of linear parameters and characteristics of multi-wire transmission lines have been considered. The method of calculation of the matrices of primary linear parameters of multi-wire transmission lines has been presented. The criteria for the accuracy of the calculation of the capacitive matrix have been formulated. It has been noted that it is necessary to accurately account for the mutual influence between the transmission line conductors for a correct estimation of the distortions of thesignals propagated in it. The influence of the linear parameters of multi-wire transmission lines on responses and eye diagrams at the end of their active conductors has been demonstrated. The influence of the distances from the extreme conductors to the boundaries of the cross-sections of transmission lines on the accuracy ofcalculating their capacitive matrices has been studied. Using the method of moments, it has been shown that known approaches to determining these distances do not always give accurate or efficient results. On the example of several transmission lines with different numbers of dielectric layers and conductors, as well as with the screen and without it, the minimum values of this distance at which it is possible to achieve an accurate and efficient calculation of their capacitive matrices have been determined.

Machine learning-based fault diagnosis for high-voltage transmission lines

In order to comply with the speed and diversification process of human economic and technological development, the power system gradually develops in the direction of intelligence and complexity, and it is urgent to combine transmission line fault diagnosis methods with machine learning pattern recognition problems in order to reflect the representative characteristics of transmission lines under different operating conditions and different operation modes. In this paper, a convolutional neural network (CNN) model is established for transmission line fault diagnosis, and a series of parameters such as weights, bias, learning rate, batch size and loss function of the proposed CNN model are debugged through experimental comparison, and the best CNN model structure is determined through experimental comparison and debugging, and the recognition accuracy is higher than other traditional machine learning algorithms, which can be as high as 98.38%, with validity, practicality and advancedness.

Equivalent transmission line characterization and multi‐layer material measurement analysis of the signal conversion process in the pulsed electro‐acoustic method

AbstractThis paper studies the equivalent transmission line model of the pulsed electro‐acoustic (PEA) method with its applications. Based on the consistency of acoustic wave behaviour inside lossy acoustic materials and voltage wave propagation in transmission line, an equivalent simulation model of the PEA system is developed, whose reliability is verified by the output from the transducer and amplifier models and the comparison with measured waveforms. For the problem of acoustic impedance mismatch between different modules, simulation indicates that the unequal impedances of semiconducting electrode and sample can affect the amplitude of the measured signal at the upper electrode side, and the reflected acoustic waves caused by the transducer can affect the charge waveform. Further simulation for multi‐layer materials finds that the reflected acoustic waves of different samples and sound absorbing module can superimpose on the charge signal. Accordingly, a selection criterion is proposed to avoid the effect of the reflected waves at the interface. As for the acoustic reflection caused by internal charge, it needs to be dealt with sequentially in calibration process, starting from the result inside the sample near ground electrode. The research can provide a foundation for analyzing the acoustic properties of the PEA method.

Dynamic Response Characteristics of Isolated-Span Transmission Lines After Ice-Shedding

Dynamic Response Characteristics of Isolated-Span Transmission Lines After Ice-Shedding

Research on foreign body detection in transmission lines based on a multi-UAV cooperative system and YOLOv7

The unique plateau geographical features and variable weather of Yunnan, China make transmission lines in this region more susceptible to coverage and damage by various foreign bodies compared to flat areas. The mountainous terrain also presents great challenges for inspecting and removing such objects. In order to improve the efficiency and detection accuracy of foreign body inspection of transmission lines, we propose a multi-UAV collaborative system specifically designed for the geographical characteristics of Yunnan's transmission lines in this paper. Additionally, the image data of foreign bodies was augmented, and the YOLOv7 target detection model, which offers a more balanced trade-off between precision and speed, was adopted to improve the accuracy and speed of foreign body detection.

Analysis of the Characteristics of Radio Frequency Power Transmission Lines Using a Voltage Current Probe in Low-Pressure Discharge

Analysis of the Characteristics of Radio Frequency Power Transmission Lines Using a Voltage Current Probe in Low-Pressure Discharge