Simulation Of Transmission Lines Research Articles

Triboelectric Nanogenerator with the Double-Mass Pendulum Integrated Spacer for Galloping Energy Harvesting of Transmission Lines.

The transmission lines galloping severely threatens the safety operation of the power grid. A reliable operation and maintenance alternative is to monitor the transmission lines by wireless sensing and warning devices. In this work, a triboelectric nanogenerator with the double-mass pendulum integrated spacer (DMPS-TENG) is proposed for harvesting the galloping energy of transmission lines and powering the wireless monitoring devices. Specifically, by introducing a double-mass pendulum system, the response frequency of the DMPS-TENG is reduced, allowing it to harvest energy at lower frequencies in the range of transmission lines galloping (0-3Hz). Hereby, enhancing the energy harvesting bandwidth and the efficiency. The experiments show that with the introduction of the double-mass pendulum, the optimum frequency of the harvester is reduced from 2.4 to 1.9Hz, enhances the harvesting bandwidth by 18%, and enables an average power output of up to 0.32mW. Additionally, to demonstrate the practical value, a prototype is designed and fabricated to perform three different application experiments in the multi-split transmission lines simulation system. This work presents an innovative approach for galloping energy harvesting of transmission lines, which can be used to inform further development of sensor networks and visualization of the power grid.

High-frequency transients in buried insulated wires: Transmission line simulations and experimental validation

This paper presents experimental results on the transient response of a buried insulated wire subjected to fast transient signals. It reports measurements of voltage and current at the sending end, as well as the voltage at the receiving end of the insulated wire. The obtained experimental results are utilized to assess the accuracy of recent formulations proposed for computing the ground-return impedance and admittance of underground cables, which are important for simulation of transients using models based on the transmission line theory. The good agreement between measurements and simulations bolsters confidence in incorporating these newly proposed expressions for computing the cable's ground-return parameters into EMT-type simulators.

Research on Ultraviolet Characteristic Parameters of DC-Positive Polarity Corona Discharge on Conductors

The detection of corona-related defects in transmission lines has been included in the work of transmission line defect detection. Ultraviolet detection technology has gradually been widely applied in the field of corona discharge detection. However, the current research on the application of ultraviolet detection technology in transmission lines is relatively simple and mainly limited to using changes in the photon count to determine whether corona discharge has occurred. To address this, this study used a mini corona cage to simulate transmission lines and measured the changes in the photon count, spot area, and corona current in the corona inception process of different types of smooth, stainless-steel conductors. This study also investigated the variations in the photon count and spot area depending on conductor corona intensity, ultraviolet imager gain, and observation distance. The results show that the photon count and spot area can, to some extent, reflect the intensity of corona discharge. Both the photon count and spot area exhibited quadratic relationships with the voltage. As the observation distance increased, both the photon count and spot area showed exponential decay. The photon count exhibited a trend of initially increasing, then decreasing, and finally increasing again with the increase of gain, while the spot area showed exponential growth with increasing gain. The photon count and spot area can complement each other to identify and characterize the intensity of corona discharge.

Coupled modelling and simulation of power transmission lines: A systematic analysis of line losses

Coupled modelling and simulation of power transmission lines: A systematic analysis of line losses

Three-dimensional Visualization of Overhead Transmission Lines with UAV-LiDAR Point Cloud Data

Three-dimensional reconstruction and visualization of overhead transmission lines is an important foundation for grid operation and maintenance management. This paper introduces a 3D visualization method of transmission lines based on the unmanned aerial vehicle (UAV) light detection and ranging (LiDAR) technology, which includes four steps: (I) Using UAV-LiDAR technology to obtain 3D point cloud data of power lines; (II) Using the least-squares method with loss minimization constraints to fit the point cloud data of the power lines, to obtain the accurate fitting function of the power lines; (III) Using the spline interpolation algorithm to draw the 3D scene in the 3D vectors, and combine with building information modeling (BIM) model to construct the transmission line visualization scene. The method of this paper can improve the authenticity and reliability of transmission line simulation and provide technical support for the digital platform of power grid management.

Comparison of Rational Krylov and Vector Fitting in Transient Simulation of Transmission Lines and Cables

This paper presents stringent comparisons between Vector Fitting (VFIT), Relaxed Vector Fitting (R-VFIT) and Rational Krylov Fitting (RKFIT) techniques in the fitting of transmission line and cable functions to rational forms while accounting for the frequency dependence of electrical parameters. The fitting procedures encapsulate new solution strategies to improve fitting performance. Various case studies are presented to assess the performance of RKFIT in terms of model order reduction, passivity violation and computing times. In addition, the use of RKFIT in obtaining the frequency dependent cable model (FDCM) is demonstrated for the first time together with a resolved case study that showed unstable behavior with the universal line model (ULM) methodology.

Textile Characterization for Wearable Antenna Application Using Transmission Line Method

This proposed work introduces the textile characterisation analysis based on the effects of fabric thickness and dielectric properties using the transmission line method for a wearable textile antenna. The return loss (S11) and transmission loss (S21) were analysed for denim, felt and Tencel in correlation with the conductivity properties using Computer Simulation Technology with Rogers 5880as the reference sample. By varying the fabric thickness from 0.5 mm to 4 mm, the optimum thickness and type of fabric can be identified from the S11and S21parameters. In the transmission line simulation, the sample-under-test is a stripline with the conductivity values from 10-2to 108S/m. Results are further plotted against the thicknesses to observe the behaviour of all three textiles samples. The results show that Felt substrate with 3 mm thickness give the best performance. The felt substrate demonstrates the best transmission performance judging from the lowest transmission loss due to the low tangent loss followed by Tencel and denim.For accuracy analysis, the actual and calculated conductivity were also presented to show the textiles performanceat low and high region of conductivity. The study reveals the importance of choosing the correct substrate with suitable dielectric and electrical properties before being implemented into the antenna design for good efficiency.

Исследование влияния переходного сопротивления на дистанционное определение места повреждения на основе одностороннего метода

Fault location on 110–220 kV overhead power lines is one of the main functions of modern relay protection devices. Currently, the actual errors of fault location based on emergency mode (EM) parameters in most cases are about 5 %. However, there are cases when they exceed 10–20 %. One-sided fault location based on EM parameters and improvement of its accuracy are important issues to study since there isn’t a communication channel on power lines for the transmission of emergency information everywhere. The main parameter that has a significant impact on the accuracy of fault location method is the transient resistance. The aim of the research is to study the effect of transient resistance on the one-sided fault location method based on EM parameters proposed by A.E. Arzhannikov. In the course of the study, the following tasks are set: assessment of the effect of transient resistance on the accuracy of the specified fault location method; determination of the polarizing value for fault location, which ensures greater accuracy of the method, including the presence of transient resistance at the place of a short circuit; defining a criterion to recognize the type of short circuit that does not depend on the transient resistance; development of a method to determine the value of the transient resistance at the fault location. To study and evaluate the errors of distance fault location based on EM parameters, a series of calculations of short circuit currents has been made for various transient resistances at the fault location and at various distances of the fault. The calculation of currents and data processing has been carried out in the ARM SRZA software package. A single overhead line with a voltage of 110 kV with a two-sided supply and a length of 70 km is chosen as the object under study. To perform the research, the primary converters are taken as ideal. The authors have obtained the estimation of the errors of the one-sided fault location method. It is proposed to use the zero-sequence current as a polarizing quantity in the indicated fault location method, which provides greater accuracy than the use of the negative sequence current. To ensure the stable operation of one-sided fault location based on EM parameters, especially in case of short circuit with significant transient resistances, the use of methods that are insensitive to transient resistances is justified. A parameter to identify the type of short circuit is proposed, the coefficient of the image Kobr. Its values are determined for each type of short circuit, a small dependence on transient resistances is found. A calculation substantiation is given for the value of the identification coefficient of two-phase faults (Phase-to-Phase and Phases-to-Earth) according to the ratio of negative and zero sequence currents. The authors have estimated the transient resistance at the fault site by the ratio of symmetrical components for the simulated power transmission line. The results of the study can be used to improve the existing methods of fault location based on EM parameters, namely: to improve their accuracy considering the transient resistance at the fault site; to improve their accuracy using a suitable polarizing value; to determine the type of short circuit more accurately by using the proposed identification parameter.

An Enhanced Method to Achieve Exact DC Values for Frequency-dependent Transmission lines

This paper proposes an improved method to enhance the dc response of a frequency-dependent transmission line model used in EMT studies. A modification to the rational function approximation of propagation and characteristic admittance matrices of a transmission line is introduced to enforce exact dc values at 0 Hz. Furthermore, weighting factors are applied to improve accuracy at low frequencies. Finally, the order of the propagation function is reduced to decrease the computational effort.The validity of the proposed approach is demonstrated using examples involving underground cables and overhead lines. First, the effect of dc correction is demonstrated by comparing transmission line frequency domain characteristics. In addition, time domain simulations via open and short circuit conditions show a more accurate simulation of HVDC transmission lines with the proposed method.

Simulation of nonuniform transmission lines

PurposeThe purpose of the paper is the simulation of nonuniform transmission lines.Design/methodology/approachThe method involves a Magnus expansion and a numerical Laplace transform. The method involves a judicious arrangement of the governing equations so as to enable efficient simulation.FindingsThe results confirm an effective and efficient numerical solver for inclusion of nonuniform transmission lines in circuit simulation.Originality/valueThe work combines a Magnus expansion and numerical Laplace transform algorithm in a novel manner and applies the resultant algorithm for the effective and efficient simulation of nonuniform transmission lines.

Large asynchronous hydro generating systems connected to TCSC compensated transmission lines (Simulation with experimental validation): A review on SSO perspectives

Large asynchronous hydro generating systems connected to TCSC compensated transmission lines (Simulation with experimental validation): A review on SSO perspectives

Bandwidths of vocal tract resonances in physical models compared to transmission-line simulations.

This study investigated how the bandwidths of resonances simulated by transmission-line models of the vocal tract compare to bandwidths measured from physical three-dimensional printed vowel resonators. Three types of physical resonators were examined: models with realistic vocal tract shapes based on Magnetic Resonance Imaging (MRI) data, straight axisymmetric tubes with varying cross-sectional areas, and two-tube approximations of the vocal tract with notched lips. All physical models had hard walls and closed glottis so the main loss mechanisms contributing to the bandwidths were sound radiation, viscosity, and heat conduction. These losses were accordingly included in the simulations, in two variants: A coarse approximation of the losses with frequency-independent lumped elements, and a detailed, theoretically more precise loss model. Across the examined frequency range from 0 to 5 kHz, the resonance bandwidths increased systematically from the simulations with the coarse loss model to the simulations with the detailed loss model, to the tube-shaped physical resonators, and to the MRI-based resonators. This indicates that the simulated losses, especially the commonly used approximations, underestimate the real losses in physical resonators. Hence, more realistic acoustic simulations of the vocal tract require improved models for viscous and radiation losses.

Имитационное моделирование воздушных линий электропередачи напряжением 610 кВ для исследования алгоритмов определения места возникновения однофазных замыканий на землю

As part of evolution of single phase to earth faults protection methods and tools in 6–10 kV networks the development of simulation study methods of these networks and their components becomes relevant. A significant direction in this area is upgrading of sensors installed directly on the wires and electrical transmission towers. These sensors are installed in the conditions of an electromagnetic field acting on them and dynamically changes both in time and space, especially during emergency modes including single phase to earth faults. Application of modern software offers a challenge for complex simulation study of electromagnetic fields distribution at the location of the measuring transducers in continuously variable electromagnetic environment. The above-noted statement determines the relevance of the research goal, which is the development of a simulation study method of 6–10 kV overhead power lines, the model of which is designed to study existing and create new single phase to earth fault location algorithms and devices. To solve the tasks set the methods of simulation study of overhead transmission lines and corresponding medium voltage networks in PSCAD and COMSOL Multiphysics software have been used. The general concept of design of a 6–10 kV network and an overhead transmission line simulation model is formulated. The geometrical parameters of the section of the model of an overhead power transmission line to simulate electromagnetic transients are selected, considering the frequency dependence of the line parameters (inductance and active resistance). The proposed model of the overhead transmission line is verified, and recommendations for its application are given. The developed “inductive” component of the proposed overhead transmission line model allows to provide high accuracy of calculation of transient components of currents and voltages during single phase to earth faults. It makes possible to use this model for the development and research of single phase to earth fault location algorithms. The developed approach to simulation study of an overhead transmission line is the field of interest for further research, as it makes it possible to calculate the components of the electric field which are observed during single phase to earth faults.

Transfer learning-based fault location with small datasets in VSC-HVDC

Fault location plays a critical role in long-distance voltage source convertor based high-voltage direct current (VSC-HVDC) transmission systems. Although machine learning-based fault location methods were proved to be effective in some simulation scenarios, the small fault data sets from practical transmission lines are always a barrier for its application. Transfer learning can reach a fast convergence with a small data set when the model has learned knowledge with large data sets which have similar distributions. This paper proposed a transfer learning-based fault location method for VSC-HVDC transmission lines and discussed its performance under different conditions. The method uses stacked de-noising auto-encoder to model the relationship between current waveforms of travelling waves and fault locations, and fine-tunes the model with small data sets from the target transmission line through transfer learning. The proposed method is tested with a simulated VSC-HVDC transmission line on real time digital simulation platform. Results show the proposed method can locate faults with small training data sets and stand the influences from fault type, grounding resistance, and noise. The research results can provide technical support for the practical application of artificial intelligence in transmission grid.

Numerical analysis of fluid-structure interaction of iced line galloping

Numerical simulation of transmission lines’ movement can reveal the variation of aerodynamic force with conductor vibration. The fluid-structure interaction is considered and, and the software FLUENT is used to numerically analyze the model responses of 0.75D crescent-shaped iced conductor with wind attack Angle of 180° based on the k-ω SST turbulence model. The numerical simulation results of unsteady galloping of the iced conductor are compared with the galloping response of displacement time history analysis. The results show that the results of the fluid-structure interaction analysis are consistent with the quasi-steady analysis.

Transmission Line Sag Measurement and Simulation Research Based on Non-Contact Electric Field Sensing.

Sag is an important indicator of the operational health of a transmission line, and its timely measurement is of great significance to maintain the stability and reliability of power systems. However, traditional contact measurements may be affected by the electromagnetic interference of conductors. In contrast, measurement methods without direct electrical contact with the subject provide greater portability and flexibility. This paper presents a study of a transmission line sag measurement and simulation based on non-contact electric field sensing. The finite element method was used to analyze the conductor distribution, establish the coupling relationships among the electric field, transmission line, and measurement point, propose a sag inverse calculation model, and assess the impact of the transmission line parameter on the curved drooping measurement. Simultaneously, sag measurement schemes for single-round and dual-circuit lines were designed for multi-conductive lines, and measurement array studies were conducted. The vertical component of the electric field in space measured by the array was obtained, which could be used to perform conductor sag measurement simply and efficiently. The proposed method will facilitate the monitoring of the overhead transmission line status, which is conducive to the effective operation of the entire system.

Fault location method for MMC-HVDC transmission line based on adaptive optimal feature reconstruction

Applying the regression mechanism of intelligent algorithm to transmission line fault location is a new research direction in recent years.The location accuracy of such methods largely depends on the feature selection of the training samples of the algorithm model.This paper proposes a feature extraction method that combines regression algorithm, waveform decomposition and optimization algorithm, which can adaptively extract optimal features according to training samples, thereby ensuring the location accuracy of the algorithm model to the greatest extent. Through the test in a MMC-HVDC transmission line simulation model, the optimal feature reconstruction method proposed in this paper can greatly improve the fault location accuracy of transmission line, and has good location performance in case of high resistance grounding fault.

Transmission Line Fault Classification of Multi-Dataset Using CatBoost Classifier

Transmission line fault classification forms the basis of fault protection management in power systems. Because faults have adverse effects on transmission lines, adequate measures must be implemented to avoid power outages. This paper focuses on using the categorical boosting (CatBoost) algorithm classifier to analyse and train multiple voltage and current data from a 330 kV and 500 km-long simulated faulty transmission line model designed using Matlab/Simulink. From it, 93,340 fault data sizes were extracted. The CatBoost classifier was employed to classify the faults after different machine learning algorithms were used to train the same data with different parameters. The trainer achieved the best accuracy of 99.54%, with an error of 0.46% for 748 iterations out of 1000. The algorithm was selected for its high performance in classifying faults based on accuracy, precision and speed. In addition, it is easy to use and handles multiple data-sets. In contrast, a support vector machine and an artificial neural network each has a longer training time than the proposed method’s 58.5 s. Proper fault classification techniques assist in the effective fault management and planning of power system control thereby preventing energy waste and providing high performance.

A modified implementation of the Folded Line Equivalent transmission line model in the Alternative Transient Program

This paper proposes a modified implementation of the Folded Line Equivalent transmission line model to represent three-phase transmission lines. The Folded line equivalent decomposes a line into its open circuit and short circuit contributions. We propose an alternative orthogonal matrix to transform single-phase transmission line parameters, voltages, and currents to the Folded Line Equivalent domain. Because the proposed matrix is orthogonal, it can directly represent bidirectional transformations using circuit components in simulation software, such as the ATP-EMTP. First, the circuit implementation of Clarke’s matrix decouples a three-phase transmission line into its modes. Then, the circuit implementation of the proposed matrix decouples each mode into its open circuit and short circuit contributions. This paper proves that the proposed approach outputs similar results as those obtained by the Universal Line Model and the JMarti model in the simulation of transmission lines under open-circuit, energization, and fault conditions. However, because the proposed model does not derive from the method of characteristics, it can run with simulation times greater than the propagation delay of the transmission line. It is shown that the proposed approach outputs accurate results for time steps that are 10%, 100%, 200%, and 400% of the propagation delay of the transmission line. Thus, one major advantage of the proposed approach is that it can be used to reduce runtimes in the representation of short transmission lines in large complex networks by increasing time steps without compromising accuracy.

Integrated numerical simulation of an electromagnetic transmission line galloping excitation test system

PurposeThis paper aims to establish the mathematical model and solve the complex calculation multi-field coupling problem for an electromagnetic overhead transmission line galloping excitation test system.Design/methodology/approachAn electromagnetic excitation test system is introduced. To calculate the vibration response of the transmission line, a transient coupled finite element model containing electromagnetic repulsive mechanism and transmission line system was established. Considering the advantages of Newmark-ß algorithm and fourth-order Runge–Kutta algorithm, the two algorithms are combined to solve the model. Compared with the simulation results of existing commercial finite element software, the accuracy of the calculation model of electromagnetic force and wire vibration response are verified.FindingsComparison results show that the proposed calculation model can accurately obtain the force of electromagnetic mechanism and the vibration response of the overhead power lines, and improve the calculation efficiency. The calculation results show that vibration under electromagnetic excitation presents a double half-wave mode, and the galloping amplitude varies according to the charging voltage.Originality/valueThis paper built the transient simulation model for a galloping test system. The Newmark-ß algorithm and the fourth-order Runge–Kutta algorithm are used to solve the model. The research results are of great significance for the actual galloping test system design.