Transmission Line Approach Research Articles

A hybrid energy harvesting approach for transmission lines based on triboelectric nanogenerator and micro thermoelectric generator

To effectively detect faults in transmission lines, monitoring the operating status of these lines is imperative. However, providing power to monitoring devices for transmission line status presents a significant challenge. In this research, a hybrid energy harvesting approach based on micro thermoelectric generator (MTEG) and triboelectric nanogenerator (TENG) is proposed, and a theoretical model for MTEG-TENG hybrid energy harvesting is established. This study develops an integrated energy harvesting prototype, which incorporates oscillating-TENG (O-TENGs), MTEGs, and a power management control unit. This prototype not only harvests energy from the vibrations of transmission lines but also converts the lines thermal energy into electricity. The Experiment results show that the maximum open-circuit voltages of O-TENG and MTEG reach 80.3 V and 1.094 V, respectively. Compared to a single MTEG energy harvesting device, the prototype of the MTEG-TENG hybrid energy harvesting device demonstrates a 5.36% improvement in energy harvesting and battery charging performance. Consequently, this approach achieves self-powered monitoring with excellent stability and lower manufacturing costs. It provides an efficient and durable power approach for transmission line status monitoring devices.

Advanced Fault Detection in Power Systems Using Wavelet Transform: SIMULINK-Based Implementation and Analysis

Traditional methods struggle to find faults in power transmission lines. This paper presents an approach for short transmission lines, leveraging the power of wavelet transforms. Traditional methods analyze time-domain signals, limiting their ability to differentiate fault transients. Wavelet transforms, offering a combined time-frequency analysis, provide a deeper understanding of these transients. A detailed short transmission line model is built in SIMULINK. Diverse fault scenarios are meticulously simulated, and current signals undergo wavelet transform analysis. Key features extracted from the wavelet coefficients act as fingerprints of potential faults. These features are then utilized to develop a robust fault detection algorithm specifically designed for short transmission lines. The proposed method promises enhanced fault detection capabilities compared to existing techniques in this domain. The results, presented in subsequent sections, will shed light on the effectiveness of wavelet transforms in empowering smarter and more reliable transmission line operations.

An improved Mini Antenna Designed at 60GHZ for a New Generation Mobile Phone

Five-generation (5G) communication systems are being required to meet the needs of small, high-speed, and big bandwidth systems [2]. This paper simulates and designs a 60GHZ rectangular micro strip patch antenna. The proposed antenna resonates at 60GHZ with a return loss of -32.126 dB, efficiency of 87.7119%, and gain of 6.96485 dBi. The patch is 2.726 x 2.364 x 0.125 mm. The radiating patch and the 50Ω micro strip feed line are matched using an iset feed transmission line approach. A Roger RT Duroid 5880 substrate, with a height of 0.125mm and a dielectric constant of 2.20 and a loss tangent of 0.0009, was selected in the design. The Advanced Design System (ADS) was used to compute the antenna's parameters and evaluate the results of simulations.

Smart grid line fault detection based on deep learning image recognition algorithm

Abstract Amid the rapid evolution of smart grids, stringent demands for reliability, safety, and efficiency have escalated for transmission lines. Nevertheless, given their extensive coverage and the complexity of their environments, traditional inspection techniques struggle to meet the rigorous standards of real-time monitoring and precision. This paper introduces a novel fault detection approach for smart grid transmission lines, leveraging advanced deep-learning image recognition algorithms. This method improves the YOLOv5 series models by combining the Convolution Attention Module (CBAM), Bidirectional Feature Pyramid Network (BiFPN), and MobileNet-V3 as the feature extraction network of YOLOv5 to achieve defect detection of hardware on transmission lines. CBAM improves the model’s sensitivity to tiny defects by focusing on key areas and features. BiFPN improves detection accuracy and robustness through efficient fusion of multi-scale features. Furthermore, the integration of MobileNet-V3 enhances both the efficiency and precision of feature extraction, ultimately elevating the overall model’s performance. Experimental results show that compared with the original YOLOv5 model, the improved algorithm can achieve 92.89% accuracy and 84.10% recall, which is better than other mainstream target detection algorithms. Especially in the detection of defects in small targets and complex backgrounds, the improved model shows stronger robustness and adaptability. This provides strong technical support for the efficient operation and maintenance of smart grids.

Modeling and experimental validation of a proposed distance protection system for MVDC transmission lines

Protecting direct current transmission lines (DC-TLs) against faults is challenging and crucial, especially when locating faults. This research aims to develop a novel distance protection approach for Medium voltage direct current transmission lines (MVDC-TLs). Various faults in the computerized experiments and practical models have been applied to the proposed system in the AC network and DC transmission lines to evaluate the performance of the proposed method. The proposed protection system employs the wavelet transforms (WT) and ANFIS as detailed coefficients ‘feature extracting’ tools and classifiers, respectively. The mechanism operation of the proposed method is composed of three stages. Firstly, it extracts the features of the faults by WT. Hence, the ANFIS training process uses such features to identify and classify the faults. The third stage utilizes the ratio value between the fault current and the healthy operation current as an input of another ANFIS model to locate faults on the DC TL. The performance of the proposed protection method has been tested and evaluated for MVDC and MVAC networks. Also, the research executes both practical and simulation experiments utilizing different faults. It examines various fault locations on the entire MVDC line. The mechanism measures the current signals on both sides of the DC-TL. The paper built the MVDC-TLs model and the different cases using the software PSCAD/EMTDC and the proposed method via MATLAB. The study tested faults along the TL in the presence of the AWGN noise. The research utilizes practical experiments to verify the accuracy of the proposer. The accuracy of the proposed fault location is 99.923 %. Based on the results of this research paper and comparison with the recent related research works, the proposed method is more effective and efficient than the previous methods in detecting, classifying, and locating system faults.

Impact of viscothermal loss on modulation instability and rogue waves in left-handed nonlinear diffractive acoustic transmission line metamaterials

In this study, the transmission line approach is used to describe the studied acoustic metamaterial model. Through Kirchoff’s pressure and volume-velocity laws and using multiple scales method, nonlinear coupled Schrödinger equations are obtained. Then, the amplitude disturbance method is applied to these equations to obtain and plot the modulational instability gain curves. Analytically, the impact of viscothermal loss on the modulational instability gain is studied. The similarity technique is used to derive integrable Manakov’s equations. First and second-order rational rogue wavelike solutions of coupled nonlinear Schrödinger are deduced. The results indicate that the modulational instability gain and Rogue wave intensities depend on the viscothermal parameter. This parameter can be considered in the design of nonlinear acoustic metamaterials to minimize the damage caused by the dynamics of freak waves.

Novel travelling wave fault location approach for overhead transmission lines

Travelling wave fault location approach for overhead transmission line is widely applied in actual power grid, which has better fault location accuracy comparing with conventional power frequency data based method. However, travelling wave fault location approach is highly related to the frequency distortion phenomenon of travelling wave propagation velocity, which includes two parts: (i) the distortion caused by reflection and refraction phenomena of transformer substation and (ii) the attenuation caused by distributed resistance of transmission line. Therefore, aiming to improve the fault location accuracy, the paper contributes to two aspects: (i) the complete theoretical analysis of the distortion phenomenon of travelling wave signal and (ii) the improved travelling wave fault location approach considering distortion phenomenon. Eventually, based on PSCAD/EMTDC simulation tool, a typical 500 kV case study model is established to verify the fault location accuracy of proposed travelling wave fault location approach under the influences of fault type issue, fault location issue and grounding resistance issue.

Transient induced voltages on aboveground pipelines parallel to overhead transmission lines

Lightning strikes to conductors of overhead lines may cause high transient induced voltages at neighbouring pipelines. Thus, the computation of these voltages is important for the safe and reliable pipeline operation. This work investigates the effects of line parameters and soil modelling on the transient voltages induced at an aboveground pipeline due to lightning strikes to a phase conductor of a nearby overhead transmission line. Three different earth formulations are evaluated: the Carson, Wise, and the method of moments with surface operator combined with the extended transmission line approaches. Computations are performed using both frequency- and time-domain models, as well as constant and frequency-dependent soil electrical properties. CIGRE lightning current waveforms are employed in simulations derived on the basis of the statistical distributions of their parameters for negative first return-strokes. Transient induced voltage waveforms differ among the evaluated lightning currents, with higher peak values for shorter and steeper current wavefronts. Conservative results are obtained for the constant soil properties and Carson’s earth formulations, which neglect, respectively, the dispersion of soil electrical properties and displacement current.

Evaluation of Polylactic Acid Polymer as a Substrate in Rectenna for Ambient Radiofrequency Energy Harvesting

This work details the design and experimental characterization of a 2D rectenna for scavenging radio frequency energy at 2.45 GHz (WiFi band), fabricated on polylactic acid polymer (PLA) using a plastronics approach. PLA is the RF substrate of both antenna and rectifier. The two transmission line (TTL) approach is used to characterize the substrate properties to be considered during design. A linearly polarized patch antenna with microstrip transmission feeding is connected to a single series diode rectifier through a T-matching network. The antenna has simulated and measured gain of 7.6 dB and 7.5 dB, respectively. The rectifier has a measured DC output power of 0.96 μW at an optimal load of 2 kΩ under RF input power of −20 dBm at 2.45 GHz. The power conversion efficiency is 9.6% in the latter conditions for a 54 × 36 mm patch antenna of a 1.5 mm thick PLA substrate obtained from additive manufacturing. The power conversion efficiency reaches a value of 28.75% when the input power is −10 dBm at 2.45 GHz. This corresponds to a peak DC power of 28.75 μW when the optimal load is 1.5 kΩ. The results compare significantly with the ones of a similar rectenna circuit manufactured on preferred RF substrate.

Analysis of Cross-Bonded Cables Using Accurate Model Parameters

This paper presents a thorough investigation of frequency and electromagnetic transient (EMT) responses of cross-bonded cables. The study adopts newly developed Line/ Cable Data (LCD) Module in an existing EMT-type simulation software. The input impedances evaluated by positive sequence and various mode energizations on a typical cross-bonded cable (CBC) in frequency domain are investigated.In addition to cross-bonded, the solid-bonded cable (SBC) and core-transposed cable (CTC) are analyzed for characteristics of input impedance. The mixed propagation modes of CBC and CTC are studied. The influence of bonding methods and cable models on transient voltages is investigated. The results simulated by the new LCD are compared with the Classical Parameter Calculation (CPC) method and validated by recently proposed extended transmission line (ETL) approach.

A Transmission Line Approach for Rough Conductor Surface Impedance Analysis

This work proposes a transmission line approach to determine the surface impedance of conductors with rough surfaces. Based on the gradient model, the roughness is represented by a gradual transition of the intrinsic impedance. Discretization and successive impedance transformations then directly yield the surface impedance. Evaluating the fields is not necessary to this end, but still feasible if required. Investigations of the proposed model confirm the field diffusion to be fully characterized by a single dimensionless ratio, which enables a comprehensive analysis of the surface impedance regarding its dependency on frequency, conductivity, and roughness.

On the Transient Analysis of Towers: A Revised Theory Based on Sommerfeld-Goubau Wave

Accurate tower models for fast transients are essential for the insulation design of overhead lines, since lightning may produce temporary or even permanent faults. The aim of the work is to further investigate the nature of the electromagnetic modes supported by the tower, and on the applicability of the transmission line approaches, originally inspired by the model proposed by Jordan. The influence of a perfectly conducting ground plane and of losses distributed along the tower will be discussed. A new approach, based on the Sommerfeld-Goubau wave formalism, is proposed to give physical insights on the propagation phenomenon along transmission line towers.

Machine learning-based ice detection approach for power transmission lines by utilizing FBG micro-meteorological sensors.

Severe icing of transmission lines causes power failures, tower collapses, and other adverse events, which hinders the normal operation of society. Existing icing monitoring methods have problems of irregular monitoring and poor accuracy. In this study, we propose a comprehensive model for predicting hard rime and glaze ice using temperature, humidity, and historical icing data. The results of the experimental verification conducted for nine icing cycles in different years and geographic locations demonstrate that the proposed technique can effectively predict multiple types of icing while ensuring correlation coefficients > 0.99 and mean squared error < 4%.

Microwave-Based Electrochemical Sensor Design by SRR Approach for ISM Sensing Applications

This paper presents a transmission line and a split ring resonator (SRR) based sensor structure with a high sensitivity capacity to discriminate various methanol mixtures. The height of the dielectric layer and thickness of copper are assigned as 1.6 mm and 0.035 mm, respectively. The overall dimensions of the sensor structure are defined as 16 mm × 16 mm × 1.6 mm . The operating frequency is selected for the ISM bands, especially around 2.45 GHz. Different methanol-water mixtures are prepared at various ratios, and then, the complex permittivity values are measured. Different sensor structures are modelled and investigated using a two-port transmission line approach. Various types of SRR based sensors are designed, and an optimum design is proposed for methanol mixture detection applications. The observed quality factor of the proposed sensor is 16.5. The resonance shifts of the transmission value ( S 21 ) are used for sensing capability around 2.45 GHz at -45 dB and 90 MHz resonance shifts. The sensitivity of the sensor has been evaluated as 1 MHz. Finally, the electric field distributions of the proposed SRR integrated transmission line are investigated. The novelty of the proposed design is to exactly sense the ratio of methanol in water with a very simple design. The proposed sensor structure can be used for methanol detection applications in medical, military, and chemical research.

Influence of Lossy Ground on High-Frequency Induced Voltages on Aboveground Pipelines by Nearby Overhead Transmission Lines

The electromagnetic interference (EMI) of overhead transmission lines (OHLs) to aboveground pipelines sharing the same right-of-ways has been a research topic for many years. Most studies focus on investigations of the induced currents and voltages at the mains frequency (50/60 Hz). However, significant voltage levels can also be induced, when the pipeline is subject to high-frequency excitation. The representation of earth conduction effects is very important to estimate accurately the level of the EMI. This article presents a detailed high-frequency analysis of OHL/pipeline configurations taking into consideration the frequency-dependent (FD) soil properties. Wise's earth formulation is adopted for the calculation of the earth return impedances and shunt admittances. Propagation characteristics, frequency-domain, and transient responses are calculated by using both the FD soil models and constant soil properties, as well as the classical transmission line approach of Carson. Frequency-domain responses calculated with Wise's formulation are compared against those obtained using the MoM-SO method of EMTP software.

Transient response of nonparallel frequency-dependent transmission lines due to nearby lightning strikes in the presence of finitely-conducting ground

Overvoltage transients due to lightning strikes is a common occurrence in power transmission lines which can ultimately lead to line outages. Simulation of transmission line networks under the influence of lighting plays a vital and essential role in predicting their transient behaviour . The transient behaviour of uniform transmission lines due to lightning has been studied extensively. However, in modern transmission line networks, nonuniformities and discontinuities such as nonparallel wire, line crossings or bends are becoming increasingly common. Therefore, in such cases, inaccuracies might be present in analysis performed using conventional uniform transmission line approaches. A recent publication by the authors analysed the transient behaviour of nonparallel and crossing transmission lines above perfect electric conductor (PEC) ground. However, the PEC assumption can only be used in a limited scope. In this paper a nonuniform transmission line model with external field coupling is presented to analyse the transient behaviour of a nonuniform wire structure due to the field coupling from a nearby lightning strike in the presence of lossy ground. Simulation results generated by the proposed model is compared with full-wave simulations and results published by other researchers. A case study to compare the results from the proposed model with a conventional uniform transmission line model under various ground-conductivity values and terminating conditions is also performed. The study indicates that the presence of nearby nonparallel lines can cause the transient behaviour of the structure to deviate from the behaviour predicted using uniform approaches. • The transient behaviour of a nonuniform wire structure a nearby lightning strike in the presence of lossy ground is studied. • Simulation results generated by the proposed model is compared with full-wave simulations and results published by other researchers. • Results from the proposed model have been compared with a conventional uniform transmission line model. • The study indicates that the presence of nearby nonparallel lines intensify the transient behaviour.

A specific modeling of ground protection system for wind power plants

This paper presents specific combined protection of grounding systems that can be applied for wind power plants. The proposed prototype design is a combination of the ferrite ring technique, surge arrester models, as well as voltage surge protector, which impacts dampen tension more effectively by building a dedicated line with a separate model. The proposed model is 100 m in width with a depth of 2 m from the soil which is based on the IEC-61643-12 study. The transmission line approach model is used to obtain a description of the behavior of lightning occurring in the soil. The simulation results show the proposed design can be applied effectively.

Overview of Transient Simulations of Grounding Systems under Surge Conditions

The present paper gives an overview of modelling methods of standard grounding systems under surge conditions, using the non-uniform transmission line approach. The model presented considers the soil ionization and the frequency dependence of the soil parameters during the current transients. Furthermore, the representation of the non-linear response of the soil is made using a shunt time-variable resistance to simulate the behavior of the grounding resistance when a surge current flows through the system. The model development and analysis are made using ATP-EMTP/ATPDraw transient software.

Assessment of Ground-Return Impedance and Admittance Equations for the Transient Analysis of Underground Cables Using a Full-Wave FDTD Method

In this paper, the validity of two extended transmission line approaches proposed for calculating the ground-return impedance and admittance of an underground insulated cable is evaluated taking as reference a full-wave approach based on the 3-D finite-difference time-domain (FDTD) method. The transient responses of an underground cable with realistic radius are calculated for a wide range of soil resistivities and cable lengths. It is shown that the extended transmission line approaches lead to transient waveforms in good agreement with the FDTD method even for relatively short cables and high soil resistivity. The limitations of a traditional formulation that neglects the influence of the ground-return admittance on the calculation of the cable parameters are also demonstrated. Overall, the results confirm the accuracy of the newly-proposed expressions for the calculation of underground cable parameters.

A distance protection approach for untransposed parallel transmission lines in case of phase-phase-ground inter-circuit faults

Distance relays’ phase and ground elements at either circuits of the parallel transmission lines undergo miscalculation of the correct fault impedance when facing inter-circuit faults. This paper proposes a distance protection approach for untransposed parallel lines in case of phase-phase-ground inter-circuit faults, which can also be served as the fault locator as its auxiliary function. It is a demanding task compared to that of transposed lines due to the mutual coupling between all six phases of the line circuits. Considering the intended faults with the fault arc and ground resistances, the line circuit model is analyzed on a time-domain basis, resulting an equation that is mathematically a linear combination of designated functions. This would provide a great chance of establishing an adaptive linear combiner with windowed inputs (W-Adaline) in consistence with the equation derived. The W-Adaline with its simple structure is capable of giving a fast and accurate estimation of the fault distance in an online manner, which is exploited for both the line distance protection and fault location. The proposed approach is readily implementable and is independent of the system configuration. It operates robustly in high-ground resistance, variable fault arc resistance and noisy conditions. Through extensive simulation studies in PSCAD/EMTDC, performance of the proposed approach would be investigated and verified in a variety of fault and system loading conditions.