Proposed Transmission Line Research Articles

Investigation of Gliding Walled Multilayer Waveguides

This article suggests a new waveguide design that utilizes a “walled” architecture. Instead of relying on conventional gap waveguide structures to create electronic bandgaps and prevent field leakage, the proposed design introduces a “walled” guiding mechanism. This technique preserves transmission while maintaining the multilayer approach and eliminates the need for nails or chemical bonds to attach the layers. Simulations were carried out in the W-band (75–110 GHz) and D-band (110–170 GHz) using several metals, and measurements were performed in the W-band using aluminum. The simulation results show that the reflection coefficient was less than −40 dB over the entire D-band. At the same time, the average insertion loss was around 0.0054 dB/mm and around 0.0065 dB/mm for silver and gold, respectively. Similarly, the reflection coefficient was less than −45 dB over the 75–110 GHz range, with an average insertion loss of 0.0018 dB/mm for silver and 0.003 dB/mm for gold, respectively. The aluminum model’s reflection coefficient was less than −35 dB, and the average insertion loss was 0.0035 dB/mm. The experimental results achieved a reflection coefficient of less than –30 dB and the average transmission coefficient was −0.2 dB, with an insertion loss of 0.002 dB/mm. The simple stacking ability of the weightless walled metal plates and easy fabrication makes the proposed transmission line a promising technology in mmWave and Terahertz applications.

TRANSMISSION SUITABILITY ROUTE MAP USING THE LEAST COST PATH ANALYSIS (LCPA)

This study uses a Least Cost Path Analysis (LCPA) to create a transmission suitability route map. Environmental issues including electromagnetic pollution, habitat fragmentation, forest clearing, and the sight of pylons and power lines, and electromagnetic pollution are just a few that may come up during the planning and construction phases. The study's objectives are to define the criteria for a suitable transmission route, map the current transmission from Kidurong to Kemena in Bintulu, Sarawak, and suggest a new, LCPA-based transmission route that meets these criteria. It is necessary to determine the criteria that influence the construction of the route. There are three main categories for the proposed routes. There are technical, human health, and natural environments. The road layer and slope layer are combined for the technical group. The residential layer is part of the human health group, and land use is associated with the natural environment. During the planning of a potential power line route, weight was assigned to the criterion maps. The outcome demonstrates that the suggested route was built based on most flat sections, with only a little portion passing through the sharpest sector because there is no other way to depart from the path to avoid it. The output route is nearly straight from the source location to the destination point. The route also curves in a couple of places to go around the step area. The proposed transmission line is inside the buffer zone, and there are no other routes in the area that are more than 1 km from the road. Class 1 has a low dwelling density; therefore, the route passes through it for the residential evaluation. Additionally, there are a few places where the route passes through class 2 because only class 2 has a lower housing density.

Assessing elements of energy justice in Colombia: A case study on transmission infrastructure in La Guajira

The United Nations declaration of a climate urgency in 2020 has intensified the need for change in energy systems across the world. This has resulted in political attention increasingly shifting to the development of low-carbon energy infrastructure. In the case of Colombia, the energy transition has brought a focus on the La Guajira region for its potential wind energy resources and the associated need for new transmission infrastructure. La Guajira is characterised by an extractive-based economy, poor socioeconomic performance and a large indigenous population. This research uses the energy justice framework to examine the justice dynamics that affect the acceptance of a proposed transmission line project. With a special focus on procedural, distributive and recognition justice, the findings that are also based on semi-structured interviews reveal interrelated equity concerns. They further highlight that recognition justice can be an underpinning force of a just transition to a low-carbon economy. The research results follow previous research but also significantly demonstrates that the roles of community advisors and experts are influential. They can foster or block energy justice. Further, this study provides evidence that the ongoing energy transition has a major hurdle of procedural justice through social acceptance. This has occurred mainly due to the legacy effects of the operations of conventional energy sources in the region. This advances the case that to achieve a just transition to a low-carbon economy, unjust legacy policies and actions of the fossil fuel industry have to be addressed.

Transmission Line Model Impedance Analysis of Lithium Sulfur Batteries: Influence of Lithium Sulfide Deposit Formed During Discharge and Self-Discharge

The effect of Li2S deposition on the impedance response of Li-S battery cells is investigated using a simplified cell design, systematic impedance spectroscopy measurements combined with transmission line modeling, and a complementary microscopy analysis. Glassy carbon cathodes are employed to build and validate the proposed transmission line model, which is later on employed to investigate the effect of various parameters of Li2S deposit (coverage, thickness, porosity) on cell’s impedance. Among others, the model is applied to study the effect of discharge and self-discharge. Finally, the simplified planar cathode is exchanged with a more conventional mesoporous carbon cathode to determine the effect of Li2S deposition on the impedance of a commercially viable cell design. We have found that Li2S deposit has little effect on the impedance response, owing to its porous structure. The most noticeable change stemming from the process of Li2S deposition is due to the depletion of polysulfide species concentration in the electrolyte, which decreases the chemical capacitance and increases the tail height in the low frequency region of the impedance spectra.

Fast electromagnetic analysis of an X-band power injection coupler of dielectric-loaded accelerator using a novel transmission line model

In this paper, a novel transmission line model of a dielectric-loaded waveguide is introduced and employed to analyze a non-uniform dielectric-loaded coupler. In this method, a dielectric-loaded waveguide is equaled by a fully dielectric-filled waveguide with the same phase constant, power flow, and dissipated powers in the dielectric part and wall of the waveguide. This leads to a set of four non-linear equations. Four unknown variables of the filled-waveguide including the real and imaginary parts of dielectric permittivity, inner radius, and conductivity of the metal body of the waveguide can be obtained by solving the equation system. To investigate the validity of the new model, an X-band tapered dielectric-loaded coupler is considered and its scattering matrix parameters are obtained by a full-wave electromagnetic (EM) software. By segmentation of the coupler structure into a large number of uniform dielectric-loaded tubes and using the proposed transmission line model for every section, the whole structure can be considered as a series of transmission lines. Then, by calculating the total transmission matrix of the coupler, the scattering matrix parameters are achieved. It is shown that there is an acceptable agreement between the total behavior of the analytical and simulation results. Moreover, the fast proposed method with a combination of optimization algorithms can provide an initial point of design for further more accurate full-wave optimizations to reduce the total time of the optimization process.

Mode matching analysis of a novel transmission line with two centrosymmetric longitudinal slots

In this paper, the mode matching (MM) method is applied to analyze the dispersion of the newly proposed transmission line (TL), centrosymmetric double-slotted line (CSDSL). For simplicity, the lateral metallic vias are replaced with the electric walls (EWs). Furthermore, four magnetic walls (MWs) are added to guarantee the boundary condition (BC) of MM. The proposed method is compared with the 3D electromagnetic field analysis (HFSS). The result shows a good agreement between the dispersions of the dominant mode obtained using MM method and HFSS. Additionally, the dispersions of the higher modes of CSDSL are also provided using the proposed method with convergent results.

Design of On-line Monitoring System of Transmission Line Based on Beidou Short Message

In view of the problem that the lack of wireless mobile network in remote mountainous areas makes the transmission line online monitoring data transmission difficult, this paper proposes a data transmission scheme using Beidou short message communication. And aiming at the problems of small data transmission and low reliability in Beidou short message communication, a new data coding method is designed. The actual results show that: the proposed transmission line online monitoring system based on Beidou short message communication has a high success rate of transmission line information collection, which is an efficient and reliable scheme for transmission line online monitoring in remote mountainous areas.

Power system stability enhancement in two machine system by using fuel cell as STATCOM (static synchronous compensator)

In this paper describes fuel cell functioning is a STATCOM to enhance the power system stability during various symmetrical and asymmetrical fault conditions. Nowadays our power utility confronting plenty of issues in retaining the stability of the system. Install the flexible alternating current transmission system (FACTS) compensator gives to be better results for this. But the expenses of compensating system extra payload to the consumers. For this reason a novel approach using fuel cell (FC) is a supply of compensation system was presented in this paper. Fuel cell (FC) was designed as a STATCOM – as a FACTS device. The potentiality of the FC STATCOM to improving transient stability of two machine system after a fault occurrence. In this paper fuzzy logic controller is a main controller was modeled to enhance the power system stability of two machine systems. Fuzzy logic controllers give the trigger pulse to improve the stability after the various fault occurrences. Proposed compensators are carried out in MATLAB simulink tool boxes. The design of with and without compensators was integrated in two machine power system and compared the results with traditional FCSTATCOM device. Various types of asymmetrical and symmetrical faults created in the proposed transmission line system. During the fault more oscillations occurred. After connecting the FC STATCOM oscillation level was reduced. Finally concluded that the results are found to be satisfactory in this proposed fuzzy logic based FC STATCOM compared with conventional FCSTATCOM.

Hardware Emulation of Energization of a Long Transmission Line by High-Frequency Power Electronic Converter

Hardware emulators, simulating a test environment in real time, are an essential tool in testing power system equipment. This article presents a hardware emulator of a programmable transmission line capable of simulating high-frequency transients. Emulation of, energization of long transmission line, requires the observer to solve transmission line or telegraphers equations in real time. This article identifies a continuous time model that captures the wave nature and suitable for real-time implementation. This article derives the discrete-time model to be solved in the observer of the hardware emulator. A step-by-step procedure is given to determine two key emulator parameters: observer sampling frequency, and switching frequency of the power amplifier considering different hardware, event, and software related constraints. For high bandwidth requirement, a high switching frequency, 100-kHz, 12-kVA silicon carbide (SiC) based voltage source converter is designed to operate under a current controller with a gain crossover frequency of 5 kHz. A system on chip that combines an Anvanced RISC Machine (ARM) processor along with an field programmable gate array (FPGA) is used to implement the observer. Experimental results verify accuracy of the designed emulator in the event of energization of a long transmission line. Though proposed transmission line emulator can only be used to study the energization of a long line with one end terminated with shunt reactor, the solution can be extended for emulation of a long line that links two sections of power grid.

Miniaturisation of branch line couplers with a compact transmission line topology based on coupled line section

This study presents a compact transmission line topology to reduce the circuit size of single- and two-section branch line couplers (BLCs). The proposed transmission line is composed of a high impedance series line and one coupled line section. The coupled line section consists of two high impedance series lines and one coupled line. The proposed line is analysed with even-odd mode analysis to derive closed-form design equations. To validate the equations, a compact single- and two-section BLCs are designed at 0.85 GHz based on the proposed line. The physical size occupied by the proposed single- and two-section BLCs is 23 and 19.5%, respectively, compared to conventional BLCs. Moreover, the proposed transmission line demonstrates the harmonic suppression characteristic due to the coupled line section. As a result of which, the second- and third-order harmonic of the proposed BLCs are suppressed. The proposed BLCs are designed, fabricated, and tested.

An Intensive Archeological Survey of the Owl Hills-Tunstill 138-KV Transmission Line Route

Oncor Electric Delivery Company, LLC (Oncor) is planning to construct the Owl Hills—Tunstill 138-kV Transmission Line Route in Culberson, Reeves and Loving Counties, Texas. Oncor contracted with Halff Associates, Inc. to conduct an intensive pedestrian survey of 18.5 miles of new 138-kV transmission line on private property. The survey was conducted January 20-24, 2020 and a total of 102 shovel tests were excavated in areas where buried archeological deposits where expected, and two 15-meter (32.8-foot) transects underwent pedestrian survey within the 70-foot (21.3-meter) wide survey corridor, which measures approximately 157 acres. Three archeological sites (41RV208, 41RV209 and 41RV213) were identified and recorded during the archeological survey. Site 41RV208 is a prehistoric occupation containing a surface deposit of 12 lithic debitage, 6 flake tools, 6 cores, 2 groundstone fragments and 40 fire cracked rocks (FCR). The site is situated on a gravelly and deflated upland that forms the western rim of the Pecos River valley. Site 41RV209 consists of a prehistoric occupation containing a surface deposit of 12 FCR, 6 lithic debitage, 3 flake tools, 2 cores, 1 uniface, and 1 biface. This site is situated on the heavily eroded west bank of Salt Creek and has been disturbed by construction activities associated with an adjacent pipeline corridor. Site 41RV213 is an abandoned section of the Atchison, Topeka & Santa Fe (ATSF) Railway that parallels U.S. Highway 285 to the east. The section of railroad in the surveyed area has undergone extensive disturbance and consists of a narrow linear piling of fill, railroad gravels and non-descript metal debris. It is Halff’s recommendation that sites 41RV208, 41RV209 and 41RV213 are ineligible for National Register of Historic Places consideration in the surveyed area and no further cultural resources investigations are warranted for the project. While shovel testing within the lower terraces of the Pecos River valley floor resulted in negative findings, most of the shovel tests in this area did not encounter restrictive deposits soil or geologic deposits that antedate the Holocene. Therefore, the installation of the transmission line poles located along the lower alluvial terraces of the Pecos River was recommended for archeological monitoring. Halff recommends that construction of the remainder of the proposed transmission line route be allowed to proceed and that no additional archaeological investigations are recommended outside of the monitoring area. However, if the proposed transmission line route alignment changes, additional archeological survey may be necessary. In addition, should any cultural resources be discovered during the construction or maintenance activities associated with the project, work in the immediate area shall cease and the Texas Historical Commission be notified of the discovery.

Additively Manufactured Dielectric Waveguides for Advanced Concepts for Millimeter-Wave Interconnects

Technology mega trends, such as autonomous driving, multiple-input multiple-output (MIMO), or multi-gigabit communication, drastically increase the demand for ultra-broadband millimeter-wave (mmW) transmission line technologies. A broadband and robust signal and data transmission between components and modules at low cost is a mandatory requirement to ensure high-performance functionality of advanced communication and radar systems. Dielectric waveguides (DWGs) are a highly suitable technology to meet these requirements due to their outstanding transmission capabilities for mmW signals coupled with their high flexibility, low weight, and low cost. Additive manufacturing (AM) processes based on dielectric materials open up new perspectives for fully automated wiring of mmW modules and systems, and they enable cost-efficient application-specific solutions. In this article, we propose novel printed DWG designs with optimized transmission performance. Measurement results of different DWG designs demonstrate the excellent functionality of the proposed transmission line and interconnection concepts. These results and the shown resiliency and practicality of the presented approaches illustrate attractive opportunities for new interconnect technologies based on new manufacturing processes.

A Tunable Transmission Line With Controllable Phase Shifting and Characteristic Impedance

Tunable transmission lines have a high demand in the 5G wireless communication applications. In this brief, a novel transmission line is presented to control both electrical length and characteristic impedance individually, creating flexible functions. For the first function, the proposed transmission line can perform as a tunable phase shifter with 90° phase tuning range and a low insertion loss variation. For the second function, the proposed transmission line can tune the characteristic impedance from 23 ${\Omega }$ to 145 ${\Omega }$ with a fixed phase delay. The ABCD -matrix method is applied to derive the design equations. For the practical implementation, the varactor equivalent parasitic resistances are considered, and the even-odd mode is applied to re-optimize the proposed two tuning functions. To verify the design theory, an experimental prototype is simulated, fabricated, and measured. Both simulation and measurement results match well with the design theory.

Effects of spatial proximity to proposed electric power lines on residents' expectations, attitudes, and protest behavior: A replication study

Governments and energy operators are frequently confronted with opposition to the construction of new high-voltage transmission lines. In this context, a recent experiment by Mueller et al. (2017) tested the so-called proximity hypothesis and found that spatial proximity to proposed transmission line corridor route alternatives significantly affected residents' likelihood of having negative risk expectations, showing low levels of support, and engaging in protest against the planned facility. Moreover, their findings suggest that the relationship between spatial proximity and the dependent variables is appropriately modeled by a distance decay function, showing that effects attenuate with increasing distance from the infrastructure site. Unfortunately, because of the fact that the study is the only one that has tested the proximity hypothesis in the context of planning new transmission lines so far, the existing evidence cannot be considered as a solid knowledge base. Therefore, to strengthen the reliability of the existing evidence, the natural experiment of Mueller et al. (2017) has to be replicated, which is the purpose of the present study. The findings of the replication clearly support the results provided by Mueller and colleagues and provide further empirical evidence that strengthens the proximity hypothesis in the context of power grid expansion.

Impedance response of porous carbon cathodes in polysulfide redox system

The transport-reaction mechanism taking place in porous cathodes used in lithium-sulfur battery cells is systematically investigated using impedance spectroscopy. The adverse effects of metallic lithium are excluded by using symmetrical carbon-carbon cells. The results obtained on two types of porous electrodes, a carbon felt and a conventional mesoporous carbon electrode, are compared to those previously obtained on a flat glassy carbon electrode. The thickness of both porous electrodes as well as the thickness of porous separator are varied and impedance spectra studied in detail. The shapes, magnitudes and trends of various impedance features could well be reproduced by a proposed transmission line model. The model is upgraded with respect to known transmission line models in two ways: diffusion in pores of electrode is taken into account and a coupling of this diffusion to diffusion in separator is carried out. The results consistently show that the migration, reaction and diffusion impedances due to processes taking place inside a typical cathode are one to two orders of magnitude smaller than the impedance due to diffusion of active species in the porous separator. However, the present findings strongly indicate that if one could suppress the leakage of polysulfides into the separator, the total impedance would drop dramatically, regardless of the actual thickness or porosity of the cathode.

Distributed Small-Signal Equivalent Circuit Model and Parameter Extraction for SiGe HBT

In this paper, we present an improved high frequency small-signal distributed model for SiGe HBTs under forward-active mode based on the transmission line theory. The distributed nature of the transistor structure is taken into account in the proposed model. The single SiGe HBT is considered to be a cascade of many infinitesimal transistors, connected with the intrinsic base resistance. The closed-form solutions of admittance parameters for the distributed model are derived by solving the transmission line equation. With reasonable approximation and simplification, the model parameters are then directly extracted based on the nonlinear rational function fitting. The new improved distributed model and parameter extraction technique are validated with a $1\times 1.2\times 30\,\,\mu \text{m}^{2}$ SiGe HBT from 100 MHz to 20.89 GHz. The simulated $S$ -parameters in the proposed transmission line model are in close agreement with the measured data, and the frequency characteristics of the transistors are well predicted.

Fast single‐end line protection method for the meshed multi‐terminal HVDC grid

In view of the short-circuit fault characteristics, the protection technique of the dc lines limits the development of the modular multi-level converter (MMC)-based HVDC grid in a large extent. This study derives the calculation formulas of the transient voltages of internal and external faults and proposes a single-end protection scheme based on the transition period (TP) from the abrupt changing point to the first extreme point of the fault voltage. Due to the current-limiting reactors, the TP of the internal fault is much shorter than that of the external fault, which is used to discriminate internal fault from external fault. A four-terminal symmetrical bipolar HVDC grid based on MMC is modelled using PSCAD/EMTDC, and simulation results demonstrate the validity of the new proposed dc transmission line protection method.

The contribution of key observation point evaluation to a scientifically rigorous approach to visual impact assessment

This study introduces scientifically rigorous methods to visual impact assessment. Images of the existing condition are edited to simulate two alternatives at 22 key observation points (KOPs) along a proposed transmission line. Scenic value and visual contrast are assessed from the images by six independent evaluators. Photo validity and rating reliability are evaluated, and found acceptable. Procedures to measure cumulative and incremental visual impacts in a view are demonstrated. Both mean ratings and effect size are used to interpret the severity of visual impacts. The cumulative impact measured by contrast ratings is unreasonably adverse at many KOPs. The incremental visual impact measured by contrast ratings is less severe than the existing transmission line’s visual impact, but still unreasonable at many KOPs. The incremental impact determined by the change in scenic value is less severe than indicated by visual contrast, but still identifies many unreasonable impacts. Burial of 84 km of the transmission line results in an improvement at the affected KOPs but unreasonable impacts remain at other locations. The exigencies of professional practice limit the number of evaluators—however, scientific rigor requires a greater number of evaluators to establish mean ratings with reasonable levels of confidence. It is proposed that this may be an opportunity to involve the public. This is the first-time effect size has been used to interpret contrast ratings, and additional reports on its effectiveness are needed. It is hoped that professionals conducting visual impact assessments will employ these procedures and report them publicly.

Faults Signature Extraction in Wind Farm Integrated Transmission Line Topology

<p>The integration of Renewable Green Energy Sources (RGES) like Wind Farm Generators (WFG), and Photo Voltaic (PV) systems into convention power system as a future solution to the increase in global energy demands, generation cost reduction, and limited climate impact. The innovation introduced protection compromise challenges in power system due to in-feeds fault current penetration from RGES on existing system, leading to an undesired trip of the healthy section of TL, equipment damages, and safety failure. A comparison study of extracted faults signature from two proposed Transmission Line (TL) network topologies with and without WFG integration, for onward fault identification, and classification model design. Descrete wavelet multiresolution Analysis (DWMRA) of extracted one-cycle fault signal signatures from 11 faults type’s scenarios in Matlab. Result demonstrated a unique fault signatures across all simulated faults scenarios harness for future work of an adaptive unit protection model for this new area of DG integration.</p>

Design and validation of miniaturize Rat Race Coupler based microstrip Balun

This work presents a compact Balun with enhanced bandwidth and better isolation between output ports using Interdigital Capacitor (IDC). Firstly, a Rat Race Coupler (RRC) is designed, later Balun is proposed by replacing the isolation port with a 50 Ω isolation resistor. The proposed Transmission line (TL) is designed using an IDC in parallel with a high impedance TL. Based on a π-equivalent circuit the proposed TL has been investigated and optimized to achieve 70.7 Ω impedance. The Balun is designed and fabricated. The simulated and fabricated results are in accord. The fractional bandwidth (FBW) of RRC and Balun are 37.5% and 33% respectively at centre frequency 2.4 GHz. The size occupied by the proposed Balun is 0.51λg × 0.22λg. The structure is low cost, uniplanar and compact.