Line Impedance Research Articles

Analysis and Design of Dual-Polarized Millimeter-Wave Filtering Magneto-Electric Dipole Antenna

A wideband dual-polarized millimeter-wave filtering magneto-electric dipole (ME-dipole) antenna design is proposed based on a transmission line model with multiple open-circuited loads. Based on the transmission line theory, the input impedance of a quarter-wavelength open-circuited transmission line is zero. Thus, a transmission line terminated with <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">N</i> open-circuited loads has <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">N</i> transmission zeros. Inspired by this conclusion, the proposed antenna structure is developed which consists of three parts: the microtrip feedlines, the ME-dipole radiator and a printed branch structure. The former three parts can be regarded as three open-circuited loads of an <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">N</i> -stub-loaded transmission line model while the last part is utilized for bandwidth improvement. By optimizing the length parameters of these three parts, three antenna radiation nulls can be generated as predicted. For verification, a dual-polarized antenna is implemented. Measurement results show that the proposed antenna has an operation bandwidth of 42.1% and an average realized gain of 7.5 dBi. In addition, it has three controllable radiation nulls and a better than 16 dB out-of-band suppression level. Above features make the proposed antenna a good candidate for 5G millimeter-wave (mm-wave) applications.

Performance evaluation of planar dipole antenna for smart home applications

In a Smart Home wireless module, the antenna generally occupies one-third of the total circuit advances in the Internet of Things (IoTs). Dipole antenna comes in various shapes, but the planar antenna is the most suitable and attractive design for the IoTs application in Smart Homes because it is smaller in size and has a thin profile, making it suitable for mounting on portable equipment. In this research, two antennae, Meandered Dipole and Wideband Planar Antenna, were designed using Advance Design System (ADS) software on a PCB size of 18.8 mm × 43.2 mm, FR4 substrate with 4.6 dielectric constant and 0.8 mm thickness using copper metal as the conducting element. The transmission line has designed width of 1.25 mm, resulting in a typical line impedance of 50 Ω. A comparison of the analysis of simulation and measurement results from feeding port 1 of the Meandered PIFA Antenna shows a better performance of 95.43% efficiency with a gain of 2.54391dBi and a return loss of −24.49 dB at resonant frequency of 2.4 GHz than that from feeding port 2 whose efficiency was only 73.99%. Whereas, the wideband planar antenna shows an average bandwidth of 93.91% from 1.3 to 2.4 GHz. This range covers the GPS applications, the 2.4 GHz ISM band, and the general WCDMA and the LTE 3GPP bands useable for smart home and IoT applications. The proposed antenna provides low power operation, extended range and compact, cost-effective designs to support vendor's customers, and make quality of life smarter and more economical with the use of the smart home device.

A 0.33–2.61-GHz Rectifier With Expanded Dynamic Input Power Range Using Microstrip Impedance Compression Circuit

In this letter, an ultra-broadband rectifier with expanded dynamic input power range (IPR) for both wireless power transfer (WPT) and radio frequency energy-harvesting (RFEH) is proposed and analyzed. Expanded dynamic IPR and broadband impedance matching are realized by utilizing a microstrip transmission line impedance compression circuit (MTLICC) with the topology of the paralleled voltage doubler. A proof-of-concept prototype shows a dynamic IPR of 8.5–23.5 dBm, a frequency range of 0.33–2.61 GHz (fractional bandwidth of 155%), PCE is greater than 50%, and a peak PEC of 79.7% (achieved at an input-power level of 19 dBm). The measurement results are in good agreement with the simulation. Covering most 3G/4G/5G/ISM frequency bands, this design is promising for RF power transmission and energy harvesting in the age of the Internet of Things systems.

Information Monitoring of Transmission Lines Based on Internet of Things Technology

To solve the problem of difficult real-time monitoring of current transmission lines, this article proposes an information-based monitoring system for transmission lines based on Internet of Things technology. The system utilizes the characteristics of strong scalability, good fault tolerance, low power consumption, and low cost of the Internet of Things. Taking the ultra-low power consumption MSP430 microcontroller and CC2430 radio frequency module as the core, a line monitoring system based on the Internet of Things is designed. The proposed design uses ZigBee wireless sensor network technology which is powered by solar energy. The collection, transmission, processing and judgment of various environmental parameters of the line are realized. The data information is transferred to the monitoring center of the upper computer through GPRS. When there is an abnormality, it can send a mobile phone short message to the person in charge to feedback the abnormal content in time. The distribution network's load symmetry allowed for the development of several locating procedures. For the three-phase symmetric scheme, the fault location approach based on line supply characteristics was employed, and for the three-phase asymmetric scheme, the fault location technique based on line impedance is proposed. One of the most vital uses for the Internet of Things is in the mitigation of power transmission line failures and disasters. Improved power transmission dependability, less financial loss, and fewer power outages are all possible thanks to the Internet of Things' cutting-edge sensing and communication technology. This research introduced the use of IoT in online monitoring system of electricity transmission line with a focus on the characteristics of the construction and development of smart grid. The results indicated that the system's highest temperature difference is 0.31 C, while the maximum humidity difference is 1.38%. The system increases the safety and manageability of electricity transmission while also fostering the widespread adoption and technical integration of the smart grid and the Internet of Things.

Enhanced the Efficiency of Electronics Circuit by using Line Impedance Stabilization Network

A Line Impedance Stabilization Network (LISN) is a crucial tool in the field of electromagnetic compatibility (EMC) testing and measurement. Its primary purpose is to ensure that conducted emissions from electrical and electronic devices are accurately measured in a controlled and standardized manner. After both circuit simulation in LTSpice firstly input noise simulation without LISN in first circuit and after that second circuit simulation in which we simulate input noise simulation with LISN we reached on the final conclusion is that by stabilizing the impedance of the power supply line, LISNs help filter out external interference and noise, allowing for precise measurements of the emissions generated by the DUT. They provide a standardized impedance interface between the device under test (DUT) and the measuring equipment, ensuring consistent and repeatable EMC testing results. We get desired result after simulation when we analysis both circuit simulation in details we get 33% improvement in frequency, noise decreases in terms of frequency and we get 3% improvement in power at output in LISN applying circuit.

A Review on the Characteristics of Line Impedance Stabilization Network

A Line Impedance Stabilization Network (LISN) is an essential component in electromagnetic compatibility (EMC) testing and measurement. Its primary purpose is to provide a standardized interface between electronic devices, such as radios, computers, and other electrical equipment, and the power supply grid during conducted emissions testing. A LISN is designed to facilitate accurate and repeatable measurements of electromagnetic interference (EMI) generated by electronic devices when they are connected to the power supply grid. It serves as an essential tool for assessing the compliance of electronic equipment with EMC standards and regulations. A low-pass filter within the LISN helps remove high-frequency noise and disturbances from the power supply, allowing only the emissions of interest to pass through for measurement. a Line Impedance Stabilization Network (LISN) is a critical tool for EMC testing and measurement, providing a standardized and controlled interface between electronic devices and the power supply grid. It enables the assessment of conducted emissions from electronic equipment, helping manufacturers ensure their products comply with EMC regulations and minimizing the risk of interference with other devices and systems.

Flexible composite suppression method for ground arc in resonant grounding system

AbstractA current‐voltage composite controller for an arc suppression inverter is designed. The current and voltage at the fault point are reduced by injecting current and regulating the neutral point voltage to completely eliminate the risk of fire and overvoltage caused by a single‐line‐to‐ground fault arc. A cascaded inverter is used, and the effects of the ground parameter measurement, line impedance voltage drop, harmonic current and arc suppression coil on the current control, voltage control and composite control methods are analysed and compared. Finally, software simulations and industrial prototype experiments show that the proposed composite control method is effective and less affected by ground parameter measurement and line impedance voltage drop and has better adaptability.

A modified mutual impedance based backup protection for series-compensated transmission lines

This paper proposes a modified mutual impedance based backup protection for series-compensated transmission line. In case of failure of current-differential scheme, distance relaying scheme provides protection by calculating and comparing positive-sequence impedance up to fault point. However, non-linear operation of metal-oxide varistor (MOV) result in continuously varying equivalent impedance across series-capacitor during fault which affects the reach and directional discrimination feature. Inter-phase mutual impedance of line up to fault point is proportional to the distance of fault from relaying point and therefore can be exploited as a reliable relaying parameter for backup protection purpose. The reason is that the equivalent impedance across MOV protected series-capacitor does not alter inter-phase mutual impedance up to fault point. This mutual impedance can be computed utilizing sequence components of voltage and current phasors measured by phasor measurement unit (PMU) at line ends. Existing mutual impedance based scheme is highly influenced by fault resistance and synchronization error. The proposed modified algorithm is developed to overcome the effects of fault resistance and synchronization error as compared to previously developed scheme. The performance is assessed for different single line-to-ground (SLG) and double line-to-ground (LLG) fault cases with variations in fault resistance, fault distance (FD) and compensation level. Simulation results affirm the advantages of proposed scheme as an extra layer of protection over conventional schemes and prove superiority in performance over existing mutual impedance based scheme. Experimental results also demonstrate the feasibility of deployment for practical applications.

Mathematical Models of the Phase Voltages of High-, Medium- and Low-Voltage Busbars in a Substation during a Phase-to-Ground Fault on High-Voltage Busbars

The electrical energy supply of industrial equipment is provided by electrical power stations with high- (HT), medium- (MV) and low-voltage (LV) busbars. Consumers are connected to either MV or LV busbars. In this paper, a real power station was considered, through which the gasoline extraction from the well gas installation is powered. Electric consumers (electric motors) supplied by a MV busbar have active power of 13.54 MW, and those fed by a LV busbar have active power of 6.4 MW. Since electrical consumers operate in explosive environments, the design and operating conditions are more severe than in the case of electrical installations operating in non-explosive environments. The case of a single phase-to-ground fault occurring on the HV transmission lines feeding the power station has been analysed. First, the mathematical models for the calculation of the phase voltages, the dissymmetry and asymmetry coefficients, the reduction coefficient of the plus sequence component, and the effective values of the phase voltages were established. The influence of the source impedance (the equivalent impedance of the HV transmission lines) and of the neutral point configuration of the HV/MV medium-voltage transformer on the calculated quantities was analysed. Then, the results obtained using the established mathematical models were compared with those obtained experimentally by provoking a single-phase-to-ground fault near the HV busbars of the real power station. This study has shown that the de-symmetrisation of the phase voltages of the MV and LV busbars is lower when using the Y/Δ connection for the HV/MV transformer. As a result, it is recommended the Y/Δ connection be used for this transformer, instead of the Y0/Δ connection.

Withdrawal Notice: Design and Analysis of an Anti-Interference Measurement Method for Transmission Line Impedance Parameters

Since the authors are not responding to the editor’s requests to fulfill the editorial requirement, therefore, the article has been withdrawn. Bentham Science apologizes to the readers of the journal for any inconvenience this may have caused. The Bentham Editorial Policy on Article Withdrawal can be found at &lt;a href=https://benthamscience.com/editorial-policies-main.php&gt;https://benthamscience.com/editorial-policies-main.php&lt;/a&gt;&lt;/p&gt; Bentham Science Disclaimer: It is a condition of publication that manuscripts submitted to this journal have not been published and will not be simultaneously submitted or published elsewhere. Furthermore, any data, illustration, structure or table that has been published elsewhere must be reported, and copyright permission for reproduction must be obtained. Plagiarism is strictly forbidden, and by submitting the article for publication the authors agree that the publishers have the legal right to take appropriate action against the authors, if plagiarism or fabricated information is discovered. By submitting a manuscript, the authors agree that the copyright of their article is transferred to the publishers if and when the article is accepted for publication.

Passive CM Filter Configuration for a Multistage Grid-Tied Solid State Transformer

<bold xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">This work proposes a common mode (CM) filter configuration for a grid-tied two-stage AC/DC solid state transformer (SST). The proposed CM filter utilizes passive components along with the heat-sinks of the individual power converter stages to mitigate the overall conducted emissions (CE) injected by the SST system into the grid. The working principle of the proposed CM filter is analyzed and elucidated using CM equivalent circuit models. In addition to CE reduction with the proposed CM filter, it is also demonstrated that the heat-sinks of the SST system can be closer to ground-potential while being impedance grounded. The effectiveness of the proposed CM filter is validated by experimentally measuring the CE of the grid-tied SST system using a Line Impedance Stabilization Network (LISN).</b>

High-Frequency Oscillation Suppression Strategy for Flexible DC Transmission Systems Based on Additional Joint Damping

Flexible DC transmission systems experience negative damping characteristics in the high-frequency range due to the delay in the system control link. This can lead to interactions between the impedance of modular multilevel converters (MMCs) and AC transmission lines, resulting in high-frequency oscillation (HFO) issues. To resolve this problem, a simplified MMC control model was developed, taking into account the current inner loop control link. The Sobol method was employed to analyze the factors influencing the impedance characteristics of MMC. Additionally, a combined approach involving a virtual passive filtering method and an equivalent current sampling method was proposed to provide additional damping. The study compared and analyzed the impact of additional damping control on the impedance characteristics and system stability of MMCs. Lastly, a flexible direct current grid connection simulation model was constructed using PSCAD to validate the effectiveness of the proposed additional damping control strategy.

REVIEW OF CONFIGURATIONS AND STRATEGIES OF CONTROL OF MICRONETWORKS BASED ON POWER ELECTRONICS

The growing implementation of distributed energy resources requires the development of the architecture of traditional electricity systems. With the growing deployment of distributed energy resources, especially for small combined heat and power plants and renewable energy sources based on distributed generation units, the architecture of the future power supply system must be transformed in order to carry out more complex operations. The article provides an overview of micronetwork configurations with greater flexibility and reliability, parameters, structures, and control methods for electronically connected distributed energy resource installations. Of the configurations considered, DC micronetwork and high-frequency AC micronetwork have shown better performance for some special applications, such as low-voltage and geographically small networks. The corresponding parameters in the structures of the blocks of distribution energy resources and the topology of power electronics are considered. With the increase in the nominal capacity of distribution power resource units, multilevel converters provide effective ways to reduce cost and increase efficiency. Methods of controlling electronically connected aggregates of distribution energy resources under different operating modes are described. Under the influence of load and line impedance characteristics, different strategies of load distribution among units of distribution energy resources, control of instantaneous active and reactive power are compared. A multi-level hierarchical control architecture, micronetwork power and energy management is described. A comparison of control architectures based on centralized and distributed technology indicates that the modern micronetwork must become smart and flexible with the help of telecommunication infrastructures and the next generation of information technology.

Design Methodology of Transmission-Line Quadruplet Filters Supported by Rigorous Circuit Transformations

This article presents a novel and rigorous technique to design transmission-line quadruplet filters. Unlike the prevailing approaches relying on electromagnetic (EM) simulations for coupling tests, the proposed design technique completely counts on rigorous circuit transformations. As all design parameters (lengths and line impedances) can be rigorously calculated from the design equations provided in this work, a quadruplet filter can be designed without conducting EM simulations to find the dimensions delivering the desired coupling coefficients. Our design approach will be demonstrated with the fourth-and fifth-order filter examples, both of which were fabricated and measured for validation.

Distributed Autonomous Economic Control Strategy for DC Microgrid

A distributed autonomous economic control strategy is proposed to realize the economic operation of the DC microgrid in the islanded state. The control strategy first introduces incremental cost in primary control, but due to the influence of line impedance, it is not possible to precisely achieve the consensus of incremental cost at each unit, and it generates a steady-state error. To overcome this problem, a distributed secondary control based on a dynamic consensus algorithm is designed on the basis of primary control, which makes each distributed generator operate under equal incremental cost. The two layers of control strategies cooperate work together to realize the hierarchical-distributed autonomous economic operation of the DC microgrid. Finally, the simulation model of the DC microgrid is constructed, which verifies the effectiveness of the proposed method.

Distributed Carrier Phase Shifting Control Method for Modular Interleaved Parallel Inverters

Modular parallel inverters with interleaving is a cost-effective approach to improve system performances. In this paper, a simple distributed carrier phase shifting control method with the local controller is proposed. First, the resultant current harmonics for modular parallel inverters are analyzed considering the crystal oscillator frequency deviation. Then, a NOR gate circuit based synchronous signal generator is constructed, which generates a common low-frequency digital synchronous signal to trigger the carrier phase shifting control. With the carrier phase detection and error compensation considering the time delay, a proportional carrier phase shifting controller with detailed parameter design considerations is proposed to dynamically adjust the carrier relative phase angles of parallel modules until they are properly interleaved. The proposed method has overcame the issue of single point of failure (i.e., high reliability) and is immune to the sampling error, line impedance voltage drop (i.e., high accuracy). Finally, different carrier phase shifting methods are compared and the experimental results have verified the effectiveness of the proposed method.

Integrated Common-Mode Filter for GaN Power Module With Improved High-Frequency EMI Performance

While the employment of wide bandgap (WBG) devices in high-frequency and high-voltage applications brings benefits such as reduced system size and improved efficiency, it aggravates the electromagnetic interference (EMI) issue due to fast switching. High-frequency EMI noise suppression relies mainly on the filter design, where the filter's performance is strongly affected by parasitics. Through analyzing the common-mode (CM) equivalent circuit of a half-bridge power module, this letter identifies the key parasitics that dominate the performance of a common-mode filter (CMF) at high frequencies. To minimize the parasitics, the concept of integrating the CMF inside the WBG power module package is developed to improve the noise attenuation. A π-type CMF is integrated with a half-bridge GaN-based power module as a prototype to validate the concept. Experiments are conducted by measuring the CM noise spectrum received by the line impedance stabilization networks (LISNs) from the hard switching of the designed power module under 70 V and 80 kHz. Comparing the measured results of the integrated CMF to the externally-added CMF, up to 50 dBμV more attenuation is achieved by the integrated CMF in the frequency range of 10 MHz to 100 MHz, verifying the theoretical analysis and the established CM equivalent circuit.

Intelligent Prediction of Transformer Loss for Low Voltage Recovery in Distribution Network with Unbalanced Load

In order to solve the problem of low voltage caused by unbalanced load in the distribution network, a transformer loss intelligent prediction model under unbalanced load is proposed. Firstly, the mathematical model of a transformer with an unbalanced load is established. The zero-sequence impedance and neutral line current of the transformer are calculated by using the Chaos Game Optimization algorithm (CGO), and the correctness of the mathematical model is proved by using actual data. Then, the correlation among network input variables is eliminated by using Principal Component Analysis (PCA), so the number of network input variables is decreased. At the same time, Sparrow Search Algorithm (SSA) is used to optimize the initial weight and threshold of the BP network, and an accurate transformer loss prediction model based on the PCA-SSA-BP is established. Finally, compared with the transformer loss prediction model based on BP network, Genetic Algorithm optimized BP network (GA-BP), Particle Swarm optimized BP network (PSO-BP) and Sparrow Search Algorithm optimized BP network (SSA-BP), the transformer loss prediction model based on PCA-SSA-BP network has been proven to be accurate by using actual data and it is helpful for low-voltage recovery in the distribution network.

TCSC Application for Transient Stabilization of Wind Turbine with Fixed Speed Induction Generator

Wind turbines (WTs) are a desirable alternative to traditional nonrenewable power resources as a result of recent environmental concerns. Some of them are fixed speed wind generator (FSWG) and have been integrated to power system by squirrel cage induction generator (SCIG). Induction machine absorbs reactive power during all operating conditions, especially at fault condition may result in severe voltage drop which can lead to generator outage. This outage disconnects a significant amount of active power and consequently leads to frequency instability. In order to prevent induction generator (IG) outages in short circuit failures, this paper investigates thyristor-controlled series capacitor (TCSC) device as a candidate solution. TCSC compensates the IG terminal voltage drop by adjusting transmission line impedance at fault condition. In the proposed method, a metaheuristic technique means that shuffled frog leaping algorithm (SFLA) has been utilized to optimize the TCSC controller gains. The proposed scheme can be applied for both SCIGs and wound rotor induction generators (WRIGs) which is another advantage of this method. Single-machine infinite bus system is considered as case study, and various operating conditions and disturbances have been considered to verify the effectiveness of the proposed method.

A lightweight waterborne acoustic meta-absorber with low characteristic impedance rods

We investigate a meta-absorber composed of impedance-matched rods for the broadband acoustic absorption. However, with a slow longitudinal wave speed, the absorber’s density is high to keep the characteristic impedance matching with that of water. To obtain a lightweight high efficiency absorber, we analyze the influence of characteristic impedance and loss factor on absorption behaviors and find that the characteristic impedance matching is not necessary and the low characteristic impedance structure can also attain the efficient absorption performance, and the high dissipation can reduce the density required for an efficient absorption. Based on this, we propose a meta-absorber composed of low characteristic impedance rubber rods in parallel coated by a rubber cover layer and backed with a stepped resin base. By the combination of the transfer matrix method and transmission line impedance transfer equation, the acoustic performance of meta-absorber is analyzed. Compared with the characteristic impedance matching rods, the low characteristic impedance rods can release restrictions on design to attain better acoustic behaviors with a lower density. Further, the integration of rods with designed lengths can motivate coherently coupled weak resonances to obtain a broadband absorption. Finally, an optimized meta-absorber is tested in a water-filled impedance tube and the experimental results agree well with the theoretical results which can achieve a broadband low frequency quasi-perfect absorption (α>0.9) in a deep subwavelength region (λ/158 at 950 Hz) with the density close to that of water. Our work finds a new mechanism that low characteristic impedance absorbing materials can achieve the high efficiency absorption with a slow longitudinal wave speed and low density and promise broad applications in the sound stealth of marine vehicles.