Ground Mesh Research Articles

Unique laboratory “Currents in the ground”

A brief description of the scientific laboratory is given, which has become a flagship in the field of electrical energy, which made it possible to obtain unique results on grounding and electrical safety, which were included in state regulatory documents. It is shown that a well-known scientific school has been created in the laboratory for the study of processes in grounding devices of electrical installations. The laboratory was founded in 1971 and has not been described previously. The article shows the main building in the form of a two-story building and a nearby stack-type pulse voltage generator for a voltage of 1,250,000 V. The circuit allows for reconnecting capacitors on floors to obtain different capacitances in the discharge. To connect to the grounding device under study, a portable overhead line with split wires is used. A map of grounding fields on the laboratory territory is provided. This allows you to design almost any design of a grounding device. Fields of vertical and horizontal grounding conductors of various lengths are used; fields of complex mesh grounding conductors; groups of single vertical electrodes of different lengths. The laboratory has several sets of self-powered electronic high-speed oscilloscopes, shielded and isolated from ground to avoid interference. The range of research questions can be significantly expanded by using already installed objects: an experimental overhead line with a voltage of 220 kV on nine reinforced concrete supports; cable line 600m long; a dynamic and thermal test stand, equipped with a circuit for obtaining industrial frequency currents of up to 4 kA at a voltage of 0.4 kV; 120 linear meters of reinforced concrete trays were laid on the field of a complex mesh grounding device for laying communication and control cables in them; two additional pulse voltage generators 1,600,000 V and 1,000,000 V (the latter allows transportation to full-scale test sites outside the laboratory); test transformers IOM-100/100.

Incorporating Hierarchical Construction for Advanced IC Packaging

Advancements in IC packaging manufacturing have given rise to the growing trend disaggregating large SoC into smaller die/chipets. This significantly raises the barrier for IC package designers with increasing design complexity and exploding pin counts. Trying to employ traditional package design solutions – where each device is modeled as a single flat entity – is time consuming and unnecessarily risks delaying production. In this paper, we present a new approach IC package floor-planning using hierarchical device modeling system assembly. The key benefit of adopting hierarchy inside of a design is clear – a seemingly large and complex design can be disaggregated into smaller and easier to manage building blocks based on collection attributes such as function and position. In IC packaging there are two key classes of design structures which lend easily to disaggregation. These are die-to-die signal interfaces and power distribution networks. Die to die signal interfaces are implemented as uniform signal bump collections placed at least twice in the system but usually used several times to link several dies. Similarly, power distribution networks typically replicated in several regions of the system design and the bump assignment often assigned to meet a specific physical implementation such as checker-board bump pattern for a two-layer power ground mesh. These design structures can in turn be placed or arrayed in various combinations to create larger composite building blocks in the full design assembly. Yet unlike in IC design, the key challenge with adopting hierarchical device modeling in IC packaging is that the top-level floorplan demands a unique signal connectivity definition regardless of the placement hierarchy. While there are brute force methods of doing this such as performing manual connectivity edits to add prefixes of suffices to the top-level signal, these are time consuming and error prone – particularly when design updates are required. To properly address the top-level connectivity, this paper introduces a novel method to assign connectivity based on topological pin regions defined over bump collections which can then be used to automatically define the top-level connectivity bump based on system attributes such as the parent instance and region names. Using topological pin regions in hierarchical construction allows design updates at the building block level to instantly propagate to the full design. Package designers need to employ all tools available to address the significant device complexity and an explosion in pin count in today’s IC packaging designs. Through hierarchical device modeling construction with topological region-based connectivity, we highlight that large and seemingly complex designs are easily broken down into easily manageable building blocks.

Designing Silicon Interposers for 2.5/3DIC Heterogeneous Integration - Meeting Foundry and OSAT Requirements

End market demand for higher performance, higher bandwidth and higher throughput processing such as AI, HPC, VR, 5G and even autonomous vehicles is driving the trend of heterogenous integration of ASICs, chiplets and memory, including HBM, onto advanced high-performance substrates using 2.5 and 3D IC assembly techniques that are manufactured using silicon or silicon-like processes. There are multiple suppliers of such advanced high-performance substrates ranging from the one stop mega foundries to multiple OSATs of different sizes. It’s fair to say that all of them have common design requirements or constraints that must pass a rigorous verification process of the manufacturing mask files (GDSII or OASIS). Such GDSII or OASIS files are post processed or exported from the physical design tools making the need to create the mask files with 100% fidelity an additional challenge to the design team. In this paper we will cover the major steps needed to design and implement an advanced silicon-based interposer that addresses common requirements of foundries and OSATs. We will talk about what each step is, why its required, any challenges that exist in addressing the step and actual design examples for each step. The major steps we will cover include: * What information you need from your manufacturer? * Definition of connectivity & floorplanning of the interposer * Defining the interposer materials stackup & vias for routing * Breakout or fanout routing from chiplet or IC pads * Power and ground mesh creation * Routing of interposer connectivity * Generation of interposer manufacturing data (GDS/OASIS) * Verification of the design to meet foundry/OSATs rules * Handoff to foundry/OSAT At the end of this paper attendees will understand what the major workflow steps for interposer design are and why. What general information they will need to obtain from their manufacturer in order to start design and how to use it. They will learn what each design step entails with clear examples which will enable creation of workflows to successfully handoff their designs to their chosen foundry or OSAT manufacturer.

Grounding System Design of the main Electrical Substation of stones and minerals breaker plant in Campeche State to comply with the NOM-001- SEDE-2012, IEEE-Std-80-2000, and the Código de Red

This article proposes the design of a grounding mesh for the main electrical substation of 150 kVA in the Breaker Plant in order to obtain a good path to drain overcurrents due to faults and prevent electrical installations from being a danger to connected equipment and users who use electrical installations, allowing voltage control to reduce the risk of shock to people who may come into contact with energized conductors; complying with current regulations NOM001-SEDE-2012, IEEE-Std-80-2000 and the Código de Red and does not represent a danger of failure for the electrical network supplying CFE. There is a grounding system based on a delta of electrodes already many years after its installation and without maintenance and ineffective that has allowed the passage of overcurrents that have damaged motors. It is intended that the new design of the grounding system be reliable and safe and that, in addition, when an electrical installation verification unit (UVIE) arrives, it provides the Load Center with the Electrical Installation Verification Opinion, signing in agreement that it is complying with the applicable provisions of NOM-001-SEDE-2012, Electrical Installations (use), based on IEEE-Std-80-2000.

Research on Magnetically Coupled Resonant Detection Method for Breakpoint of Four Mesh Grounding Grid

Research on Magnetically Coupled Resonant Detection Method for Breakpoint of Four Mesh Grounding Grid

제한된 면적에서 심타식 접지봉의 경제성 및 안전전압 유지성능에 관한 연구

In this paper, in order to design an effective grounding electrode in a confined space, the application of a deep-drilled ground rod together with a mesh grounding electrode is proposed. The CDEGS program was used to calculate the maximum safe current of the earthing electrode for each case, and the performance and economic feasibility of the earthing electrode were compared and analyzed through this data. In addition, ground electrode characteristics according to frequency changes were also compared. As a result of the study, it was confirmed that the role of the vertical earth electrode is very important when designing the earth electrode in a small space, and that the deep-drilled earth rod can effectively reduce the area of the earth grid. However, it was found that the ability to secure the safety voltage of the vertical earth electrode was greatly reduced in the frequency domain.

멀티 블록 격자 재분할이 자동차 공기역학에 미치는 영향

The impact of multi-block mesh refinement on automobile aerodynamics was investigated using three refinement methods: (1) overall mesh refinement, (2) ground mesh refinement, and (3) prism layer control. The open source CFD code, OpenFOAM V10, was utilized and simulations were conducted on the full-scale Notchback DrivAer model. For each method, the effects of mesh refinement were analyzed by refining different regions. In the overall mesh refinement study, successive multi-block grid refinement regions were established - the grid size becomes finer as the block is closer to the car surface. The lift coefficient was affected by grid refinement in regions near the automobile body. The ground mesh refinement study was conducted by controlling two grid sizes related to the ground region: volume mesh and surface mesh. The prediction of drag coefficient was fairly robust with ground region refinement, and the lift coefficient was more accurate with a smaller ground region grid. However, an excessively small surface grid reduced the accuracy of both drag and lift coefficients. In the prism layer study, the accuracy of the drag coefficient was independent of the prism layer setup, while the layer thickness and expansion ratio had a significant impact on the lift coefficient.

The performance evaluation of pleated electret filters enhanced by electrostatic enhanced method

The filtration efficiency deterioration over operating time due to exposure to particles, organic solvents and other factors is an obvious defect of electret filter, especially during the coronavirus pandemic. Electrostatic enhanced method has been proposed as a promising way to improve the filtration efficiency and service time of electret filters without increasing the pressure drop. In this work, the effect of discharge electrode structure and operation mode of the electrostatic enhanced structure(EES) on the filtration efficiency of commercial pleated electret filters were studied firstly, then the EES was installed in a special designed prototype air purifier, two key indicators of air purifiers(clean air delivery rate (CADR) and cumulate clean mass (CCM)) were tested to evaluate the actual performance improvement of electret filters by the electrostatic enhanced method. It was found that the discharge electrode structure had significant influence on the filtration efficiency and multi-wire array electrode was more suitable for the discharge electrode to pleated filter to ground mesh structure used in this paper. The decayed electrostatic charges of pleated electret filter cannot be recharged again through the EES in actual operation condition. The filtration efficiency improvement of the test pleated electret filters was dominantly contributed by particle charging. The filter polarizing induced by the external electric field was helpful in increasing the filtration efficiency when the particles were charged while its effect on uncharged particles was almost negligible. Besides, the actual performance of the prototype air purifier indicated that the EES can alleviate the filtration efficiency deterioration of test electret filters and extend the service life of H11 and H13 filters by more than 3 and 1.5 times respectively according to the CCM test results.

Morphology and Dust-Suppression Evaluation of Fugitive Dust Particles in Beijing

Fugitive dust particles are important contributors to urban ambient particulate matter (PM), while their emissions have been ignored or greatly underestimated in previous studies, leading to the underestimation of PM concentrations and health impacts. Thus, studying the morphology of fugitive dust, taking appropriate dust-suppression measures, and evaluating dust-suppression effects are crucial to the prevention and control of fugitive dust. In this study, we investigated the morphology and composition of dust particles from different dust sources, including bare land, stock dump, construction, and road dust. Afterwards, different dust-suppression measures including fence interception nets, bare ground mesh nets, and road dust-suppressants were undertaken to simulate and analyze their dust-suppression effects. Finally, the height concentration profiling method was used to comprehensively evaluate the on-site dust-suppression effect, which can not only accurately evaluate the dust-suppression effect, but also predict the dust-suppression ability in a wide range. Gaining insights into the morphology and composition of dust from representative sources is an important step forward to prevent and control fugitive dust, and selecting an appropriate dust-suppression effect evaluation method will provide a beneficial guide for effectively controlling PM pollution in the future.

A component-based method for the optimization of stiffener layout on large cylindrical rib-stiffened shell structures

In the present work, an optimization method is proposed in order to produce innovative stiffening layouts for large stiffened cylindrical shell structures, as they appear in the aerospace industry. A component-based logic is applied on a ground mesh of structural elements (shells and beams), which was inspired by techniques of explicit topology optimization on solid elements (plane or tridimensional massive models). Geometric components, representing the layout of the stiffeners (i.e. location, shape and size), are projected onto the ground mesh, resulting in controlled sets of active beam elements. These sets constitute the structural representation of the stiffeners’ layout in the optimization model, which is then used to evaluate the objective and constraint functions of the optimization problem as well as their semi-analytical sensitivities. By applying the optimization method to compliance minimization problems, we show the efficiency and accuracy of the proposed method and its capability to handle a typical aerospace structure, such as a space-launcher part: a stiffened cylindrical shell in presence of an access hatch.

An electrostatic scheme realizing the complete interception of fog droplets by corona discharge-induced ion wind

The interception of fog is of great significance for industrial production and human activities. Owing to the simple structure and convenient installation, the fog mesh is widely adopted to intercept droplets in industrial and practical applications. However, the interception mechanism and requirements in high droplet concentration, result in a low inherent interception efficiency. Therefore, a novel method that can completely intercept fog droplets and enhance the local droplets number concentration by changing the direction of fog entering the electric field by using ion wind, is put forward in this paper. Experimental results show that the introduction of ion wind can improve the interception efficiency to reach nearly 100%. In addition, the droplets number concentration near the ground mesh electrode can reach two times of the initial number concentration. The experiment also studied the optimal interception voltage under different electrode spacing, which is meaningful to guide the industrial application of using ion wind to intercept droplets. This method can completely intercept the fog droplets, and further reduce the lower limit of the fog concentration required by the fog mesh to intercept droplets.

Effect of Ground Conditions and Mesh Size of Net-type Barrier on Debris Flow Behavior

Debris flow is a type of landslide that occurs mainly in mountain valley areas during heavy rainfall. Various types of barriers have been installed in South Korea to reduce the damage caused by debris flows. However, there is no reasonable design standard when installing the barrier, and an experimental study for the performance evaluation of barriers is insufficient. In this study, the performance of the net-type barrier was evaluated by analyzing the effect of the ground conditions and mesh size of the net-type barrier on the debris flow behavior by reducing the front velocity and deposition volume. As a result, for areas with less fine content, the efficiency of the net-type barrier increased as the mesh size of the net-type barrier decreased. Accordingly, the ground conditions and mesh size of the net-type barrier significantly influence the performance of the net-type barrier. The damage caused by debris flow can be sufficiently reduced through the reasonable design of a net-type barrier.

Transient Voltage Programming in Electric Power Grounding System

Liner equations with n variables can be solved if there are n equations, the matrix is formed n x n square matrix, using the inverse matrix method. In this research, the linear equation used comes from the rod and mesh grounding system method, which is solved by the finite element method to calculate the grounding impedance, from the results of other research researchers. Here the researcher wants to inform in this study how to solve the linear equation with a calculation program. And the research results are plotted in Cartesian coordinates V = V (t). The results of this calculation program can be used to estimate how much the transient voltage is in the ground rod / mesh in the place where the electrical power system substation will be built when lightning strike with an amplitude of 34 kA/switching with a current of 34 kA/step with a current of 34 kA crash it. To adjust the transient voltage by adjusting the length of the finite element, required in accordance with the applicable safety level, while the subsequent arrangement can by increasing the number of mesh or increasing the length of the mesh.

Increasing the Production Yield of White Oyster Mushrooms With Pulsed Electric Fields

Pulsed electric field (PEF) technology can be utilized to increase the growth rate and total yield and alter the nutritional composition of agricultural crops. We investigated the efficacy of PEF treatment on the Pleurotus Ostreatus white oyster mushroom species. Mushroom sawdust substrates in buckets were stimulated with a combination of two rod-to-plate electrode geometries with peak electric field strengths of 1.46 and 6.67 kV/cm through unipolar pulses with approximately 20 kV amplitude. Total electrical energy of 62.3 kJ (0.017 kWh) over 30 days of excitation was delivered to each mushroom bucket. The total yield of the stimulated group showed a 34% increase compared with the control group. The experiment was repeated, and the stimulated buckets showed a 45.5% increase in yield relative to the control. A proximate analysis of the fruiting bodies was examined postexcitation for the moisture, fat, protein, and ash content. The stimulated group shows a slight increase in mean crude fat and protein content compared with the control group. Furthermore, the grounding mesh electrode interface with the fruiting substrate was found to contribute to about 10% higher ash content compared with the control group.

Needle electrode design of pulsed high voltage discharge reactor for performance enhancement of 4-chlorophenol degradation in highly conductive solution

In this paper, a pulsed high voltage discharge (PHVD) reactor composed of a new type of high-voltage (HV) needle electrode and mesh grounding electrode was utilized to degrade 4-chlorophenol (4-CP). The effect of needle installation position on 4-CP degradation efficiency in solution systems with different conductivities was studied. It is verified that the recessed- and flush-tip structures could effectively overcome the main technical problem of protruded-tip HV electrode, which is that how to maintain stable discharge in the solution with high conductivity. When the conductivity of solution surpassed 116 μS cm−1, the recessed-tip and flush-tip electrodes possessed higher energy efficiency than that of the protruded-tip electrode. Within 40 min, the flush-tip electrode had the highest 4-CP removal rate (86.2%) in pure water, which could further increased to 95.8% via increasing immersion depth of net electrode. Comprehensively considering the experimental results of 4-CP removal rate, discharge characteristic and tail gas emission, it is indicated that the optimal installation positions were 0-F and 5-R. Meanwhile, the increase in immersion depth could reduce the generation of tail gas (e.g. O3 and NOX) obviously. The possible mechanism of 4-CP degradation via PHVD was proposed.

Analysis and Mitigation of Ground Grid Lightning Potential Rise

Grid design depends mainly on bringing grounding resistance, mesh voltage, and step voltage below tolerable limits when subjected to any ground fault. But, it should be noticed that the grid performance has to be tested when subjected to lightning stroke. The performance of the grid under impulse current differs than that of under power–frequency fault. In this paper ATP-EMTP software is used to analyze the performance of the ground grid when subjected to lightning stroke. Different methods are suggested to mitigate the lightning overvoltage, all of these methods depend mainly on modifying the design by adding more conductors or rods at specific places. The case study under consideration is Al-Mostakbal substation 220/22 kV which is located in Al-Mostakbal city, Cairo, Egypt.

Development of an Ultra-Fast Photomultiplier Tube With Pulse-Dilation Technology

A pulse dilation photomultiplier tube (PD-PMT) has been developed. The photoelectrons energy is modulated by a time-dependent electric field between photocathode and ground mesh. Then, the photoelectron pulse is dilated as it transits in a relatively long drift region from mesh to microchannel plate (MCP). The dilated electron pulse is gained by the MCP and then detected by the output collector. Because the temporal width is magnified, the temporal resolution of the photomultiplier tube is better than that of the output collector alone. The result shows that the temporal resolution of the detector is improved to be 25 ps by using pulse-dilation technology, which is much better than 300 ps temporal resolution while without pulse-dilation. The ramp electrical pulse dilates the electron signal to improve the temporal response by about 10 times.

Enhanced Power and Ground Mesh Structure for IR-Drop Reduction

New enhanced power/ground mesh structure is presented for voltage drop (IR drop) reduction on power distribution network in integrated circuits (ICs). The new structure focuses on the length of the overall power/ground mesh wire pattern, reducing it by using a complex dotted line wire pattern instead of the usual mesh straps, which brings to wire length reduction on almost 40%, while via count on changed metal layer remained the same. Measurements of the voltage drop prove that with proposed mesh structure IR drop reduced about 76% for power net compared to standard mesh structure but runtime for mesh creation is increased due to more complex patterns. Proposed structure can be used in advanced technology nodes where IR drop phenomenon has become critical for performance of the ICs.

A Two-Layer Soil Model for the Calculation of Electrical Parameters of Grounding Systems under Lightning Strikes

—This article aims to overcome the drawback of the consideration a uniform soil model in approaches based on the transmission line model by considering a two-layer soil structure. In this regard, the electrical parameters equations for the two-layer soil model based on the method of images in the literature which are suitable for power frequency waves are developed to be applicable to the lightning studies. Also, the developed equations are then used in the multiconductor transmission line approach to study the lightning behaviors of grounding systems. Furthermore, in order to check the validity of the procedure, the results of the multiconductor transmission line approach are compared with those obtained by the electromagnetic field approach through the simulation of horizontal, vertical and mesh grounding grids. The results show the accuracy of the two-layer soil model for the lightning analysis of grounding systems.

Plasma states and carbon film deposition in glow discharge connected to dielectric barrier discharge

We developed a plasma source by connecting a direct current glow discharge (GD) with a dielectric barrier discharge (DBD) via a ground mesh (DB-GD). Based on the Langmuir probe measurements, the electron density of the DB-GD increased and the electron temperature decreased compared with those of the GD. Calculations of the electron energy distribution functions revealed that the DB-GD possessed a lower density of high-energy electrons and higher density of low-energy electrons than the GD did. We also confirmed that the DB-GD generated with methane gas was capable of producing an amorphous carbon film.