Grid Design Research Articles

A new hybrid risk assessment process for cyber security design of smart grids using fuzzy analytic hierarchy processes

Abstract IT vulnerabilities, cyber threats, and resulting risks significantly impact the stability of current and future power grids. The results of a Risk Assessment process contribute to a better understanding of the causes and nature of the associated risks. The risks assessed by experts are available in both numerical and linguistic representations – this makes it beneficial to include a combination of linguistic and numerical analyses. In this paper, we propose a new Hybrid Risk Assessment method based on fuzzy logic, leading to more precise results. The presented approach specifies the variables and membership functions of fuzzy logic with reference to Smart Grids. For this propose, a case study with five risk events in a small-scale Smart Grid is carried out as an example. The results can then support decision-makers in ensuring grid stability.

Topology comparative assessment for hybrid medium-voltage AC/DC networks

Recently, there has been significant growth in integrating renewable energy generation and electric vehicles and deploying new technologies into the electrical networks, leading to new challenges for planning, design, operation, control and protection of the distribution grid. In particular, an increasing amount of large-scale DC load and generation is expected to be connected to the distribution system, especially at the MV level. Thus, adoption of new grid topologies is required and among others, hybrid AC/DC networks have emerged as an attractive pathway to meet new grid operational requirements. This paper evaluates future hybrid AC/DC distribution systems at the MV level, considering potential network topologies and new technologies. Steady-state analysis is performed to compare five topologies of hybrid MV AC/DC networks. Key technologies for such hybrid grids such as voltage source converters and fast charging stations are considered. The results provide quantitative comparisons between topologies regarding large-scale DC load and generation integration capability, contingency operation, sensitivity analysis. Several challenges presented to the protection and fault location that are caused by the adoption of new topologies are also identified. The topologies are compared by network losses, voltage and power factor constraints, analysing the different benefits and drawbacks of the hybrid AC/DC topologies.

Thermodynamic-based method for supporting design and operation of thermal grids in presence of distributed energy producers

Thermodynamic-based method for supporting design and operation of thermal grids in presence of distributed energy producers

TCI Tester: A Chip Tester for Inductive Coupling Wireless Through-Chip Interface

The building block computation system is constructed by stacking various chips three-dimensionally. The stacked chips incorporate the same TCI IP (Through Chip Interface Intellectual Property) but cannot provide identical characteristics, requiring adjustments in power supply and bias voltage. However, providing characteristics measurement hardware for all chips is difficult due to the limitation of chip area or pin numbers. To address this problem, we developed TCI Tester, a small chip to measure electric characteristics by stacking on TCI of every chip. By stacking two TCI Tester chips, it appears that the up-directional data transfer has a stricter condition than down directional one on power supply voltage and operational frequency. Also, the transfer performance is poorer than designed. Similar measurement results are obtained by stacking TCI Tester on other chips with TCI IP. To investigate the reason, we analyzed the power grid resistance of various chips with the TCI IP. Results also showed that the chips with higher resistance have a narrow operational condition and poorer performance. The results suggest that the power grid design is important for keeping the performance through the TCI channel.

Priorities in smart grid design research

Priorities in smart grid design research

The Grass Square Latch Paving Agency Based on the Bionic Spinning Knife

To better solve the problem of land desertification, this paper designed a portable grass grid-laying robot to lay grass squares to prevent wind and sand fixation. Among them, the ploughing module was proposed to use a bionic rotary tillage knife to improve soil cutting efficiency. By analyzing the characteristics of the forefoot claw contour curve of the groundhog, the point cloud data of the claw toe profile curve was obtained by reverse engineering technique, and then the Gaussian equation of the contour curve was fitted by MATLAB and the toe tip profile fitting curve was obtained. The BT model of the obtained fitting curve was applied to the national standard rotary tillage knife to design a preliminary bionic rotary tillage knife. When W0 was 50 mm and θ was 35°, the resistance of the rotary tillage knife was the least and the cutting performance was the best, and the final bionic rotary tillage knife was designed. In the field test, the data pointed out that compared with the traditional national standard rotary tillage knife, the maximum stress of the bionic rotary tillage knife was only 32.21 MPA, the average torque decreased by 10.16% compared with the national standard rotary tillage knife, the average power decreased by 7.68% to 71.4 KW, the tool quality was reduced by 8.26%, and the crushing rate was greatly improved. This study can provide some reference for the design of grass grid laying machines and rotary tillage knives to reduce resistance and consumption.

Finite element analysis of low-profile reconstruction plates for atrophic mandibles: a comparison of novel 3D grid and conventional plate designs.

This study aimed to compare the reconstruction with type 2.4 and three-dimensional (3D) grid plates relating the areas of weakness to anatomical regions of force incidence in atrophic mandibles with and without segmentation using finite element analysis (FEA). Strength and force quality in the mandible were also determined. The atrophic mandible models with and without segmentation were divided into four groups, and the behavior of each plate was analyzed using finite element analysis. In the atrophic mandible without segmentation using the type 2.4 reconstruction plate, the highest stress concentration in the plate was observed in the posterior region of the mandibular body and in the grid type 3D reconstruction plate was observed in the mandibular angle. In the segmented atrophic mandible with the 2.4 reconstruction plate, higher stress concentration was observed in the mandibular segment defect. Analysis of the 3D grid-like reconstruction plate revealed that the geometry of the plate conferred greater stiffness to the assembly, as the most significant stress concentration was observed at the mandibular angle. The width of the plate design may influence the strength, not the thickness.

Wasting petabytes: A survey of the Sentinel-2 UTM tiling grid and its spatial overhead

Following Landsat’s practice, Sentinel-2 multispectral satellite products are delivered as raster images projected onto the Universal Transversal Mercator (UTM) spatial reference system, which divides Earth into 60 longitudinal zones. Locally, this guarantees high spatial accuracy, while also easing the interoperability with many regional and governmental datums. On top, the Sentinel-2 product grid uses the Military Grid Reference System (MGRS) tiling scheme to facilitate manageable data slices and straightforward multitemporal image stacking. Although most convenient for small-area applications, activities with a larger geographic scope suffer from this approach and its overhead, as both data duplication and ambiguity appear along UTM zone overlaps and MGRS tile borders. In practice, such areas that are covered by multiple and incongruent grid pixels are known but just tolerated, and their degree has not been measured so far.In this paper, we illuminate the nature and patterns of these overlaps, and calculate the resulting spatial redundancy over the global land surface. We found that the total land area is enlarged in the Sentinel-2 grid definition by 33%, which is a value similar to the simple and single-zoned Plate Carrée projection. The number of co-located grid pixels for a single location ranges from 1 up to 6, with on average more redundancy at mid- and high-latitudes. With regard to global satellite archives in times of big data and increased energy costs, the examined grid appears as a suboptimal choice, inducing complexity and overhead at an unreasonable level. Owing to the grid design, e.g., the yearly Sentinel-2 user product volume (Level-1C and -2A) is inflated by 1 petabyte, entailing cascading downstream costs of storage, bandwidth, and computing.

Development of the equivalent Great Britain 36-zone power system for frequency control studies

This paper presents a dynamic model of the equivalent Great Britain (GB) 36-zone power system, which can be used for reliable and realistic assessment of emerging load frequency control mechanisms. Flexible architecture of the presented dynamic test system permits a broad range of security of supply and small-signal stability studies for design of future power grids. It can be particularly useful for academic research, but also for undertaking feasibility studies in power industries. The proposed dynamic test system, which is obtained through network reduction of the original full-scale GB transmission power system developed by National Grid Electricity System Operator (NGESO) Company, provides detailed information about the GB power system. In this regard, the required data and modelling approaches to develop the 36-zone system are provided in detail. The presented dynamic test system represents the system topology, impedance characteristics and electromechanical oscillations of the original GB power system however, it is not an exact equivalent of the master GB system. Illustrative dynamic models of the key system components, including synchronous generators, automatic voltage regulators, power system stabilizers, hydro and steam turbines models along with speed governing systems are presented. Dynamic behavior of 36-zone test system in response to infeed loss contingencies is investigated. Particularly, the impact of changes in the system inertia on the system electromechanical modes is examined using the modal analysis approach. In this context, the mode shape concept is employed to determine dominant generators and contribution of different zones in the low frequency oscillations. Moreover, time-domain simulations are undertaken to validate the modal analysis results. Additionally, the condition of different zones from the viewpoint of frequency nadir and maximum rate of change of frequency for various contingencies and extreme cases are examined.

DE07 Enhancing social media engagement for Clinical and Experimental Dermatology: the educational journal of the British Association of Dermatologists: a quality improvement project

Abstract Social media is an efficient method for direct communication between a journal, clinicians and patients. Increased social media engagement also increases the impact factor of medical journals (O’Kelly F, Nason GJ, Manecksha RP et al. The effect of social media (#SoMe) on journal impact factor and parental awareness in paediatric urology. J Pediatr Urol 2017; 13:513). The aim of this quality improvement project was to assess the impact of three interventions on social media success (defined as reach, engagement or follower count) of the Clinical and Experimental Dermatology Instagram page (@ced_journal), founded in July 2020. Impact on reach, engagement and follower count was investigated after each intervention cycle. Cycle 1 (April–June 2022) investigated the impact of a checkerboard grid design to increase visual appeal, standardized journal branding and a consistent posting schedule. User analytics revealed a large proportion of Middle Eastern followers, and, therefore, cycle 2 (July–October 2022) used non-English hashtags to target these audiences. Cycle 3 (November–December 2022) investigated the boost in engagement through encouraging authors who had recently published in the journal to post their publication on their personal accounts and tag the journal. Qualitative data were gathered from the Meta Business Suite and directly from the Instagram page. Data were analysed using GraphPad. Cycle 1 resulted in mean increases in content reach by 568% (P < 0.001), unique profile visits by 281% (P = 0.014) and number of new followers by 642% (P = 0.188). Cycle 2 demonstrated a mean increase in the number of new followers by 194% (P = 0.025) but did not significantly increase the reach (P = 0.414) or number of new profile visits (P = 0.410). There was no significant increase in reach (P = 0.229), unique profile visits (P = 0.055) or number of new followers (P = 0.397) in cycle 3. This study demonstrates improvements in social media success following cycles 1 and 2. Cycle 3 results emphasize the importance of novel interventions in further varying content to maintain and further increase engagement, as well as studying additional factors that influence engagement, such as standardized journal branding across all social media platforms. Overall, this study emphasizes the effectiveness of innovative and interactive education resources for disseminating dermatology research among scientific and nonscientific users, which can be adopted by other dermatology journals.

Design, Modeling, and Analysis of IEEE Std 80 Earth Grid Design Refinement Methods Using ETAP

The design of a compliant, safe, and reliable substation earth grid is not a straightforward process; in most cases, it requires some additional measures to be taken due to various constraints that differ from environment to environment, such as soil resistivity, a high fault level, a limited surface area, construction budget, etc. The IEEE Std 80-2013 proposes various refinement methods that can be applied to address different situations. For this study, the current limiting method, current diversion method, and touch and step voltage increment method were applied using the Electrical Transient Analysis Program (ETAP). A power system was designed, where a fault current generated by the supply transformers and back-fed by the power system’s motors was exported to the earth grid. Using this fault current, various simulations were conducted to assess the performance of the earth grid. The analysis results show that the application of the current limiting method using neutral earthing resistors has a great impact on the design of the earth grid as this method significantly reduces the fault current injected into the earth grid. Furthermore, by applying the current diversion method, the amount of fault current injected into the earth grid is reduced by a fair amount, which improves the performance of the earth grid. Lastly, increasing the tolerable limits of touch and step voltages by reducing the fault clearance times significantly improves the compliance of the earth grid as the clearance time is reduced. From this study, it is therefore concluded that, by implementing the refinement methods depending on the design requirements and feasibility of the application, one can improve the compliance state of an earth grid.

Smart Contract Design in Distributed Energy Systems: A Systematic Review

Blockchain technology and, in particular, smart contracts based on it, offers a new, decentralized mechanism for entering into and fulfilling contracts in diverse markets. Energy markets are no exception, and indeed, the decentralized nature of the blockchain may be particularly important for them as the penetration of residential prosumers offering microgeneration to the grid grows. At this time, however, the literature on smart contracts in energy markets—and particularly their interaction with the technical infrastructure of the smart grid—is limited and scattered. There is a need to consolidate these studies into a comprehensive understanding of the state-of-the-art in smart contract design for the smart grid. However, no existing reviews focus on smart contracts in energy systems. The scope of our study is the role of smart contracts in energy systems and what limitations they encounter. We conduct a systematic review of this topic, focusing on systems that have been implemented as prototypes. These studies provide key evidence on the scalability of smart contracts for energy systems and their interaction with the technical elements of the smart grid. We selected a pool of 76 papers meeting our criteria, with three others excluded for misinterpreting fundamental aspects of blockchains and smart contracts. After reviewing each paper, we found that this literature falls into four categories: market operations, ancillary services, auditing and monitoring, and cybersecurity. We then identify and examine the cross-cutting concerns of data storage in and interoperability between blockchains. We finally discuss the implications of our findings for future research. In particular, there is likely to be a complex interplay between the data generated and stored via the blockchain versus the data required to meet energy system reliability targets and market obligations for participants.

Optimal Generation Capacity Allocation and Droop Control Design for Current Sharing in DC Microgrids

Considering the increasing amounts of renewable energy generation and energy storage required to meet ambitious environmental goals, it is clear that the next generation of power grids will be dominated by converter-connected devices. In addition, the increasing share of loads connected via power electronics and the general transition to non-synchronous grids with distributed generators make dc microgrids an attractive future alternative. However, achieving optimal utilization of distributed generators in such cases is a complex task, as the performance depends on both the grid and control design. In this paper, we consider such a case where the optimal utilization of distributed generators is achieved by optimal power sharing while taking into account the grid topology, the available generators, and the way they are controlled. For the latter, we consider a droop-based decentralized control scheme whose primary objective is to achieve voltage regulation in the allowable operating range. A novel mixed-integer optimization approach is proposed to identify the optimal converter size and location in the network so that the microgrid can operate safely and with optimal use of the available resources. Time-domain simulations are used to validate the proposed approach and demonstrate its robustness to uncertainty in generator availability.

Design and Implementation of Hardware in the Loop Simulation Test Platform for Photovoltaic Inverter

In order to ensure the performance and safety of photovoltaic grid connected inverter, based on hardware in the loop simulation technology, the design and implementation of photovoltaic grid connected inverter simulation and test platform are discussed. The system structure, principle and main functions of the platform are introduced. The simulation and test platform is composed of simulation and monitoring computer, simulation and measurement interface device, programmable power supply and test instruments. In the platform, the programmable DC power supply, the programmable AC power supply and RLC load is used to simulate the characteristics of solar panels, power grid and load respectively. The test process is controlled by LabWindows/CVI software interface, and the test data collection is completed through power quality analyser, power analyser, oscilloscope and simulation and measurement interface device. The simulation test software completes the data analysis and realizes the full-automatic detection of the grid connected inverter. The established hardware in the loop simulation test platform of photovoltaic grid connected inverter has the ability to conduct comprehensive test and detection of photovoltaic grid connected system, which can be used to verify and evaluate the photovoltaic inverter before it is connected to the power grid.

Sustainable Power Grid Expansion: Life Cycle Assessment, Modeling Approaches, Challenges, and Opportunities

Electric demand is steadily increasing, hence requiring continuous investments in modernizing, and expanding power grids worldwide. Traditionally, power system planning projects have considered minimizing the costs of capacity expansion and minimizing the amount of energy not served as the main objectives. With climate change policies enforcing the decommissioning of fossil-fuel-based generation, new clean and renewable generation technologies are being considered for power system capacity expansion projects. However, the environmental impacts of energy resources are not limited to carbon emissions and their contribution to global warming. In fact, every power generation technology can result in undesired impacts during its entire life cycle, which could negatively affect air quality, water resources, material resources, and/or human health. This paper provides an overview of how to assess the sustainability of power systems and power generation technologies based on life cycle assessment (LCA). A review of LCA, as applied to power systems and generation technologies, is presented with a discussion of general findings, challenges, and limitations. A review of the literature is then provided related to how sustainability objectives are currently incorporated in power grid design and capacity expansion models. Finally, shortcomings of the current models are discussed, along with opportunities for future research.

Narrow Line Width Ni–Cu–Sn Front Contact Metallization Patterns for Low‐Cost High‐Efficiency Crystalline Silicon Solar Cells using Nano‐Imprint Lithography

An in‐house‐developed nanoimprint lithography system is designed and developed to demonstrate a commercially viable method for creating Ni–Cu–Sn‐based narrow linewidth finger patterns capable of effectively reducing shadow loss in the front contact metallization on industrial silicon solar cells. Finite element analysis simulation studies estimate that an optimal force of 138 MPa is required to generate damage‐free patterns during nanoimprinting process. The poly (methyl methacrylate) residual layer is removed using reactive ion etching, which enhances the adhesion strength of Ni–Cu–Sn metallization. A low ohmic contact layer at the Si/Ni interface develops after sintering at 420 °C and formation of NiSi layer is confirmed through X‐ray photoelectron spectroscopy analysis as a function of Ar+ ion etching time. An average cell efficiency of 18.10% is achieved for silicon solar cells with micropatterned Ni/Cu/Sn‐based narrow linewidth front contact grid design, which can exhibit ≈1% enhancement in cell efficiency compared to commercial Ag screen‐printed solar cells. The Ni/Cu/Sn‐based front contact metallization can improve the cell performance by ≈6% compared to the commercial Ag screen‐printed metallization by reducing shadow loss and thereby indicating its suitability toward deploying for cost‐effective industrial solar cell manufacturing.

A novel approach to predicting the stability of the smart grid utilizing MLP-ELM technique

Evaluating and forecasting stability across different conditions is essential since smart grid stabilization is among the most significant characteristics that could be employed to assess the functionality of smart grid design. Some intelligent methods to foresee stability are required to mitigate unintended instability in a smart grid design. This is due to the rise in domestic and commercial constructions and the incorporation of green energy into smart grids. It is currently hard to forecast the stability of the smart grid. In this framework, a smart grid with reliable mechanisms is being implemented to meet the fluctuating energy demands as well as providing more availability. The involvement of consumers and producers is one of the many factors influencing the grid's stability.This study suggested anovelapproach for locating stability statistics in smart grid systems utilizing machine learning frameworks was presented. This paper outlined the multi-layer perceptron-Extreme Learning Machine (MLP-ELM)methodology to predict the sustainability of the smart grid. Additionally, this utilized the principal component analysis (PCA) approach for extracting features. In addition to an empirical assessment and a comparison to various approaches, this article presents an implementation result for smart grid stability. Simulation findings demonstrate that the suggested MLP-ELM approach outperforms traditional machine learning techniques, with accuracy reaching up to 95.8%, precision at 90%, recall at 88%, and F-measure at 89%.

Selecting optimal support grids for super-resolution cryogenic correlated light and electron microscopy

Cryogenic transmission electron microscopy (cryo-TEM) and super-resolution fluorescence microscopy are two popular and ever improving methods for high-resolution imaging of biological samples. In recent years, the combination of these two techniques into one correlated workflow has gained attention as a promising route towards contextualizing and enriching cryo-TEM imagery. A problem that is often encountered in the combination of these methods is that of light-induced damage to the sample during fluorescence imaging that renders the sample structure unsuitable for TEM imaging. In this paper, we describe how absorption of light by TEM sample support grids leads to sample damage, and we systematically explore the importance of parameters of grid design. We explain how, by changing the grid geometry and materials, one can increase the maximum illumination power density in fluorescence microscopy by up to an order of magnitude. Finally, we demonstrate the significant improvements in super-resolution image quality that are enabled by the selection of support grids that are optimally suited for correlated cryo-microscopy.

Distribution grid electrical performance and emission analysis of combined cooling, heating and power (CCHP)-photovoltaic (PV)-based data center and residential customers

As the number of data centers is increasing worldwide, there are concerns about their growing electricity demand on power grids and its impact on the environment. These concerns can be mitigated at the urban scale by utilizing the waste heat generated by data centers and multi-energy hub integration. Using Combined Cooling, Heating, and Power (CCHP) and Photovoltaic (PV) systems within a data center, in combination with district energy network connections, can create energy interactions with residential customers in a multi-energy hub. However, connecting large energy consumers and distributed energy systems to the electrical distribution grid presents challenges due to the conventional design of the power grid with unidirectional electricity flow. There is a lack of understanding about the grid impact of data centers with multi-energy systems regarding electrical performance parameters, energy demand, and emissions. To address these open issues, we developed an hourly energy interaction model that includes a CCHP-PV-based data center and residential customers. In addition, the CCHP-PV-based data center was operated with a cost-optimized energy scheduling. We conducted six case studies to distinguish the specific effects of CCHP, PV, and district energy network connections. The model takes into account hourly outdoor temperatures, energy prices, and varying energy demands to capture the seasonal impact on electrical performance parameters and energy results. From an energy and environmental perspective, CCHP-PV systems can eliminate the data center's electricity demand from the grid, reduce residential energy demand, and decrease carbon dioxide equivalent emissions. This cleaner production and energy exchange further support the United Nations Sustainable Development goals. The experimental results showed a 43% reduction in power loss in the distribution grid and helped the data center's main electrical bus and residential bus against the voltage drop phenomenon. The CCHP-PV-based data center with district heating and cooling connection reduced the peak hour electricity demand on the grid by 39% and annual electricity consumption from the grid by 66%. Furthermore, Greenhouse Gas Protocols (GHG) Scope-2 emissions associated with the data center's grid electricity consumption and only residential electricity consumption were reduced by 77% and 36%, respectively.

A Scenario Reduction Method of PV Output Based on NBSO Algorithm and STDI Index

Photovoltaic output has strong randomness and volatility. Research on the scenario reduction method of PV output is of great significance for the planning, design, and operation of power grids. This paper proposes Nonlinear Brain Storm Optimizer (NBSO) to improve the k-means algorithm, and uses the Standard Deviation Based Index (STDI) to evaluate the effectiveness of clustering. The simulation results show that the clustering method proposed in this paper can effectively reduce the PV output scenes, and the generated typical scene set can fit the output volatility and diversity of the initial scenes.