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Recent advancements in network-connected devices have led to a rapid increase in the deployment of smart devices and enhanced grid connectivity, resulting in a surge in data generation and expanded deployment to the edge of systems. Classic cloud computing infrastructures are increasingly challenged by the demands for large bandwidth, low latency, fast response speed, and strong security. Therefore, edge computing has emerged as a critical technology to address these challenges, gaining widespread adoption across various sectors. This paper introduces the advent and capabilities of edge computing, reviews its state-of-the-art architectural advancements, and explores its communication techniques. A comprehensive analysis of edge computing technologies is also presented. Furthermore, this paper highlights the transformative role of edge computing in various areas, particularly emphasizing its role in power systems. It summarizes edge computing applications in power systems that are oriented from the architectures, such as power system monitoring, smart meter management, data collection and analysis, resource management, etc. Additionally, the paper discusses the future opportunities of edge computing in enhancing power system applications. [ABSTRACT FROM AUTHOR]

Soft-switching technologies can effectively solve the problem of switching losses caused by increasing switching frequency of grid-connected inverters. As a branch of soft-switching technologies, load-side resonant soft-switching is a hotspot for applications of high-frequency inverters, because it has the advantage of achieving soft-switching without using additional components. However, the traditional PI control strategy based on the linear model is prone to destabilization and non-robust dynamic performance when large signal perturbation occurs. In this paper, a novel Passivity-Based Control (PBC) method is proposed to improve the dynamic performance of load-side resonant soft-switching grid-connected inverter. Besides, the model based on the Port Controlled Hamiltonian (PCH) model of the soft switching inverter is carried out, and the passivity-based controller is designed based on the established model using the way of interconnection and damping assignmentpassivity based control (IDA-PBC). Both stable performance and dynamic performance of the load-side resonant soft-switching inverter can be improved over the whole operating range. Finally, a 750 W load-side resonant soft-switching inverter simulation model is built and the output performance is compared with the traditional PI control strategy under stable and dynamic conditions. The simulation results show that the proposed control strategy reduces the harmonic distortion rate and improves the quality of the output waveforms. [ABSTRACT FROM AUTHOR]

Electric power generation is quickly transitioning toward nontraditional inverter-based resources (IBRs). Prevalent devices today are solar PV, wind generators, and battery energy storage systems (BESS) based on electrochemical packs. These IBRs are interconnected throughout the power system via power electronics inverter bridges, which have sophisticated controls. This paper studies the impacts and benefits resulting from the integration of grid forming (GFM) inverters and energy storage on the stability of power systems via replicating real events of loss of generation units that resulted in large load shedding events. First, the authors tuned the power system dynamic model in Power System Simulator for Engineering (PSSE) to replicate the event records and, upon integrating the IBRs, analyzed the system dynamic responses of the BESS. This was conducted for both GFM and grid following (GFL) modes. Additionally, models for Grid Forming Static Synchronous Compensator (GFM STATCOM), were also created and simulated to allow for quantifying the benefits of this technology and a techno-economic analysis compared with GFM BESSs. The results presented in this paper demonstrate the need for industry standardization in the application of GFM inverters to unleash their benefits to the bulk electric grid. The results also demonstrate that the GFM STATCOM is a very capable system that can augment the bulk system inertia, effectively reducing the occurrence of load shedding events. [ABSTRACT FROM AUTHOR]

Demand flexibility plays a crucial role in mitigating the intermittency of renewable power sources. This paper focuses on an active distribution grid that incorporates flexible heat and electric demands, specifically heat pumps (HPs) and electric vehicles (EVs). Additionally, it addresses photovoltaic (PV) power generation facilities and electrical batteries to enhance demand flexibility. To exploit demand flexibility from both heat and electric demand, along with the integration of PVs and batteries, Control and Communication Mechanisms (CCMs) are formulated. These CCMs integrate demand flexibility into the distribution grids to obtain economic benefits for private households and, at the same time, facilitate voltage control. Concerning EVs, the paper discusses voltage-based droop control, scheduled charging, priority charging, and up-/down-power regulation to optimize the charging and discharging operations. For heat demands, the on-off operation of the HPs integrated with phase change material (PCM) storage is optimized to unlock heat-to-power flexibility. The HP controllers aim to ensure as much self-consumption as possible and provide voltage support for the distribution grid while ensuring the thermal comfort of residents. Finally, the developed CCMs are implemented on a small and representative community of an active distribution grid with eight houses using Power Factory software and DIgSILENT simulation language (DSL). This scalable size of the active distribution network facilitates the careful study of symbiotic interaction among the flexible load, generation, and different houses thoroughly. The simulation results confirm that the integration of flexible demands into the grid using the designed CCMs results in the grid benefiting from stabilized voltage control, especially during peak demand hours. [ABSTRACT FROM AUTHOR]

The inherent constraints of grid‐forming converters affect their ability to maintain voltage source characteristics within a specific operational range. In response to these limitations, ongoing pilot projects involving grid‐forming technology have adjusted their current thresholds up to three times the rated current, significantly exceeding the traditionally threshold of 1.2 times the rated current. This paper aims to investigate the effects of current thresholds on the dynamic responses of grid‐forming converters under large disturbances, with the intention of identifying an optimal current threshold that meets the grid's demands for maintaining voltage source characteristics and overall stability. A novel power angle relationship is introduced, integrating current limits and anti‐windup voltage controls into the equivalent circuit models of these converters. Analytical expressions for stable and unstable equilibrium points are derived, improving insights into the converters' dynamic behaviour and their resilience to phase jumps across various current thresholds and short‐circuit ratios. Findings indicate that higher current thresholds substantially improve phase jump limits and withstand capabilities. The paper concludes with proposed configurations and optimization strategies for current thresholds, all supported by experimental validation. [ABSTRACT FROM AUTHOR]

With the progress of communication technology, the cost of optical fiber and 5G continues to decrease, and data transmission becomes more convenient and fast, making it possible to realize differential protection of distribution network by various intelligent algorithms using signal waveforms. Aiming at the problem that the traditional relay protection device can not meet the actual demand when the single-phase ground fault occurs in the distribution network with distributed generation, this paper proposes a new differential protection scheme. The characteristic mode decomposition improved by the whale optimization algorithm is used to decompose the zero-sequence current waveform collected at both ends of the line. Based on the basic principle of current differential protection, the derivative dynamic time warping of the component with the largest fault feature can effectively solve the problem that the grounding current of the distribution network cannot meet the working requirements of the differential protection device, and ensure the safe and stable operation of the system. Finally, based on MATLAB software, the performance of this method is comprehensively evaluated by simulating different fault conditions, so as to ensure the feasibility and accuracy of this method in the case of diversified faults when the distributed generation is used as part of the power supply. [ABSTRACT FROM AUTHOR]

The work is based on a collaboration between Hiroshima University and Kure KOSEN College. This paper presents the design concept, hardware, and applications of a single-phase synchronous inverter (SSI), a specially designed grid-forming inverter (GFM) for single-phase micro-grid (SMGs). The SSI is designed for the conventional 100/200 V distribution network and is based on the concept of "Non-Interference Core (NIC) dynamic model". Novel contributions of this paper are: (1) A root mean square (RMS) model of NIC-SSI was developed, combined with the conventional power system model, and verified through the comparison with the hardware-in-the-loop (HIL) simulation and SSI hardware experiments; (2) using the developed RMS simulation tool, the stabilization effect of the SSIs was investigated in condition under which the SSIs are massively installed in a distribution system; (3) off-grid SMG operations using SSIs under various ill-conditioned loads were demonstrated. The results show that the SSI has the considerable ability of grid stability enhancements for frequency, transient, and small-signal stabilities. The proposed SMG using SSIs is promising. [ABSTRACT FROM AUTHOR]

Recently, Egypt has recognized the pivotal role of High Performance Computing in advancing science and innovation. Additionally, Egypt realizes the importance of collaboration between different institutions and universities to consolidate their own computational and data resources into a unified platform to serve different disciplines (e.g., scientific, industrial, governmental). Otherwise, additional resources would be needed to be purchased with the associated cost, effort, and time difficulties (e.g., setup, administration, maintenance, etc.). Thus, this paper delves into the architecture and capabilities of the EN-HPCG grid using two different workload management systems: (i) Slurm (Open-Source) and (ii) PBS Pro (Licensed). This paper compares the performance of the grid between Slurm and PBS Pro in specific high-throughput computing (HTC) applications using the NAS Grid parallel benchmark (NGB) to determine which workload manager is more suitable for EN-HPCG. The evaluation includes grid-level performance metrics such as throughput, and the number of tasks completed as a function of time. Also, the presented methodology aims to assist potential partners in their decision-making process to join the EN-HPCG grid, with a focus on the site speed-up metric. Our results showed that, unless an open-source solution without cost and license problems is an obligation (in which case, Slurm is the viable solution), then it is not advisable to integrate a cluster with high-speed hardware with a cluster possessing outdated hardware when using the Slurm scheduler. In contrast, the PBS Pro scheduler takes into account online decision-making in a dynamic environment using a unified grid. [ABSTRACT FROM AUTHOR]

This paper presents the topology and machine learning-based intelligent control of high-power PV inverter for maximum power extraction and optimal energy utilization. Modular converters with reduced components economic and reliable for high power applications. The proposed integrated intelligent machine learning based control delivers power conversion control with maximum power extraction and supervisory control for optimal load demand control. The topology of the inverter, operating modes, power control and supervisory control aspects are presented. Simulation is carried out in MATLAB/SIMULINK to verify the feasibility of the proposed inverter and control algorithm. The experimental study is presented to validate the simulation results. The operational performance of the proposed topology is evaluated in terms of operational parameters such as regulation of output power, and load relay control and is compared to existing topologies. The economic performance is also evaluated in terms of power switch sizing and reliability in power delivery concerning switch or power sources failure. [ABSTRACT FROM AUTHOR]

The advent of distributed generation has brought with it a plethora of challenges for the nascent power systems that are being deployed on a large scale. Firstly, the majority of power electronic converters connected to the grid are in current source mode, which results in a lack of inertia and an inability to provide effective inertia or achieve damping support during fluctuations in grid frequency. Secondly, the issue of power quality, caused by the presence of harmonics, is becoming increasingly severe. This is particularly problematic in microgrids or systems with high line impedance, where harmonics can be amplified, thereby further compromising the stability of the power system. To address the deficiency in system inertia, numerous scholars are currently utilizing grid-forming (GFM) technology to achieve virtual inertia. In order to address the issue of system harmonics, it is possible to install active power filter (APF) devices at the point of common coupling (PCC), which serve to mitigate the effects of harmonics. This paper puts forth a proposal for the implementation of an APF with virtual inertia, based on PR + RC composite control. This composite control mechanism serves to enhance the harmonic suppression capabilities of the APF. The introduction of a frequency droop enables the capacitor voltage amplitude to be adjusted during fluctuations in system frequency, thereby achieving virtual inertia and providing active support for system frequency. The experimental results demonstrate that this strategy not only reduces the total harmonic distortion (THD) by 13% in comparison to PI control, indicating excellent harmonic suppression performance, but also allows the system to be inert, achieving positive results in suppressing frequency fluctuations during transients. [ABSTRACT FROM AUTHOR]

Distributed photovoltaic (PV) in the distribution network accounted for an increasing proportion of the distribution network, and the power quality of the distribution network of the power quality problem is more and more significant. In this paper, the voltage regulation methods for low-voltage distribution networks containing high-penetration PV are investigated. First, the working principles of the four voltage control methods are introduced: energy storage system configuration, regulating the reactive power output of PV inverters, restricting the active power output of PV, adjusting the switching positions of on-load regulator trap changer and distribution network reconfiguration, and then, in combination with the recent related research, the optimization of each method is compared horizontally with its respective concerns and characteristics. The optimization of each method is compared horizontally with the recent studies to find out the focus and characteristics of each method, and the shortcomings of each method are explored. Coordinated voltage control through multiple flexibility resources has become the mainstream voltage regulation scheme, and distribution network voltage regulation is considered from the perspective of flexibility resources. The three types of flexibility resources, namely, source, network, and storage, have been widely used in distribution network voltage regulation. Although load-side resources have become one of the main regulation resources of the new type of power system, the current study introduces less about the participation of load-side flexibility resources in voltage regulation of LV distribution networks and advancing the application of load-side resources in voltage regulation of LV distribution networks is the focus of future research. Then, the important role of load-side flexibility resources in voltage regulation is described in three parts, namely, the important role of load-side resources, the development trend, and the suggestions for promoting the coordination of source-network-load-storage flexibility resources, aiming to promote the application of load-side resources in voltage regulation in LV distribution networks, and the suggestions and programs are proposed for the technological challenges faced by voltage regulation. In the context of today's new power system emphasizing the interaction of source, network, load, and storage, new technologies and methods for solving voltage problems in LV distribution networks are prospected, with a view to providing certain reference value for the actual operation and optimization of distribution network systems. [ABSTRACT FROM AUTHOR]

This paper deals with the position detection of automated guided vehicles (AGVs) in dynamic resonant-inductive wireless power transfer (WPT) systems. A position detection is necessary to activate the correct transmitting coil. One of the simplest and most effective approaches for a position detection method is to use optical or magnetic position sensors for each coil. However, due to needing a high number of sensors, this technique is relatively expensive. Therefore, an AGV position detection technique based on a reduced number of optical or magnetic sensors (by a factor of two) is proposed. The proposed detection technique was verified experimentally by using a scaled-down prototype of the dynamic WPT system. The proposed approach can be easily implemented by uploading a specific program code to a microcontroller. The microcontroller with the code developed by us was used for processing data from AGV position detection sensors, activating a suitable transmitting coil and controlling an inverter of the dynamic WPT system. As shown by the experiments, due to the proposed approach for the position detection of AGVs and activation of transmitting coils, the number of the position detection sensors is reduced by a factor of two, leading to reductions in the overall cost and level of complexity of the dynamic WPT system without degrading its performance. [ABSTRACT FROM AUTHOR]

This paper presents an innovative control scheme designed to significantly enhance the power factor of AC/DC boost rectifiers by integrating an adaptive neuro-fuzzy inference system (ANFIS) with predictive current control. The innovative control strategy addresses key challenges in power quality and energy efficiency, demonstrating exceptional performance under diverse operating conditions. Through rigorous simulation, the proposed system achieves precise input current shaping, resulting in a remarkably low total harmonic distortion (THD) of 3.5%, which is well below the IEEE-519 standard threshold of 5%. Moreover, the power factor reaches an outstanding 0.990, indicating highly efficient energy utilization and near-unity power factor operation. To validate the theoretical findings, a 500 W laboratory prototype was implemented using the dSPACE ds1104 digital controller. Steady-state analysis reveals sinusoidal input currents with minimal THD and a power factor approaching unity, thereby enhancing grid stability and energy efficiency. Transient response tests further demonstrate the system's robustness against load and voltage fluctuations, maintaining output voltage stability within an 18 V overshoot and a 20 V undershoot during load changes, and achieving rapid response times as low as 0.2 s. Comparative evaluations against conventional methods underscore the superiority of the proposed control strategy in terms of both performance and implementation simplicity. By harnessing the strengths of ANFIS-based voltage regulation and predictive current control, this scheme offers a robust solution to power quality issues in AC/DC boost rectifiers, promising substantial energy savings and improved grid stability. The results affirm the potential of the proposed system to set new benchmarks in power factor correction technology. [ABSTRACT FROM AUTHOR]

Due to increasing load demand and the energy crisis, microgrids (MGs) have attracted more attention. The idea and technology of microgrids (MGs) have undergone significant advancements largely aimed at enabling the automation of distribution systems and enhance the integration of renewable energy sources (RESs). In this paper, the MG is a combined form of various distributed generations (DGs), battery energy storage system (BESS), and plug-in hybrid electric vehicles (PHEVs). A novel approach is introduced to minimize the operational expenses of the grid-connected low-voltage microgrid by leveraging a probabilistic expert optimization technique. This methodology takes into account various factors such as power supply costs, power dissipation, PHEV charging requirements, and the optimal capacity of BESS. Three charging techniques are proposed in this paper to control the PHEVs' charging demand at homes and public charging stations. This study employs a comprehensive model to simulate a whole day, accounting for the stochastic charging requirements of PHEVs, load profiles, RESs outputs, and variations in energy price. To address the inherent nonlinearity of the optimization problem, the energy management within the MG is tackled using the slime mould algorithm, a population-based stochastic optimizer. The primary goal is to minimize operational costs in the microgrid by optimizing the efficient utilization of available resources. [ABSTRACT FROM AUTHOR]

Peer-to-peer energy trading is an innovative idea that overcomes several technological and industrial hurdles. It allows industries and consumers, including knowledgeable prosumers, to trade excess energy with distributed generation sources, such as solar, wind, and electric vehicles, thus promoting a significant reduction in overall energy consumption. Real-Time Pricing (RTP) is increasingly essential in integrating smart home device Demand Response (DR) strategies. RTP improves energy management and enables customers to respond intelligently to price fluctuations. In this vein, this paper proves how DR and peer-to-peer (P2P) energy trading could affect energy prices by allowing producers (consumers) and smart home users to interact directly rather than through the traditional grid. The two-pronged planning approach substantially contributes to the reduction of electricity costs. DR enables P2P energy trading, while deep learning algorithms adapt smart home devices to RTP dynamics. Simulation results show that using P2P energy trading and DR in smart homes can significantly eliminate costs. This hybrid approach increases the energy efficiency of Smart Grid (SG) 2.0 technology and makes it more adaptable and cost-effective. [ABSTRACT FROM AUTHOR]

The Modular Multilevel Converter (MMC) is a promising converter for medium-/high voltage applications due to its various features. The waveform quality could be enhanced further by expanding the number of generated voltage levels, which increases the number of submodules (SMs); however, this improvement enlarges the size and cost of the converter, posing a persistent challenge. Hence, there exists a trade-off between power quality and the size and complexity of the converter. To verify the performance of such a complex converter and to validate the effectiveness of the control system, especially in the absence of a physical system, Real-Time (RT) simulation becomes crucial. However, the large number of components of a MMC creates important numerical challenges and computational difficulties in RT simulation. This paper proposes a grid-connected MMC employing a Z Packed U-Cell converter as a SM to generate a higher number of voltage levels while minimizing the required number of SMs. The ZPUC-MMC is implemented on an FPGA-based RT simulation platform using Electric Hardware Solver to reduce computational burden and simulation time, while improving the accuracy of the obtained results. Conventional controllers of MMCs are applied to assess the effectiveness and robustness of the proposed system during steady-state and dynamic operations. [ABSTRACT FROM AUTHOR]

With the advancement of regulations regarding the reduction in carbon emissions, renewable energy communities have come into the picture. However, many implications come with the installation of these communities from a cybersecurity point of view. The software platforms responsible for managing and controlling them handle a lot of crucial information, and therefore, tampering with these data can lead to several impacts on the operation of these communities and, in turn, the power grid as well. This paper examines the plausible impacts that can be caused by altering certain parameters of the system that make it a potential cyber attack target. The analysis is done by observing how the grid responds to these manipulations for both low-voltage as well as medium-voltage systems. These systems are designed along with integrated energy communities and are implemented in MATLAB/Simulink R2022b software. The observations are made by plotting the grid voltage and power profiles in normal as well as attacked conditions. [ABSTRACT FROM AUTHOR]

This paper describes research on the harmonic-distortion capacity of a single-stage photovoltaic (PV) 3.68 kWp generator in a microgrid configuration. An overview of various harmonic compensator methods used in PV generators is presented to evaluate their advantages and disadvantages. Proportional-resonant (PR) structures with harmonic compensators (HCs) are designed, modeled, and validated through real-time tests. The modeling of harmonic compensation structures for a photovoltaic inverter using MATLAB/SIMULINK R2022a is explained in detail. The harmonic compensation capacity of a PV generator inverter is studied under voltage harmonics, grid frequency variation, and voltage unbalance. The contributions of this work are, firstly a bibliographic analysis of various strategies currently used for harmonic compensation in grid-connected inverters and secondly, a detailed explanation of the modeling of harmonic compensation structures using MATLAB/SIMULINK. Finally, a demonstration of the improvement in energy quality that results from using harmonic compensation techniques in photovoltaic generators in microgrid configurations affected by grid disturbances is performed. The obtained results show that harmonic compensation strategies based on resonant filters are a good alternative for the reduction of harmonic voltage distortion in the presence of grid disturbances such as frequency variation and voltage unbalance. [ABSTRACT FROM AUTHOR]

With the increasing demand for electricity, microgrid systems are facing issues such as insufficient backup capacity, frequent load switching, and frequent malfunctions, making research on microgrid resilience crucial, especially to improve system power supply reliability. This paper proposes a method for analyzing the resilience metric of new energy grid-connected microgrid system, and proposes optimization strategies to improve resilience. Firstly, a measurement method for the resilience of the microgrid system is established based on the operating characteristics of the system components. Secondly, the sensitivity relationship between system resilience and parameters is established, and an optimization model for resilience improvement strategies of microgrid systems based on parameter sensitivity is constructed. Finally, simulation verification is conducted based on the IEEE 37-node microgrid system. The results show that the proposed measurement method can scientifically and reasonably measure the resilience of the microgrid system, and the resilience improvement strategy significantly improves the operational resilience, verifying the effectiveness and robustness of the proposed analysis method. [ABSTRACT FROM AUTHOR]

Modern power systems have several measurement devices for reliable, safe, and improved operation and control. Due to the high infiltration of inverter‐based resources, protecting modern power systems has become challenging. This paper proposes a new protection scheme based on the computation of 'discrepant impedance' using real‐time protocol services for data exchange. The sampled values of voltages and currents are transmitted to a central processing unit to implement the protection scheme. With the development of digital instrument transformers (IEC 61869‐9), the current and voltage samples are directly interfaced wired or wirelessly to the IEC 61850‐9‐2 process bus. The proposed protection scheme is validated with grid forming and grid following inverters on Consortium for Electric Reliability Technology Solutions (CERTS) microgrid network using a real‐time digital simulator. The protection scheme is independent of the type of energy sources and their control philosophy, operation modes and topology of the microgrid network. [ABSTRACT FROM AUTHOR]

Since the integration of electronic devices and intelligent electronic devices into the power grid, power quality (PQ) has consistently remained a significant concern for system operators and experts. Maintaining high standards of power quality is crucial to preventing malfunctions and faults in electric assets and connected loads. Recently, PQ studies have shifted their focus to a specific frequency range, previously not considered problematic—the supraharmonic 2 kHz to 150 kHz range. This range is not populated by easily recognizable harmonic components of the 50 Hz to 60 Hz mains fundamental, but by a combination of intentional emissions, switching non-linearities and byproducts, and various types of resonances. This paper aims to provide a detailed analysis of the impact of supraharmonics (SHs) on power network operation and assets, focusing on the most relevant documented negative effects, namely power loss and the heating of grid elements, aging of dielectric materials, failure of medium voltage (MV) cable terminations, and interference with equipment and power line communication (PLC) technology in particular. Under some shareable assumptions, limits are derived and compared to existing ones for harmonic phenomena, providing a clear identification of the primary issues associated with supraharmonics and suggestions for the standardization process. Strictly related is the problem of grid monitoring and assessment of SH distortion, discussing the suitability of normative requirements for instrument transformers (ITs) with a specific focus on their accuracy. [ABSTRACT FROM AUTHOR]

Static compensators (STATCOMs) are often used in distribution systems to enhance power quality. There is a need to enhance the performance of STATCOM to optimize its utilization and facilitate the provision of additional ancillary services. This paper employs the multilayer discrete noise-eliminating second order generalized integrator (MDNESOGI) to regulate the quasi-impedance source inverter (qZSI)-STATCOM for power exchange with the grid. Compared to conventional second-order generalized integrator (SOGI), MDNESOGI exhibits a higher capability for rejecting DC offset. In instances of abnormal grid operation or system malfunction, the inclusion of DC rejection capability enhances the robustness and reliability of the system. The suggested control algorithm only requires two integrators, three mathematical operators, and a damping factor, making it far easier to implement than transformation-based methods. The distorted load current is broken down into its active and reactive components using this control mechanism. The reference currents are then calculated by multiplying these parts by their corresponding voltage standards. The DC offset is reduced and transient oscillations in the weight component are eliminated by adjusting the damping factor. The suggested algorithm effectively handles power quality tasks like (a) reducing harmonic distortion, (b) compensating for reactive power, (c) adjusting for power factor, and (d) balancing the load under different conditions in the distribution system. The experimental study results are used to examine the stability of the proposed control scheme in both static and dynamic scenarios. In addition, a comparison to traditional methods is provided to demonstrate the new method's superiority. Experimentation results show that the suggested controller is superior to its contemporaries in all scenarios where power quality is a factor, meeting the IEEE standard requirements. [ABSTRACT FROM AUTHOR]

Optimal power flow (OPF) analysis enables the in-depth study and examination of islanded microgrid design and operation. The development of the analysis framework, including modeling, formulating, and selecting effective OPF solvers, however, is a nontrivial task. As a result, this paper presents a tutorial on an OPF modeling framework, offering a mathematical model that can be readily implemented using established open-source software tools such as OpenDSS, Pyomo, and IPOPT. The framework is versatile, capable of representing single-phase and unbalanced three-phase islanded microgrids. Various inverter models, such as those of grid forming and following equipped with their operating characteristics, can be incorporated. The efficacy of the proposed framework is demonstrated in studying the OPF of single-phase and three-phase microgrids. [ABSTRACT FROM AUTHOR]

In this paper, with the development of an intelligent power system idea, sustainable energy sources were increasingly deployed, including transmission and distribution systems networks. As a result, optimal use of cascaded H-bridge inverter topologies (MLIs) and power distribution operations is critical for long-term power generation. Traditionally, selective harmonics reduction models must be performed to achieve the optimal switching frequency of multilevel inverters. This research aims to determine the switching frequency for wind-incorporated multilevel inverters to reduce overall harmonic components used in grid applications. This research adds towards the best possible solution by employing multiple newly established adaptive optimization techniques: MNSGA-II and salp swarm. The well-known genetic algorithm and particle swarm optimization are used for the wind-tied multilevel inverters optimization issue. Sevenlevel, eleven-level, and fifteen-level MLIs were employed to reduce overall harmonic distortion. The reliability and convergence rate of simulated data with various modulation indices for seven-, eleven-, and fifteen-level MLIs are obtained and compared. Models are developed based on MATLAB Simulink and are used to validate quantitative measurements. [ABSTRACT FROM AUTHOR]

The power industry is currently undergoing a rapid transformation toward the maximum utilization of renewable energy resources. In grid-connected renewable energy systems, enhancing the voltage stability during the fluctuations in renewable energy outputs can be achieved using a transformer with built-in on-load tap changing. It is one of the main traditional voltage regulation techniques utilized to improve the voltage profile in the power grid. Due to the unpredictable nature of renewable energy penetration, the frequent operation of an on-load tap changer (OLTC) may increase significantly. Despite the proposed methods used to optimize the location and size of renewable generation, there is a lack of empirical or detailed studies that have been looking at the issue of tap changers, mainly the impact of renewable energy storage allocation. The main aim of this paper is to find a compromise approach to mitigate unnecessary tap-changing operation time by wisely siting and sizing the renewable energy storage system (RESS). Initially, a generalized method is proposed to formulate an analytical optimization framework coupled with a renewable storage index. This approach is employed to evaluate the behavior of OLTC in a grid-connected renewable energy system. The formulation is then used to model a decision-making approach to confirm the location and size of RESS, using the analytic network process (ANP) with entropy and technique for order of preference by similarity to an ideal solution (TOPSIS). The performance of the proposed approach is evaluated and compared using the IEEE benchmark networks. Aspects in relation to the predictions of future operations about the management of renewable energy storage in coordination with voltage regulators in the smart grid context, that will be the subject matter of additional studies are also discussed. [ABSTRACT FROM AUTHOR]

• The unified dq-frame and sequence domain impedance models considering the phase difference effect of the grid-forming converter with different power synchronization controls are established. • Reveal why is the difference in the impedance of the GFM using different APCs, e.g., the P-ω droop, P-δ droop, and VSG. • Discuss whether a GFM with different APCs is vulnerable to specific grid strength. • Reveal how the phase difference effect deteriorates the GFM system's power quality. • Provide new insights into future research, design guidelines, and improvement of the stability and performance of the GFM system. The grid-forming converters (GFMs) have been widely employed to support the power grid. Yet, the phase difference effect (PHE) caused by active power control (APC) on the system's design and stability is still inexplicable. This paper comprehensively investigates the PHE in the GFM under six APCs in terms of the developed impedance models. We observed that GFM exhibits nearly equal dq-frame impedance across six APCs when the PHE is disregarded. However, when accounting for PHE, the impedance of GFM with P-δ droop-based APCs differs significantly from that with P-ω droop- and virtual synchronous generator (VSG)-based APCs. Additionally, the sequence impedance of GFM with P-ω droop- and VSG-based APCs appears to be largely decoupled, whereas P-δ droop-based APCs introduce substantial sequence impedance coupling. Stability and coupling analyses indicate that the P-δ droop-based GFM must work in a weaker grid for stable operation compared to other APC-based GFM. Furthermore, the resulting frequency coupling leads to a higher amplitude of the coupled frequency (2f 1 -f) than the dominant frequency (f). Lastly, theoretical analysis is verified by experiments, providing new insights into the future research and design guidelines of GFM. [ABSTRACT FROM AUTHOR]

Inverters are essential in converting solar panel-generated direct current (DC) into alternating current (AC) for seamless integration with electrical grids. This paper presents the modeling and analysis of a single-phase grid-connected H-bridge neutral point clamped inverter using the Sliding Mode Control (SMC) method. Addressing challenges in meeting control objectives – like fast dynamic response, precise reference tracking, robustness against parameter variations, cost-effectiveness, and compliance with grid standards such as low harmonic distortion and minimal DC transfer to the grid – the study employs the boundary layer method to minimize the SMC method's chattering phenomenon. The use of proportional-resonant (PR) control maintains the robustness of the SMC method against parameter changes, while the boundary layer effectively reduces chattering. A transfer function between the measured grid current and the reference grid current was also derived to investigate the effect of the filter parameters on the system. Furthermore, the proposed control method naturally mitigates resonance in the LCL filter and minimizes leakage current via a symmetrical LCL filter and specialized modulation scheme. Simulations conducted using MATLAB/Simulink® validate achievement of control objectives, steady-state performance, dynamic response, robustness to parameter variations, and adherence to grid standards. [ABSTRACT FROM AUTHOR]

Grid-connected micro-inverters, known for their straightforward wiring and operational stability, have garnered increasing interest from both industry and academia. However, the operational inefficiency of conventional inverters, the issue of distorted output waveforms, and the safety concerns with alternating current (AC) and direct current (DC) safety isolation limit the wide availability and utilization of micro-inverters. In order to overcome this problem, this research proposes a circuit topology consisting of two flyback circuits connected in parallel on the primary side of the transformer for safe isolation. Additionally, soft switches are incorporated into the flyback circuit at the front stage, with a voltage total harmonic distortion (THD) of less than 3.0 %. This study also develops a small-signal model to help with obtaining the current loop parameters. Parametric design and simulation studies with PLECS software confirmed the circuit architecture and control technique's accuracy. A 600 W prototype's design, analysis, and experimental validation are described. The proposed inverter has an efficiency of up to 97.2 %. The design and control methods employed in this paper offer a conceptual framework and engineering reference for relevant research and practical applications. [ABSTRACT FROM AUTHOR]

Researching cluster partitioning and adjustment methods is essential for effectively implementing cluster control strategies and ensuring the safe operation of power grids amid challenges like reverse power flow and voltage violations resulting from large-scale distributed photovoltaic grid integration. The paper comprehensively evaluates factors including electrical distance, supply-demand balance, and power transmission. It introduces a method for partitioning and dynamically adjusting distributed photovoltaic clusters, based on an improved adaptive genetic algorithm (AGA). Firstly, a comprehensive performance index is introduced based on modularity, incorporating intra-cluster power supply rate and inter-cluster power transmission. Next, an unweighted adjacency matrix is employed to encode chromosomes, and an adaptive optimization parameter adjustment strategy is introduced to enhance the AGA, ensuring both direct node connectivity within clusters and improved global solution performance during optimization. By integrating these comprehensive indicators with AGA, a cluster partitioning optimization model is formulated based on the comprehensive indicator system. The IEEE 33-node system is utilized for cluster partitioning simulation analysis with this model. The outcomes demonstrate that, in contrast to the single modularity index-based cluster partitioning approach, the proposed comprehensive indicator method enhances the intra-cluster active and reactive power supply rates by approximately 20.34% and 28.61%, respectively, while decreasing inter-cluster power transmission by roughly 24.98%. Furthermore, in scenarios of insufficient photovoltaic power output, the cluster scheme, after dynamic strategy adjustment, notably mitigates system voltage fluctuations and network losses. [ABSTRACT FROM AUTHOR]

[Display omitted] • Limiting only fundamental component of the reference current is proposed. • Adaptive virtual impedance scheme is designed to reduce control effort. • DG's voltage distortion prevenience is achieved by the proposed FRT approach. • Angle droop control method is utilized for single-phase and three-phase DGs. • State space analysis is performed to confirm stability of proposed FRT approach. Reducing the control effort and limiting the output current of grid-forming inverters with the ability of voltage distortion prevenience in islanded microgrids under harmonic and asymmetrical fault conditions are the main objectives of this paper, which have not been investigated so far. In the proposed fault ride through (FRT) approach for inverter-based distributed generation (DG) resource, the current limiting strategy (CLS) only decreases the fundamental component of the reference value of inverter current to a value less than the threshold limit. In other words, harmonic components of the reference value of the inverter current remain unchanged in the proposed CLS to prevent DG's output voltage distortion. Moreover, an adaptive reference voltage modification scheme is designed based on the virtual impedance concept and by using the reference current reduction coefficient obtained from the proposed CLS. This scheme avoids the voltage controller saturation as well as eliminates the need to use the anti-windup technique for the proportional-resonant (PR) controller. The output impedance-based stability analysis is also performed based on the closed-loop dynamics of the proposed FRT approach to present a basis for the selection of the key parameter. Comparative studies performed by MATLAB/SIMULINK software approve the superior performance of the proposed method under severe asymmetrical faults and different nonlinear loads than an existing peak detection (PD)-based CLS. Furthermore, state space analysis indicates the stability of the proposed control structure with different values for the reference current reduction coefficient specifying the fault depth indirectly. [ABSTRACT FROM AUTHOR]

In recent years, single-stage boost inverters with common ground have shaped the inverter markets due to the many benefits associated with these types of inverters, including their high efficiency, single control scheme, and integrated boost converter. A new boost-type inverter that utilizes a common ground and has fewer switches is proposed in this article. It uses two DC-link capacitors connected in parallel and discharged independently while being charged simultaneously. The voltage for the positive and negative half cycles is supplied by the capacitors located at the top and bottom of the circuit, respectively. In addition, a comparison is made between the proposed circuit and the boost inverter already in use in the literature. Using PLECS as the computing software, the efficiencies are determined depending on the various percentages of output power. To validate performance, present experimental data, and attain the best possible efficiency of 97%, a 400 W prototype model is constructed. In addition to that, the breakdown of the costs is shown. [ABSTRACT FROM AUTHOR]

In islanded operation, precise power sharing is an immensely critical challenge when there are different line impedance values among the different-rated inverters connected to the same electrical network. Issues in power sharing and voltage compensation at the point of common coupling, as well as the reverse circulating current between inverters, are problems in existing control strategies for parallel-connected inverters if mismatched line impedances are not addressed. Therefore, this study aims to develop an improved decentralized controller for good power sharing with voltage compensation using the predictive control scheme and circulating current minimization between the inverters' current flow. The controller was developed based on adaptive virtual impedance (AVI) control, combined with finite control set–model predictive control (FCS-MPC). The AVI was used for the generation of reference voltage, which responded to the parameters from the virtual impedance loop control to be the input to the FCS-MPC for a faster tracking response and to have minimum tracking error for better pulse-width modulation generation in the space-vector form. As a result, the circulating current was maintained at below 5% and the inverters were able to share an equal power based on the load required. At the end, the performance of the AVI-based control scheme was compared with those of the conventional and static-virtual-impedance-based methods, which have also been tested in simulation using MATLAB/Simulink software 2021a version. The comparison results show that the AVI FCS MPC give 5% error compared to SVI at 10% and conventional PI at 20%, in which AVI is able to minimize the circulating current when mismatch impedance is applied to the DGs. [ABSTRACT FROM AUTHOR]

This study proposes an example of a wireless charging station design for a small-scale vehicle available on the market. The article analyzes basic transmitter inverter topologies and their compensation methods in terms of flexibility of control, tolerance to uncertainty in positioning, and the possibility of decreasing the integration price. Our comprehensive analysis focuses on the battery voltage range, energy capacity, cost, and travel distance. We evaluate the constraints of efficiency, transmitted power, amount of used material, and size of the energy delivery system based on our design example. The aim is to increase the penetration of wireless technology in terms of convenience and integration capabilities. [ABSTRACT FROM AUTHOR]

This paper introduces a novel approach to enhance the control algorithm for a single-phase shunt active power filter(SAPF) by integrating a new technique into a 5-level cascaded multilevel inverter (MLI) with Photo Voltaic (PV) array integration. Due to the integration of non-linear loads in the grid, such as computers, variable speed drives, and other solid-state equipment, non-sinusoidal currents are drawn, introducing harmonics that distort the voltage and current waveforms. It is essential to mitigate these harmonics, and integrating Shunt Active Power Filters (SAPFs) gives the grid the ability to inject active power. In order to improve power quality and achieve active and reactive power balance, this integration requires an imperative control method. This work extracts the fundamental component of the load current and efficiently handles grid distortions such as DC offset, phase shift, and harmonics using a phase lock loop (PLL) based on a Modified Notch Filter Second Order Generalised Integrator (MNFSOGI). Using MATLAB/Simulink software modelling, experimental validation utilising the OPAL-RT real-time data simulator verifies the proposed system's operation. The control algorithm, which has been painstakingly designed and verified, allows feed-forward current estimate from the PV array, synchronization template obtained from the grid voltage signal, and estimation of both fundamental and non-linear load currents. The performance of the MNFSOGI-PLL is additionally compared with that of the conventional E-PLL, MAF-PLL and DSOGI-PLL techniques. By attaining power balance in multilevel inverters under distorted grid conditions, this research substantially contributes to improving power quality. According to simulation and experimental results, the Total Harmonic Distortion (THD) of the grid current is found to be 1.50% in normal grid and 3.96% in distorted grid which is less than 5%, by IEEE-1547 standards. Moreover, the limitations of the presented multilevel inverter system are highlighted by the disadvantages of traditional 2-level inverters, which include increased harmonics, restricted voltage levels, and poorer power quality. [ABSTRACT FROM AUTHOR]

In vehicle‐to‐grid (V2G) applications, a voltage source inverter (VSI) directly connects to a residential load or grid for DC/AC conversion and power flow control. In VSI, dead‐time is employed to prevent the breakdown of switching devices, however, the introduction of dead‐time leads to distortions of output voltage and current in both stand‐alone and grid‐tie modes. For the case of a power factor of 1, by analyzing the dead‐time effect of digital‐controlled double‐frequency sinusoidal pulse width modulation, a compensation amount is proposed to introduce in the modulation signals, the value of which is half of the delay register that generates a dead‐time of td. Moreover, considering the phase delay caused by hardware and software filtering in sampling, the grid‐tie mode control strategy based on dead‐time compensation is further proposed, which introduces the grid voltage as a feedforward signal. A 3.5 kW V2G experimental prototype is built and tested to verify the feasibility of the proposed strategies. The simulation and experimental results show that the proposed methods are effective for both modes, which improve the output distortion for different dead‐time without additional hardware circuits. [ABSTRACT FROM AUTHOR]

In the context of integrating Renewable Energy Sources, Microgrid (MG) development is pivotal, particularly as a foundational technology for Smart-Grid evolution. Despite advancements in control techniques, challenges persist in ensuring system stability and accurate power sharing across diverse operational conditions and load types. The objective of this research is to control numerous paralleled inverters-based distributed generators (DGs) that contribute to power sharing in an island MG. The proposed methodology involves developing an innovative small-signal model for islanding MGs that incorporate virtual impedances. Subsequently, optimization algorithms based on Genetic Algorithm (GA) and Particle Swarm Optimization (PSO) are proposed and compared for designing the virtual impedances. These algorithms analyze all potential operating points, aiming to minimize reactive power mismatches while maximizing MG stability. The suggested objective function facilitates the simultaneous achievement of these objectives. The proposed approaches were tested using MATLAB-Simulink software, and the comparison of the results between conventional approach and the proposed optimal approaches shows significant improvement in terms of the dynamic response during load changes, such as a decrease in response time by up to 20%, a reduction in overshoot percentage by approximately 15%, and a settling time improvement of nearly 25%. These quantified improvements highlight the effectiveness of the GA and PSO methods in minimizing the reactive power-sharing error while optimizing MG performance and stability. [ABSTRACT FROM AUTHOR]

Non-intrusive load monitoring (NILM) can identify each electrical load and its operating state in a household by using the voltage and current data measured at a single point on the bus, thereby behaving as a key technology for smart grid construction and effective energy consumption. The existing NILM methods mainly focus on the identification of pre-trained loads, which can achieve high identification accuracy and satisfying outcomes. However, unknown load identification is rarely involved among those methods and the scalability of NILM is still a crucial problem at the current stage. In light of this, we have proposed a non-intrusive load identification method based on a Siamese network, which can be retrained after the detection of an unknown load to increase the identification accuracy for unknown loads. The proposed Siamese network comprises a fixed convolutional neural network (CNN) and two retrainable back propagation (BP) networks. When an unknown load is detected, the low-dimensional features of its voltage–current (V-I) trajectory are extracted by using the fixed CNN model, and the BP networks are retrained online. The finetuning of BP network parameters through retraining can improve the representation ability of the network model; thus, a high accuracy of unknown load identification can be achieved by updating the Siamese network in real time. The public WHITED and PLAID datasets are used for the validation of the proposed method. Finally, the practicality and scalability of the method are demonstrated using a real-house environment test to prove the ability of online retraining on an embedded Linux system with STM32MP1 as the core. [ABSTRACT FROM AUTHOR]

The liquid air energy storage (LAES) technology has received widespread attention for its advantages of high energy storage density, a wide range of applications, safety, environmental protection and hygiene, flexible device regulation, and large energy storage scale and is developing toward high-parameter and large-capacity energy storage. However, due to the late start of research in China, large-scale LAES has not been put into commercial operation so far, and the lack of in-depth understanding of the dynamic characteristics of LAES has seriously impeded the development of the system design and regulation technology, which limits the development and popularization of LAES. In this study, a dynamic mathematical model of the liquid air energy storage system is established based on the SIMULINK platform of MATLAB software. The dynamic characteristics of the system in the energy release stage are analyzed, a control model of the grid-connected speed control system is established, and an optimized control strategy is obtained by using a linear active disturbance rejection controller and by analyzing the response under typical disturbances. The model and the results of this study provide a reference for the understanding of the dynamic characteristics of LAES and the control of the speed control system, and the control strategy can effectively reduce the problem of high overshooting of the rotor of the expander and reach a stable state in a shorter time, which is of practical significance for promoting the application and popularization of LAES. [ABSTRACT FROM AUTHOR]

As a modern power grid that integrates advanced communication technology, sensor measurement technology, and intelligent control technology, the smart grid has good economy, reliability, and stability. Building a strong smart grid has important strategic significance for developing the national economy and improving Comprehensive National Power. The balance of electricity supply and demand, as a physical feature of the power system, determines the energy matching relationship between generation and consumption. Unreasonable power generation may lead to unmet electricity demand, as well as excess electricity and waste of resources. The energy storage has solved the problem of imbalance between supply and demand in most environments. The energy storage equipment provides a buffer space for electric energy, effectively adjusts the time unevenness of power grid load, realizes peak shaving and valley filling, and reduces the operation cost of the power grid. Taking the aboveground energy storage power station as the research object, the 3-D unsteady model of the small and medium-sized compressed energy storage system was established by using the FLUENT simulation software, and the correctness was verified through experimental methods. The influence of different environmental temperatures, chamber inflation flow rate, the thermodynamic characteristics of the surface condition and working chamber of the and energy storage were studied. The results show that the environmental temperature and expansion flow of oil storage chamber have important effects on its thermodynamic characteristics, while the surface conditions of oil storage chamber wall have little effect on its thermodynamic characteristics. [ABSTRACT FROM AUTHOR]

• The utility death spiral of China power sector due to grid-abandoners is deeply researched. • The Bass diffusion model is applied to evaluate the installation of rooftop PV systems and hybrid PV-BESS. • The utility death spiral is unlikely to occur under low-solar radiation in China's power sector. • Several significant inner drivers of rooftop PV systems and hybrid PV-BESS expansion are investigated. • The high-solar radiation, falling costs of PV and BESS, and increasing retail price can provoke grid abandonment through rooftop PV systems and hybrid PV-BESS expansions. Nowadays, owing to the price and technological advantages, photovoltaic (PV) and battery energy storage systems (BESS) have rapidly developed in China. The self-production and consumption of PV and BESS are causing consumers to abandon the power grid. However, this potential of grid abandonment in China's power sector remains unclear. Therefore, this paper deeply investigates the interaction between grid abandonment and the distribution price of utility, namely the utility death spiral to explore the potential in China. A method based on the innovation diffusion theory is proposed to reveal the causal loop of the death spiral. The Bass diffusion model, an approach of innovation diffusion theory, is applied to estimate the installations of rooftop PV systems and hybrid PV-BESS. After that, the distribution price, grid utilization level, and utility recovery cost based on China's price structure are evaluated. Sensitivity analyses are conducted to investigate several significant inner drivers of the rooftop PV systems and hybrid PV-BESS expansions. Results indicate that the utility death spiral is unlikely to occur in China with low-solar radiation, while it will occur in a high-solar radiation scenario with 57% penetration of rooftop PV systems. Compared with the return rates of the utility requirement, the cost reduction of PV and BESS, and even a 1% growth in the retail price cause the death spiral. When the death spiral occurs, the permeations of PV and BESS in the cost reduction scenario are 51% and 56%, while the permeations are 52% and 51% in the scenario of 1% growth of the retail price. Additionally, several possible solutions to avoid the death spiral are discussed, such as discriminatory prices, business models, price mechanisms, and support mechanisms. [ABSTRACT FROM AUTHOR]

Many applications rely on a correct estimation of the convective boundary layer (CBL) depth over mountainous terrain, but often these applications use numerical model simulations. Although models inevitably smooth terrain, the amount of smoothing depends on grid spacing. We investigate the behavior of the CBL in coarse- and fine-grid models applied to mountainous terrain by using output from an operational mesoscale modeling system and by performing quasi-idealized simulations. We investigate different areas in different climate zones using different CBL top derivation methods, grid spacing ratios, planetary boundary layer (PBL) schemes, and terrain smoothing. We find that when compared to fine-grid simulations, CBL depths are systematically larger in coarse domains over mountaintops, and to a lesser extent in valleys. On average, differences between coarse- and fine-domains over mountaintops could reach around 10%. In certain locations, differences could be as high as 25%. We attribute the result to terrain smoothing. Similarly, when using a coarse-grid CBL height (relative to mean sea level) interpolated using fine-grid terrain information, there is good agreement with fine-grid CBL depths over mountaintops and less agreement in valleys. Our results have implications for applications that use output from coarse model grids in mountainous terrain. These include inverse modeling studies (e.g., greenhouse gas budget estimations or integrated water vapor transport), PBL evaluation studies, climate research, air quality applications, planning and executing prescribed burns, and studies associated with precipitation over mountainous terrain. [ABSTRACT FROM AUTHOR]