Technologies

Editorial

Jump to: Research, Review

3 pages, 135 KB

Open AccessEditorial

Editorial for the Special Issue on Next-Generation Distribution System Planning, Operation, and Control

by Da Xu, Xiaodong Yang, Juan Wei and Xiaoshun Zhang

Technologies 2026, 14(2), 100; https://doi.org/10.3390/technologies14020100 - 3 Feb 2026

Viewed by 368

Abstract

The past years have seen a progressive process of urbanization and upgrading, along with the intelligentialization and popularity of supply-demand sides through advanced information and communication technologies [...] Full article

(This article belongs to the Special Issue Next-Generation Distribution System Planning, Operation, and Control)

Research

Jump to: Editorial, Review

18 pages, 1970 KB

Open AccessArticle

Robustness Assessment of Cyber-Physical Power Systems Considering Cyber Network Performance

by Xingle Gao, Yanchen Liu, Xi Zhang and Hua Shao

Technologies 2026, 14(1), 22; https://doi.org/10.3390/technologies14010022 - 31 Dec 2025

Viewed by 385

Abstract

The integration of cyber and physical networks in modern power system introduces complex interdependencies that necessitate effective robustness assessment frameworks. In this paper, we propose a novel robustness assessment method for cyber-physical power systems (CPPS), which integrates structural and functional robustness. Firstly, an [...] Read more.

The integration of cyber and physical networks in modern power system introduces complex interdependencies that necessitate effective robustness assessment frameworks. In this paper, we propose a novel robustness assessment method for cyber-physical power systems (CPPS), which integrates structural and functional robustness. Firstly, an interdependent dynamic hierarchical network model that accounts for static topological structure, functional attributes and dynamic operational characteristics of cyber-physical power system is established. Based on the model, a probabilistic cascading failure model considering topological connectivity loss, power flow overload, cyber functional failures, and cyber-physical dependence is proposed. The proposed model quantifies the cross-layer impact of cyber-layer impairments (such as communication delay and data loss) on physical-layer operation. Finally, the impacts of cyber network performance and initial failure modes on the robustness of the coupled system are analyzed. The results show that an excellent processing performance and topological connectivity of cyber network can enhance the robustness of the coupled system, and the failure of high-degree nodes is more likely to trigger more severe cascading failure results than the failure of high-betweenness nodes. Full article

(This article belongs to the Special Issue Next-Generation Distribution System Planning, Operation, and Control)

► Show Figures

Figure 1

30 pages, 4434 KB

Open AccessArticle

A Feature-Enhanced Approach to Dissolved Gas Analysis for Power Transformer Health Prediction Through Interpretable Ensemble Learning and Multi-Model Evaluation

by Rania A. Ibrahim and Ahmed Hebala

Technologies 2026, 14(1), 6; https://doi.org/10.3390/technologies14010006 - 21 Dec 2025

Cited by 2 | Viewed by 1086

Abstract

Dissolved Gas Analysis (DGA) is a diagnostic strategy that monitors oil-immersed transformers by correlating their health status with various insulation degradation by-products, where the Health Index (HI) offers a unified metric for asset evaluation. Existing studies frequently emphasize classification accuracy or single-model regression, [...] Read more.

Dissolved Gas Analysis (DGA) is a diagnostic strategy that monitors oil-immersed transformers by correlating their health status with various insulation degradation by-products, where the Health Index (HI) offers a unified metric for asset evaluation. Existing studies frequently emphasize classification accuracy or single-model regression, overlooking interpretability, feature reduction, and systematic benchmarking. This paper introduces a feature-enhanced multi-experimental methodology for HI prediction incorporating SHapley Additive exPlanations (SHAP) in a dual role—as both an interpretability and a feature selection tool. Models from four algorithmic families (linear, kernel/tree-based, boosting, and hybrid ensembles) were systematically benchmarked using a publicly available dataset. Results demonstrate that the proposed LightGBM–CatBoost hybrid ensemble, enhanced by SHAP-guided feature pruning, achieves superior predictive accuracy while reducing model complexity and improving transparency. Unlike prior works carried out using the same dataset, the proposed framework not only provides a balanced approach that combines interpretability and reduced complexity, but also surpasses previous regression-based approaches, reducing MAE and RMSE by 4.93% and 2.31%, respectively, and enhancing HI predictive accuracy by 1.45%. Full article

(This article belongs to the Special Issue Next-Generation Distribution System Planning, Operation, and Control)

► Show Figures

Figure 1

22 pages, 698 KB

Open AccessArticle

Model Predictive Load Frequency Control for Virtual Power Plants: A Mixed Time- and Event-Triggered Approach Dependent on Performance Standard

by Liangyi Pu, Jianhua Hou, Song Wang, Haijun Wei, Yanghaoran Zhu, Xiong Xu and Xiongbo Wan

Technologies 2025, 13(12), 571; https://doi.org/10.3390/technologies13120571 - 5 Dec 2025

Cited by 1 | Viewed by 900

Abstract

To improve the load frequency control (LFC) performance of power systems incorporating virtual power plants (VPPs) while reducing network resource consumption, a model predictive control (MPC) method based on a mixed time/event-triggered mechanism (MTETM) is proposed. This mechanism integrates an event-triggered mechanism (ETM) [...] Read more.

To improve the load frequency control (LFC) performance of power systems incorporating virtual power plants (VPPs) while reducing network resource consumption, a model predictive control (MPC) method based on a mixed time/event-triggered mechanism (MTETM) is proposed. This mechanism integrates an event-triggered mechanism (ETM) with a time-triggered mechanism (TTM), where ETM avoids unnecessary signal transmission and TTM ensures fundamental control performance. Subsequently, for the LFC system incorporating VPPs, a state hard constrained MPC problem is formulated and transformed into a “min-max” optimisation problem. Through linear matrix inequalities, the original optimisation problem is equivalently transformed into an auxiliary optimisation problem, with the optimal control law solved via rolling optimisation. Theoretical analysis demonstrates that the proposed auxiliary optimisation problem possesses recursive feasibility, whilst the closed-loop system satisfies input-to-state stability. Finally, validation through case studies of two regional power systems demonstrates that the MPC approach based on MTETM outperforms the ETM-based MPC approach in terms of control performance while maintaining a triggering rate of 33.3%. Compared with the TTM-based MPC algorithm, the MTETM-based MPC method reduces the triggering rate by 66.7%, while maintaining nearly equivalent control performance. Consequently, the results validate the effectiveness of the MTETM-based MPC approach in conserving network resources while maintaining control performance. Full article

(This article belongs to the Special Issue Next-Generation Distribution System Planning, Operation, and Control)

► Show Figures

Figure 1

23 pages, 3028 KB

Open AccessArticle

A Differentiation-Aware Strategy for Voltage-Constrained Energy Trading in Active Distribution Networks

by Wei Lou, Min Pan, Junran Zhouyang, Cheng Zhao, Ming Wang, Licheng Sun and Yifan Liu

Technologies 2025, 13(12), 557; https://doi.org/10.3390/technologies13120557 - 28 Nov 2025

Viewed by 605

Abstract

Free trading of distributed energy resources (DERs) is an effective way to enhance local renewable consumption and user-side economic efficiency. Yet unrestricted sharing may threaten operational security. To address this, this paper proposes a voltage-constrained, differentiated resource-sharing framework for active distribution networks (ADNs). [...] Read more.

Free trading of distributed energy resources (DERs) is an effective way to enhance local renewable consumption and user-side economic efficiency. Yet unrestricted sharing may threaten operational security. To address this, this paper proposes a voltage-constrained, differentiated resource-sharing framework for active distribution networks (ADNs). The framework maximizes users’ economic benefits and renewable absorption while keeping system voltages within safe limits. A local energy market with prosumers and the distribution network operator (DNO) is established. Prosumers optimize trading decisions considering transaction costs, wheeling charges, and operational costs. Based on this, a generalized Nash bargaining model is developed with two sub-problems: cost optimization under voltage constraints and payment negotiation. The DNO verifies prosumer decisions to ensure system constraints are satisfied. This paper quantifies prosumer heterogeneity by integrating market participation and voltage regulation contributions, and proposes a differentiated bargaining model to improve fairness and efficiency in DER trading. Finally, an ADMM-based distributed algorithm achieves market clearing under AC power flow constraints. Case studies on modified IEEE 33-bus and 123-bus systems validate the method’s effectiveness, the allocation of benefits between producers and consumers is more equitable, and the costs for highly engaged producers and consumers can be reduced by 46.75%. Full article

(This article belongs to the Special Issue Next-Generation Distribution System Planning, Operation, and Control)

► Show Figures

Figure 1

21 pages, 6004 KB

Open AccessArticle

A Frequency Regulation Strategy for Thermostatically Controlled Loads Combining Differentiated Deadband and Dynamic Droop Coefficients

by Meng Liu, Song Gao, Na Li, Yudun Li and Yuntao Sun

Technologies 2025, 13(11), 510; https://doi.org/10.3390/technologies13110510 - 8 Nov 2025

Viewed by 854

Abstract

With a large number of traditional thermal power units being replaced by inverter-based resources, the system inertia and regulation capability have significantly decreased in certain countries, exposing a critical gap in traditional generation-side-dominated frequency regulation strategies. The decline in system inertia deteriorates frequency [...] Read more.

With a large number of traditional thermal power units being replaced by inverter-based resources, the system inertia and regulation capability have significantly decreased in certain countries, exposing a critical gap in traditional generation-side-dominated frequency regulation strategies. The decline in system inertia deteriorates frequency dynamics, creating a critical need for load-side regulation. To enhance frequency stability in low-inertia power systems, this paper proposes a frequency regulation strategy for thermostatically controlled loads (TCLs). The strategy incorporates a differential deadband that adjusts response thresholds based on frequency deviation, along with dynamic droop coefficients that self-adapt according to real-time TCL capacity. First, the operational principles of TCLs and the frequency response characteristics of thermal power units are analyzed to establish the foundation for load-side frequency regulation. Second, building upon the spatiotemporal distribution characteristics of system frequency, the nodal frequency under high renewable energy penetration is derived, and a differential dead zone setting method for TCLs is proposed. Then, a dynamic droop coefficient tuning method is developed to enable adaptive parameter adjustment according to the real-time regulation capacity of TCLs. Finally, these key elements are integrated within a hybrid control framework to formulate the complete TCL frequency regulation strategy. Simulation results demonstrate a 0.342% improvement in frequency nadir and 0.253% reduction in settling time compared to conventional methods, while ensuring reliable TCL operation. This work presents a validated solution for enhancing frequency stability in renewable-rich power systems, where the proposed framework with nodal frequency-based deadbands and adaptive droop coefficients demonstrates effective regulation capability under low-inertia conditions. Full article

(This article belongs to the Special Issue Next-Generation Distribution System Planning, Operation, and Control)

► Show Figures

Figure 1

16 pages, 924 KB

Open AccessArticle

Optimal Control Strategy and Evaluation Framework for Frequency Response of Combined Wind–Storage Systems

by Jie Hao, Huiping Zheng, Xueting Cheng, Yuxiang Li, Liming Bo and Juan Wei

Technologies 2025, 13(6), 259; https://doi.org/10.3390/technologies13060259 - 19 Jun 2025

Cited by 2 | Viewed by 1566

Abstract

The increasing integration of wind turbines into the power grid has reduced the system frequency stability, necessitating the integration of energy storage systems in primary frequency regulation. This paper proposes an MPC-based control method to optimize the frequency response of a combined wind–storage [...] Read more.

The increasing integration of wind turbines into the power grid has reduced the system frequency stability, necessitating the integration of energy storage systems in primary frequency regulation. This paper proposes an MPC-based control method to optimize the frequency response of a combined wind–storage system. An evaluation system is also developed to characterize frequency response stability and guide power dispatch. First, the system model and state-space equations for MPC are established. Then, the control strategy is proposed to achieve the combined objective of minimizing power variation and frequency deviation. Finally, frequency stability is assessed using the evaluation system. MATLAB/Simulink case studies confirm the effectiveness of the proposed method in enhancing frequency regulation performance. The results show that this control strategy not only accelerates the response speed of the system frequency but also reduces its fluctuations, thereby improving the frequency stability of the system. Full article

(This article belongs to the Special Issue Next-Generation Distribution System Planning, Operation, and Control)

► Show Figures

Figure 1

17 pages, 3108 KB

Open AccessArticle

Optimal Transient Control Scheme for Grid-Forming Permanent Magnet Synchronous Generator-Based Wind Farms

by Pan Hu, Dan Liu, Kan Cao and Lai Wei

Technologies 2025, 13(6), 215; https://doi.org/10.3390/technologies13060215 - 26 May 2025

Cited by 1 | Viewed by 891

Abstract

In this paper, an optimal transient control (OTC) scheme is proposed to improve the transient stability of the grid-forming (GFM) wind farm (WF) based on the transient stability of the WTs. The converter’s current operating safety range is considered to quantify the maximum [...] Read more.

In this paper, an optimal transient control (OTC) scheme is proposed to improve the transient stability of the grid-forming (GFM) wind farm (WF) based on the transient stability of the WTs. The converter’s current operating safety range is considered to quantify the maximum KES capabilities of the WTs. At the WF control level, the global transient voltage control problem is solved by optimizing the output reactive power of different WTs of the WF. At the WT control level, the transient stability of WT is improved by regulating the output power and weak magnetic current. The simulation results in MATLAB/Simulink show that the proposed control scheme can more efficiently improve the transient stability of WT by suppressing the DC bus voltage fluctuations and enhancing the voltage support capability of WT compared with the traditional control schemes. Full article

(This article belongs to the Special Issue Next-Generation Distribution System Planning, Operation, and Control)

► Show Figures

Figure 1

30 pages, 7670 KB

Open AccessArticle

Comparative Analysis of Energy Consumption and Performance Metrics in Fuel Cell, Battery, and Hybrid Electric Vehicles Under Varying Wind and Road Conditions

by Ahmed Hebala, Mona I. Abdelkader and Rania A. Ibrahim

Technologies 2025, 13(4), 150; https://doi.org/10.3390/technologies13040150 - 9 Apr 2025

Cited by 13 | Viewed by 7943

Abstract

As global initiatives to reduce greenhouse gas emissions and combat climate change expand, electric vehicles (EVs) powered by fuel cells and lithium-ion batteries are gaining global recognition as solutions for sustainable transportation due to their high energy conversion efficiency. Considering the driving range [...] Read more.

As global initiatives to reduce greenhouse gas emissions and combat climate change expand, electric vehicles (EVs) powered by fuel cells and lithium-ion batteries are gaining global recognition as solutions for sustainable transportation due to their high energy conversion efficiency. Considering the driving range limitations of battery electric vehicles (BEVs) and the low efficiency of internal combustion engines (ICEs), fuel cell hybrid vehicles offer a compelling alternative for long-distance, low-emission driving with less refuelling time. To facilitate their wider scale adoption, it is essential to understand their energy performance through models that consider external weather effects, driving styles, road gradients, and their simultaneous interaction. This paper presents a microlevel, multicriteria assessment framework to investigate the performance of BEVs, fuel cell electric vehicles (FCEVs), and hybrid electric vehicles (HEVs), with a focus on energy consumption, drive systems, and emissions. Simulation models were developed using MATLAB 2021a Simulink environment, thus enabling the integration of standardized driving cycles with real-world wind and terrain variations. The results are presented for various trip scenarios, employing quantitative and qualitative analysis methods to identify the most efficient vehicle configuration, also validated through the simulation of three commercial EVs. Predictive modelling approaches are utilized to estimate a vehicle’s performance under unexplored conditions. Results indicate that trip conditions have a significant impact on the performance of all three vehicles, with HEVs emerging as the most efficient and balanced option, followed by FCEVs, making them strong candidates compared with BEVs for broader adoption in the transition toward sustainable transportation. Full article

(This article belongs to the Special Issue Next-Generation Distribution System Planning, Operation, and Control)

► Show Figures

Figure 1

18 pages, 5092 KB

Open AccessArticle

Predicting the Temperature of a Permanent Magnet Synchronous Motor: A Comparative Study of Artificial Neural Network Algorithms

by Nabil El Bazi, Nasr Guennouni, Mohcin Mekhfioui, Adil Goudzi, Ahmed Chebak and Mustapha Mabrouki

Technologies 2025, 13(3), 120; https://doi.org/10.3390/technologies13030120 - 17 Mar 2025

Cited by 9 | Viewed by 2582

Abstract

The accurate prediction of temperature in Permanent Magnet Synchronous Motors (PMSMs) has always been essential for monitoring performance and enabling predictive maintenance in the industrial sector. This study examines the efficiency of a set of artificial neural network (ANN) models, namely Multilayer Perceptron [...] Read more.

The accurate prediction of temperature in Permanent Magnet Synchronous Motors (PMSMs) has always been essential for monitoring performance and enabling predictive maintenance in the industrial sector. This study examines the efficiency of a set of artificial neural network (ANN) models, namely Multilayer Perceptron (MLP), Long Short-Term Memory (LSTM), Recurrent Neural Network (RNN), and Convolutional Neural Network (CNN), in predicting the Permanent Magnet Temperature. A comparative evaluation study is conducted using common performance indicators, including root mean square error (RMSE), mean absolute error (MAE), and coefficient of determination (R²), to assess the predictive accuracy of each model. The intent is to identify the most favorable model that balances high accuracy with low computational cost. Full article

(This article belongs to the Special Issue Next-Generation Distribution System Planning, Operation, and Control)

► Show Figures

Figure 1

15 pages, 912 KB

Open AccessArticle

A Three-Level Service Quality Index System for Wind Turbine Groups Based on Fuzzy Comprehensive Evaluation

by Xueting Cheng, Jie Hao, Yuxiang Li, Juan Wei, Weiru Wang and Yaohui Lu

Technologies 2024, 12(11), 234; https://doi.org/10.3390/technologies12110234 - 20 Nov 2024

Cited by 2 | Viewed by 2409

Abstract

The maintenance and upkeep costs of wind farms and their internal wind turbines have been increasing annually. Therefore, a systematic evaluation of their operating status is of great importance in guiding reductions in maintenance and upkeep costs. In this aspect, this article proposes [...] Read more.

The maintenance and upkeep costs of wind farms and their internal wind turbines have been increasing annually. Therefore, a systematic evaluation of their operating status is of great importance in guiding reductions in maintenance and upkeep costs. In this aspect, this article proposes a three-level service quality index system of “key component–wind turbine–wind farm” based on the fuzzy comprehensive evaluation method. Firstly, raw data on the wind farm are preprocessed to avoid the impact of abnormal data on the evaluation results. Then, the data types are classified and the degradation degree of each indicator is calculated. Based on the entropy weight method, the weight of each indicator is weighted and summed to obtain the overall membership degree. Finally, the overall health level is determined according to the “maximum membership degree”, which is the evaluation result. This article conducts an evaluation experiment based on the actual operating data of Gansu Huadian Nanqiu Wind Farm. The example shows that the proposed strategy can systematically evaluate the health level of wind farms and predict the future trends of health status changes. The research results can provide reference for the reasonable arrangement of unit scheduling, operation, and maintenance plans in wind farms. Full article

(This article belongs to the Special Issue Next-Generation Distribution System Planning, Operation, and Control)

► Show Figures

Figure 1

Review

Jump to: Editorial, Research

31 pages, 529 KB

Open AccessReview

Review of Virtual Power Plant Response Capability Assessment and Optimization Dispatch

by Junhui Huang, Hui Li and Zhaoyun Zhang

Technologies 2025, 13(6), 216; https://doi.org/10.3390/technologies13060216 - 26 May 2025

Cited by 21 | Viewed by 9667

Abstract

Functioning as a smart aggregation entity that combines distributed energy resources, energy storage systems, and flexible loads, virtual power plants (VPPs) serve as a pivotal technology in advancing the decarbonization and flexibility enhancement of modern power systems. Initially, we summarize the developmental context, [...] Read more.

Functioning as a smart aggregation entity that combines distributed energy resources, energy storage systems, and flexible loads, virtual power plants (VPPs) serve as a pivotal technology in advancing the decarbonization and flexibility enhancement of modern power systems. Initially, we summarize the developmental context, evolutionary trajectory, and conceptual framework of VPPs. The architecture is functionally partitioned into three tiers: the aggregation layer, communication layer, and dispatch optimization layer (central layer). The dispatch optimization layer of VPPs serves as the “intelligent brain” connecting physical resources with electricity markets, whose core lies in achieving “controllable, adjustable, and optimizable” distributed resources through algorithmic and data-driven approaches, driving the energy system transition towards low-carbon, flexible, and efficient directions. Next, we critically examine core technologies in the dispatch optimization layer, particularly the response capacity assessment and optimal resource scheduling. Its content mainly focuses on the latest research on the aggregated resource response capability evaluation, virtual power plant dispatching optimization models, and dispatching strategies. Conclusively, we analyze prevailing technical bottlenecks and summarize significant advancements, concluding with prospective insights into future research frontiers and developmental priorities for VPPs. In the future energy system transition, VPPs will play an increasingly important role. It is foreseeable that the utilization efficiency of renewable energy will be significantly enhanced, and the energy market will become more diverse and vibrant. We look forward to VPPs integrating more quickly and effectively into daily life, transforming lifestyles and helping people collectively step into a low-carbon, green future. Full article

(This article belongs to the Special Issue Next-Generation Distribution System Planning, Operation, and Control)

► Show Figures

Graphical abstract

42 pages, 1390 KB

Open AccessReview

Pathways to 100% Renewable Energy in Island Systems: A Systematic Review of Challenges, Solutions Strategies, and Success Cases

by Danny Ochoa-Correa, Paul Arévalo and Sergio Martinez

Technologies 2025, 13(5), 180; https://doi.org/10.3390/technologies13050180 - 1 May 2025

Cited by 12 | Viewed by 9599

Abstract

The transition to 100% renewable energy systems is critical for achieving global sustainability and reducing dependence on fossil fuels. Island power systems, due to their geographical isolation, limited interconnectivity, and reliance on imported fuels, face unique challenges in this transition. These systems’ vulnerability [...] Read more.

The transition to 100% renewable energy systems is critical for achieving global sustainability and reducing dependence on fossil fuels. Island power systems, due to their geographical isolation, limited interconnectivity, and reliance on imported fuels, face unique challenges in this transition. These systems’ vulnerability to supply–demand imbalances, voltage instability, and frequency deviations necessitates tailored strategies for achieving grid stability. This study conducts a systematic review of the technical and operational challenges associated with transitioning island energy systems to fully renewable generation, following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) methodology. Out of 991 identified studies, 81 high-quality articles were selected, focusing on key aspects such as grid stability, energy storage technologies, and advanced control strategies. The review highlights the importance of energy storage solutions like battery energy storage systems, hydrogen storage, pumped hydro storage, and flywheels in enhancing grid resilience and supporting frequency and voltage regulation. Advanced control strategies, including grid-forming and grid-following inverters, as well as digital twins and predictive analytics, emerged as effective in maintaining grid efficiency. Real-world case studies from islands such as El Hierro, Hawai’i, and Nusa Penida illustrate successful strategies and best practices, emphasizing the role of supportive policies and community engagement. While the findings demonstrate that fully renewable island systems are technically and economically feasible, challenges remain, including regulatory, financial, and policy barriers. Full article

(This article belongs to the Special Issue Next-Generation Distribution System Planning, Operation, and Control)

► Show Figures

Figure 1

40 pages, 8054 KB

Open AccessReview

Solid State Transformers: A Review—Part I: Stages of Conversion and Topologies

by Dragoș-Mihail Predescu and Ștefan-George Roșu

Technologies 2025, 13(2), 74; https://doi.org/10.3390/technologies13020074 - 10 Feb 2025

Cited by 5 | Viewed by 13342

Abstract

Solid State Transformers (SSTs) represent an emerging technology that seeks to improve upon traditional Low-Frequency Transformers (LFTs) with Medium-Frequency Transformers (MFTs) of reduced core size while incorporating modular converter structures as their input and output stages. In addition to magnetic circuit reduction, SSTs [...] Read more.

Solid State Transformers (SSTs) represent an emerging technology that seeks to improve upon traditional Low-Frequency Transformers (LFTs) with Medium-Frequency Transformers (MFTs) of reduced core size while incorporating modular converter structures as their input and output stages. In addition to magnetic circuit reduction, SSTs provide enhanced functionalities such as power factor correction, voltage regulation, and the capability to interface with various sources and loads. However, owing to the novelty of SSTs and the various proposed implementations, a general review would difficult to follow and might not be able to adequately analyze each aspect of SST structures. This complexity underscores the need for a new division of information and classification based on the number of conversion stages, which is the main contribution of this study. Converter functionalities are derived based on the number of stages. Utilizing these functionalities along with existing and proposed implementations, converter topologies are identified and then detailed in terms of their respective functionalities, advantages, disadvantages, and control schemes. The subsequent chapters provide a comparative analysis of the different topologies and present existing SST implementations. For this analysis, metrics such as the number of SST stages, power flow, voltage control, power quality, and component count are used. Based on the resulting analysis, single-stage SSTs are a promising solution that emphasize economy and high power density, while multi-stage SSTs are also a viable solution thanks to their ease of control and flexible design. This paper constitutes the first part of a two-part review. The second part will focus on the degrees of design freedom (such as multilevel structures/cells) and provide a generalized approach to modularity within SST systems. Full article

(This article belongs to the Special Issue Next-Generation Distribution System Planning, Operation, and Control)

► Show Figures

Figure 1

30 pages, 13507 KB

Open AccessReview

Solid-State Transformers: A Review—Part II: Modularity and Applications

by Dragoș-Mihail Predescu and Ștefan-George Roșu

Technologies 2025, 13(2), 50; https://doi.org/10.3390/technologies13020050 - 28 Jan 2025

Cited by 5 | Viewed by 8617

Abstract

The Solid-State Transformer (SST) is a complex conversion device that intends to replace the Low-Frequency Transformers (LFTs) used in various power applications with Medium- or High-Frequency Transformers (MFTs/HFTs) that integrate modular converter structures as their input and output stages. The purpose is to [...] Read more.

The Solid-State Transformer (SST) is a complex conversion device that intends to replace the Low-Frequency Transformers (LFTs) used in various power applications with Medium- or High-Frequency Transformers (MFTs/HFTs) that integrate modular converter structures as their input and output stages. The purpose is to obtain additional capabilities, such as power factor correction, voltage control, and interconnection of distributed supplies, among others, while reducing the overall volume. Given the expansive research conducted in this area in the past years, the volume of information available is large, so the main contribution of this paper is a new method of classification based on the modular construction of the SST derived from its applications and available constructive degrees of freedom. This paper can be considered the second part of a broader review in which the first part presented the fundamental converter roles and topologies. As a continuation, this paper aims to expand the definition of modularity to the entire SST structure and analyze how the converters can be combined in order to achieve the desired SST functionality. Three areas of interest are chosen: partitioning of power, phase modularity, and port configuration. The partitioning of power analyzes the fundamental switching cells and the arrangement of the converters across stages. Phase modularity details the construction of multiphase-system SSTs. Finally, the types of input/output ports, their placements, and roles are discussed. These characteristics are presented together with the applications in which they were suggested to give a broader context. Full article

(This article belongs to the Special Issue Next-Generation Distribution System Planning, Operation, and Control)

► Show Figures

Figure 1

Journal Menu

Journal Browser

Next-Generation Distribution System Planning, Operation, and Control

Share This Special Issue

Special Issue Editors

Special Issue Information

Keywords

Benefits of Publishing in a Special Issue

Related Special Issue

Published Papers (15 papers)

Editorial

Research

Review

Further Information

Guidelines

MDPI Initiatives

Follow MDPI