Journal of Modern Power Systems and Clean Energy

ISSN 2196-5625 CN 32-1884/TK

Highlights
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  • This paper captures an engaging—and at times heated—Power-Globe (PG) discussion of evolving definitions of smart grid technologies. The exchange took place between December 2024 and January 2025. The primary objective of this paper is to clarify some of the ambiguities surrounding the term “smart grid” over the past two decades, as highlighted in the spirited PG debate. “Smart grids” have sometimes been advocated as a panacea to resolve the tension between competing objectives for the provision of electricity (specifically, making it reliable, clean, and affordable). This paper examines the term “smart grid” in terms of raw technical functionalities, applications, and use cases, some of which may get closer than others to meeting the aspirational promises. While smart technology should expand our menu of options, it will not absolve us of the need to make hard decisions.
  • This paper provides an overview of the application potential of artificial intelligence (AI) in power systems and points towards prospective developments in the fields of AI that are promised to play a transformative role in the evolution of power systems. Among the basic requirements, also imposed by regulation in some places, are trustworthiness and interpretability. Large language models, foundation models, as well as neuro-symbolic and compound AI models, appear to be the most promising emerging AI paradigms. Finally, the trajectories along which the future of AI in power systems might evolve are discussed, and conclusions are drawn.
  • Planning the low-carbon transition pathway of the power sector to meet the carbon neutrality goal poses a significant challenge due to the complex interplay of temporal, spatial, and cross-domain factors. A novel framework is proposed, grounded in the cyber-physical-social system in energy (CPSSE) and whole-reductionism thinking (WRT), incorporating a tailored mathematical model and optimization method to formalize the co-optimization of carbon reduction and carbon sequestration in the power sector. Using the carbon peaking and carbon neutrality transition of China as a case study, clustering method is employed to construct a diverse set of strategically distinct carbon trajectories. For each trajectory, the evolution of the generation mix and the deployment pathways of carbon capture and storage (CCS) technologies are analyzed, identifying the optimal transition pathway based on the criterion of minimizing cumulative economic costs. Further, by comparing non-fossil energy substitution and CCS retrofitting in thermal power, the analysis high-lights the potential for co-optimization of carbon reduction and carbon sequestration. The results demonstrate that leveraging the spatiotemporal complementarities between the two can substantially lower the economic cost of achieving carbon neutrality, providing insights for integrated decarbonization strategies in power system planning.
  • In a high-risk sector, such as power system, transparency and interpretability are key principles for effectively deploying artificial intelligence (AI) in control rooms. Therefore, this paper proposes a novel methodology, the evolving symbolic model (ESM), which is dedicated to generating highly interpretable data-driven models for dynamic security assessment (DSA), namely in system security classification (SC) and the definition of preventive control actions. The ESM uses simulated annealing for a data-driven evolution of a symbolic model template, enabling different cooperative learning schemes between humans and AI. The Madeira Island power system is used to validate the application of the ESM for DSA. The results show that the ESM has a classification accuracy comparable to pruned decision trees (DTs) while boasting higher global inter-pretability. Moreover, the ESM outperforms an operator-defined expert system and an artificial neural network in defining preventive control actions.
  • To address environmental concerns, there has been a rapid global surge in integrating renewable energy sources into power grids. However, this transition poses challenges to grid stability. A prominent solution to this challenge is the adoption of battery energy storage systems (BESSs). Many countries are actively increasing BESS deployment and developing new BESS technologies. Nevertheless, a crucial initial step is conducting a comprehensive analysis of BESS capabilities and subsequently formulating policies. We analyze the current roles of BESS and review existing BESS policies worldwide, which focuses on key markets in Asia, Europe, and the U.S.. Using collected survey data, we propose a comprehensive three-phase framework for policy formulation, providing insights into future policy development directions.
  • Electric vehicles (EVs) are becoming more popular worldwide due to environmental concerns, fuel security, and price volatility. The performance of EVs relies on the energy stored in their batteries, which can be charged using either AC (slow) or DC (fast) chargers. Additionally, EVs can also be used as mobile power storage devices using vehicle-to-grid (V2G) technology. Power electronic converters (PECs) have a constructive role in EV applications, both in charging EVs and in V2G. Hence, this paper comprehensively investigates the state of the art of EV charging topologies and PEC solutions for EV applications. It examines PECs from the point of view of their classifications, configurations, control approaches, and future research prospects and their impacts on power quality. These can be classified into various topologies: DC-DC converters, AC-DC converters, DC-AC converters, and AC-AC converters. To address the limitations of traditional DC-DC converters such as switching losses, size, and high-electromagnetic interference (EMI), resonant converters and multiport converters are being used in high-voltage EV applications. Additionally, power-train converters have been modified for high-efficiency and reliability in EV applications. This paper offers an overview of charging topologies, PECs, challenges with solutions, and future trends in the field of the EV charging station applications.
  • The accurate prediction of photovoltaic (PV) power generation is significant to ensure the economic and safe operation of power systems. To this end, the paper establishes a new digital twin (DT) empowered PV power prediction framework that is capable of ensuring reliable data transmission and employing the DT to achieve high accuracy of power prediction. With this framework, considering potential data contamination in the collected PV data, a generative adversarial network is employed to restore the historical dataset, which offers a prerequisite to ensure accurate mapping from the physical space to the digital space. Further, a new DT-empowered PV power prediction method is proposed. Therein, we model a DT that encompasses a digital physical model for reflecting the physical operation mechanism and a neural network model (i.e., a parallel network of convolution and bidirectional long short-term memory model) for capturing the hidden spatiotemporal features. The proposed method enables the use of the DT to take advantages of the digital physical model and the neural network model, resulting in enhanced prediction accuracy. Finally, a real dataset is conducted to assess the effectiveness of the proposed method.
  • Oscillations caused by small-signal instability have been widely observed in AC grids with grid-following (GFL) and grid-forming (GFM) converters. The generalized short-circuit ratio is commonly used to assess the strength of GFL converters when integrated with weak AC systems at risk of oscillation. This paper provides the grid strength assessment method to evaluate the small-signal synchronization stability of GFL and GFM converters integrated systems. First, the admittance and impedance matrices of the GFL and GFM converters are analyzed to identify the frequency bands associated with negative damping in oscillation modes dominated by heterogeneous synchronization control. Secondly, based on the interaction rules between the short-circuit ratio and the different oscillation modes, an equivalent circuit is proposed to simplify the grid strength assessment through the topological transformation of the AC grid. The risk of sub-synchronization and low-frequency oscillations, influenced by GFL and GFM converters, is then reformulated as a semi-definite programming (SDP) model, incorporating the node admittance matrix and grid-connected device capacities. The effectiveness of the proposed method is demonstrated through a case analysis.
  • As renewable energy continues to be integrated into the grid, energy storage has become a vital technique supporting power system development. To effectively promote the efficiency and economics of energy storage, centralized shared energy storage (SES) station with multiple energy storage batteries is developed to enable energy trading among a group of entities. In this paper, we propose the optimal operation with dynamic partitioning strategy for the centralized SES station, considering the day-ahead demands of large-scale renewable energy power plants. We implement a multi-entity cooperative optimization operation model based on Nash bargaining theory. This model is decomposed into two subproblems: the operation profit maximization problem with energy trading and the leasing payment bargaining problem. The distributed alternating direction multiplier method (ADMM) is employed to address the subproblems separately. Simulations reveal that the optimal operation with a dynamic partitioning strategy improves the tracking of planned output of renewable energy entities, enhances the actual utilization rate of energy storage, and increases the profits of each participating entity. The results confirm the practicality and effectiveness of the strategy.
  • The utilization of high-voltage direct current (HVDC) lines for the segmentation of the European power grid has been demonstrated to be a highly effective strategy for the mitigation of the risk of cascading blackouts. In this study, an accurate and efficient method for determining the optimal power flow through HVDC lines is presented, with the objective of minimizing load shedding. The proposed method is applied to two distinct scenarios: first, the segmentation of the power grid along the Pyrenees, with the objective of segmenting the Iberian Peninsula from the rest of Europe; and second, the segmentation of the power grid into Eastern and Western Europe, approximately in half. In both scenarios, the method effectively reduces the size of blackouts impacting both sides of the HVDC lines, resulting in a 46% and 67% reduction in total blackout risk, respectively. Furthermore, we have estimated the cost savings from risk reduction and the expenses associated with converting conventional lines to HVDC lines. Our findings indicate that segmenting the European power grid with HVDC lines is economically viable, particularly for segmenting the Iberian Peninsula, due to its favorable cost-risk reduction ratio.
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    Volume 14, Issue 2, 2026

    >Review
  • Huangqing Xiao, Huichen Gan, Ying Huang, Lidong Zhang, Ping Yang

    2026,14(2):383-398, DOI: 10.35833/MPCE.2025.000269

    Abstract:

    The rapid development of large-scale offshore wind power (OWP) calls for more cost-effective and reliable collection and transmission technologies. This paper explores three emerging collection technologies: medium-frequency alternating current (AC) collection, direct current (DC) collection, and AC collection without substation; and three transmission technologies: voltage source converter-based high-voltage direct current based on compact modular multilevel converters (MMCs), diode rectifier unit (DRU) based high-voltage direct current (DRU-HVDC), and high-voltage direct current (HVDC) based on hybrid converters. It systematically reviews recent research advancements in these technologies, analyzes critical technical challenges, and identifies key future development trends, providing practical insights to guide the design and optimization of OWP projects. At the collection level, a higher frequency reduces the size of critical equipment in offshore platforms but also leads to increased cable costs. DC offshore wind farms offer advantages such as lower cable costs. However, the design of high-power DC transformers presents challenges. At the transmission level, the size and weight of MMCs can be minimized through topology improvement and control optimization. The practical deployment of DRUs and HVDC systems depends on the technology maturity of grid-forming wind turbines. Moreover, critical aspects of hybrid converters such as capacity design, coordinated control, and stability analysis require further in-depth investigation.

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  • Jianlin Li, Zelin Shi, Zhonghao Liang

    2026,14(2):399-415, DOI: 10.35833/MPCE.2025.000608

    Abstract:

    With the increasing integration of large-scale renewable energy (RE) sources into power systems, electricity-hydrogen coupling system has emerged as a transformative solution through flexible energy conversion and complementary utilization of electricity and hydrogen. It effectively addresses structural challenges in conventional energy systems regarding spatiotemporal regulation, environmental constraints, and supply security while creating significant opportunities in technological innovation and industrial transformation, accelerating the transition from traditional fossil fuels to clean energy. This paper reviews the strengths and limitations of the electricity-hydrogen coupling system in production, storage, and utilization in scenarios of high RE penetration. It examines the architectural frameworks and current development status of key technologies within the electricity-hydrogen coupling system, and builds on their operational characteristics across multiple timescales to analyze both short-term energy balance control and medium- and long-term optimal dispatch. This paper further investigates representative application scenarios, systematically evaluates demonstration projects deployed, and critically analyzes prevailing challenges alongside prospective research pathways.

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  • >Original Paper
  • Jiawei Zhao, Jingbo Dong, Huijie Cheng, Leming Zhou

    2026,14(2):416-429, DOI: 10.35833/MPCE.2025.000255

    Abstract:

    Due to structural differences and parameter mismatches, power oscillation may arise when the diesel generator (DG) and virtual synchronous generator (VSG) operate in parallel, especially when the periodic pulsed load (PPL) is integrated. This paper analyses the power oscillation mechanism in the paralleled system of DG and VSG and provides an in-depth discussion of the novel phenomenon of power oscillation induced by PPL. The results show that power oscillation is amplified as the PPL pulse frequency approaches the inherent oscillation frequency of the paralleled system. Furthermore, the inherent control delay of the DG speed governor exacerbates the power oscillation. To address this issue, a dynamic phase compensator (DPC) is proposed and integrated into the VSG control loop. By detecting the difference between the instantaneous output power of VSG and its steady-state theoretical value, the proposed DPC provides additional phase compensation to the VSG output phase, effectively suppressing power oscillation for the paralleled system of DG and VSG integrated with PPL. Finally, experimental results validate the theoretical analysis and demonstrate the effectiveness of the proposed DPC.

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  • Jaume Girona-Badia, Juan Carlos Olives-Camps, Vinicius Albernaz Lacerda, Eduardo Prieto-Araujo, Oriol Gomis-Bellmunt

    2026,14(2):430-441, DOI: 10.35833/MPCE.2025.000144

    Abstract:

    This paper analyzes the effect of a frequency estimator in a grid-forming (GFM) synchronization control on the stability and control performance. GFM control for power converters has been proposed as a promising solution to enhance the stability and resilience of electrical systems dominated by power electronics. However, no consensus has been reached on the control structure for this operation mode. Moreover, the interactions between different GFM schemes and frequency estimators are not completely defined in the literature. In this paper, the effect of adding a frequency estimator to the two main industry-class synchronization controls, i.e., droop and virtual synchronous machine (VSM), is studied. Additionally, different AC voltage measurement points, tuning, and structures of frequency estimator are considered. Two distinct analyses are performed to discuss the characteristics of different configurations① an analytical study on the control performance of different configurations, and a small-signal analysis to ensure system stability. Finally, the results are validated using dynamic simulations, followed by a discussion. This paper concludes that the droop should be avoided when applying a frequency estimator, and other structures such as the VSM are more desirable.

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  • Yangyang Chen, Wei Han, Youhao Hu, Hanlei Tian, Yilin Zhang, Junyu Fan

    2026,14(2):442-453, DOI: 10.35833/MPCE.2025.000206

    Abstract:

    The increasing use of distributed generation has revealed limitations in conventional power electronic converters, which are unable to provide sufficient inertia and damping support to the grid. As a result, virtual synchronous generator (VSG) has gained widespread adoption for regulating the output voltage and frequency. However, VSG may encounter challenges such as generating large inrush currents and power fluctuations during on-grid switching, significantly reducing the efficacy of virtual synchronous control strategies. Therefore, this study optimizes the dynamic performance of VSG based on grid-connected switching control strategy using radial basis function neural network (RBFNN) integrated nonlinear active disturbance rejection control (NLADRC) approach. In comparison with the conventional pre-synchronization control strategy, the proposed strategy effectively suppresses system variable oscillations through the NLADRC approach. This facilitates the rapid restoration of system output frequency, voltage, and power to the steady state, thereby enhancing transient stability. Moreover, the RBFNN-NLADRC approach leverages the robust fitting capability of the network for obtaining dynamic parameter information, which allows for gain parameter tuning, further enhancing the effectiveness of the proposed strategy. Finally, verifications conducted in MATLAB/Simulink and a Starsim hardware-in-the-loop environment illustrate the superiority and feasibility of the proposed strategy.

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  • Liciane Otremba, Renato M. Monaro, Gilney Damm, Cristiano M. Verrelli

    2026,14(2):454-465, DOI: 10.35833/MPCE.2024.000824

    Abstract:

    The application of a virtual synchronous generator (VSG) to provide virtual inertia in isolated microgrids has emerged as a promising control strategy for converter-interfaced renewable energy sources. However, tuning the VSG parameters requires an accurate characterization of frequency dynamics, which remains a challenge, particularly in hybrid microgrids combining conventional and renewable units. In this context, this paper proposes a reduced-order model to support the parameter tuning of VSGs in an isolated hybrid microgrid composed of an oil and gas facility powered by gas generators connected to an offshore wind turbine. A VSG-based control strategy is applied on the grid-side converter of the wind turbine, allowing it to contribute to frequency regulation and inertia emulation. An analytical formulation is developed to determine the frequency nadir, its time of occurrence, and the rate of change of frequency based on the fixed parameters of the gas generators and the tunable parameters of the VSG. A procedure for parameter tuning to attain the desired frequency dynamics is derived from the analytical formulation. Simulations based on MATLAB/Simulink Simscape Electrical model demonstrate the effectiveness of the proposed procedure by illustrating its consistency in guiding parameter tuning and achieving the desired frequency dynamics.

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  • Lei Chen, Tianhao Wen, Yuqing Lin, Yang Liu, Yingjie Qin, Qing-Hua Wu

    2026,14(2):466-477, DOI: 10.35833/MPCE.2024.001166

    Abstract:

    The traditional power system dominated by synchronous generators is gradually evolving into a modern power system featured by high-penetrated renewable energy. As a key technology for high-penetrated renewable energy, the grid-forming voltage source converter (GFM-VSC) has received increasing attention. However, the large-disturbance stability analysis of power systems with multiple GFM-VSCs is still a challenging problem due to various limitations of existing methods, including huge computational burden and difficulty in considering network losses. This paper is intended to address these issues from the perspective of reduced-order modeling and domain of attraction (DA) estimation. The innovations involve three aspects. First, the reduced-order modeling method for power systems with multiple GFM-VSCs is proposed using the standard dual-time-scale model in singular perturbation theory. Second, an expanding annular domain (EAD) algorithm is developed to estimate the DA with an entire boundary to analyze the large-disturbance stability of power systems. Third, the conditions of using the reduced-order modeling method based on singular perturbation theory have been clarified. The validity of the reduced-order modeling method is illustrated on a modified 39-bus system with 10 GFM-VSCs.

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  • Han Wu, Tao Wang, Xiang Meng, Lijian Wu

    2026,14(2):478-491, DOI: 10.35833/MPCE.2025.000148

    Abstract:

    To reduce the cost of offshore wind power generation systems, the configuration of the offshore wind farm employing doubly-fed induction generator (DFIG) connected to the diode rectifier unit-based high-voltage direct current (DRU-HVDC) system has emerged as an attractive solution. The control strategy of the DFIG plays a crucial role in ensuring reliable operation of the offshore wind power generation system due to the uncontrollable nature of the diode rectifier unit (DRU). This paper proposes a self-synchronized grid-forming control strategy for the DFIG in offshore wind farm connected to DRU-HVDC system. Considering the unique power characteristics of the DRU, the proposed strategy constructs a novel power synchronization control loop, which achieves self-synchronization of the DFIGs in offshore wind farm without any communication network. Additionally, the harmonic distortion induced by the natural commutation characteristic of the DRU introduces significant electromagnetic ripples to the DFIG through the stator windings. To mitigate this, an electromagnetic oscillation reduction method based on harmonic current injection is incorporated into the structure of the proposed strategy. Simulation results based on MATLAB/Simulink validate the effectiveness of the proposed strategy and the electromagnetic oscillation reduction method.

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  • Zhenxiang Liu, Yanbo Chen, Jiahao Ma, Zhi Zhang

    2026,14(2):492-502, DOI: 10.35833/MPCE.2025.000029

    Abstract:

    The high penetration of renewable energy sources interfaced throush power electronic converters often leads to small-signal stability issues. Therefore, it is critical to quantify the impact of control parameters in multiple grid-connected converters on the small-signal stability of power system. To this end, this paper derives the small-signal stability criterion and provides the quantitative analysis of parameter sensitivity for multiple grid-connected converter systems (MGCCSs) based on extended Gershgorin theorem, thereby clarifying the influence of control parameters on the small-signal stability and providing the foundation for adaptive control. Crucially, leveraging this sensitivity analysis, we propose an adaptive control strategy involving targeted parameter adjustment for the identified weak links to ensure that the system operates with a specified stability margin. Both theoretical analysis and simulation prove the effectiveness of the proposed adaptive control strategy in the improving the small-signal stability of MGCCSs. Importantly, the proposed adaptive control strategy also demonstrates the significant potential for online application to adaptively compensate the small-signal stability margin in real time.

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  • Yuejian Wu, Xiaoming Dong, Tianguang Lu, Zhengqi Liu, Chengfu Wang

    2026,14(2):503-513, DOI: 10.35833/MPCE.2025.000150

    Abstract:

    The coordinated dispatch of interconnected grids characterized by maldistributed sustainable energy encounters challenges with regional privacy. Thus, this study proposes a non-iterative robust economic dispatch method for interconnected grids based on tie-line power transfer regulation. The economic dispatch model with uncertainties is transformed into a two-layer robust model and further treated as a single-layer linear model by strong duality theorem. Then, the intra-regional submodules are established by temporal and spatial decomposition to enable parallel execution. The inter-regional power transfer feasible region (PTFR) and intra-regional operation cost feasible region (OCFR) are evaluated using multi-parameter programming theory to protect the private and sensitive information of each region and to ensure cost efficiency of dispatch results. Additionally, the boundaries of feasible regions are adjusted by the conservatism budget to address multiple fluctuation intervals of stochastic factors. Finally, the information of feasible regions is shared between each intra-regional operator along with central coordination layer, generating feasible regions of joint economic dispatch along with inter-regional power transfer constraints. The intra-regional dispatch strategy could be rapidly obtained following the decision-making of inter-regional dispatch by mapping relations. Case studies by three modified IEEE test systems demonstrate the preciseness and effectiveness of the proposed method.

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  • Sina Hashemi, Balaji V. Venkatasubramanian, Pierluigi Mancarella, Mathaios Panteli

    2026,14(2):514-528, DOI: 10.35833/MPCE.2024.001371

    Abstract:

    Power grids face significant threats from severe disturbances, often triggered by extreme weather, leading to widespread cascading power outages. Although intentional controlled islanding (ICI) is an effective last-resort operational mitigation strategy employed by system operators worldwide to prevent complete cascading blackouts, the impact of large-scale disturbances, particularly weather-induced cascading outages, on when and where to implement the ICI, is neither adequately considered nor reflected in current operational decision-making standards and procedures. This paper proposes a holistic cascading-driven ICI framework that seamlessly integrates advanced weather-related event modelling and cascading risk quantification of high-impact low-probability (HILP) (or tail-risk) events by using a novel ICI based on decision-making mechanism for enhancing the power grid operational resilience. The proposed framework provides a portfolio of mitigation actions proportional to cascading impacts, differentiating between tail-risk events and expected (average) events typically addressed in reliability-oriented studies and current industry practices, while being tailored to both near-real-time operations and short-term operational planning. The proposed framework involves system splitting around black-start units while forming stable and self-sufficient islands, thereby enhancing reliability and resilience. Studies on the IEEE 39-bus and IEEE 118-bus systems demonstrate the effectiveness with a significant improvement in served demand across all simulated initiating events, including up to N - 6 contingencies.

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  • Zhaoqin Hu, Yunpeng Xiao, Xiuli Wang, Xifan Wang

    2026,14(2):529-540, DOI: 10.35833/MPCE.2025.000233

    Abstract:

    The increase in the penetration rate of renewable energy exacerbates the rise in system short-circuit level. Thus, short-circuit constraints (SCCs) are crucial in the co-optimization of transmission and generation expansion planning. The deregulated environment further complicates this process by assigning responsibilities for transmission and generation to separate market entities. This paper proposes a multi-period co-optimization method of transmission and wind turbine generation expansion planning to address this challenge. The transmission expansion planning (TEP) problem limits the short-circuit level, which could be elevated by lines, synchronous generators, and wind turbine generators. The method is formulated as a tri-level mixed-integer linear programming (MILP) problem, where an equilibrium problem with equilibrium constraints is formed at the second and third levels. This problem is restructured into a MILP problem with Nash equilibrium conditions via complementarity problem reformulation. We propose an iterative algorithm targeting the SCCs to solve it. The effectiveness of the proposed method is validated on the IEEE 24-bus reliability test system through comparisons with three existing TEP methods, analyzing the impact of SCCs and generation expansion planning on TEP and the system operating cost under a deregulated environment.

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  • Wenlong Wu, Zhongguan Wang, Xialin Li, Li Guo, Yixin Liu, Jiaqing Zhai, Chengshan Wang

    2026,14(2):541-551, DOI: 10.35833/MPCE.2024.001345

    Abstract:

    High penetration of wind power into power grids deteriorates system frequency stability. Wind turbines (WTs) are required by grid codes to participate in primary frequency regulation (PFR) by adjusting their rotor speed to utilize the stored kinetic energy. However, frequency support causes a change in rotor speed, and hence, the PFR capability of a wind farm is limited by a time-varying boundary. As the mechanical transient process of the WT is determined by wind speed, it is necessary to forecast the PFR capability of wind farms based on wind speed distribution, to arrange the system scheduling plan while considering dynamic safety. In this paper, a physics-informed probability distribution assessment method is proposed for the PFR capability of wind farms considering wind speed uncertainty. Constructing the analytical correlation relationship between state variables based on Koopman-operator-theory-based state space transformation, the probability density function of the maximum feasible droop coefficient of a wind farm is derived based on the wind speed probability distribution. The simulation results demonstrate that the proposed method achieves a five-order-of-magnitude reduction in computational time compared with the Monte Carlo and time-domain simulation methods, and possesses the advantages of independence from physical parameters and random sampling errors, as well as a simple analytical expression of the probability distribution of PFR capability.

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  • Hangyue Liu, Cuo Zhang, Jiawei Wang, Ke Meng, Zhao Yang Dong

    2026,14(2):552-563, DOI: 10.35833/MPCE.2025.000285

    Abstract:

    Conventional joint operation of integrated electricity and heating systems faces severe challenges, including non-convex models and computation complexity. Additionally, there are adverse impacts from the uncertainties of renewable distributed generators, as well as electrical and thermal loads. This paper proposes an optimal joint operation method of integrated electricity and heating systems based on multi-agent deep reinforcement learning (DRL) method. Firstly, a new hydraulic-thermal flow algorithm that is compatible with DRL training environment is developed. Then, a stochastic distributed optimization model is formulated with multiple agents to minimize network power losses while avoiding operation constraint violations under the spatial and temporal uncertainties. Last, a multi-agent deep deterministic policy gradient is adopted combined with offline neural network training via exploration in a virtual environment and online optimization of joint operation. A numerical case study indicates the effectiveness of the proposed method and solution robustness against spatial and temporal uncertainties.

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  • Yan Li, Fei Lin, Zhongping Yang, Xiaochun Fang, Hu Sun, Zhihong Zhong

    2026,14(2):564-576, DOI: 10.35833/MPCE.2025.000412

    Abstract:

    The deployment of wayside energy storage systems (WESSs) in substations is a key strategy for enhancing the energy efficiency of urban rail transit (URT). Existing research on energy management in traction power system (TPS) with WESS primarily focuses on improving the utilization of surplus regenerative braking energy in the system. However, due to the ambiguous output characteristics of TPS with WESS, it is challenging to address the optimization of overall system energy consumption from the perspective of power flow control, marking a significant distinction from flexible traction power systems (FTPSs) based on bidirectional substations. To address this issue, this paper proposes an integrated energy storage substation (IESS) control method and develops a steady-state equivalent model along with a DC power flow model for TPS with IESSs. Furthermore, under the framework of optimal power flow, this paper achieves both optimized control and flexible power supply for the TPS with IESS. Simulation results based on real-world operation scenarios demonstrate that the proposed method effectively optimizes the TPS power flow and reduces the total system energy consumption, offering new insights into the construction of FTPS based on the IESS.

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  • Gen Zhao, Huaiyuan Zhang, Jianhua Wang, Zhengyou He

    2026,14(2):577-589, DOI: 10.35833/MPCE.2025.000257

    Abstract:

    Constructing self-sustained highway transportation energy systems (HTESs) hinges on effective sustainable energy planning along highways. Addressing the complex spatial-temporal distribution characteristics of sources and loads presents a formidable challenge in accurately determining the siting and sizing of sustainable energy installations. In this study, we utilize a map rasterization approach and decentralized connection models for quantifying the spatial-temporal distribution characteristics of sources and loads. Leveraging these insights, the source-load-network cooperative operation models in uncertain scenarios, which seamlessly integrate highway and electricity networks, are built and embedded in the multi-objective robust planning model, enabling dynamic resource and demand management. The proposed planning model simultaneously optimizes the capacity, location, and connectivity of wind and photovoltaic power plants in HTES, while improving the robustness. Moreover, a multi-objective-oriented evaluation framework that adjusts the planning priorities based on three key dimensions – investment economy, self-sustained operation, and energy utilization efficiency – is formulated. The dynamic weight allocation mechanism enables tailored planning schemes that address diverse operational objectives effectively. Simulations of an actual HTES validate the effectiveness of the proposed planning model, demonstrating its capability to harmonize the inherent variabilities in the spatial-temporal distribution of sources and loads. The results highlight the significant variability in outcomes based on different objective orientations, underscoring the adaptability potential of the proposed planning model in designing futuristic HTES.

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  • Bozhen Jiang, Hongyuan Yang, Yidi Wang, Qin Wang, Hua Geng

    2026,14(2):590-601, DOI: 10.35833/MPCE.2024.000940

    Abstract:

    The smart grid infrastructure has recorded extensive real-time electricity consumption data, particularly at the levels of distribution transformers and below for short-term load forecasting (STLF). However, training individual short-term load forecasting model (SLFM) for each STLF scenario at these levels substantially increases the computational costs. To address this challenge, this paper proposes a transfer learning-based model training method for STLF. The proposed method is rooted in transfer learning principles and tailored to the unique characteristics of the aforementioned levels, incorporating several key steps. First, an approach for extracting key peak and valley points based on peak width and peak prominence is proposed for simplifying the evaluation of load sequence similarity. Subsequently, these key points are clustered using a density-based spatial clustering of applications with noise approach to ensure proper alignment along the time axis. Secondly, temporal and distribution similarity metrics are introduced to establish a performance guarantee for the transferred SLFM. Subsequently, a hierarchical clustering method groups load sequences, utilizing temporal similarity to quantify distances among sequences and distribution similarity to optimize cluster number selection. To minimize generalization error and further reduce computational costs, a modified bagging method is proposed and applied during the transferred SLFM fine-tuning. Empirical evidence from a study conducted in Guiyang, China demonstrates that the proposed method maintains the SLFM performance without degradation and significantly reduces computational costs by a minimum of 92.23% across multiple scenarios.

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  • Heshi Wang, Wenxia Liu, Rui Cheng, Fuxin Wang, Tianlong Wang

    2026,14(2):602-614, DOI: 10.35833/MPCE.2025.000070

    Abstract:

    This paper proposes an online hierarchical volt/var control (VVC) for unbalanced distribution networks using diagonal-scaling alternating direction method of multipliers (DS-ADMM). Under the hierarchical VVC strategy, local photovoltaic (PV) agents only exchange limited information with the center agent and adjust reactive power outputs in real time, with the goal of minimizing the voltage deviations and reactive power regulation costs in the time-varying environment. A diagonalized auxiliary matrix is constructed and developed from the Hessian matrix using preconditioning methods, which is then combined with alternating direction method of multipliers (ADMM) to design the DS-ADMM with improved convergence speed. The DS-ADMM is applied to the hierarchical VVC strategy, further improving the tracking capability and performance for time-varying environmental changes. Simulation studies on a modified IEEE 123-bus unbalanced distribution network are conducted to verify the effectiveness of the hierarchical VVC strategy using DS-ADMM and its robustness under non-ideal communication conditions, and its scalability is further validated on the modified IEEE 8500-node test feeder.

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  • Xuyuan Gong, Kaigui Xie, Changzheng Shao, Yifan Su, Bo Hu, Dong Zheng

    2026,14(2):615-628, DOI: 10.35833/MPCE.2025.000145

    Abstract:

    The form of hybrid AC/DC is a trend in power distribution systems. The resilience against extreme weather depends on the coordination of cyber and physical systems. Therefore, it is necessary to study the post-disaster recovery of AC/DC hybrid cyber-physical distribution systems (CPDSs). Voltage source converters (VSCs) are critical cyber-physical devices in hybrid AC/DC distribution systems (HDSs) that offer flexibility in post-disaster recovery. However, existing literature on the role of VSC commonly ignores the unreliable communication. In this paper, we quantify the impact of communication failures on VSCs and propose an adaptive switching model of VSC control modes that enhances both the emergency islanding and service restoration phases of post-disaster recovery. This paper also introduces a scheduling model of multi-type repair resources including power failure repair crews, communication failure repair crews, and emergency communication vehicles for joint the restoration of CPDSs. The system recovery model is also presented. Finally, a novel optimization framework combining adaptive switching of VSC control modes, scheduling of multi-type repair resources, and system recovery is proposed to improve the post-disaster recovery efficiency. The effectiveness and superiority of the proposed framework are demonstrated through numerical experiments in a modified IEEE 123-bus system.

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  • Rufeng Zhang, Haodong Liu, Lizhong Lu, Yunjing Liu, Linbo Fu, Xiaozhuo Guan

    2026,14(2):629-641, DOI: 10.35833/MPCE.2025.000221

    Abstract:

    The integration of numerous distributed energy resources into distribution networks (DNs) can induce large voltage fluctuations and network loss. We introduce a collaborative active and reactive power optimization (CARPO) method for DNs and microgrids (MGs) to efficiently improve the voltage quality and mitigate network loss. First, the CARPO method and models for the DNs and MGs (DMs) are intended to reduce voltage deviations, minimize network loss, and improve the operation efficiency of the entire system. Second, to protect MGs, we aggregate privacy-preserving feasible operation regions of the active and reactive power outputs from distributed energy resources in MGs. A scaled-down MG equivalent model, which ensures high accuracy, is derived for optimal DN operation. Third, based on the equivalent projection theory, the optimal operation flow of DMs with non-iterative projection method is achieved to reduce the computational complexity. The DM model is decomposed into sub-models for the DM levels. The optimal solutions of the coordination variables are obtained for MG power scheduling. Finally, the proposed CARPO method is evaluated through simulation in a modified IEEE 33-bus DN. The results demonstrate that the proposed CARPO method can optimize the system operation and improve the economy of DMs.

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  • Amin Mansour Saatloo, Abbas Mehrabi, Nauman Aslam, Mousa Marzband

    2026,14(2):642-654, DOI: 10.35833/MPCE.2025.000076

    Abstract:

    The global transition toward net zero emissions has accelerated the integration of distributed generators (DGs), particularly renewable energy sources (RESs), energy storage systems, plug-in electric vehicles (PEVs), and fuel-cell electric vehicles (FEVs). Therefore, we propose a decentralized energy management model tailored to the operational dynamics of a community of independent microgrids (MGs) at the transmission level, integrated with DGs, PEVs, FEVs, and hydrogen-based technologies, forming power- and hydrogen-based microgrids (P&HMGs). Managed by a third-party aggregator, P&HMGs strategically participate in the wholesale electricity market (WEM) by consolidating bids and offers. The WEM operates between generators and suppliers. The participating generators in WEM are connected to the transmission level, including power plants and large-scale RESs. The strategic behavior of P&HMGs is modeled using bi-level programming that unveils the potential of P&HMGs to synergize and participate in WEM as a price-maker. Moreover, to cope with the data privacy of P&HMGs and improve the scalability and security of MGs, a fast alternating direction method of multipliers (ADMM) running on a mobile edge computing (MEC) system is proposed as a decentralized energy management approach. Further, a bidirectional long short-term memory (BiLSTM) network considering robust optimization is presented to control the intermittency of electrical load and RESs. The results obtained from case studies confirm a considerable reduction in operation costs in light of the proposed model.

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  • Haiteng Han, Xiangchen Jiang, Can Huang, Chen Wu, Sheng Chen, Qingxin Shi, Zhinong Wei

    2026,14(2):655-668, DOI: 10.35833/MPCE.2025.000312

    Abstract:

    As renewable energy and environmental protection gain prominence, community microgrid has become crucial for promoting resource sharing and improving energy efficiency. This paper presents a multi-stage optimization strategy of community microgrid considering fair allocation and risk management, utilizing the Vickrey-Clarke-Groves (VCG) mechanism and the glue value-at-risk (GlueVaR) method. The proposed strategy integrates carbon with the collective self-consumption (CSC) framework, using GlueVaR to manage uncertainties in photovoltaic (PV) power generation by balancing economic performance with extreme risk management. Compared with traditional risk management, the GlueVaR method offers a more comprehensive characterization of both tail risks and central tendency, enabling more robust decision-making under uncertainties. The VCG mechanism ensures accurate supply and demand reporting, thereby optimizing resource allocation. The proposed strategy aims to promote fair allocation, enhance community welfare, reduce carbon emissions, and optimize energy utilization. A distributed alternating direction method of multipliers (ADMM) algorithm is employed to improve the computational efficiency and preserve the privacy of community members, making the proposed strategy scalable to various community microgrid sizes. Case studies confirm that the proposed strategy significantly enhances community welfare, reduces carbon emissions, and strengthens system stability and security. Furthermore, by fostering fair and transparent transactions among members, the cohesion of the community is reinforced for long-term sustainability.

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  • Longyan Li, Abdulelah S. Alshehri, Maher M. Alrashed, Chao Ning

    2026,14(2):669-681, DOI: 10.35833/MPCE.2025.000218

    Abstract:

    The proliferation of distribution-level green electricity and hydrogen resources entails an efficient local energy market (LEM). However, the existing LEM designed for electricity-hydrogen trading falls short of modeling multi-level mechanisms and accounting for the carbon intensity of hydrogen production. To bridge this gap, we propose a carbon-aware multi-level LEM for electricity-hydrogen trading based on a distributionally robust game framework, where hydrogen-based microgrids (HMGs) supply hydrogen to heterogeneous hydrogen users (HUs) including hydrogen refueling stations and industrial users. In this game framework, the coordination between HMGs and HUs is cast as a multi-leader multi-follower Stackelberg game. Specifically, HMGs determine an integrated hydrogen-carbon price, and carry out electricity trading through a non-cooperative game. Meanwhile, HUs act as followers, adjusting hydrogen purchasing strategies. Furthermore, the self-dispatching of HMGs and HUs is modeled as distributionally robust optimization problems considering source-load and hydrogen demand uncertainties, respectively. To hedge against these uncertainties, a novel Bayesian nonparametric hybrid ambiguity set is constructed based on local Wasserstein balls and moment information. Finally, the equilibrium of the proposed game framework is theoretically proved, and a distributed algorithm is developed to obtain this equilibrium. Comparative studies validate that the proposed game framework outperforms the existing ones, demonstrating a total income increasement of 12.3% and a carbon emission reduction of 11.6%.

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  • Xu Wang, Hanxiao Wu, Guanxun Diao, Chen Fang, Canbing Li, Kai Gong, Chuanwen Jiang, Wentao Huang, Shenxi Zhang

    2026,14(2):682-694, DOI: 10.35833/MPCE.2025.000358

    Abstract:

    Flexible ramping product (FRP) trading has emerged as a highly effective solution to cope with the volatility and uncertainty introduced by the increasing integration of renewable energy sources. This paper proposes a bidding method for electric vehicle aggregators (EVAs) in the FRP trading market. To effectively articulate the spatiotemporal operational characteristics intrinsic to EVAs, a charging and swapping flexibility aggregation model is formulated. The model is developed by accurately simulating the charging and swapping demands of plug-in electric vehicles and battery-swapping electric vehicles in different charging modes. A novel bilevel optimization model is developed to address the conflicting objectives in the FRP trading market between the EVAs and electric vehicles (EVs), aiming to optimize the incentive prices and charging strategies. The upper level optimizes the bidding profits of EVAs, whereas the lower level models the EV charging behavior using the charging and swapping flexibility aggregation model. To solve the high computational complexity of the high-dimensional nonconvex optimization problem owing to the vast number of EVs, a data-driven evolutionary algorithm incorporated with a zebra optimization algorithm is adopted. Owing to the limited data available for training high-quality agent models in real scenarios, a semi-supervised learning-based tri-training algorithm is adopted to enhance the efficiency of data utilization. Case studies validate the effectiveness of the proposed method.

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  • Davide del Giudice, Angelo Maurizio Brambilla, Federico Bizzarri, Daniele Linaro, Samuele Grillo

    2026,14(2):695-708, DOI: 10.35833/MPCE.2024.001204

    Abstract:

    The growing deployment of electric mobility calls for static and dynamic grid studies to investigate to which extent it affects the grid operation and how to validate the countermeasures. Detailed electric vehicle (EV) models, which allow analyzing electrical variables at the EV charger and battery levels, are inadequate for this purpose, as they can have an excessive complexity and are computationally burdensome for large-scale grid studies. To address this issue, we exploit a detailed EV model using an analytical approach, and develop an equivalent model of EVs with fast chargers that is easy to implement and computationally efficient, while retaining adequate accuracy. Simulation results of distribution and transmission systems, modified by adding fleets of EVs, are used to demonstrate the compatibility of the proposed model for static and dynamic grid studies, even when different cathode chemistries and charging strategies are adopted.

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  • Cangbi Ding, Chenyi Zheng, Yi Tang, Chaohai Zhang, Xingning Han

    2026,14(2):709-720, DOI: 10.35833/MPCE.2024.001276

    Abstract:

    Voltage interaction between the rectifier and inverter buses is recognized as a critical factor in embedded direct current (EDC) transmission systems, where at least two ends are within a single synchronous AC network, as it significantly affects power flow distribution, voltage stability, and power system planning. Conventional methods for evaluating voltage interaction are insufficient to accurately represent the complicated interplay between responses of the AC-DC network and the internal controllers within EDC transmission systems. To address this issue, this paper proposes an analytical calculation method of a novel voltage interaction evaluation index for various types of EDC transmission systems, which enables precise evaluation of the voltage interaction between the rectifier bus and inverter bus in an EDC transmission system. The proposed method comprehensively accounts for the influence of voltage interaction under small disturbances through the AC network, as well as the influence of voltage interaction under the same disturbance between converter buses through internal controller responses. Numerical simulations are used to analyze the parametric dependence of the index, and its accuracy is demonstrated through dynamic simulation.

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  • Babak Abdolmaleki, Gilbert Bergna-Diaz

    2026,14(2):721-734, DOI: 10.35833/MPCE.2025.000099

    Abstract:

    This paper proposes a centralized secondary control for real-time steady-state optimization of multi-terminal high-voltage direct current (HVDC) grids, considering both voltage and current limits. This control begins with detailed dynamic models of key grid components, including modular multilevel converter (MMC) stations and their control layers, followed by the derivation of a quasi-static input-output model suitable for steady-state control. Using this model, a general optimization problem is formulated, and the associated Karush-Kuhn-Tucker (KKT) conditions are characterized. A secondary controller based on primal-dual dynamics is then proposed to adjust the voltage setpoints of dispatchable MMCs, ensuring convergence to a steady state that satisfies the optimal conditions. The inclusion of current constraints necessitates partial knowledge of the network model, which naturally supports a centralized framework. To reduce the communication burden, a communication triggering mechanism is introduced that limits message exchanges between the control center and MMC stations without degrading performance. The proposed controller is validated through case studies using an offshore multi-terminal HVDC grid with heterogeneous MMC stations, simulated in MATLAB/Simulink. Results confirm that the proposed controller drives the system to optimal operation, while significantly reducing the communication burden without compromising performance.

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  • Qi Xie, Zixuan Zheng, Yifei Guo, Jianbing Xu, Jialong Wu, Xianyong Xiao, Jie Ren, Donghui Song

    2026,14(2):735-747, DOI: 10.35833/MPCE.2025.000242

    Abstract:

    The sending-end system of line-commutated converter based high-voltage direct current (LCC-HVDC) systems is vulnerable to transient voltage disturbances (TVDs), posing a significant threat to voltage stability. This paper proposes a novel strategy to maximize the dynamic voltage support (DVS) capability of LCC-HVDC systems under various TVDs. The physical mechanisms underlying DVS in LCC-HVDC systems are systematically analyzed, forming the basis for an optimization model that maximizes the DVS capability while incorporating security constraints at both the rectifier and inverter ends. To address the challenge of directly solving the model, an optimality analysis with intuitive geometric interpretations is performed. Based on these insights, a two-stage optimal DVS control strategy for LCC-HVDC systems is developed to iteratively approach the optimal solution through coordinated control of the rectifier and inverter stations. The effectiveness and superiority of the proposed strategy in supporting the sending-end system are validated through dynamic simulations, and its applicability under practical operating conditions is discussed.

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  • Mohammadmahdi Asghari, Amir Ameli, Mohsen Ghafouri, Mohammad N. Uddin

    2026,14(2):748-759, DOI: 10.35833/MPCE.2024.001332

    Abstract:

    Stealthy false data injection attacks (SFDIAs) targeting state estimation can bypass the bad data detection module, mislead operators with false system states, and potentially result in erroneous decisions and physical damages. While most existing studies focus on single-step SFDIAs, multi-step SFDIAs pose a greater threat due to their forward-looking nature, where each step is strategically planned to amplify the cumulative impact. Therefore, this paper focuses on multi-step SFDIAs and presents a vulnerability assessment framework that leverages a Markov decision process (MDP) and bi-level optimization to quantify the system vulnerability to this type of attack. The MDP models the sequential and strategic nature of these attacks, with states reflecting evolving system conditions influenced by prior actions. At each state, actions derived through bi-level optimization identify attack vectors that maximize line overloads, potentially triggering the tripping of transmission lines. The MDP is solved using Q-learning, enabling the calculation of a vulnerability index that assists operators in assessing the impact of multi-step SFDIAs and identifying the attackers most critical action at each step of multi-step SFDIAs. The effectiveness of the proposed vulnerability assessment framework is validated through simulations on the IEEE 39-bus test system.

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  • Ronald Kfouri, Rabih A. Jabr, Izudin Džafić

    2026,14(2):760-772, DOI: 10.35833/MPCE.2025.000178

    Abstract:

    Despite recent progress in solving the state estimation problem, its real-time performance remains challenged by the presence of bad data, increasing computational demands for detection and identification. A state estimator uses neighboring measurements to estimate the system states, similar to how a graph neural network (GNN) refines node embeddings (bus states) based on messages from neighboring nodes. This paper proposes a GNN-based framework that detects and identifies bad data before providing measurements to the state estimator. The framework incorporates grid topology, employs node and edge features, and exploits correlations of measurement data to enhance identification accuracy. Specifically, an edge-conditioned GNN is developed to transform graph-based features into categories that detect bad measurements and identify their sources. The generated dataset uses historical load profiles and includes conventional and synchrophasor measurements to emulate real-life applications. The proposed framework is tested on MATPOWER 6-bus and IEEE 14-, 30-, 118-, and 300-bus systems. The results demonstrate high accuracy and illustrate graph-learning patterns. Thus, operators can take preventive actions before the bad measurements propagate through the state estimator.

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      • Ricardo J. Bessa, Spyros Chatzivasileiadis, Ning Zhang, Chongqing Kang, Nikos Hatziargyriou

        2026,14(1):23-36, DOI: 10.35833/MPCE.2025.000990

        Abstract:

        This paper provides an overview of the application potential of artificial intelligence (AI) in power systems and points towards prospective developments in the fields of AI that are promised to play a transformative role in the evolution of power systems. Among the basic requirements, also imposed by regulation in some places, are trustworthiness and interpretability. Large language models, foundation models, as well as neuro-symbolic and compound AI models, appear to be the most promising emerging AI paradigms. Finally, the trajectories along which the future of AI in power systems might evolve are discussed, and conclusions are drawn.

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      • Chen-Ching Liu, Anjan Bose

        2026,14(1):1-6, DOI: 10.35833/MPCE.2025.001004

        Abstract:

        This paper tries to summarize the attempts to apply artificial intelligence (AI) to power systems, particularly power system planning and operations which require significant computer analysis. Although the term AI was coined earlier, this paper considers the beginning to be in the 1980s when the first expert systems were applied to power engineering. Of course, many of the analytical techniques applied can be traced to earlier statistical analysis and pattern recognition. The concept of expert systems was very much in line with the concept of AI. The various methods for applying AI to power systems are traced here. The historical journey in this paper closes with the great explosion of AI applications in the last decade when almost all power system analysis is trying to utilize AI techniques to help the transformation of the power system into a more efficient and carbon-free system. This proliferation of research in the application of AI is covered in the other papers in this series.

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      • Om Malik, Jay Liu, Marcelo Simões, Chris Dent, Kai Strunz, Jeffrey Wischkaemper, Vladimiro Miranda, Trevor Gaunt, Math Bollen, Mladen Kezunovic, Daniel Kirschen, Antonio Gomez-Exposito, Robin Podmore, Harold Kirkham, Panayiotis Moutis, Anjan Bose, Ian Hiskens, Gene Preston, Canbing Li, Hasala Dharmawardena, Alexandra von Meier, Leigh Tesfatsion, Paulo Ribeiro

        2025,13(6):1845-1853, DOI: 10.35833/MPCE.2025.000807

        Abstract:

        This paper captures an engaging— and at times heated—Power-Globe (PG) discussion of evolving definitions of smart grid technologies. The exchange took place between December 2024 and January 2025. The primary objective of this paper is to clarify some of the ambiguities surrounding the term “ smart grid” over the past two decades, as highlighted in the spirited PG debate. “ Smart grid” has sometimes been advocated as a panacea to resolve the tension between competing objectives for the provision of electricity (specifically, making it reliable, clean, and affordable). This paper examines the term “ smart grid” in terms of raw technical functionalities, applications, and use cases, some of which may get closer than others to meeting the aspirational promises. While smart technology should expand our menu of options, it will not absolve us of the need to make hard decisions.

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      • Yanghao Yu, Haiyang Jiang, Ning Zhang, Pei Yong, Fei Teng, Jiawei Zhang, Yating Wang, Goran Strbac

        2025,13(5):1593-1603, DOI: 10.35833/MPCE.2024.001101

        Abstract:

        Adequacy is a key concern of power system planning, which refers to the availability of sufficient facilities to meet demand. The capacity value (CV) of variable renewable energy (VRE) generation represents its equivalent contribution to system adequacy, in comparison to conventional generators. While VRE continues to grow and increasingly dominates the generation portfolio, its CV is becoming non-negligible, with the corresponding impact mechanisms becoming more complicated and nuanced. In this paper, the concept of CV is revisited by analyzing how VRE contributes to power system balancing at a high renewable energy penetration level. A generalized loss function is incorporated into the CV evaluation framework considering the adequacy of the power system. An analytical method for the CV evaluation of VRE is then derived using the statistical properties of both hourly load and VRE generation. Through the explicit CV expression, several critical impact factors, including the VRE generation variance, source-load correlation, and system adequacy level, are identified and discussed. Case studies demonstrate the accuracy and effectiveness of the proposed method in comparison to the traditional capacity factor-based methods and convolution-based methods. In the IEEE-RTS79 test system, the CV of a 2500 MW wind farm (with 40% renewable energy penetration level) is found to be 6.8% of its nameplate capacity. Additionally, the sensitivity of CV to various impact factors in power systems with high renewable energy penetration is analyzed.

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      • Damià Gomila, Benjamín A. Carreras, José-Miguel Reynolds-Barredo, María Martínez-Barbeito, Pere Colet, Oriol Gomis-Bellmunt

        2025,13(5):1556-1567, DOI: 10.35833/MPCE.2024.000768

        Abstract:

        The utilization of high-voltage direct current (HVDC) lines for the segmentation of the European power grid has been demonstrated to be a highly effective strategy for the mitigation of the risk of cascading blackouts. In this study, an accurate and efficient method for determining the optimal power flow through HVDC lines is presented, with the objective of minimizing load shedding. The proposed method is applied to two distinct scenarios: first, the segmentation of the power grid along the Pyrenees, with the objective of segmenting the Iberian Peninsula from the rest of Europe; and second, the segmentation of the power grid into Eastern and Western Europe, approximately in half. In both scenarios, the method effectively reduces the size of blackouts impacting both sides of the HVDC lines, resulting in a 46% and 67% reduction in total blackout risk, respectively. Furthermore, we have estimated the cost savings from risk reduction and the expenses associated with converting conventional lines to HVDC lines. Our findings indicate that segmenting the European power grid with HVDC lines is economically viable, particularly for segmenting the Iberian Peninsula, due to its favorable cost-risk reduction ratio.

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      • Mingyu Yang, Yusheng Xue, Bin Cai, Feng Xue

        2025,13(5):1481-1494, DOI: 10.35833/MPCE.2024.001135

        Abstract:

        Planning the low-carbon transition pathway of the power sector to meet the carbon neutrality goal poses a significant challenge due to the complex interplay of temporal, spatial, and cross-domain factors. A novel framework is proposed, grounded in the cyber-physical-social system in energy (CPSSE) and whole-reductionism thinking (WRT), incorporating a tailored mathematical model and optimization method to formalize the co-optimization of carbon reduction and carbon sequestration in the power sector. Using the carbon peaking and carbon neutrality transition of China as a case study, clustering method is employed to construct a diverse set of strategically distinct carbon trajectories. For each trajectory, the evolution of the generation mix and the deployment pathways of carbon capture and storage (CCS) technologies are analyzed, identifying the optimal transition pathway based on the criterion of minimizing cumulative economic costs. Further, by comparing non-fossil energy substitution and CCS retrofitting in thermal power, the analysis highlights the potential for co-optimization of carbon reduction and carbon sequestration. The results demonstrate that leveraging the spatiotemporal complementarities between the two can substantially lower the economic cost of achieving carbon neutrality, providing insights for integrated decarbonization strategies in power system planning.

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      • Francisco S. Fernandes, Ricardo J. Bessa, João Peças Lopes

        2025,13(4):1113-1126, DOI: 10.35833/MPCE.2024.000478

        Abstract:

        In a high-risk sector, such as power system, transparency and interpretability are key principles for effectively deploying artificial intelligence (AI) in control rooms. Therefore, this paper proposes a novel methodology, the evolving symbolic model (ESM), which is dedicated to generating highly interpretable data-driven models for dynamic security assessment (DSA), namely in system security classification (SC) and the definition of preventive control actions. The ESM uses simulated annealing for a data-driven evolution of a symbolic model template, enabling different cooperative learning schemes between humans and AI. The Madeira Island power system is used to validate the application of the ESM for DSA. The results show that the ESM has a classification accuracy comparable to pruned decision trees (DTs) while boasting higher global interpretability. Moreover, the ESM outperforms an operator-defined expert system and an artificial neural network in defining preventive control actions.

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      • Zhiyuan Meng, Xiangyang Xing, Xiangjun Li, Jiadong Sun

        2025,13(3):1064-1077, DOI: 10.35833/MPCE.2024.000404

        Abstract:

        The virtual synchronous generator (VSG), utilized as a control strategy for grid-forming inverters, is an effective method of providing inertia and voltage support to the grid. However, the VSG exhibits limited capabilities in low-voltage ride-through (LVRT) mode. Specifically,the slow response of the power loop poses challenges for VSG in grid voltage support and increases the risk of overcurrent, potentially violating present grid codes. This paper reveals the mechanism behind the delayed response speed of VSG control during the grid faults. On this basis, a compound compensation control strategy is proposed for improving the LVRT capability of the VSG, which incorporates adaptive frequency feedforward compensation (AFFC), direct power angle compensation (DPAC), internal potential compensation (IPC), and transient virtual impedance (TVI), effectively expediting the response speed and reducing transient current. Furthermore, the proposed control strategy ensures that the VSG operates smoothly back to its normal control state following the restoration from the grid faults. Subsequently, a large-signal model is developed to facilitate parameter design and stability analysis, which incorporates grid codes and TVI. Finally, the small-signal stability analysis and simulation and experimental results prove the correctness of the theoretical analysis and the effectiveness of the proposed control strategy.

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      • Zhe Chen, Zhihao Li, Da Lin, Changjun Xie, Zhewei Wang

        2025,13(3):904-914, DOI: 10.35833/MPCE.2024.000606

        Abstract:

        Hybrid energy storage is considered as an effective means to improve the economic and environmental performance of integrated energy systems (IESs). Although the optimal scheduling of IES has been widely studied, few studies have taken into account the property that the uncertainty of the forecasting error decreases with the shortening of the forecasting time scale. Combined with hybrid energy storage, the comprehensive use of various uncertainty optimization methods under different time scales will be promising. This paper proposes a multi-time-scale optimal scheduling method for an IES with hybrid energy storage under wind and solar uncertainties. Firstly, the proposed system framework of an IES including electric-thermal-hydrogen hybrid energy storage is established. Then, an hour-level robust optimization based on budget uncertainty set is performed for the day-ahead stage. On this basis, a scenario-based stochastic optimization is carried out for intra-day and real-time stages with time intervals of 15 min and 5 min, respectively. The results show that the proposed method improves the economic benefits, and the intra-day and real-time scheduling costs are reduced, respectively; by adjusting the uncertainty budget in the model, a flexible balance between economic efficiency and robustness in day-ahead scheduling can be achieved; reasonable design of the capacity of electric-thermal-hydrogen hybrid energy storage can significantly reduce the electricity curtailment rate and carbon emissions, thus reducing the cost of system scheduling.

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      • Jalal Sahebkar Farkhani, Özgür Çelik, Kaiqi Ma, Claus Leth Bak, Zhe Chen

        2025,13(3):840-851, DOI: 10.35833/MPCE.2023.000925

        Abstract:

        Traditional protection methods are not suitable for hybrid (cable and overhead) transmission lines in voltage source converter based high-voltage direct current (VSC-HVDC) systems. Accordingly, this paper presents the robust fault detection, classification, and location based on the empirical wavelet transform-Teager energy operator (EWT-TEO) and artificial neural network (ANN) for hybrid transmission lines in VSC-HVDC systems. The operational scheme of the proposed protection method consists of two loops an EWT-TEO based feature extraction loop, and an ANN-based fault detection, classification, and location loop. Under the proposed protection method, the voltage and current signals are decomposed into several sub-passbands with low and high frequencies using the empirical wavelet transform (EWT) method. The energy content extracted by the EWT is fed into the ANN for fault detection, classification, and location. Various fault cases, including the high-impedance fault (HIF) as well as noises, are performed to train the ANN with two hidden layers. The test system and signal decomposition are conducted by PSCAD/EMTDC and MATLAB, respectively. The performance of the proposed protection method is compared with that of the traditional non-pilot traveling wave (TW) based protection method. The results confirm the high accuracy of the proposed protection method for hybrid transmission lines in VSC-HVDC systems, where a mean percentage error of approximately 0.1% is achieved.

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      • Linguang Wang, Xiaorong Xie, Wenkai Dong, Yong Mei, Aoyu Lei

        2025,13(3):747-756, DOI: 10.35833/MPCE.2024.000630

        Abstract:

        With the rapid integration of renewable energy, wide-band oscillations caused by interactions between power electronic equipment and grids have emerged as one of the most critical stability issues. Existing methods are usually studied for local power systems with around one hundred nodes. However, for a large-scale power system with tens of thousands of nodes, the dimension of transfer function matrix or the order of characteristic equation is much higher. In this case, the existing methods such as eigenvalue analysis method and impedance-based method have difficulty in computation and are thus hard to utilize in practice. To fill this gap, this paper proposes a novel method named the smallest eigenvalues based logarithmic derivative (SELD) method. It obtains the dominant oscillation modes by the logarithmic derivative of the k-smallest eigenvalue curves of the sparse extended nodal admittance matrix (NAM). An oscillatory stability analysis tool is further developed based on this method. The effectiveness of the method and the tool is validated through a local power system as well as a large-scale power system.

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      • Wenping Qin, Xiaozhou Li, Xing Jing, Zhilong Zhu, Ruipeng Lu, Xiaoqing Han

        2025,13(2):675-687, DOI: 10.35833/MPCE.2024.000118

        Abstract:

        The virtual power plant (VPP) facilitates the coordinated optimization of diverse forms of electrical energy through the aggregation and control of distributed energy resources (DERs), offering as a potential resource for frequency regulation to enhance the power system flexibility. To fully exploit the flexibility of DER and enhance the revenue of VPP, this paper proposes a multi-temporal optimization strategy of VPP in the energy-frequency regulation (EFR) market under the uncertainties of wind power (WP), photovoltaic (PV), and market price. Firstly, all schedulable electric vehicles (EVs) are aggregated into an electric vehicle cluster (EVC), and the schedulable domain evaluation model of EVC is established. A day-ahead energy bidding model based on Stackelberg game is also established for VPP and EVC. Secondly, on this basis, the multi-temporal optimization model of VPP in the EFR market is proposed. To manage risks stemming from the uncertainties of WP, PV, and market price, the concept of conditional value at risk (CVaR) is integrated into the strategy, effectively balancing the bidding benefits and associated risks. Finally, the results based on operational data from a provincial electricity market demonstrate that the proposed strategy enhances comprehensive revenue by providing frequency regulation services and encouraging EV response scheduling.

        • 1
      • Ji-Soo Kim, Jin-Sol Song, Chul-Hwan Kim, Jean Mahseredjian, Seung-Ho Kim

        2025,13(2):622-636, DOI: 10.35833/MPCE.2023.000723

        Abstract:

        To address environmental concerns, there has been a rapid global surge in integrating renewable energy sources into power grids. However, this transition poses challenges to grid stability. A prominent solution to this challenge is the adoption of battery energy storage systems (BESSs). Many countries are actively increasing BESS deployment and developing new BESS technologies. Nevertheless, a crucial initial step is conducting a comprehensive analysis of BESS capabilities and subsequently formulating policies. We analyze the current roles of BESS and review existing BESS policies worldwide, which focuses on key markets in Asia, Europe, and the U.S.. Using collected survey data, we propose a comprehensive three-phase framework for policy formulation, providing insights into future policy development directions.

        • 1
      • Shengren Hou, Edgar Mauricio Salazar, Peter Palensky, Qixin Chen, Pedro P. Vergara

        2025,13(2):597-608, DOI: 10.35833/MPCE.2024.000391

        Abstract:

        The optimal dispatch of energy storage systems (ESSs) in distribution networks poses significant challenges, primarily due to uncertainties of dynamic pricing, fluctuating demand, and the variability inherent in renewable energy sources. By exploiting the generalization capabilities of deep neural networks (DNNs), the deep reinforcement learning (DRL) algorithms can learn good-quality control models that adapt to the stochastic nature of distribution networks. Nevertheless, the practical deployment of DRL algorithms is often hampered by their limited capacity for satisfying operational constraints in real time, which is a crucial requirement for ensuring the reliability and feasibility of control actions during online operations. This paper introduces an innovative framework, named mixed-integer programming based deep reinforcement learning (MIP-DRL), to overcome these limitations. The proposed MIP-DRL framework can rigorously enforce operational constraints for the optimal dispatch of ESSs during the online execution. This framework involves training a Q-function with DNNs, which is subsequently represented in a mixed-integer programming (MIP) formulation. This unique combination allows for the seamless integration of operational constraints into the decision-making process. The effectiveness of the proposed MIP-DRL framework is validated through numerical simulations, demonstrating its superior capability to enforce all operational constraints and achieve high-quality dispatch decisions and showing its advantage over existing DRL algorithms.

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      • Wang Xiang, Mingrui Yang, Jinyu Wen

        2025,13(2):452-461, DOI: 10.35833/MPCE.2024.000229

        Abstract:

        Conventional offshore wind farm (OWF) integration systems typically employ AC cables to gather power to a modular multilevel converter (MMC) platform, subsequently delivering it to onshore grids through high-voltage direct current (HVDC) transmission. However, scaling up the capacity of OWFs introduces significant challenges due to the high costs associated with AC collection cables and offshore MMC platforms. This paper proposes a diode rectifier (DR)-MMC hub based hybrid AC/DC collection and HVDC transmission system for large-scale offshore wind farms. The wind farms in proximity to the offshore converter platform utilize AC collection, while distant wind farms connect to the platform using DC collection. The combined AC/DC power is then transmitted to the offshore DR-MMC hub platform. The topology and operation principle of the DR-MMC hub as well as the integration system are presented. Based on the operational characteristics, the capacity design method for DR-MMC hub is proposed. And the control and startup strategies of the integration system are designed. Furthermore, an economic comparison with the conventional MMC-HVDC based offshore wind power integration system is conducted. Finally, the technical feasibility of the proposed integration scheme is verified through PSCAD/EMTDC simulation with the integration scale of 2 GW.

        • 1
      • Wei Kong, Kai Sun, Jinghong Zhao

        2025,13(1):276-288, DOI: 10.35833/MPCE.2023.001027

        Abstract:

        The hydrogen energy storage system (HESS) integrated with renewable energy power generation exhibits low reliability and flexibility under source-load uncertainty. To address the above issues, a two-stage optimal scheduling model considering the operation sequences of HESSs is proposed for commercial community integrated energy systems (CIESs) with power to hydrogen and heat (P2HH) capability. It aims to optimize the energy flow of HESS and improve the flexibility of hydrogen production and the reliability of energy supply for loads. First, the refined operation model of HESS is established, and its operation model is linearized according to the operation domain of HESS, which simplifies the difficulty of solving the optimization problem under the premise of maintaining high approximate accuracy. Next, considering the flexible start-stop of alkaline electrolyzer (AEL) and the avoidance of multiple energy conversions, the operation sequences of HESS are formulated. Finally, a two-stage optimal scheduling model combining day-ahead economic optimization and intra-day rolling optimization is established, and the model is simulated and verified using the source-load prediction data of typical days in each season. The simulation results show that the two-stage optimal scheduling reduces the total load offset by about 14% while maintaining similar operating cost to the optimal day-ahead economic optimization scheduling. Furthermore, by formulating the operation sequences of HESS, the operating cost of CIES is reduced by up to about 4.4%.

        • 1
      • Zizhen Guo, Wenchuan Wu

        2025,13(1):179-189, DOI: 10.35833/MPCE.2023.000624

        Abstract:

        With photovoltaic (PV) sources becoming more prevalent in the energy generation mix, transitioning grid-connected PV systems from grid-following (GFL) mode to grid-forming (GFM) mode becomes essential for offering self-synchronization and active support services. Although numerous GFM methods have been proposed, the potential of DC voltage control malfunction during the provision of the primary and inertia support in a GFM PV system remains insufficiently researched. To fill the gap, some main GFM methods have been integrated into PV systems featuring detailed DC source dynamics. We conduct a comparative analysis of their performance in active support and DC voltage regulation. AC GFM methods such as virtual synchronous machine (VSM) face a significant risk of DC voltage failure in situations like alterations in solar radiation, leading to PV system tripping and jeopardizing local system operation. In the case of DC GFM methods such as matching control (MC), the active support falls short due to the absence of an accurate and dispatchable droop response. To address the issue, a matching synchronous machine (MSM) control method is developed to provide dispatchable active support and enhance the DC voltage dynamics by integrating the MC and VSM control loops. The active support capability of the PV systems with the proposed method is quantified analytically and verified by numerical simulations and field tests.

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      • Francisco Jesús Matas-Díaz, Manuel Barragán-Villarejo, José María Maza-Ortega

        2025,13(1):102-114, DOI: 10.35833/MPCE.2024.000316

        Abstract:

        The integration of converter-interfaced generators (CIGs) into power systems is rapidly replacing traditional synchronous machines. To ensure the security of power supply, modern power systems require the application of grid-forming technologies. This study presents a systematic small-signal analysis procedure to assess the synchronization stability of grid-forming virtual synchronous generators (VSGs) considering the power system characteristics. Specifically, this procedure offers guidance in tuning controller gains to enhance stability. It is applied to six different grid-forming VSGs and experimentally tested to validate the theoretical analysis. This study concludes with key findings and a discussion on the suitability of the analyzed grid-forming VSGs based on the power system characteristics.

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      • Yanqiu Jin, Zheren Zhang, Zheng Xu

        2025,13(1):87-101, DOI: 10.35833/MPCE.2024.000432

        Abstract:

        This study analyzes the stability and reactive characteristics of the hybrid offshore wind farm that includes grid-forming (GFM) and grid-following (GFL) wind turbines (WTs) integrated with a diode rectifier unit (DRU) based high-voltage direct current (HVDC) system. The determination method for the proportion of GFM WTs is proposed while considering system stability and optimal offshore reactive power constraints. First, the small-signal stability is studied based on the developed linear model, and crucial factors that affect the stability are captured by eigenvalue analysis. The reactive power-frequency compensation control of GFM WTs is then proposed to improve the reactive power and frequency dynamics. Second, the relationship between offshore reactive power imbalance and the effectiveness of GFM capability is analyzed. Offshore reactive power optimization methods are next proposed to diminish offshore reactive load. These methods include the optimal design for the reactive capacity of the AC filter and the reactive power compensation control of GFL WTs. Third, in terms of stability and optimal offshore reactive power constraints, the principle and calculation method for determining the proportion of GFM WTs are proposed, and the critical proportion of GFM WTs is determined over the full active power range. Finally, case studies using a detailed model are conducted by time-domain simulations in PSCAD/EMTDC. The simulations verify the theoretical analysis results and the effectiveness of the proposed determination method for the proportion of GFM WTs and reactive power optimization methods.

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      • Hang Shuai, Buxin She, Jinning Wang, Fangxing Li

        2025,13(1):79-86, DOI: 10.35833/MPCE.2023.000882

        Abstract:

        This study investigates a safe reinforcement learning algorithm for grid-forming (GFM) inverter based frequency regulation. To guarantee the stability of the inverter-based resource (IBR) system under the learned control policy, a model-based reinforcement learning (MBRL) algorithm is combined with Lyapunov approach, which determines the safe region of states and actions. To obtain near optimal control policy, the control performance is safely improved by approximate dynamic programming (ADP) using data sampled from the region of attraction (ROA). Moreover, to enhance the control robustness against parameter uncertainty in the inverter, a Gaussian process (GP) model is adopted by the proposed algorithm to effectively learn system dynamics from measurements. Numerical simulations validate the effectiveness of the proposed algorithm.

        • 1
      • Ghazala Shafique, Johan Boukhenfouf, François Gruson, Frédéric Colas, Xavier Guillaud

        2025,13(1):66-78, DOI: 10.35833/MPCE.2024.000822

        Abstract:

        Grid-forming (GFM) converters are recognized for their stabilizing effects in renewable energy systems. Integrating GFM converters into high-voltage direct current (HVDC) systems requires DC voltage control. However, there can be a conflict between GFM converter and DC voltage control when they are used in combination. This paper presents a rigorous control design for a GFM converter that connects the DC-link voltage to the power angle of the converter, thereby integrating DC voltage control with GFM capability. The proposed control is validated through small-signal and transient-stability analyses on a modular multilevel converter (MMC)-based HVDC system with a point-to-point (P2P) GFM-GFM configuration. The results demonstrate that employing a GFM-GFM configuration with the proposed control enhances the stability of the AC system to which it is connected. The system exhibits low sensitivity to grid strength and can sustain islanding conditions. The high stability limit of the system with varying grid strength using the proposed control is validated using a system with four voltage source converters.

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      • Qianhong Shi, Wei Dong, Guanzhong Wang, Junchao Ma, Chenxu Wang, Xianye Guo, Vladimir Terzija

        2025,13(1):55-65, DOI: 10.35833/MPCE.2024.000759

        Abstract:

        Oscillations caused by small-signal instability have been widely observed in AC grids with grid-following (GFL) and grid-forming (GFM) converters. The generalized short-circuit ratio is commonly used to assess the strength of GFL converters when integrated with weak AC systems at risk of oscillation. This paper provides the grid strength assessment method to evaluate the small-signal synchronization stability of GFL and GFM converters integrated systems. First, the admittance and impedance matrices of the GFL and GFM converters are analyzed to identify the frequency bands associated with negative damping in oscillation modes dominated by heterogeneous synchronization control. Secondly, based on the interaction rules between the short-circuit ratio and the different oscillation modes, an equivalent circuit is proposed to simplify the grid strength assessment through the topological transformation of the AC grid. The risk of sub-synchronization and low-frequency oscillations, influenced by GFL and GFM converters, is then reformulated as a semi-definite programming (SDP) model, incorporating the node admittance matrix and grid-connected device capacities. The effectiveness of the proposed method is demonstrated through a case analysis.

        • 1
      • Ni Liu, Hong Wang, Weihua Zhou, Jie Song, Yiting Zhang, Eduardo Prieto-Araujo, Zhe Chen

        2025,13(1):15-28, DOI: 10.35833/MPCE.2023.000842

        Abstract:

        With the increase of the renewable energy generator capacity, the requirements of the power system for grid-connected converters are evolve, which leads to diverse control schemes and increased complexity of systematic stability analysis. Although various frequency-domain models are developed to identify oscillation causes, the discrepancies between them are rarely studied. This study aims to clarify these discrepancies and provide circuit insights for stability analysis by using different frequency-domain models. This study emphasizes the limitations of assuming that the transfer function of the self-stable converter does not have right half-plane (RHP) poles. To ensure that the self-stable converters are represented by a frequency-domain model without RHP poles, the applicability of this model of grid-following (GFL) and grid-forming (GFM) converters is discussed. This study recommends that the GFM converters with ideal sources should be represented in parallel with the P / Q - θ / V admittance model rather than the V - I impedance model. Two cases are conducted to illustrate the rationality of the P / Q - θ / V admittance model. Additionally, a hybrid frequency-domain modeling framework and stability criteria are proposed for the power system with several GFL and GFM converters. The stability criteria eliminates the need to check the RHP pole numbers in the non-passive subsystem when applying the Nyquist stability criterion, thereby reducing the complexity of stability analysis. Simulations are carried out to validate the correctness of the frequency-domain model and the stability criteria.

        • 1
      • Haiyu Zhao, Hongyu Zhou, Wei Yao, Qihang Zong, Jinyu Wen

        2025,13(1):3-14, DOI: 10.35833/MPCE.2024.000722

        Abstract:

        Grid-following voltage source converter (GFL-VSC) and grid-forming voltage source converter (GFM-VSC) have different dynamic characteristics for active power-frequency and reactive power-voltage supports of the power grid. This paper aims to clarify and recognize the difference between grid-following (GFL) and grid-forming (GFM) frequency-voltage support more intuitively and clearly. Firstly, the phasor model considering circuit constraints is established based on the port circuit equations of the converter. It is revealed that the voltage and active power linearly correspond to the horizontal and vertical axes in the phasor space referenced to the grid voltage phasor. Secondly, based on topological homology, GFL and GFM controls are transformed and mapped into different trajectories. The topological similarity of the characteristic curves for GFL and GFM controls is the essential cause of their uniformity. Based on the above model, it is indicated that GFL-VSC and GFM-VSC possess uniformity with regard to active power response, type of coupling, and phasor trajectory. They differ in synchronization, power coupling mechanisms, dynamics, and active power-voltage operation domain in the quasi-steady state. Case studies are undertaken on GFL-VSC and GFM-VSC integrated into a four-machine two-area system. Simulation results verify that the dynamic uniformity and difference of GFL-VSC and GFM-VSC are intuitively and comprehensively revealed.

        • 1
      • Sheng Chen, Jingchun Zhang, Zhinong Wei, Hao Cheng, Si Lv

        2024,12(6):1697-1709, DOI: 10.35833/MPCE.2023.000887

        Abstract:

        Green hydrogen represents an important energy carrier for global decarbonization towards renewable-dominant energy systems. As a result, an escalating interdependency emerges between multi-energy vectors. Specifically, the coupling among power, natural gas, and hydrogen systems is strengthened as the injections of green hydrogen into natural gas pipelines. At the same time, the interaction between hydrogen and transportation systems would become indispensable with soaring penetrations of hydrogen fuel cell vehicles. This paper provides a comprehensive review for the modeling and coordination of hydrogen-integrated energy systems. In particular, we analyze the role of green hydrogen in decarbonizing power, natural gas, and transportation systems. Finally, pressing research needs are summarized.

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      • Xiaoyu Zhang, Yushuai Li, Tianyi Li, Yonghao Gui, Qiuye Sun, David Wenzhong Gao

        2024,12(5):1472-1483, DOI: 10.35833/MPCE.2023.000351

        Abstract:

        The accurate prediction of photovoltaic (PV) power generation is significant to ensure the economic and safe operation of power systems. To this end, the paper establishes a new digital twin (DT) empowered PV power prediction framework that is capable of ensuring reliable data transmission and employing the DT to achieve high accuracy of power prediction. With this framework, considering potential data contamination in the collected PV data, a generative adversarial network is employed to restore the historical dataset, which offers a prerequisite to ensure accurate mapping from the physical space to the digital space. Further, a new DT-empowered PV power prediction method is proposed. Therein, we model a DT that encompasses a digital physical model for reflecting the physical operation mechanism and a neural network model (i.e., a parallel network of convolution and bidirectional long short-term memory model) for capturing the hidden spatiotemporal features. The proposed method enables the use of the DT to take advantages of the digital physical model and the neural network model, resulting in enhanced prediction accuracy. Finally, a real dataset is conducted to assess the effectiveness of the proposed method.

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      • Jorge Uriel Sevilla-Romero, Alejandro Pizano-Martínez, Claudio Rubén Fuerte-Esquivel, Reymundo Ramírez-Betancour

        2024,12(5):1357-1369, DOI: 10.35833/MPCE.2023.000461

        Abstract:

        In practice, an equilibrium point of the power system is considered transiently secure if it can withstand a specified contingency by maintaining transient evolution of rotor angles and voltage magnitudes within set bounds. A novel sequential approach is proposed to obtain transiently stable equilibrium points through the preventive control of transient stability and transient voltage sag (TVS) problems caused by a severe disturbance. The proposed approach conducts a sequence of non-heuristic optimal active power re-dispatch of the generators to steer the system toward a transiently secure operating point by sequentially solving the transient-stability-constrained optimal power flow (TSC-OPF) problems. In the proposed approach, there are two sequential projection stages, with the first stage ensuring the rotor angle stability and the second stage removing TVS in voltage magnitudes. In both projection stages, the projection operation corresponds to the TSC-OPF, with its formulation directly derived by adding only two steady-state variable-based transient constraints to the conventional OPF problem. The effectiveness of this approach is numerically demonstrated in terms of its accuracy and computational performance by using the Western System Coordinated Council (WSCC) 3-machine 9-bus system and an equivalent model of the Mexican 46-machine 190-bus system.

        • 1
      • Jingtao Zhao, Zhi Wu, Huan Long, Huapeng Sun, Xi Wu, Chingchuen Chan, Mohammad Shahidehpour

        2024,12(5):1333-1344, DOI: 10.35833/MPCE.2023.000372

        Abstract:

        With the large-scale integration of distributed renewable generation (DRG) and increasing proportion of power electronic equipment, the traditional power distribution network (DN) is evolving into an active distribution network (ADN). The operation state of an ADN, which is equipped with DRGs, could rapidly change among multiple states, which include steady, alert, and fault states. It is essential to manage large-scale DRG and enable the safe and economic operation of ADNs. In this paper, the current operation control strategies of ADNs under multiple states are reviewed with the interpretation of each state and the transition among the three aforementioned states. The multi-state identification indicators and identification methods are summarized in detail. The multi-state regulation capacity quantification methods are analyzed considering controllable resources, quantification indicators, and quantification methods. A detailed survey of optimal operation control strategies, including multiple state operations, is presented, and key problems and outlooks for the expansion of ADN are discussed.

        • 1
      • Qifan Chen, Siqi Bu, Chi Yung Chung

        2024,12(4):1003-1018, DOI: 10.35833/MPCE.2023.000526

        Abstract:

        To tackle emerging power system small-signal stability problems such as wideband oscillations induced by the large-scale integration of renewable energy and power electronics, it is crucial to review and compare existing small-signal stability analysis methods. On this basis, guidance can be provided on determining suitable analysis methods to solve relevant small-signal stability problems in power electronics-dominated power systems (PEDPSs). Various mature methods have been developed to analyze the small-signal stability of PEDPSs, including eigenvalue-based methods, Routh stability criterion, Nyquist/Bode plot based methods, passivity-based methods, positive-net-damping method, lumped impedance-based methods, bifurcation-based methods, etc. In this paper, the application conditions, advantages, and limitations of these criteria in identifying oscillation frequencies and stability margins are reviewed and compared to reveal and explain connections and discrepancies among them. Especially, efforts are devoted to mathematically proving the equivalence between these small-signal stability criteria. Finally, the performance of these criteria is demonstrated and compared in a 4-machine 2-area power system with a wind farm and an IEEE 39-bus power system with 3 wind farms.

        • 1
      • Jie Xu, Hongjun Gao, Renjun Wang, Junyong Liu

        2024,12(3):886-899, DOI: 10.35833/MPCE.2023.000213

        Abstract:

        The increasing integration of intermittent renewable energy sources (RESs) poses great challenges to active distribution networks (ADNs), such as frequent voltage fluctuations. This paper proposes a novel ADN strategy based on multi-agent deep reinforcement learning (MADRL), which harnesses the regulating function of switch state transitions for the real-time voltage regulation and loss minimization. After deploying the calculated optimal switch topologies, the distribution network operator will dynamically adjust the distributed energy resources (DERs) to enhance the operation performance of ADNs based on the policies trained by the MADRL algorithm. Owing to the model-free characteristics and the generalization of deep reinforcement learning, the proposed strategy can still achieve optimization objectives even when applied to similar but unseen environments. Additionally, integrating parameter sharing (PS) and prioritized experience replay (PER) mechanisms substantially improves the strategic performance and scalability. This framework has been tested on modified IEEE 33-bus, IEEE 118-bus, and three-phase unbalanced 123-bus systems. The results demonstrate the significant real-time regulation capabilities of the proposed strategy.

        • 1
      • Zhoujun Ma, Yizhou Zhou, Yuping Zheng, Li Yang, Zhinong Wei

        2024,12(3):852-862, DOI: 10.35833/MPCE.2023.000204

        Abstract:

        This paper proposes a distributed robust optimal dispatch model to enhance information security and interaction among the operators in the regional integrated energy system (RIES). Our model regards the distribution network and each energy hub (EH) as independent operators and employs robust optimization to improve operational security caused by wind and photovoltaic (PV) power output uncertainties, with only deterministic information exchanged across boundaries. This paper also adopts the alternating direction method of multipliers (ADMM) algorithm to facilitate secure information interaction among multiple RIES operators, maximizing the benefit for each subject. Furthermore, the traditional ADMM algorithm with fixed step size is modified to be adaptive, addressing issues of redundant interactions caused by suboptimal initial step size settings. A case study validates the effectiveness of the proposed model, demonstrating the superiority of the ADMM algorithm with adaptive step size and the economic benefits of the distributed robust optimal dispatch model over the distributed stochastic optimal dispatch model.

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