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A review of demand response capability assessment based on CPSS perspective
Kairui ZHANG, Hao MING, and Ciwei GAO

Date posted: 4-22-2024
DOI: https://doi.org/10.19781/j.issn.1673-9140.2024.01.003

The combination of cyber-physical-social systems and demand response assessment is reviewed. First, the history and framework of cyber-physical systems are analyzed. Then, summaries are provided for the existing research on demand response, including the significance, classification, and evaluation methods of demand response potential assessment, as well as the data sources for demand response capability assessment, including questionnaire surveys and operational data collection. In terms of the combination of cyber-physical-social systems and demand response, the physical domain, information domain and social domain foundation of demand response are analyzed respectively, and the corresponding modeling methods and research contents are introduced. Finally, prospects are provided for market assessment mechanisms, rapid simulation and modeling technologies, and demand response management under integrated energy systems.

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Optimal planning strategies for power grid topology Steiner minimum tree to enhance resilience capability
Yunpeng ZHAI, Dongqi LIU, Haolan LIANG, and Wei LI

Date posted: 12-18-2025
DOI: https://doi.org/10.19781/j.issn.1673-9140.2025.05.001

Energy security is related to the overall situation of economic and social development.In recent years, deliberate attacks and disasters against the power grid have occurred frequently, and the power system has become an important target of attacks in international conflicts.In order to enhance the ability of the power grid to resist deliberate attacks and disasters and ensure the safe operation of the national energy infrastructure, a Steiner minimum tree planning method is proposed for the power supply network topology to the improvement of invulnerability.Firstly, the grid structure strength index and operation vulnerability index are designed for the grid planning problem.A dual-layer planning model is constructed with the grid structure strength, network connectivity, and network operation status as the upper targets, and the line investment cost, node construction cost, and network loss cost as the lower targets.Secondly, based on the complex network theory, the topology mapping model of the power grid is built.The important areas and nodes of the power grid are divided according to the load demand and capacity demand of nodes.Then, the problem of power grid planning is transformed into a regional Steiner tree problem, and nodes are added in the region to re-plan the grid structure in important areas.Finally, the heuristic algorithm is combined with the mathematical programming problem.The artificial fish swarm algorithm is used to optimize the solution.The 39-node grid structure is applied for simulation verification.The calculation results show that the proposed method can improve the strength of the grid structure by 64.60% and reduce the operation risk by 71.38 %.

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Summary of research on electricity theft behavior detection methods
Yu XIAO, Zhi YE, Rui HUANG, Mouhai LIU, Rui XIA, and Yunpeng GAO

Date posted: 11-6-2023
DOI: https://doi.org/10.19781/j.issn.1673-9140.2023.04.001

The non‑technical losses caused by electricity theft in the power system have always been a pressing issue for power grid companies to urgently address. With the deployment of a large number of smart meters in the power grid, the use of user‑side data collected by the power metering automation system to accurately detect electricity theft has attracted widespread attention from researchers and power grid companies. Firstly, the basic classification of users' electricity stealing behavior, evaluation indicators and existing electricity theft detection data sets are introduced. Then, from the four aspects of grid state analysis, machine learning, game theory and hardware, the existing detection methods of electricity theft behavior are comprehensively sorted, analyzed and compared, and the basic ideas, advantages and disadvantages of each method are summarized. Finally, the current challenges in the field of electricity theft behavior detection are deeply analyzed, and a prospective outlook on the focus of future research work is provided.

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Multi -dimensional time -frequen cy charac terization of transient waveforms on transmission line faults in ne w electric power systems
Li ZHANG, Shengnan LI, Shiya o WANG, Shoudong XU, Xiaotian LU, and Jinrui TANG

Date posted: 10-22-2025
DOI: https://doi.org/10.19781/j.issn.1673-9140.2025.04.003

When large-scale new energy，energy sto rage，and large-capacity flexible alternative current （AC） and direct current （DC） transmission equipment are integrated into new electric power systems，steady-state power frequency phase，and sequence component of current and voltage waveforms in transmission line faults are mainly depend on the low voltage ride through strategy of power electronic equipment，emergency control strategy，and current limiting link of electronic components and devices.The performance of traditional relay protection algorithms is significantly based on the power frequency.A new relay protection algorithm based on non-power-frequency transient components can make full use of the transient charging and discharging process caused by transmission line faults to distinguish between internal and external faults.Inspired by information-theoretic methods for characterizing waveform features，a multi-dimensional time-frequency characterization approach is proposed，which is based on the amplitude and variation rate of transient components in both the time-domain waveform and spectral distribution.This method fully exploits the differences in transient waveform features between internal and external faults on transmission lines.The research results show that some time-frequency characterization indexes are less affected by the power electronic equipment in the given time window and frequency band，while exhibiting significant differences between internal and external faults.The proposed characterization method can be applied to the study and testing of new relay protection algorithms，providing strong support for the safe and reliable operation of new electric power systems.

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Research review on microgrid of integrated photovoltaic‑energy storage‑charging station
Qin YAN and Guoxiang YU

Date posted: 4-22-2024
DOI: https://doi.org/10.19781/j.issn.1673-9140.2024.01.001

To address the challenges posed by the large-scale integration of electric vehicles and new energy sources on the stability of power system operations and the efficient utilization of new energy, the integrated photovoltaic-energy storage-charging model emerges. The synergistic interaction mechanisms and optimized control strategies among its individual units have also become key issues urgently needing resolution in smart grid development. Due to the characteristics of integrated generation, load, and storage, mutual complementarity of supply and demand, and flexible dispatch, the photovoltaic-energy storage-charging (PV-ESS-EV) integrated station micro-grid (ISM) mode, incorporating "PV- PV-ESS-EV + intelligent building" features, has become a focal point for energy conservation, carbon reduction, and energy transition in China. In consideration of the challenges faced by the operational mode of microgrids, such as the strong uncertainty of distributed energy sources and the unclear interaction mechanisms during islanded and grid-connected operation, various aspects of the PV-ESS-EV ISM are reviewed, including its unit modules, key technologies, and operational states. Additionally, the current research status of PV-ESS-EV is summarized while future development trends are discussed, and the challenges that need to be addressed are examined. The research findings have important theoretical and practical implications for exploring the regulatory potential of various demand-response resources under economic incentives, ensuring the reliability of power grid supply, and serving as valuable references for both theory and practice.

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A quantification method of moisture degree of oil -paper insulation based on Stacking heterogeneous integration
Menghong FANG, Yang ZOU, Xiaoxuan CHEN, Yu HUANG, and Tao JIN

Date posted: 10-22-2025
DOI: https://doi.org/10.19781/j.issn.1673-9140.2025.04.026

To address the issues of the limitations of the current transformer oil-paper insulation system moisture assessment model selection and the low directivity of the feature indexes for insulation moisture assessment under the synergistic effect of aging and moisture，a quantification method of the moisture degree of oil-paper insulation based on Stacking heterogeneous integration is proposed.Firstly，the mechanism analysis is conducted about the change trend of the macro insulation state under the synergistic effect of aging and moisture synergism at the micro-medium level，and multi-source heterogeneous moisture feature indexes that can eliminate the interference of aging are extracted，forming a highly correlated feature set with moisture.Secondly，based on four types of heterogeneous algorithms that are integrated based on the fusion learning idea of Stacking，the primary assessment system of the overall model is constructed，and output noise is reduced through the Optuna hyper-parameter tuning framework.Finally，the stack data after weight assignment is utilized to train the sub-assessment system，and then a weighted and improved Stacking model is built to quantify the moisture degree of the oil-paper insulation system.Lastly，the effectiveness of the proposed model is validated in moisture assessment by taking the measured data as an example.The model can serve as a reference for assessing moisture in transformer oil-paper insulation systems.

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Joint regulation strategy of rural distribution networks for renewable energy accommodation and seasonal load supply
Zhumeng SONG, Bao WANG, Jianxiong JIA, Fei WU, Li ZHANG, Chengjia ZHANG, and Xiaodong YANG

Date posted: 2-1-2026
DOI: https://doi.org/10.19781/j.issn.1673-9140.2025.06.008

In view of the problems of new energy accommodation and seasonal load supply pressure in a rural distribution network with extensive access to electric vehicles and new energy power generation, a joint regulation strategy is proposed which utilizes soft open points to achieve coordinated cooperation of flexible interconnection of transformers, orderly charging of electric vehicles, and rational economic expansion of transformer capacity, thereby ensuring seasonal load demand in renewable energy distribution networks while enhancing renewable energy accommodation capacity. Firstly, the usage and load characteristics of different transformer districts in rural areas under the background of renewable energy are analyzed. Secondly, the orderly charging model of electric vehicles, the transformer capacity evaluation system model, and the cooperative regulation operation model are established. Thirdly, the constructed nonlinear optimization model is transformed into a second-order cone programming model through convex relaxation and linearization methods. Finally, simulation experiments are carried out by using the improved 33-node distribution network, which confirms the practical rationality and effectiveness of the regulation strategy proposed in this paper. The research findings demonstrate that the proposed strategy can effectively improve the transformer utilization rate in rural areas and enhance the renewable energy accommodation capacity, as well as the seasonal load supply capacity when transformer capacity is insufficient.

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Robust control of output voltage of DAB converter by super -twisted sliding mode method
Jianlin LI, Laixin GUO, and Penghui HAN

Date posted: 10-22-2025
DOI: https://doi.org/10.19781/j.issn.1673-9140.2025.04.021

The traditional sliding mode control （SMC） used for the isolated dual active bridge （DAB） converter is robust and can improve the dynamic performance of nonlinear systems.To address the disadvantages of buffeting and decreasing tracking performance，a super-twisted sliding mode control （ST-SMC） method is proposed to enhance the output voltage regulation ability and robust control ability of the converter.The ST-SMC method is adopted，and the technical advantages of the sliding mode controller are combined to effectively eliminate the buffeting problem.During the design of the sliding mode controller，the average mathematical model of the DAB converter under single-phase shift control is fully considered，and the design process is effectively simplified.The stability and robustness of the direct current （DC） output voltage of the DAB converter are improved effectively，and accurate reference voltage tracking is realized.In addition，the method provides robust control over parametric uncertainties，and the steady-state output voltage of the DC converter contains fewer ripple components than traditional SMC and PI controllers.Finally，based on the TMS 320F28335 digital controller，a 1kW DAB converter prototype is installed to verify the effectiveness of this new control method.

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IES‑PLAN platform‑based planning and design solution for integrated energy systems
Mingyang GAO, Suyang ZHOU, Wei GU, Qingquan CHEN, Yue QIU, and Aobo GUAN

Date posted: 7-23-2025
DOI: https://doi.org/10.19781/j.issn.1673-9140.2025.03.022

Establishing an integrated energy system (IES) is an effective means to promote the efficient utilization of energy resources. Reasonable planning and design software for IESs can provide tailored design solutions according to engineering needs. However, the lack of multi-scenario-compatible planning software remains a bottleneck for the widespread industrial application of IESs. To address this issue, a comprehensive and highly reliable IES plan (IES-PLAN) design platform has been developed to scientifically guide users in designing reliable, low-carbon, and efficient IESs. The platform offers a graphical interaction interface, allowing users to flexibly set planning scenarios and goals based on their needs. To validate the platform’s effectiveness and practicality, a simulation case study is conducted based on the “Nanjing Hospital IES.” The results demonstrate the platform’s responsiveness and planning performance under different customized requirements, achieving reduced energy costs and improved energy utilization efficiency.

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Resilience enhancement strategy for distribution network considering coordination of intelligent soft open points and multiple emergency resources
Zifa LIU and Wenbo XUE

Date posted: 7-23-2025
DOI: https://doi.org/10.19781/j.issn.1673-9140.2025.03.001

In view of the significant impact of extreme events on power system security, enhancing grid resilience has become a research hotspot. Therefore, a pre-event prevention and post-event coordinated recovery strategy considering intelligent soft open points (SOPs) and multiple emergency resources is proposed to improve the resilience of the distribution system. In the pre-event stage, to effectively reduce post-event resource scheduling time, a robust optimization model considering the uncertainty of power output is constructed based on predicted fault scenarios. A column-and-constraint generation algorithm is used to obtain pre-event deployment decisions. In the post-event stage, to minimize the curtailed load power through dynamic scheduling, a coordinated recovery strategy using intelligent SOPs and multiple emergency resources is developed, combined with pre-event deployment decisions and traffic network conditions. To address the computational complexity of the multi-source recovery model, an auxiliary induction objective function acceleration algorithm is designed to speed up the solution. Finally, the effectiveness of the proposed strategy in improving the distribution network resilience is verified using an improved IEEE 33-node distribution system case study.