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Research on optimization of electric vehicle charging scheduling in rainy season based on peak valley difference electricity price model
Zhikun LUO, Wenhao YE, Yaohong CHEN, Qin YAN, Shusheng WU, and Jinxin WANG

Date posted: 10-22-2025
DOI: https://doi.org/10.19781/j.issn.1673-9140.2025.04.011

To address the issues of increased energy consumption of electric vehicles，grid load，and peak valley difference caused by high humidity and temperature in the rainy season in Southern China，a charging price model based on peak valley difference is proposed to stimulate electric vehicles to participate in demand response，so as to stabilize the peak valley difference of grid load and improve the economic benefits of electric vehicle users.Firstly，the Monte Carlo simulation is used to analyze and predict the disordered charging load of electric vehicles，considering factors such as high temperature and humidity during the rainy season in Southern China.Then，a peak-valley differential charging price model is built to minimize the peak valley difference of the power grid and the user charging cost.Lastly，simulation analysis is conducted on the model using the MATLAB application.The research shows that the proposed model considering the high humidity and temperature of the rainy season in Southern China is more accurate.The model can reduce the peak valley difference rate，improve the economic benefits of users，and realize the smoothing and optimization of grid load.The research provides a reference for a new electric vehicle charging scheduling.

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Method for anomaly detection of converter valve voiceprints based on improved denoising auto-encoder
Yisheng YU, Zhihong WANG, Yunya ZHOU, Zhanfan ZHOU, Yu YAN, Yu YU, and Mingzhu TANG

Date posted: 2-1-2026
DOI: https://doi.org/10.19781/j.issn.1673-9140.2025.06.017

The converter valve, as a key equipment in high-voltage direct current transmission converter stations, may experience an abnormal state when operated for a long time. To address the problem that non-intrinsic background noise in the valve hall may cause voiceprint anomalies and unstable anti-noise performance of the converter valve, an anomaly detection method for the converter valve based on voiceprint signal filter banks (Fbank) features and an improved denoising auto-encoder (IDAE) is proposed. Firstly, the voiceprint data generated during the operation of the converter valve is collected; the Fbank features of the voiceprint data are extracted; the samples containing temporal information through sliding window (SW) processing are obtained. Then, a denoising auto-encoder (DAE) based on environmental noise and dual channels is constructed to train normal samples, and multiple feature thresholds are calculated through fused directional distance (FDD) reconstruction error. Finally, speech, white noise, and industrial background noise with different signal-to-noise ratios are added to the test data for comprehensive performance evaluation. The experimental results show that compared with other anomaly detection models, the proposed method has better performance and stronger noise resistance.

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Single-phase grounding fault line selection method for active distribution network with energy storage power stations
Xiaoran WANG, Chunju FAN, Yan HU, Haoyu ZHU, Hulin LIU, Hai YE, Zhongping LIU, and Yong HOU

Date posted: 12-18-2025
DOI: https://doi.org/10.19781/j.issn.1673-9140.2025.05.006

With the continuous integration of large-scale new energy, the scale of power grids and distribution networks is constantly expanding.Due to the large number of power electronic devices in the grid, the traditional fault line selection scheme for small current grounding systems can hardly ensure the line selection accuracy.To solve this problem, the fault characteristics of active distribution networks with energy storage power stations when single-phase grounding faults occur are analyzed, namely the different fault characteristics during the charging and discharging of energy storage power stations and the distribution characteristics of single-phase grounding fault current in resonant grounding systems.Then, a fault line selection method that actively injects characteristic electrical quantities based on the control strategy of energy storage power stations is proposed.Then, a detailed analysis and research on the injection quantity frequency selection method suitable for high-precision fault line selection is conducted, including the control strategy of energy storage power stations and its parameter selection principle.Finally, a line selection criterion based on the 10 Hz component in the zero-sequence current is proposed.The PSCAD/EMTDC simulation verifies the effectiveness of the energy storage power station control strategy, the correctness of the fault line selection theory, and the effectiveness of the scheme implementation.

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A review of vehicle-grid interaction with introduction of virtual power plants
Yanxia WANG, Yuchen WANG, and Shaojun GAN

Date posted: 4-30-2026
DOI: https://doi.org/10.19781/j.issn.1673-9140.2026.02.002

The advent of virtual power plants (VPPs) promotes the development of the interaction between electric vehicles (EVs) and the power grid, and plays an important role in promoting the load balance of urban power grids. By systematically reviewing the relevant literature on EVs, integrated photovoltaic storage and charging stations, and VPPs and their aggregators, this paper analyzes the vehicle-grid interactions with the introduction of VPPs, summarizes the commonly used EV load forecasting methods, and describes the siting and capacity planning model of integrated photovoltaic storage and charging stations. Further, it summarizes the game relationship among the grid layer, the VPP and its aggregator, and the user layer in the process of vehicle-grid interaction. Finally, it summarizes the existing studies, and provides an outlook on the future development of vehicle-grid interaction by combining with the case studies of the VPPs of different countries.

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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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Detective effect of oscillation on different defects of cable from the perspective of materials and electric field
Jihe YUAN, Yang YANG, Xi ZHANG, Huayong HUANG, Xianjin WANG, and Kai ZHOU

Date posted: 9-4-2020
DOI: https://doi.org/10.19781/j.issn.16739140.2020.04.006

The effect of the oscillating wave on the interfacial and internal defects of cable from the perspective of the electric field is studied in order to understand the test results of the oscillating wave voltage method for different defects in cables. Firstly, an oscillating wave test platform is set up to partial discharge tests the artificial defective models including longitudinal knife defects and external semiconductor lap defects. Then, the excitation characteristics of oscillation wave are analyzed primarily by PDIV and PRPD. Furthermore, the electric field distribution of cables with defects are simulated by utilizing a finite element simulation software in threedimension. Artificial defects with different sizes are fabricated to represent the diversity of the defect site and the characteristics of defective discharges are explained by the electric field distortion at the defects. Experimental and simulation results show that: it is hard to detect the internal defects due to the filling of hard grease by using the oscillation wave voltage method, whereas interfacial defects of poor connection of outer semiconductor has better characterization results.

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Active damping control based on virtual resistance for stand‑alone DC microgrid
Xin TANG, Shuai WANG, Zhen LI, and Xin HUANG

Date posted: 7-23-2025
DOI: https://doi.org/10.19781/j.issn.1673-9140.2025.03.021

Due to the presence of a large number of constant power loads (CPLs) in a stand‑alone DC microgrid, the damping of the DC microgrid is reduced, leading to oscillations and even significant drops in the DC bus voltage. To address this issue, an active damping method is proposed to improve system stability. The damping of the converter is increased to suppress the resonant peak by connecting a virtual resistance in parallel at the port of the energy storage converter without adding extra sensors. The method for designing the active damping parameters is provided, and the effect of the proposed parallel virtual resistance method on system stability is analyzed using the frequency stability criterion. The performance of this method is also compared with that of the conventional damping method. Experimental results verify that the parallel virtual resistance method can effectively improve the stability of a stand‑alone DC microgrid system in a wide frequency band.

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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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Research on multi-objective planning of power transmission network considering power angle stability
Zifa LIU and Haoyu ZHENG

Date posted: 2-1-2026
DOI: https://doi.org/10.19781/j.issn.1673-9140.2025.06.001

With the continuous improvement of the p enetration level of renewable energy in the power transmission network, the negative resistance effect of the unit side caused by the grid connection of new energy is significantly enhanced, which brings severe challenges to the power angle stability of the power system and then restricts the ability of new energy consumption. In this study, the power angle stability characteristics of multi-node power transmission networks are systematically analyzed by establishing a ternary single-port coupling equivalent model including traditional generator sets, new energy access nodes, and equivalent load networks. Different from the traditional stand-alone system analysis method, a static power angle stability margin quantification index suitable for complex power grid structures is innovatively proposed, which can effectively characterize the system operation boundary, tackling the bottleneck posed by the marked nonlinearity of existing static voltage stability indexes and their inadequacy for grid planning optimization. Then, a marginal index linearization strategy based on the improved McCormick envelope method is proposed. By integrating ε constraint theory and the multi-objective mixed integer programming method, a power transmission network expansion planning model with both economy and stability is constructed. In particular, the Pareto optimal solution set screening mechanism is used to realize multi-objective collaborative optimization to ensure the optimal comprehensive performance of the planning scheme. The HRP-38 high-proportion new energy grid planning case is verified, which fully proves the effectiveness and engineering applicability of the model.

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Ultra‑low frequency oscillation control method considering dead zone and limiting optimization of hydraulic turbine governor
Jiawei WANG, De ZHANG, Yuzheng XIE, and Ancheng XUE

Date posted: 6-5-2025
DOI: https://doi.org/10.19781/j.issn.1673-9140.2025.02.008

The dead zone and limiting of a hydraulic turbine governor have a great influence on the characteristics of the ultra-low frequency oscillations (ULFOs), which can even lead to the oscillation of the positive damping system under large disturbance. However, the existing control methods for ULFOs mainly focus on optimizing proportional‑integral‑derivative (PID) control parameters of hydraulic turbine governors to improve system damping, without considering the dead zone and limiting parameters concurrently. This paper proposes a ULFO control method considering the dead zone and limiting optimization of the turbine governor and verifies its effectiveness and superiority. Firstly, in a non-smooth single hydro-generator power system (SHPS) with dead zone and limiting, the causes of continuous oscillation with constant amplitude involving dead zone and limiting are analyzed, and the influence of relevant parameters is analyzed, obtaining the qualitative demand for control parameter optimization. Then, a comprehensive evaluation index including the suppression effect of the non-smooth part, the amplification effect of the smooth part, and the performance of the primary frequency regulation is established. Additionally, the optimization parameters are solved using a particle swarm optimization algorithm, and a specific application case of the proposed method is presented. Finally, the proposed method is compared with the control method that does not consider dead zone and limiting optimization, in three simulation systems: SHPS, a four-machine two-area system, and a large-scale power grid model. The proposed method shows improved performance in primary frequency regulation and resistance to disturbance.