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最新刊期
卷 47 ， 期 10 ， 2023
- 摘要：As a secondary energy carrier complementary to electricity, hydrogen energy is expected to play a critical role in the future low-carbon energy system. To explore the hydrogen economy in the context of the new power system, the electrolytic hydrogen technology that is a key link in the coupling between electricity and other energy fields is focused on, and the technical and economic analysis and application prospects are made. First, the research status of electrolytic hydrogen technology at home and abroad are reviewed from two perspectives of technology development level and application in energy systems. Then, the economic model of electrolytic hydrogen is established, and the technical and economic analysis of electrolytic hydrogen under the background of new power systems is carried out based on the technical characteristics of new power systems. Finally, the application prospect of electrolytic hydrogen technology is analyzed from three aspects of local hydrogen development policy, terminal hydrogen demand potential, and support for new power systems.关键词：new power system;electrolytic hydrogen;carbon neutrality;technical and economic analysis;hydrogen demand prediction4|2|0更新时间：2025-06-16
- 摘要：Improving the capacity of accommodating renewable energy (RE) is the most important goal of the new power systems. Starting from the demand side, it is necessary to study an evaluation method for the RE share of customers, so as to guide and motivate the majority of customers to consume more RE. To this end, this paper proposes an evaluation method for the RE share, which is based on the marginal contributions of the customer time-series electricity consumption curve to RE accommodation. First, the marginal contribution index on the RE accommodation is defined and derived based on the load profile which is independent of the electricity consumption level. Secondly, considering the customers of pure load and customers of producer-consumer park with adjustable load, energy storage and distributed energy sources, respectively, an evaluation method for the RE share is proposed based on the marginal contribution index. Finally, different types of customers are constructed to evaluate the RE share and the case study verifies the rationality of the RE share evaluation method. The results show that the park customers can obtain higher RE share by improving the similarity between the shape of net load and the trend of RE power generation in the system, accommodating local RE, reasonably optimizing the adjustable load and energy storage operation mode, etc., and thus improve the capacity of accommodating RE in the whole power grid.关键词：new power system;renewable energy accommodation;renewable energy share;marginal contribution;park2|3|0更新时间：2025-06-16
- 摘要：Currently, distributed photovoltaics (PVs) on the user side are showing a low-end quantitative expansion trend of decentralized construction and disorderly access, which is difficult to meet the needs of large-scale deep development and sustainable development of distributed PV power generation under the low-carbon transformation of the power grid. This paper explores the integrated development and operation mode of distributed PV clusters, and proposes a game strategy for cluster development of users-side distributed PV resource. Firstly, a distributed PV cluster development and operation model with cluster operators as the main body is constructed. Secondly, a prediction method for user PV development behavior is proposed for two development modes: self-built PV or rented site. Then, the game relationship between cluster operators and users in the allocation of PV development resources is revealed, and a two-layer optimization model of distributed PV resource Stackelbery game is constructed. Finally, the simulation results validate the effectiveness of the proposed method in guiding the orderly and rational development and reasonable and efficient configuration of user-side distributed PV.关键词：distributed photovoltaic;cluster development;photovoltaic site lease;Stackelberg game;bi-level optimization2|2|0更新时间：2025-06-16
Power Energy Transition for Carbon Emission Peak and Carbon Neutrality
- 摘要：The integration of high proportion of distributed photovoltaic (PV) into distribution networks brings new challenges. It causes voltage overlimit problems, seriously limits the PV hosting capacity of the distribution network, and also reduces the power generation efficiency. Therefore, the optimization strategy and method of time-of-use electricity price for the PV hosting capacity improvement of the distribution network are proposed. Firstly, the influence of the distributed PV integration on voltage distribution and peak-valley time division of the load curve is analyzed, and then an optimization model of time-of-use electricity price that comprehensively considers the characteristics of PV output and the net load curve is established. Secondly, based on the Tent chaotic reverse learning initialization strategy and Gaussian perturbation strategy, the imperialist competition algorithm is modified from two aspects of improving the quality of the initial population and strengthening the movement of the empire’s position to enhance its global optimization ability, and it is used to solve the problems such as time-of-use electricity price optimization, etc. Finally, taking the IEEE 33-bus system as a case study, the PV hosting capacity of distribution networks is analyzed, and the results show that the proposed method can improve the PV hosting capacity, and has practicality and effectiveness.关键词：distribution network;photovoltaic;hosting capacity;time-of-use electricity price;demand response;imperialist competition algorithm2|0|0更新时间：2025-06-16
- 摘要：Aiming at the problem of node voltage overlimit caused by high penetration of distributed photovoltaics connected to the distribution network, a voltage regulation strategy for energy storage based on cluster partition is proposed. The strategy includes distribution network cluster partition and voltage regulation strategy for distributed energy storage. First, the distribution network is divided into clusters through the improved modularity index. Then, on the premise of considering the energy storage power and state of charge (SOC), the mathematical model of energy storage optimized voltage regulation is constructed. The energy storage in the cluster is allocated according to the total power required by the cluster where the node voltage exceeds the limit, to determine the energy storage timing-action-power when the operation benefit of distributed energy storage is the largest. Finally, the voltage fluctuation, distribution network loss and energy storage operation economy under different schemes are analyzed. The comparison between the two schemes shows that the corresponding scheme of the proposed strategy not only effectively controls the node voltage and reduces network loss, but also achieves good economy.关键词：distribution network;distributed energy storage;distributed photovoltaic;voltage regulation;cluster optimization4|5|0更新时间：2025-06-16
- 摘要：In recent years, as one of the effective ways to utilize renewable energy, microgrids play an increasingly important role in the new power system and achieve remarkable progress. However, the massive access of microgrids has changed the single-stage dispatching mode of the traditional distribution network, and brought rather onerous tasks to the calculation and communication in the dispatching process. The existing dispatching schemes fail to take into account the interests of distribution network operators and microgrids as well as other multiple entities, nor can it meet the requirements of computing efficiency and communication privacy in the dispatching process. In this regard, a hierarchical cooperative dispatching strategy of multi-microgrid and distribution networks based on a multi-agent algorithm is proposed. First, considering the leader-follower relationship between distribution network operators and microgrids in power market operation, a power transaction model of multi-microgrid and distribution networks based on two-layer Stackelberg game is constructed. Then, the power coordinated dispatching of multi-microgrid and distribution networks is expressed as a Markov decision process, and the Stackelberg equilibrium is solved by using data-driven multi-agent deep deterministic policy gradient algorithm. Finally, a numerical case based on the modified IEEE 33-bus system is analyzed to verify the effectiveness of the proposed model and algorithm.关键词：multi-microgrid;distribution network;Stackelberg game;multi-agent;deep deterministic policy gradient algorithm;collaborative dispatching2|0|0更新时间：2025-06-16
- 摘要：By making full use of regulation ability of the cascade hydropower, the complementary generation of cascade hydro-photovoltaic (PV) systems is an important way to promote clean energy accommodation. In this paper, considering the uncertainty of PV output, a short-term optimal dispatch model of the cascade hydro-photovoltaic complementary system is introduced with the aim of maximizing expectation of the total accommodation power. This model takes the unit as the minimum dispatch unit, and the constraints for the power plant, the unit and the power grid are carefully modelled. Through the rational distribution of cascade load in power plants and time periods, the dual role of cascade hydropower in power support and PV coordination is explored, thus the overall power consumption level is improved. In terms of model solving, linearization methods and modeling techniques such as piecewise linear approximation, introduction of 0-1 integer variables, and generation head discretization are used to deal with nonlinear constraints. The original model is transformed into a mixed-integer linear programming (MILP) problem which can be solved by CPLEX tool in Java programming environment. Finally, the proposed model is applied to a hydro-photovoltaic complementary system consists of 4 hydropower plants, 15 units and 2 photovoltaic clusters in southwest China, the effectiveness of the proposed model and solution method is verified.关键词：cascade hydropower plant;optimal dispatch;multi-energy complementary system;maximizing expectation of accommodation power;mixed-integer linear programming2|0|0更新时间：2025-06-16
- 摘要：As the scale of wind farms increases, the coupling between wind farms and power grid is strengthened during asymmetric short-circuit fault in the grid, which may increase the risk of voltage instability. Aimed at the current technical specification for connecting wind farm to power system, the analysis method for static voltage stability of radial wind farms during the stage of asymmetric short-circuit fault in the grid is studied. The impedance model considering the coupling between multiple wind farms and connecting lines is established. According to the dynamic reactive power support requirements during the asymmetric fault, the voltage stability of wind farms is analyzed to obtain the voltage interaction between the positive and negative sequence impedances of wind farms and power grid. The analytical results show that the proposed method can accurately judge whether the static voltage is stable during the stage of asymmetric short-circuit fault in the grid when multiple wind farms satisfy the current guideline of wind power grid connection. Finally, the correctness of the theoretical analysis and effectiveness of the proposed method are verified by simulations.关键词：wind farm;short-circuit fault;wind power grid connection;dynamic reactive power;static voltage stability2|0|0更新时间：2025-06-16
- 摘要：Less measurement information and insufficient measurement accuracy are the important problems that affect the accuracy of the state estimation for distribution networks. Traditional algorithms based on determining physical topology relay on the accurate parameters of the distribution network, while ordinary neural network models are easily disturbed by outliers and missing data. In order to solve the above problems, this paper proposes a robust state estimation method of the distribution network based on deep graph learning. The proposed model transfers the information based on physical topology knowledge, and implements the global graph attention mechanism to aggregate node information, which realizes the task of robust state estimation under various topologies. By embedding the physical topology knowledge and attention mechanism and integrating the deep learning technology, the model can learn the deep structural information of data, so as to master the feature mapping rules of various topologies and acquire the ability to resist outliers and interference. The experimental results show that the model has better estimation accuracy and robustness when learning with multi-topology data. In addition, the model can use the historical operation data of multi- topologies to improve the estimation accuracy. Compared with other algorithms, the proposed method has stronger robustness and interpretability.关键词：distribution network;state estimation;graph attention mechanism;graph neural network;deep learning;physical information fusion2|2|0更新时间：2025-06-16
- 摘要：The existing equivalent circuits and calculation methods for analysis of residual current in the low-voltage distribution network haven’t taken into account TN-C and TN-C-S systems, which is difficult to meet the requirements of distinguishing grounding faults and load switching. Therefore, a modeling and calculation method for low-voltage distribution networks with various grounding types is proposed. For the circuit equations of different grounding types, a fourth-order phase-mode transformation matrix is proposed, and the independent 1 mode, 2 mode, coupled 0 mode and N-line mode are obtained. The residual current mode network is then obtained by adjusting and transferring the mutual impedance of 0 mode and N-line mode. According to the boundary conditions of grounding faults and load switching, the equivalent circuits of residual current analysis are constructed, and the calculation formulas of electrical quantities are derived. Simulation and test results show that the proposed method has strong applicability and high calculation accuracy, which provide a theoretical analysis basis for the research of grounding fault protection technologies.关键词：low-voltage distribution network;residual current;grounding fault;load switching;equivalent circuit2|0|0更新时间：2025-06-16
- 摘要：Reasonable energy management strategy is of great significance to control the peak power of charging load and reduce the power fluctuation when the battery energy storage system is configured in the electric vehicle fast charging station. However, the effectiveness of the energy management strategy depends on the accurate load forecasting, which cannot be completely accurate due to environmental influences and forecasting models. Based on the above problems, in order to cope with the impact of charging load uncertainty in the energy storage management strategy of charging stations, this paper proposes a robust real-time control strategy for energy storage considering the load forecasting uncertainty. First, current load forecasting methods are analyzed and load forecasting results are modelled. Then, the robust predictive control method is used to establish the system model and design the control strategy respectively with the objective of minimizing the electricity charge of charging stations and the state of charge (SOC) fluctuation of the energy storage system. The uncertainty model is eliminated through robust counterpart transformation to effectively cope with the impact of the load forecasting uncertainty. Case studies show that the proposed robust control strategy can effectively reduce the peak charging load by comparing the results of model predictive control and logical threshold control, which verifies the effectiveness of the strategy.关键词：electric vehicle;charging station;load forecasting;real-time control;robust predictive control;battery energy storage system2|0|0更新时间：2025-06-16
- 摘要：With the development of power systems, probabilistic power flow analysis of interconnected power grids is necessary to take into account the influence of uncertain factors such as renewable energy generation and load fluctuations, and the continuous expansion of power grids will significantly increase the corresponding computation burden. Therefore, in order to improve the calculation efficiency of the probability power flow for interconnected power grids, a probabilistic power flow calculation method for interconnected power grid is proposed based on external network static equivalent method and unscented transformation method. Firstly, the unscented transformation method is used to generate the set of sample points for the probabilistic modeling of equivalent parameters at the boundary, and the external network static equivalent method based on multiple operation points is proposed, that is, each sample point obtains equivalent parameters based on the results of its improved DC power flow calculation, to establish the probability model of the input random variables of the internal network after equivalence. Then, a new set of sample points is generated by the unscented transformation method through the probability model, so as to calculate the probabilistic power flow of the internal network after equivalence. Finally, the accuracy and speed advantages of the proposed method are demonstrated on multiple test systems. The proposed method reduces the dimension of input random variables and the system size in probabilistic power flow calculation with the help of the probability equivalent technology, thus reducing the number of deterministic power flow calculations and the single calculation time required for its analysis, and realizing the double dimension reduction in the calculation of this application.关键词：interconnected power grid;probabilistic power flow calculation;external network static equivalent method;unscented transformation method2|1|0更新时间：2025-06-16
- 摘要：As the power system gradually moves toward a new ecosystem of energy interconnection and the deep coupling of the network layer and physical layer, the threat of network attacks on the power system keeps rising. The source identity (ID) spoofing attack, as a new and complex, strong stealthy false data injection attack, can cause the grid control system to misjudge and cause system paralysis. To address this problem, a spatial feature based method is proposed for detecting false data injection attacks on synchronous measurements of power grids. It has extracted different spatial features of the synchronous measurement devices at different locations by variational modal decomposition (VMD) and improved discrete orthonormal Stockwell transform (IDOST), so as to extract the authentication information of the measurement data without losing the spatial features of the measurements. Combined with the light convolutional neural network (LCNN) to evaluate the likelihood of measurement data being attacked by source ID to enhance the speed of detection response. The effectiveness of the method is verified by the detection results of actual multi-point synchronous measurement data.关键词：wide area measurement system;synchronous measurement data;false data injection attack;convolutional neural network3|0|0更新时间：2025-06-16
Basic Research
- 摘要：With the large-scale integration of renewable energy, the rotational inertia, the frequency characteristics, and the support capacity of different regions in the power system have changed greatly. The extraction and identification of frequency features can provide a basis for the recognition of power grid characteristics and further analysis of inertia evaluation, frequency control, and network security. Based on a large number of measured data from the source-grid-load full-view synchronous measurement system, this paper analyzes the clustering phenomenon related to the frequency and the AC power grid structure, and proposes a frequency spatial correlation identification method based on the Pearson correlation coefficient. A “frequency fingerprint” extraction method based on convolutional neural networks is proposed to extract the high-latitude features of the power grid characteristics in the frequency domain. Furthermore, the measured frequency signals of ten cities, such as Beijing and Changzhi, are tested and analyzed, and the identification accuracy is given, which verifies the effectiveness of the proposed method and provides a basis for the subsequent frequency characteristic analysis, inertia evaluation and cyber attack identification of the power system.关键词：power grid characteristic frequency feature extraction;information source location recognition;Pearson correlation coefficient;variational mode decomposition (VMD);convolution neural network (CNN)2|1|0更新时间：2025-06-16
- 摘要：The deep neural network based on massive sample data can significantly improve the fault diagnosis effect of power transformers, but in the actual environment, the local data of each transformer are isolated by “data islands”, which makes it difficult to conduct the centralized in-depth training. Federated learning can realize the common modeling of multi-source data. However, the non-independent and identically distributed unbalanced data of each transformer will seriously degrade the performance of the algorithm. Aiming at the above problems, a power transformer fault diagnosis mechanism with unbalanced sample data based on federated learning is proposed. Different from the traditional intensive training method of deep learning, this paper adopts the distributed training method of multiple participants. Each participant uses the LeNet-5 deep neural network for local training, the central server aggregates local models, and introduces an improved data sharing strategy to selectively distribute the cloud shared data to reduce the imbalance of non-independently and identically distributed data. The experimental results show that the mechanism realizes the cooperative training of each transformer with independent and unbalanced data, and the diagnosis accuracy of transformer fault types can reach 97%.关键词：power transformer;fault diagnosis;LeNet-5 network;federated learning;non-independently and identically distributed data2|1|0更新时间：2025-06-16
- 摘要：To deal with the problems of high current stress and low operation efficiency of the DC transformer combining modular multilevel structure and series-connected switches under conditions of low voltage on the medium-voltage side and low load, this paper proposes a current optimal control strategy based on the inner-phase-shift control of the low-voltage side full-bridge. By adopting the phase-shift control, the zero-level interval is generated at the port of the high-frequency transformer, and the peak current of the transmission inductor can be suppressed, which reduces the current stress and loss of devices. The current stress is analyzed by studying the operation modes of the DC transformer, and the optimal control strategy is established based on the goal of current stress optimization. This strategy adopts the method of calculating phase-shift angle in segments, which achieves a good closed-loop control effect while maintaining the soft switching characteristics of switch tubes. The effectiveness of the proposed optimal control strategy is verified by the simulation and the prototype experiment.关键词：DC distribution network;DC transformer;modular multilevel structure;current stress;zero voltage switching;phase-shift control2|1|0更新时间：2025-06-16
- 摘要：The frequency coupling effect of the modular multilevel converter affects the impedance characteristics of the converter, and then affects the effectiveness of high-frequency resonance suppression measures. Firstly, the frequency coupling effect is considered to establish the AC-side admittance matrix model of the modular multilevel converter. Secondly, the influence of common high-frequency resonance suppression measures on the system frequency coupling effect is quantitatively analyzed. The result shows that the frequency coupling effect of the system has a tendency to intensify with the common high-frequency resonance suppression measures. Then, a measure to suppress both the frequency coupling effect and the high-frequency resonance is proposed. Finally, the Guangxi-side model of Luxi back-to-back asynchronous grid-connection project in China in PSCAD/EMTDC is taken as an example to verify the correctness of the model and the effectiveness of the proposed measure.关键词：modular multilevel converter based high voltage direct current (MMC-HVDC);admittance modeling;frequency coupling effect;high-frequency resonance;stability analysis;suppression measure2|1|0更新时间：2025-06-16
- 摘要：Voltage sag risk assessment is helpful for voltage sag prevention and sensitive user siting. The simulation-based methods have a large amount of data which cannot reflect the influence of actual environment, and the data-driven methods have few samples with uneven distribution. So it is difficult to know the voltage sag risk of each bus in the whole network. Therefore, a voltage sag risk assessment method based on the fusion of simulated and measured data is proposed. First, the influencing factors of voltage sag risk are selected from simulated and measured data, and then the comprehensive quantitative index of the influence domain characterizing the voltage sag propagation characteristics is constructed. Second, the tail class oversampling and the head class undersampling are used to construct the simulation source domain dataset, and the gradient descent method is improved by knowledge transfer and Armijo-Goldstein criterion to construct the residual voltage multiple regression prediction model for the buses without measured data. Finally, the voltage sag risk level is classified by combining the predicted results with the voltage sag tolerance characteristics. The analysis of an actual power grid case shows that the accuracy and convergence performance of the proposed method are improved compared with the existing commonly used methods, and the voltage sag risk in the whole network can be evaluated quickly and accurately.关键词：voltage sag;risk assessment;knowledge transfer;Armijo-Goldstein criterion2|0|0更新时间：2025-06-16
- 摘要：In the low-resistance grounded system, the grid-side neutral point of the grid-connected distributed generator (DG) adopts the low-resistance grounding method, which can reduce the over-voltage of island system during the fault operation and change the single-phase grounding fault characteristics of the original low-resistance grounded system. Therefore, the existing high-resistance grounding fault protection scheme is not applicable. This paper analyzes the single-phase grounding fault characteristics of the distribution system in which the neutral points of both main grid and DG are grounded with low resistance. According to the zero-sequence current amplitude and phase characteristics of faulty lines and non-faulty lines, the lines are divided into two regions. Zone 1 includes the line connecting the neutral points, and zone 2 includes the lines except for connecting the neutral points. A regionalized zero-sequence protection scheme based on zero-sequence phase differential protection and zero-sequence current amplitude ratio protection is proposed. Finally, MATLAB/Simulink is used to build the simulation model. The accuracy of the proposed protection scheme is verified by the simulation of the low-impedance grounding faults, linear high-impedance grounding faults, and non-linear high-impedance grounding faults.关键词：low-resistance grounded system;distributed generator;high-impedance grounding fault;zero-sequence phase differential protection;zero-sequence current amplitude ratio protection2|1|0更新时间：2025-06-16
- 摘要：To meet the requirements of online computing speed of state estimation for the large-scale power grid, this paper proposes a fast rotation strategy of Givens orthogonal transformation based on row sparsity isostructuralism. This strategy takes advantage of the distribution characteristics of the state estimation measurement of the large-scale power grid and the sparsity of the weighted Jacobian matrix, dynamically selects rotating row pairs according to the row isomorphism pattern, and selects the rotation pivot and ranks the rows based on the row sparsity, which reduces the non-zero fill-in amount and the number of Givens rotation, and greatly reduces the computation time. The calculation results of a large-scale power grid show that the proposed strategy has a higher computation efficiency without changing the calculation accuracy, and the efficiency of the Givens rotation and the number of intermediate non-zero fill-in elements are effectively improved, which fully meets the requirements of real-time state estimation for the large-scale power grid.关键词：power system;state estimation;Givens orthogonal transformation;sparse matrix;weighted Jacobian matrix;row sparsity isostructuralism (RSI)2|1|0更新时间：2025-06-16
Application Research
- 摘要：The traditional power frequency AC transmission mode is limited by the charging reactive power of long-distance submarine cables, and the DC transmission mode is restricted by the construction and maintenance cost of the offshore converter station. The flexible fractional frequency transmission system greatly increases the transmission capacity as well as the transmission distance by reducing the transmission frequency, and is competitive in the field of high-efficiency offshore wind power transmission. This paper firstly discusses the advantages of the flexible frequency fractional transmission system. And then, it describes the construction planning technology with frequency optimization and the stability analysis method with the different frequency interaction characteristics in detail. Furthermore, it analyzes how the frequency change influences the characteristics of key fractional frequency equipment, and focuses on the comparison between ferromagnetic AC/AC converter and power electronic converter. Finally, it expounds the prospect of some technical difficulties, such as static, dynamic as well as electromagnetic transient characteristics analysis, prototype development and system validation.关键词：flexible fractional frequency transmission;offshore wind power;construction planning;frequency optimization;stability analysis2|0|0更新时间：2025-06-16
Review
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