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最新刊期
卷 48 ， 期 10 ， 2024
- 摘要：With the gradual replacement of synchronous units by renewable energy generation represented by wind and photovoltaic power, the frequency regulation resources of systems are insufficient, and the anti-interference ability is declining, and the frequency security problem is highlighted. The fast frequency support provided by renewable energy stations has become an inevitable requirement for the construction of a new power system. The fast frequency support of renewable energy stations is the result of the coordinated efforts of multiple internal equipment and links, which is influenced and constrained by multiple factors such as wind and solar resources, control strategies, and power grid conditions. Quantitative evaluation of the fast frequency support capability of renewable energy stations is the basis for guiding the optimal control of station frequency regulation, analyzing the frequency response characteristics of the new power system, and realizing the interaction between frequency regulation resources of stations and power grids. This paper provides a comprehensive overview of the evaluation of the fast frequency support capability of renewable energy stations. First, the fast frequency support characteristics of stations are analyzed, and the definition of the fast frequency support capability of stations is given. Then, the evaluation index system of the fast frequency support capability of the stations is sorted out from the three dimensions of state attribute, control characteristic and frequency regulation effect, and the common calculation methods of various evaluation indices are analyzed and commented. Finally, key technical issues worthy of attention and further research are proposed.关键词：fast frequency support;renewable energy station;active power control;capability assessment;inertia support;primary frequency regulation4|1|0更新时间：2025-06-16
- 摘要：The uncertainty of the power output of wind farms and photovoltaic power plants brings significant technical challenges to the optimal dispatch of power systems. This paper mainly introduces the research status and future research direction prospect of the optimal dispatch methods for power systems considering the uncertainty of renewable energy. Firstly, various uncertain optimal dispatch (UOD) methods are discussed including stochastic optimization (SO) methods, robust optimization (RO) methods, combined SO and RO methods and artificial intelligence technology-based methods. SO methods include scenario-based method, chance-constrained programming method and approximate dynamic programming method. RO methods include traditional RO method and distributionally RO method. Combined SO and RO methods include sample RO method and distributionally robust chance-constrained programming method. Secondly, the form of the optimization model, the principles of model transformation and solution, as well as the advantages and disadvantages for each method are introduced. Finally, the future research directions of UOD are prospected, including the UOD problem with multiple objectives and the multi-objective uncertain optimization method, the UOD problem of transmission and distribution systems and the distributed uncertain optimization method, the UOD problem considering the stability constraints and the uncertain optimization method with ordinary differential equation constraints, and the UOD problem of integrated energy systems considering the pipeline transmission dynamics and the uncertain optimization method with partial differential equation constraints.关键词：renewable energy power system;uncertain optimal dispatch;stochastic optimization;robust optimization;approximate dynamic programming3|1|0更新时间：2025-06-16
Review·Perspective
- 摘要：After the blackout, how to make full use of the limited available capacity in the restoration process to quickly restore more valuable restoration goals is the key issue for the power system to quickly restore power supply and reduce power outage losses. To make full use of the restoration capacity of high-proportion renewable energy power supply in the new power system, a restoration decision-making method is proposed based on the unified evaluation for the importance of new power system restoration targets. Firstly, aiming at the importance evaluation for renewable energy power supply to be restored, a scenario generation method for multi-step expected sequence of renewable energy power supply considering temporal and spatial correlation is proposed. Secondly, considering the active cooperative ability of energy storage and flexible load, a unified evaluation method for the importance based on the net income of restoration is established for the restoration targets such as independent power supply, power supply cluster and substation bus to be restored, and it is revealed that the essence of restoration stage is a special case of the optimization result of the source-grid-load collaborative restoration order. Then, with the goal of maximizing the expected net income of power grid restoration scheme, an optimization model of unified and coordinated source-grid-load restoration control for new power systems is established. Finally, based on the IEEE 118-bus case system, it is verified that the proposed method can dynamically evaluate the importance of restoration targets during the restoration process, so as to effectively guide the efficient allocation of the restoration capacity and maximize the restoration benefit.关键词：restoration control;new power system;restoration target;importance evaluation;power supply cluster5|1|0更新时间：2025-06-16
- 摘要：Power grid planning decision-makers and operators still have difficulty in effectively mastering the changes in the new power system inertia level with various influencing factors in the future high-proportion asynchronous power source access scenarios, and cannot effectively formulate response measures for low-inertia scenarios. To address this challenge, the main differences between inertia estimation methods for planning decisions and control operation in two different scenarios are compared and analyzed. The challenges and research framework of medium- and long-term inertia level estimation from three perspectives of basic methods, time scales, and target objects are elaborated. Based on this, the estimation method for the medium- and long-term inertia level tendency based on planning data is proposed, which realizes a rapid estimation of the range of system inertia changes in different future operation scenarios, and the application scenarios of medium- and long-term estimation from the perspective of inertia safety are explained. The proposed method has been applied to the analysis of inertia changing tendency and safety grading warning of the “14th Five-Year Plan” system in a provincial power grid in China. The extreme penetration rate of asynchronous power source and the minimum start-up scale of synchronous power sources are analyzed based on inertia safety requirements.关键词：inertia estimation;inertia security;minimum start-up scale;renewable energy;synchronous power source5|0|0更新时间：2025-06-16
- 摘要：The frequency security problem caused by the weak inertia characteristic of the new power system is essentially the decrease of the equivalent inertia. Therefore, the quantitative estimation of the minimum inertia requirement of the new power system has become an urgent engineering problem to be solved. To this end, an evaluation method for the minimum inertia requirement is proposed. Firstly, a spatial frequency response (SFR) model of the multi-machine system is proposed considering thermal power units, wind turbines, and asynchronous machines participating in frequency regulation, and based on the quantitative analysis of the system frequency characteristics, an equivalent inertia mathematical model for power systems is established considering the virtual inertia characteristics of wind turbines and asynchronous motors. Secondly, taking the initial rate of change of frequency (RoCoF) and the maximum frequency deviation as the frequency security constraints, the minimum inertia requirement of power systems is evaluated based on the frequency response model. Finally, the effectiveness of the proposed method is verified on MATLAB/Simulink and PSD/BPA simulation platforms.关键词：new power system;minimum inertia;quantitative estimation;virtual inertia;asynchronous machine;frequency security3|0|0更新时间：2025-06-16
- 摘要：Accurately estimating the system inertia is crucial for supporting the safe operation of future low-inertia power systems. This paper proposes a system inertia estimation method based on electromechanical response features under the framework of random data-driven analysis, which realizes the estimation of regional effective inertia from stochastic response signals. First, by combining the stochastic Koopman theory with random dynamic system, the coupling relationship between electromechanical features and system inertia in the stochastic Koopman space is derived. Then, the subspace dynamic mode decomposition (SDMD) algorithm is used to extract system electromechanical response features in a data-driven way. This algorithm achieves a low-rank approximation of the system state matrix while compressing the data through orthogonal projection and singular value decomposition, effectively reducing the influence of observation noise on the calculation results. Finally, numerical simulations on the IEEE 4-machine 2-area system and the IEEE 10-machine 39-bus system verify the effectiveness and robustness of the proposed method.关键词：data-driven;stochastic Koopman theory;stochastic response signal;inertia estimation;subspace dynamic mode decomposition (SDMD)5|2|0更新时间：2025-06-16
- 摘要：Aiming at the unintended virtual inertia problems in the multi-converter DC systems based on the analogous virtual synchronous generator (AVSG), a general analysis method for virtual inertia of the multi-converter DC systems is proposed, which effectively corrects the system-level external characteristics of the equivalent AVSG. Firstly, multiple control loops of AVSG are equated to one equivalent control loop of AVSG, and an equivalent single AVSG model of the DC system is established. Secondly, a system-level virtual inertia evaluation method is proposed to evaluate the system-level virtual inertia from the perspective of frequency-domain response characteristics of the output impedance of the equivalent single AVSG model. Thirdly, the influence of the voltage proportional-integral (PI) control parameters on the virtual inertia characteristics is discussed. And the coordinated design between the voltage PI control parameters and the virtual inertia coefficients is carried out. Finally, a switching model of the multi-converter DC system is built on the PLECS simulation software and RT-BOX hardware-in-the-loop experimental platform. The effectiveness and feasibility of the equivalent single AVSG model and the coordinated design of control parameters are verified in various experimental conditions.关键词：analogous virtual synchronous generator (AVSG);output impedance;DC system;equivalent reduced-order model;virtual inertia;coordinated design4|1|0更新时间：2025-06-16
- 摘要：The low inertia response characteristics of the DC microgrid may lead to bus voltage fluctuation over the limit when uncertain disturbances occur in the system. To solve this problem, this paper constructs the intelligent load with the DC electric spring (DCES) as the core. The mapping relationship between DC motor dynamic energy and inertia energy of intelligent load is analyzed. The equivalent virtual inertia is injected on the demand side and the DCES output voltage deviations caused by uncertainty disturbances are compensated quickly. Aiming at multi-DCES cooperative control, a dynamic event-triggering mechanism is designed to solve global consistency errors with the minimum communication requirements. The real-time online update of the expected trajectories of DCES output voltages is achieved. A feedback linearization controller with the minimum phase characteristics is proposed, which transforms the traditional voltage-current double-loop control into energy single-loop control. The DCES energy function is built and the state variable space is reshaped into the Grassmann manifold. The complete decoupling and accurate linearized transformation of the system are realized. The expected trajectories of DCES output voltages are tracked accurately, which ensures global asymptotic stability at the same time. The experimental results based on dSPACE show that the proposed method can realize the regulation control of DC microgrid bus voltages under the conditions of external uncertain disturbance and internal parameter perturbation. The proposed method has the characteristics of fast dynamic response, good stability, strong robustness and excellent immunity.关键词：DC microgrid;electric spring;energy function;virtual inertia;dynamic event-triggering mechanism;feedback linearization control;voltage regulation control5|7|0更新时间：2025-06-16
- 摘要：The primary frequency regulation capability of doubly-fed wind turbines that participate in the primary frequency regulation by releasing rotor kinetic energy varies with external conditions, especially wind speed fluctuations. It is necessary to dynamically estimate the primary frequency regulation capability to provide a basis for power system operation planning, control strategy formulation, etc. Based on the analysis of the power conversion dynamic process of doubly-fed wind turbines participating in the primary frequency regulation, a simplified analytical model for the primary frequency regulation is proposed, which takes into account dynamic changes in the rotor speed of doubly-fed wind turbines. With the analytical solution of its primary frequency regulation capability, the impact of wind speed fluctuations on the primary frequency regulation capability of doubly-fed wind turbines can be quickly analyzed. A probability analysis description of the primary frequency regulation capability of doubly-fed wind turbines is proposed, and the probability distribution characteristics of the primary frequency regulation capability of doubly-fed wind turbines with wind speed fluctuations are obtained using point estimation and Gram-Charlier series expansion. The simulation verifies the accuracy of the proposed dynamic analytical model and the feasibility and effectiveness of the probability estimation method for the primary frequency regulation capability.关键词：wind power generation;doubly-fed wind turbine;primary frequency regulation;rotor kinetic energy;probability estimation5|1|0更新时间：2025-06-16
- 摘要：Impedance analysis method is widely used for stability research of interconnected systems with power electronic converters due to its simplicity and effectiveness. However, when using traditional methods for the frequency-domain impedance modelling, nonlinear transformations (Park transform and its inverse transform) are required for the coordinate system transformation, which can lead to convolutional operations and corresponding frequency shifts of different periodic components, and the process is relatively cumbersome. This paper proposes an equivalent impedance modeling method of direct-drive permanent magnet synchronous generator (D-PMSG) based on time-domain differential operators of complex vectors to solve the above problems. This method directly linearizes small signals within the neighborhood of the stable operation trajectory of the time-domain periodic system, and the exponential rotation factor is used to flexibly reflect the time-varying characteristics of the system after disturbance. By combining time-domain differential operators to effectively characterize the dynamic characteristics of the control links in interconnected systems, the repeated transformation of the coordinate system during frequency-domain impedance modeling is avoided, and the complexity of analytical modeling is greatly reduced. In addition, the proposed method can more clearly explain the physical meaning of the frequency coupling phenomenon generated by the grid-connected inverter of the D-PMSG when the interconnected system is disturbed. At the same time, it can explain the impact of the initial phase of the fundamental voltage on the phase frequency characteristics of the coupling component. Finally, the effectiveness of the proposed algorithm is verified through simulation.关键词：complex vector;impedance modeling;direct-drive permanent magnet synchronous generator (D-PMSG);frequency coupling;system stability analysis5|1|0更新时间：2025-06-16
- 摘要：To improve the operation efficiency and investment effectiveness of the user-side energy storage, an optimal configuration method of shared energy storage (SES) in the industrial park considering full-cycle economic benefits in the market environment is proposed. On the one hand, the method could reduce energy storage capacity requirements by coordinating differentiated adjustment needs among different users. On the other hand, it could expand profit channels by integrating the flexible adjustment capabilities of users and SES to participate in the demand response market, and the full-operation-cycle economic benefits calculation of the SES is considered to reduce the investment risks. Firstly, based on the trading rules of the electricity market, a park SES operation mode with multiple industrial users forming cooperative alliances is proposed. Secondly, with the goal of minimizing the total cost of the alliance during the operation cycle, an SES bi-level optimal configuration model is established. The upper-level model aims to form an SES planning scheme that maximizes investment effectiveness, while the lower-level model comprehensively considers some factors such as time-of-use electricity prices and demand response default risks to form the optimal bidding and scheduling mode for energy storage, and accurately quantifies the operation benefits of SES throughout the full operation cycle based on time-series evolution laws of market, correcting the upper-level results. Then, the model is converted into a single-level model by using the approximate Karush-Kuhn-Tucker (KKT) condition for solution. Combining the rain flow counting method and the iterative method, the impact of SES capacity decay on its configuration scheme is quantified, and the investment cost of each industrial user is apportioned by using the bilateral Shapley value method. Finally, numerical simulations are conducted to validate the effectiveness of the proposed method and analyze the impact of some factors such as energy storage profit mode, SES capacity decay, and demand response default risk on the economic benefits of SES investment.关键词：electricity market;time-series evolution;industrial park;shared energy storage (SES);demand response;optimal configuration;bi-level model7|1|0更新时间：2025-06-16
- 摘要：Continuous high-temperature weather is prone to cause tension in the supply-demand balance of the power grid. Besides, charging loads of electric vehicles (EVs) may further aggravate the peak load due to the large charging power and high spatial-temporal distribution randomness. However, EVs also have the potential to provide high-quality peak-shaving resources. For the urban power grid in the high-temperature weather, this paper studies the simulation and the spatial guidance methods of urban charging loads considering user willingness. First, the formation process of vehicle travel behaviors is analyzed based on the planned behavior theory, and a travel model of EVs based on the Markov chain is constructed to analyze travel trajectories in different scenarios. Besides, a calculation method of vehicle energy consumption based on travel mileage and time duration is proposed, and a charging option model considering user willingness is established. The proposed models are adopted to finely simulate the spatial-temporal distribution of charging loads. Finally, a spatial guidance strategy for urban charging loads based on low-valley charging discounts is proposed, and the particle swarm optimization algorithm is used to optimally solve the charging discounts. The simulation results show that the user travel willingness changes regularly in the high-temperature weather, and the simulation results of urban charging loads considering the effects of high-temperature weather and user willingness are more in line with reality. Moreover, the spatial-temporal shifting of charging loads after conducting the low-valley charging discount can effectively alleviate the load difference between the peak and valley of the urban power grid. Besides, it can also improve the economy of vehicle usage and power system operation.关键词：electric vehicle (EV);charging load;high-temperature weather;travel willingness;charging guidance7|1|0更新时间：2025-06-16
- 摘要：Aiming at the problem of limited load forecasting accuracy due to high sensitivity of inter-load correlation and poor seasonal generalization in the regional integrated energy system (IES), a multivariate load combination forecasting method based on the combination of decomposition algorithms and meta-learning is proposed. First, the correlation between multivariate loads in different time periods is quantified based on the dynamic maximal information coefficient, and the characteristic input variables are constructed according to the dynamic correlation results. Then, the load sequence is divided into multiple sub-sequence units by window sliding and divided into multiple tasks by variational modal decomposition to avoid the forward-looking bias problem caused by the overall decomposition. Finally, the subsequence is forecasted using a bi-directional long short-term memory model and the gradient iterations are reduced by a model-agnostic meta-learning algorithm, which reconstructs the subsequence and then fuses the fully connected layers to output the prediction. Based on the IES dataset of Arizona State University Tempe Campus, USA, the proposed hybrid model is verified to have higher IES multivariate load forecasting accuracy.关键词：load forecasting;variational modal decomposition;meta-learning;maximal information coefficient;bi-directional long short-term memory5|1|0更新时间：2025-06-16
Basic Research
- 摘要：The existing power supply restoration methods for the integration of high proportion of distributed generators (DGs) into the distribution network have not fully considered the fault ride-through characteristics of DGs. The paper proposes a multi-stage power supply restoration method for distribution networks based on distributed control to fully utilize the grid support capability of DGs. The fault ride-through characteristics and power grid support capacity of DGs are analyzed. Based on different operation modes of the distribution network after the integration of high proportion of DGs, a load capacity estimation method and DG classification processing strategy are proposed. A power supply restoration model with distributed control is established, and a multi-connection path selection strategy is proposed based on the capacity margin index of the tie line. Finally, a multi-stage power supply restoration scheme adapted to the integration of high proportion of DGs into the distribution network is proposed. The proposed method can better leverage the support role of DGs and improve the ability to quickly restore power supply. The effectiveness of the proposed method is verified through simulation cases.关键词：distributed generator;distribution network;low voltage ride-through (LVRT);distributed control;power supply restoration7|1|0更新时间：2025-06-16
- 摘要：In response to the issue of voltage overlimit caused by high-penetration distributed photovoltaic integration into distribution networks and the challenges faced by traditional centralized control, such as communication delays, large computational load, and excessive control devices, a method for reactive voltage self-regulation and coordination control in distribution networks based on cluster dynamic partition is proposed. First, a day-ahead centralized reactive voltage optimization model is established and the on/off plans for discrete reactive compensation devices are scheduled. For intra-day dispatch, an intra-day reactive voltage rolling optimization model is developed with the objective of minimizing node voltage deviations, and the distributed coordination control among clusters is achieved by combining the synchronous alternating direction method of multipliers (SADMM). Then, the fluctuation of the node voltages in the cluster is suppressed by the real-time control of the intra-cluster local voltages. Finally, the correctness and effectiveness of the proposed method are verified by using an improved IEEE 33-node system and an actual 60-node distribution network in a certain area as cases.关键词：distribution network;distributed generator;cluster partition;synchronous alternating direction method of multipliers;reactive voltage optimization;coordination control5|0|0更新时间：2025-06-16
- 摘要：The single-unit multiplication method is commonly used for fault steady-state modeling of inverter-interfaced generator stations to simply estimate the short-circuit current level. But its calculation accuracy needs to be improved. First, the decisive effect of active power output and voltage dips on the steady-state current output of the power generation unit under the constraints of the low voltage ride-through control strategy is analyzed in this paper. Then, the output characteristic curve of the fault steady-state current is derived. Based on this, the effects of the differences in electrical distance and active power output of the station on the calculation error of single-unit multiplication method are analyzed. On the basis of error analysis, an improved single-unit multiplication method considering the distribution characteristics of power generation units is proposed. The method uses the equivalent impedance to equate the electrical distance between the power generation unit and point of common coupling in the calculation of the voltage at the access point of the power generation unit. The station grouping is equated into two units for reducing the impact of the difference in active power output between the power generation units on the short-circuit characteristics. Simulation analysis in different scenarios shows that the improved method has a large improvement in the calculation accuracy compared with single-unit multiplication method. The method proposed has good engineering practicality as it can achieve station grouping and short-circuit current aggregation with simple calculations.关键词：inverter-interfaced generator;fault current;short-circuit current;single-unit multiplication;error analysis5|0|0更新时间：2025-06-16
- 摘要：DC fault protection is one of the main challenges faced by the development of flexible DC transmission systems, and the use of flexible control of modular multilevel converters (MMCs) to achieve current limiting has become a current research hotspot. The active current limiting of MMC reduces the rate of change and amplitude of fault current, which can lead to difficulties in fault diagnosis and protection selection. In this paper, a flexible DC transmission system with symmetrical single-pole connection is taken as the research object. Using the collaborative control and protection strategy and combining the active current limiting control and fault identification, the method for identifying and cutting off fault areas based on active current limiting factor is proposed to achieve the identification and removal of bipolar short-circuit fault areas. Firstly, by adding a fault current target preset controller to the MMC current inner loop controller, the variation of fault current can be quickly tracked after a fault occurs, and the DC voltage output by the MMC can be adaptively adjusted to control the fault current near the preset target reference value. Secondly, the fault area is quickly determined based on the current limiting factors output by the fault current target preset controller at different fault locations. Finally, simulation analysis is conducted in different fault scenarios of the four-terminal flexible DC transmission system in PSCAD/EMTDC, verifying the feasibility and effectiveness of the proposed collaborative control and protection strategy.关键词：flexible DC transmission;modular multilevel converter (MMC);fault current limiting;control and protection collaboration;short-circuit fault5|1|0更新时间：2025-06-16
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Key Link Identification Algorithm for Power Communication Network Based on Primary and Backup Routes
摘要：With the development of power grid intelligence, the structure of power communication networks is becoming more complex and the number of services is increasing. In order to identify the key link in the power communication network, a key link identification algorithm is proposed for power communication networks based on the primary and backup routing. Firstly, according to the importance of each service, bandwidth and the distribution of primary and backup routes, the circuit model is integrated into the power communication network model to obtain the initial reliability of the network service layer and the transmission layer. Secondly, the link importance is calculated according to the reliability decline of the network service layer and transmission layer by the re-routing of flow-through services after link failure. Finally, the key link identification algorithm is designed to identify key links based on the values of link importance. Simulation experiments are carried out in the power communication networks of a city in eastern Inner Mongolia Autonomous Region and a city in Jiangsu Province, and the rationality of the proposed algorithm is verified by comparison and analysis with different key link identification algorithms.关键词：power communication network;key link identification;primary and backup routes;link failure5|1|0更新时间：2025-06-16
Application Research
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