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最新刊期
卷 50 ， 期 4 ， 2026
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Frequency Coupling Impedance Model: Theoretical Basis, Modeling Methods and Application Constraints AI导读
摘要：Impedance-based analysis method has been widely used to solve the problem of broadband oscillation in new power systems. However, the academia has not fully recognized the applicability of a commonly used frequency coupling impedance model. Therefore, this paper first clarifies that the theoretical basis of the frequency coupling impedance model is the harmonic state-space (HSS) theory. Then, three modeling methods for frequency coupling impedance model are introduced, and correlations between different modeling methods are sorted out. It is clarified that the essence of harmonic linearization is “frequency domain (harmonic domain) linearization” and the advantages of harmonic linearization methods are emphasized. Finally, key factors that constrain the rational application of frequency coupling impedance models are analyzed, including solution details, verification methods and scopes of application, aiming to provide a reference for subsequent research.关键词：new power system;impedance-based analysis method;frequency coupling;impedance model;broadband oscillation;harmonic linearization26|24|0更新时间：2026-02-28
Review·Perspective
- 摘要：In flexible DC grid-connected system of offshore wind power, there exists a possibility of simultaneous occurrence of medium-frequency oscillation (MFO) and sub-synchronous oscillation (SSO). At present, most of the related oscillation research work only focuses on the formation mechanism of single-frequency oscillations, making it difficult to reveal the interaction paths among different frequency oscillation modes when MFO and SSO appear simultaneously. Therefore, this paper focuses on the analysis of the interaction and suppression mechanism between MFO and SSO in the flexible DC grid-connected system of offshore wind power. Firstly, modal analysis method is utilized to investigate the possibility of the simultaneous occurrence of MFO and SSO in the flexible DC grid-connected system of offshore wind power. Subsequently, based on the dynamics of the grid-side inverter and its controller, the interaction path between MFO and SSO is analyzed to reveal the mechanism of secondary oscillation components generated by their combined action. Finally, oscillation suppression methods have been studied to achieve the effective suppression of MFO, SSO and secondary oscillations.关键词：offshore wind power;wind power grid-connected system;flexible DC;modal analysis method;sub-synchronous oscillation (SSO);medium-frequency oscillation (MFO);secondary oscillation24|6|0更新时间：2026-02-28
- 摘要：Low-frequency AC (LFAC) transmission has become a competitive solution for mid-to-long-distance offshore wind power transmission. The onshore frequency converter, as the core equipment of the LFAC system, predominantly employs the modular multilevel matrix converter (M3C). However, M3C faces challenges such as complex structure and high cost. Replacing the M3C with a back-to-back frequency converter based on the diode rectifier unit (DRU) and modular multilevel converter (MMC) can significantly reduce costs. Nevertheless, due to its uncontrolled characteristic, the DRU can’t be independently used to establish the LFAC system. Therefore, this paper proposes a collaborative operation scheme between wind farms and the DRU-MMC back-to-back converter. Wind turbines adopt virtual synchronous grid-forming control to establish the LFAC system. System power balance is achieved via the MMC DC voltage self-tracking control at the frequency converter station. This scheme can collaboratively maintain stable LFAC voltage and frequency, as well as real-time power balance within the system. Moreover, the proposed control scheme enables the offshore wind farms to provide inherent inertia response, along with stable fault ride-through capability for both onshore power grid low-voltage faults and offshore AC system faults. Finally, a system model with four wind farms has been developed in MATLAB/Simulink to validate the feasibility and effectiveness of the proposed control scheme.关键词：offshore wind power;low-frequency AC transmission;modular multilevel converter (MMC);diode rectifier unit (DRU);virtual synchronous control;grid-forming control;inertia;fault ride-through10|7|0更新时间：2026-02-28
- 摘要：There is a significant difference in wind speed within offshore wind farms, making signal measurement and transmission difficult and costly, which poses challenges to frequency control of wind farms. Therefore, a frequency control method for the offshore wind farm based on trajectory optimization and pinning consensus algorithm is proposed. Firstly, the principles of pinning consensus (PC) algorithm are discussed. A scheme is proposed to generate pinning signals from virtual leadership nodes and achieve optimal control of wind farm power by optimizing the pinning signals. A general form of the pinning signal function is designed based on the adjustable rotor kinetic energy of the wind turbine and the frequency variation law after disturbance. Subsequently, by taking into account the PC control, a single-machine equivalent model of the wind farm is constructed. It is pointed out that due to the consensus of the dynamic behavior of wind turbines in the field, the single-machine equivalent model of the wind farm has good accuracy and can meet the accuracy requirements of system frequency calculation. Finally, with the goal of control costs and considering frequency safety constraints, the coordinated optimization of control measures such as wind power, energy storage, and demand response is carried out to determine the coordinated optimization frequency control scheme and the optimal pinning signal for the wind farm. To verify the effectiveness of the proposed method, it is applied to the frequency control decision of a modified IEEE 3-machine 9-bus system. Simulation results show that optimizing wind power can be achieved by adjusting the pinning signal, reducing control costs while ensuring frequency safety. This method requires less signal measurement and communication, and has a fast calculation speed.关键词：offshore wind farm;frequency control;trajectory;rotor kinetic energy;pinning consensus algorithm;single-machine equivalent model8|4|0更新时间：2026-02-28
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Coordinated Control of Inertia Support for Offshore Wind Power Based on DRU-HVDC Transmission System AI导读
摘要：The high-voltage direct current (HVDC) system transmission scheme for large-scale offshore wind farms through diode rectifier units (DRUs) has significant advantages in economic and technological aspects. However, it is difficult for deep and remote offshore wind farms to timely obtain the frequency change information of the power grid at the receiving end and provide inertia support due to the cost of long-distance communication equipment and the influence of communication delay. Therefore, this paper proposes a fast and low-delay frequency mapping-restoration method based on the operation characteristics of DRU converter station, which coordinately controls DC capacitor energy storage-wind turbine rotor kinetic energy to participate in the inertia response. First, the topology and steady-state operation characteristics of the offshore wind farm via DRU-HVDC transmission system are introduced. Then, the virtual inertia control method is adopted in the converter station at the receiving end, which maps the grid frequency change into DC voltage change. At the same time, the coupling characteristics between the offshore AC-side and DC-side electrical variables are clarified during the operation of the DRU converter station The wind turbine only needs to locally detect the voltage amplitude and power to restore the grid frequency information, and then coordinately controls to release DC capacitor energy and wind turbine rotor kinetic energy based on the restored frequency information. Finally, the simulation model of offshore wind farm via DRU-HVDC transmission system is built in PSCAD/EMTDC environment, and the simulation results verify the feasibility of the proposed frequency mapping-restoration method and inertia response coordinated control method, which reduces the effect of communication delay on the system inertia response speed and improves the inertia level of the power grid at the receiving end.关键词：diode rectifier unit;high-voltage direct current (HVDC) system;offshore wind farm;frequency mapping-restoration;energy storage;rotor kinetic energy;inertia response3|3|0更新时间：2026-02-28
Key Technologies for Offshore Wind Power System
- 摘要：For the goal of carbon emission peak and carbon neutrality, accurate accounting of indirect carbon emissions associated with electricity consumption of electricity consumers is of significant importance. Addressing the problems in the carbon emission accounting on the electricity consumer side such as insufficient traceback accuracy and ambiguous allocation of environmental benefits, a traceback method of carbon emissions based on contract paths is proposed. First, by constructing the virtual transmission paths for electricity trading contracts, a direct correlation mechanism between the electricity consumption behaviors of electricity consumers and the carbon attributes on power generation sides is established. Second, a coordinated decomposition model for contracted electricity quantities of multiple power sources is constructed to achieve the temporal matching between renewable energy power output and electricity consumer load. A carbon responsibility attribution mechanism based on trading types is further established, forming a complete accounting method system of carbon emissions on the electricity consumer side. On this basis, the differences in accuracy and fairness between the proposed method and the conventional accounting method are compared and analyzed. Finally, a case study using real trading data is conducted, and the results show that the proposed method can effectively identify the power supply structure characteristics of power sources for electricity consumers, and accurately quantify the carbon emission reduction contribution of green electricity.关键词：contract path;electricity consumer;carbon emission;accounting;traceback;green electricity2|3|0更新时间：2026-02-28
- 摘要：Under the trend of widely integrating clean energy resources such as photovoltaics (PV) and electric vehicles (EVs) into the low-carbon scheduling of virtual power plants (VPPs), how to generate high-quality scenarios that are suitable for low-carbon scheduling under source-load uncertainty conditions has become a key issue in enhancing the economic and low-carbon nature of VPPs. However, existing scenario generation methods generally lack effective modeling of source-load joint perturbations and their sensitivity structure with respect to carbon allowances, resulting in generated samples being insufficiently aligned with the scheduling objectives. To address this issue, this paper proposes a scenario generation method for low-carbon scheduling of VPPs based on a carbon-aware modulated diffusion model. First, a low-carbon scheduling model is constructed to reveal the sensitivity propagation paths of carbon allowances under source-load perturbations. Then, the carbon sensitivity features are extracted from historical data and embedded into the noise injection, network structure, and loss function of a denoising diffusion probabilistic model, enabling structured modeling and modulation of key perturbation paths and introducing conditional variables to construct source-load joint scenarios specific to the target scheduling day. Finally, simulation experiments are conducted using actual data to verify the significant advantages of the proposed method in terms of scenario generation quality and low-carbon scheduling adaptability. The proposed method can serve as an input scenario generation tool for low-carbon scheduling of VPPs, enhancing the practicality and adaptability of scenarios in uncertainty modeling and decision-making support.关键词：virtual power plant;low-carbon scheduling;carbon allowance;scenario generation;diffusion model;uncertainty;sensitivity3|3|0更新时间：2026-02-28
- 摘要：Reasonably characterizing the closed set of wind farm output uncertainty is the foundation for achieving robust control of power grid. Based on the quantitative laws of impact of the wind farms on stability, this paper proposes an improved data processing method that significantly reduces the risk of stability control. For modeling multi-wind farm and multi-period uncertainties, the spatio-temporal correlation of output errors and the impact of ramping errors on reserve configuration are comprehensively considered. A convex uncertainty set is constructed using wide-area ellipsoidal and hyperplane constraints. Furthermore, a parameter solution method based on high-dimensional volume minimization is proposed, which coordinates relevant constraint boundaries to ensure the model satisfies multiple preset confidence probabilities. Finally, the proposed method is validated using actual wind farm data. The results show that this method reduces the volume of the uncertainty set by 12%, effectively improving model accuracy and applicability.关键词：wind farm;power prediction;robust control;uncertainty;stability;spatio-temporal correlation4|4|0更新时间：2026-02-28
- 摘要：The surge in electric vehicle (EV) charging load has made the frequency of distribution network reconfiguration increase significantly. Dynamic topology adjustment reshapes the energy supply relationships between nodes, causing systematic errors in forecasting models based on static topology assumptions due to feeder path mismatches. To address this, this paper proposes a multi-time series forecasting method based on dynamic graph neural network. It introduces a dynamic graph neural network into the distribution network reconfiguration scenario, establishing an explicit mapping relationship between time-varying topology and charging load forecasting. For the dynamic reconfiguration process of the distribution network, a correlation graph is used to model the dynamic coupling process between nodes, and an attention mechanism is employed to enhance the global feature capture capability of the graph forecasting module. Subsequently, an inference module is used to quantify the influence of correlation graphs during different historical periods on each node at the current moment. A gated recurrent network module extracts temporal features from high-dimensional latent features and outputs the forecasting results. Finally, experimental results based on an actual dataset show that the proposed method effectively improves load forecasting accuracy in flexible distribution network reconfiguration scenarios and has good robustness关键词：distribution network;electric vehicle;load forecasting;dynamic reconfiguration;graph neural network;Attention mechanism;gated recurrent network5|3|0更新时间：2026-02-28
- 摘要：At present, with the high penetration of renewable energy grid-connection and the increasing fluctuation of loads, the challenge of uncertainty in distribution network operation is becoming more severe. How to achieve accurate and efficient risk assessment in complex high-dimensional scenarios has become an urgent key problem. To address this, this paper proposes a polynomial chaos expansion (PCE) method with dual sparsification to rapidly evaluate the operation risk of distribution networks under the influence of uncertain factors such as renewable energy output fluctuations. First, at the basis-function level, the hyperbolic truncation and least absolute shrinkage and selection operator (Lasso) regression are used to sparsify the basis functions, which significantly alleviates the exponential growth of the number of basis functions with polynomial order in traditional PCE. Then, at the collocation-point level, the Clenshaw-Curtis quadrature rule and the Smolyak sparse grid are applied to sparsify the collocation points, which effectively reduces the computational complexity while maintaining model accuracy. Finally, the simulation results on the IEEE 33-bus, IEEE 118-bus, and 322-bus distribution systems show that, compared with traditional PCE method, the proposed method significantly improves computational efficiency while maintaining result accuracy.关键词：distribution network;risk assessment;polynomial chaos expansion;basis function;sparsification;collocation point3|2|0更新时间：2026-02-28
- 摘要：Existing algorithms for security regions in distribution network often suffer from low searching efficiency and redundant search paths when handling uncertainties of wind and photovoltaic output. This is due to their reliance on single-distribution assumptions for scenario generation, which ignores spatio-temporal correlations. To address these issues, this paper proposes an adaptive search algorithm for security regions in distribution network considering the uncertainties of wind and photovoltaic output. Firstly, a joint distribution model of wind and photovoltaic output is constructed using kernel density estimation and the mixed Copula function. Spatio-temporal coupling scenarios are then generated through Monte Carlo sampling and reduced via K-means clustering. Secondly, an adaptive hybrid search strategy is proposed, combining adaptive interval segmentation with sensitivity matrix guidance in a two-step process of initial iteration and secondary correction. This strategy dynamically adjusts the search direction based on key constraints, significantly reducing redundant search paths and computation time while achieving robust boundary approximation. Finally, algorithm performance is optimized through a parallel computing acceleration mechanism. The effectiveness of the proposed method is validated on an IEEE 33-bus distribution system.关键词：distribution network;security region;uncertainty;wind and photovoltaic output;search path;spatio-temporal correlation3|1|0更新时间：2026-02-28
- 摘要：The intensity and spatio-temporal distribution of rainstorm disasters exhibit strong uncertainty and heterogeneity, posing serious challenges to the secure and reliable operation of urban distribution networks. First, this paper establishes a coordinated emergency command and dispatch framework for urban distribution and drainage networks considering the spatio-temporal nonuniformity of rainstorms. A mutual emergency prevention and control mechanism is proposed to coordinate the repair and reconfiguration of the distribution network and reservoir-sluice-pump synergetic clusters of the drainage network. Next, this paper reveals the superposition and expansion mechanisms of catastrophic positive feedback considering the interactive propagation between urban flooding accidents and power equipment failures. It further quantifies critical conditions of rainfall intensity and drainage failures that trigger large-scale power outages in cities due to disasters. Furthermore, a risk emergency coordination decision-making model for urban distribution, watershed, and drainage networks with heterogeneous nonlinear partial differential constraints is formulated. Moreover, based on implicit differential discretization and piecewise linearization, a solution method for emergency coordination decision-making for urban distribution and drainage networks is proposed. Finally, the simulation analysis is carried out on the disaster-affected distribution network in Ningxiang, Hunan Province, China, in a typical rainstorm scenario. The results show that the proposed emergency coordination method can effectively reduce distribution network load loss and floodwater depth during rainstorm disasters.关键词：distribution network;drainage network;risk;emergency coordination;partial differential constraint;rainstorm disaster;spatio-temporal distribution3|2|0更新时间：2026-02-28
- 摘要：With the increasing complexity and uncertainty of microgrid systems, designing secondary frequency regulation control methods that combine both stability and output tracking capabilities is crucial for the safe and reliable operation of the system. To this end, this paper proposes a secondary frequency regulation method for microgrids based on structured neural networks. First, by leveraging the equilibrium point independent passivity widely present in physical systems, the secondary frequency regulation problem for microgrids is formulated as a strictly monotonic proportional-integral (PI) control structure, and the PI parameters are parameterized as the gradient of a strictly convex neural network (SCNN). Second, the SCNN is constructed using a Softplus-β activation function with tunable coefficients, which not only ensures its universal approximation capability but also effectively adapts to the diverse communication constraints in microgrids. Furthermore, by employing the gradient of the strictly convex function constructed by the SCNN as a Lyapunov function, an end-to-end stability proof for the system is provided. Simulation results show that, compared with other unstructured neural network control methods which may lead to system instability, the proposed method not only guarantees system stability but also outperforms traditional control methods in both transient and steady-state performance.关键词：microgrid;secondary frequency regulation;uncertainty;stability;neural network;proportional-integral (PI) control;equilibrium point;independent passivity3|3|0更新时间：2026-02-28
- 摘要：With the increasing proportion of renewable energy generation, the grid strength in areas with high renewable energy integration is continuously weakening. Traditional grid-following wind turbines based on phase-locked loop (PLL) struggle to maintain stable operation under weak grid conditions. Against the backdrop of the growing application of grid-forming wind turbines, it is crucial to explore their potential in actively supporting system frequency.Firstly, this paper establishes a detailed electromagnetic transient model for grid-forming wind turbines. Based on the virtual synchronous generator control, load shedding reserve control is introduced to maintain a relatively stable active power regulation margin. Next, by analyzing the limitations of traditional adaptive frequency regulation control and the typical frequency response curves of systems with grid-forming turbines, a comprehensive adaptive control strategy based on segmented frequency response processes is proposed. Finally, a grid-connected model of direct-drive wind turbines is built on the MATLAB/Simulink simulation platform, and the proposed adaptive control strategy is compared with traditional adaptive control strategies. The results show that the proposed control strategy significantly enhances the frequency support capability of grid-forming wind turbines.关键词：grid-forming;wind turbine;grid strength;virtual synchronous machine;frequency regulation;frequency response;electromagnetic transient model;adaptive control;load shedding6|1|0更新时间：2026-02-28
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Active Frequency Response Strategy for Wind Turbines Considering Wind-Thermal Power Coordination AI导读
摘要：Active frequency response control strategy serves as an important technical means to enhance the primary frequency regulation capability of wind turbines. However, existing studies predominantly focus on the design of response mechanisms for wind turbines while ignoring the impact of multi-energy coordinated output on frequency response characteristics. To address this issue, this paper proposes an active frequency response strategy considering the wind-thermal power coordination. Firstly, considering the frequency regulation contribution of wind power and governor dynamics, an improved system frequency response model is established. Based on this model, the time-domain analytical solution for system frequency response under power disturbances is derived. Secondly, by following the design principles of wind-thermal power coordination and peak-valley complementarity of frequency response components, a power trajectory model for the frequency support phase of wind turbines is constructed. Furthermore, comprehensively considering the effects of wind speed and wind power penetration rate, an adaptive power trajectory design in the frequency support withdrawal phase is developed using a Logistic function. Finally, the simulation validates the feasibility and effectiveness of the proposed strategy in improving the frequency dynamic characteristics.关键词：wind turbine;primary frequency regulation;frequency response;wind-thermal power coordination;peak-valley complementarity3|2|0更新时间：2026-02-28
Basic Research
- 摘要：Short-circuit faults of power grid cause voltage source converters (VSCs) to be in the low voltage ride-through (LVRT) state. During this process, the stability of the phase-locked loop (PLL) and the transient overvoltage after recovery are two critical problems of security and stability. The PLL parameters and the current reference values during the LVRT process are key influencing parameters. This paper proposes a method for calculating the parameter security region that comprehensively considers PLL stability during the LVRT process and transient overvoltage after recovery. Firstly, to address the issue of deviation between the initial point and the equilibrium point affecting the effectiveness of traditional small-disturbance stability criteria, a phase-locked stability analytical analysis method and a parameter security region considering initial point deviation are proposed. Secondly, transient overvoltage constraints are specified, and the parameter security region under transient overvoltage constraints is calculated based on the analytical expression of the terminal voltage throughout the entire process. Finally, the intersection is found to obtain the parameter security region that comprehensively considers PLL stability and transient overvoltage. The effectiveness of the derived parameter security region is validated by MATLAB/Simulink simulation results.关键词：voltage source converter (VSC);low voltage ride-through (LVRT);phase-locked loop (PLL);stability;transient overvoltage;parameter security region4|3|0更新时间：2026-02-28
- 摘要：After being subjected to a large disturbance, the grid-forming converter (GFM) will switch from the voltage source mode to the current limiting mode, which poses a risk of being unable to exit the current limiting mode after the disturbance is cleared and experiencing power-frequency overvoltage during the recovery period. Currently, research on the transient synchronization and power-frequency overvoltage coupling stability mechanisms of GFM is still insufficient. Therefore, first, by using power characteristic curves combined with the phasor method, the phase angle evolution and voltage boundary violation of the GFM operating point after a large disturbance are analyzed. A mode switching rule based on the output phase angle of the GFM is proposed. On this basis, the transient recovery process of the GFM is further investigated, and a power-frequency overvoltage criterion during the recovery period is analytically derived. Then, based on the mode switching rule and the power-frequency overvoltage criterion, the concept of the optimal fault-clearing phase interval is proposed, which balances synchronization stability and overvoltage limitation. Finally, an improved strategy considering both transient synchronization and power-frequency overvoltage coupling stability is proposed, and its effectiveness is verified through PSCAD/EMTDC simulation.关键词：grid-forming control;large disturbance;transient stability analysis;coupling;controller design;mode switching;power-frequency overvoltage3|2|0更新时间：2026-02-28
- 摘要：The integration of high-proportion renewable energy sources leads to the changes in the frequency characteristics of power systems. As a result, transient loss-of-synchronism assessment has become crucial for system security, requiring accurate calculation of transient stability margins and the implementation of over-frequency generator tripping measures to mitigate the risk of system splitting induced by generator desynchronization. However, most existing studies consider generator tripping from a system-wide perspective and lack regional partitioning for refined generator tripping. Therefore, this paper proposes a dynamic cluster partitioning strategy based on multi-dimensional indicators. By using the analytic hierarchy process, electrical and dynamic characteristics are integrated to form generator clusters. Combined with a flexible partitioning method, membership functions are constructed to enable re-partitioning of boundary nodes. Furthermore, a fast assessment model of transient stability regions is developed based on the extended equal area criterion (EEAC) to analyze the transient stability margins of the partitioned regions. Simulation analysis is carried out in a power transmission scenario in Northwest China. The results show that the proposed cluster partitioning method is rational and effective, demonstrating its engineering applicability in complex power transmission scenarios.关键词：power system;transient stability margin;over-frequency generator tripping;region partitioning;analytic hierarchy process;fuzzy membership function;extended equal area criterion (EEAC)3|2|0更新时间：2026-02-28
- 摘要：With the development of Energy Internet and multi-energy system (MES), response behaviors on the demand side show the characteristic of complex multi-dimensional cyber-physical-social coupling. To enhance the scheduling capability of multi-energy service providers (MESPs) over demand-side resources and mitigate the response risks caused by user response deviations, it is necessary to fully consider the response characteristics of users when implementing integrated demand response (IDR), and develop effective risk management strategies. Firstly, at the cyber-physical level, the substitutable characteristics of multi-energy coupling and the dynamic fatigue characteristics across multiple time periods are considered. At the social level, a rationality factor and a cognitive weighting function are introduced to characterize the incomplete cognitive rationality of users in social contexts. Secondly, a risk correlation matrix is built to achieve the quantitative characterization of strongly correlated IDR risks, which are then decoupled via orthogonal diagonalization. Furthermore, Shannon entropy is used to construct a risk dispersion index, and a risk dispersion management strategy of IDR with cyber-physical-social fusion is proposed. Finally, through the simulation, it shows that the proposed model not only reduces the risk losses for the MESP, but also increases the benefits of users for participating in IDR, achieving a win-win situation for all parties involved.关键词：integrated demand response;cyber-physical-social fusion;user response characteristic;risk management2|1|0更新时间：2026-02-28
Application Research
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