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最新刊期
卷 49 ， 期 22 ， 2025
- 摘要：With the ongoing advancement of new power system construction in China, the green and low-carbon transformation of energy is accelerating and upgrading. The proportion of renewable energy installed capacity has significantly increased, and a large number of power electronic devices have been integrated into the power grid. Great changes, including reduced moment of inertia and weakened reactive power support capabilities, have taken place on the source, load, and grid sides of the power system. In this context, the power system requires equipment to possess new characteristics, namely corresponding features of synchronous machines and the ability to actively support the power grid. This paper elaborates on the main characteristics of the new power system from three aspects: demands of the new power system, grid-forming converter technology, and typical equipment and engineering applications. In addition, the working principle and various topologies of grid-forming converters are analyzed. Subsequently, based on the existing research and practical projects, the engineering application cases of four typical grid-forming converters, namely grid-forming flexible DC, grid-forming static compensator, grid-forming static var generator, and grid-forming energy storage, are described. Finally, development suggestions and prospects are proposed based on the current research status of grid-forming technology, providing references for further engineering applications.关键词：new power system;grid-forming converter;engineering application;moment of inertia;grid-forming flexible DC;grid-forming static compensator;grid-forming static var generator;grid-forming energy storage3|1|0更新时间：2026-02-28
- 摘要：The grid-forming technology has broad application prospects in the new power system. The grid-forming energy storage converter is its key equipment. Under the grid-forming control, load power fluctuations directly affect the output power of energy storage devices. Batteries are difficult to adapt to complex power demands due to their slow discharge rate, and frequent discharging reduces their service life. Hybrid energy storage converters incorporating supercapacitors present an effective solution to this issue. For the DC-side energy storage devices in the grid-forming hybrid energy storage converter, this paper proposes a communication-free adaptive coordinated control strategy. This strategy adaptively switches control modes through the identification of power types. It performs frequency division control in response to power fluctuations and utilizes the supercapacitor to independently handle power demands when facing pulsed power. This strategy not only extends the service life of the battery, but also effectively enhances the utilization rate of supercapacitors, improves the overall performance of the converter, and does not require communication lines. Experimental results verify the feasibility and effectiveness of the control strategy.关键词：grid-forming converter;energy storage;communication-free control;adaptive coordinated control2|0|0更新时间：2026-02-28
- 摘要：The establishment of a new power system requires grid-connected inverters to be able to flexibly adapt to complex power grid conditions. The use of traditional dual-mode grid-following/grid-forming control for grid-connected inverters has problems of mode switching and complex control, while there exist problems of multiple control parameters and complicated design when virtual oscillator control is adopted. To this end, by referring to the oscillating voltage self-formation principle of nonlinear oscillators simulated through virtual oscillator control, an oscillator-resembled phase locked loop-less unified power and voltage controller (OR-PLL-less UPVC) for grid-connected inverters is proposed. The OR-PLL-less UPVC consists of power control module, voltage self-formation module, and voltage magnitude regulation module. First, the structure and operation principle of each module in OR-PLL-less UPVC are introduced, and the control law of the inverter output voltage is analyzed. Then, the state-space model of the system is established to analyze its small-signal stability. Finally, through simulation and real-time controller hardware-in-loop experiments, it is verified that the proposed OR-PLL-less UPVC can autonomously adjust the inverter port voltage under variations in parameters such as grid-side line impedance, power grid voltage/frequency, and track the power dispatching instructions, achieving the unified grid-following/grid-forming control under complex operating conditions.关键词：new power system;inverter;oscillator;phase locked loop;unified control;power dispatch;voltage support2|1|0更新时间：2026-02-28
- 摘要：Grid-forming (GFM) inverters effectively alleviate the issues of low inertia and weak grid stability caused by increasing renewable energy penetration. However, the virtual inertia of the GFM inverter may induce overcurrent during the power grid frequency drop. To address this issue, based on the power angle variation during the frequency drop, this paper reveals that the power angle increment between the GFM inverter and the power grid is the dominant factor causing the GFM inverter overcurrent during the power grid frequency drop, and a current-limiting strategy is required to avoid the overcurrent. To prevent repeated switching of the current-limiting strategy and achieve fast overcurrent protection, this paper proposes a switching logic based on an event-triggered SR latch. This method utilizes the event-triggered logic to respond to overcurrent events in real time, thereby achieving fast overcurrent protection. Then, an adaptive frequency tracking strategy based on power angle increment is proposed, and the virtual impedance is adaptively calculated based on the residual power angle increment in the initial phase of overcurrent. The proposed method not only suppresses the overcurrent during power grid faults, enhances the synchronous stability of the system, but also has fault recovery ability. In addition, the bandwidth analysis of the closed-loop transfer function of the adaptive frequency tracking strategy demonstrates that this strategy has good compatibility. Finally, simulation and experimental results verify the effectiveness and accuracy of the proposed method.关键词：grid-forming (GFM) inverter;frequency drop;inertia;current-limiting;power angle increment;frequency tracking;virtual impedance;overcurrent protection2|1|0更新时间：2026-02-28
- 摘要：Due to differences in parameters such as inertia, damping, and impedance of grid-forming converters operating in parallel, the transient interactions between converters are intensified, increasing the risk of transient synchronization instability of converters. Multi-machine transient stability cooperative control is key in improving the transient stability of grid-connected systems. To this end, based on the transient interaction model of a parallel grid-forming converter system, this paper reveals the multi-machine instability mechanism that may be induced by the power angle driving effect of transient interaction energy and proposes a cooperative frequency synchronization stabilization control method for multiple grid-forming converters. On one hand, the transient interaction energy is reduced through frequency synchronization control to maintain synchronous and stable operation among converters. On the other hand, by calculating the center frequency through weighted virtual kinetic energy, the acceleration energy of converters with larger virtual kinetic energy is dissipated, thereby improving the transient stability of the converters relative to the system. The improvement of system stability under the condition of the parallel system connecting to a large power grid is demonstrated using a Lyapunov energy function for the proposed control method. Furthermore, by constructing the stability region of the converter parallel system considering cooperative control, it is verified that the cooperative control method can effectively expand the system stability region, providing guidance for parameter optimization. Finally, the correctness of the proposed method is validated through simulations and experiments.关键词：transient stability;grid-forming converter;cooperative control;frequency synchronization;stability region;energy function;parameter optimization4|0|0更新时间：2026-02-28
- 摘要：Given the insufficient inertia and the lack of fast frequency support measures in wind power regional systems, it has become a new research focus to realize dual target support of active power-frequency and reactive power-voltage for wind farms by using the grid-forming transformation of self-provided high voltage direct-hanging grid-following static var generator in the wind farm. First, taking the static self-synchronous compensator with the supercapacitor as the research object, this paper analyzes the influence of key control and electrical parameter changes on the phase space variation process of the power angle of the static self-synchronous compensator. Then, the constraint relationship among equivalent inertia, supercapacitor capacitance and active power-frequency support capability is clarified. Moreover, by analyzing the essential reasons for the dual-objective control contradiction of the static self-synchronous compensator, a switching strategy for active power hysteresis control modes based on the state of charge of the supercapacitor is proposed, which improves the active power-frequency support capability for the static self-synchronous compensator on the premise of ensuring the reactive power compensation. Finally, simulation cases verify the correctness of the theoretical analysis and the effectiveness of the proposed strategy.关键词：wind farm;grid-forming converter;static self-synchronous compensator;active power;frequency support;phase space trajectory;hysteresis control2|1|0更新时间：2026-02-28
- 摘要：Grid-forming direct-drive wind turbines emulate the characteristics of synchronous generators, and can actively support the grid voltage and improve the frequency response. Existing research primarily focuses on the frequency response or grid-connected stability of specific grid-forming control strategies, with a lack of comparative studies on the dynamic characteristic differences among various grid-forming control strategies. This paper establishes small-signal frequency-domain dynamic models of reactive power-voltage, active power-frequency, and voltage-current relationships for three typical grid-forming direct-drive wind turbines: virtual synchronous generator (VSG) control, droop control, and inertia synchronization control (ISC). The differences among these three grid-forming direct-drive wind turbines in terms of voltage response capability, frequency response capability, and adaptability to grid strength are compared. Furthermore, the influence of key control parameters on the dynamic characteristics is analyzed. Finally, the correctness of the theoretical analysis is verified through simulations and experimental results. The results indicate that droop control performs best in voltage support capability, VSG control excels in frequency support capability, while ISC shows better adaptability under strong grid conditions. The research results can provide valuable references for the selection and application of grid-forming control strategies.关键词：grid-forming control;direct-drive wind turbine;virtual synchronous generator;droop control;inertia synchronous control;voltage support;frequency support2|1|0更新时间：2026-02-28
- 摘要：Grid-forming (GFM) devices, with their voltage/frequency active support capabilities, are driving the evolution of power systems toward a typical hybrid system structure. However, due to the multiple control links and high model orders of GFM devices, as well as their complex dynamic interaction with grid-following (GFL) devices, the reasonable representation and reduced-order modeling of their dynamic characteristics face challenges, which restrict the accuracy of system strength quantitative evaluation. Focusing on the problem of small-signal synchronous stability from the perspective of system phase-angle strength, an equivalent modeling method for GFM devices that takes into account the dynamic interaction between GFM and GFL devices is proposed. First, a phase-angle loop incorporating dynamic interactions between two types of devices is constructed. The synchronization stability conditions of the hybrid system are analyzed based on the complex torque coefficient method and the positive net damping criterion. Furthermore, GFM devices are reduced to an ideal voltage source with equivalent series impedance, whose equivalent impedance parameters and positive net damping coefficients can jointly characterize the voltage source characteristics of GFM devices and their contributions to system strength, and support the quantitative evaluation of system strength based on short-circuit ratio (SCR) indicators. The proposed method can be implemented on a black-box model and is suitable for various GFM control strategies with inner loops. Finally, the effectiveness of the method is verified through simulation, and the influence of different control parameters on the equivalent modeling results is analyzed.关键词：hybrid system;system strength;quantitative evaluation;grid-forming device;grid-following device;equivalent modelling2|4|0更新时间：2026-02-28
Grid-forming Technology
- 摘要：Aiming at the wide-band oscillation issues caused by the large-scale grid-connected power conversion system (PCS), the existing oscillation suppression strategies have failed to effectively suppress the multi-band resonances caused by the frequency coupling effects. Considering oscillation frequency coupling characteristics induced by nonlinear links such as the phase-locked loop (PLL), this paper proposes an improved adaptive active damping resonance suppression method. First, based on the complex topology of actual power grids, a PCS grid-connected system model is established, and the oscillation risk areas of the interconnected system are identified according to the Nyquist stability criterion. Then, during the design of the cascaded trap stage, the frequency coupling effect caused by PLL control is further considered. By real-time measurement of current and voltage information between the PCS and the power grid, the trap parameters are set and adjusted, enabling the PCS to provide positive damping across the entire frequency band, i.e., with the phase angle within ±90°, thus adapting to the complex and variable operation conditions of the power grid and achieving adaptive oscillation suppression in the PCS grid-connected system. Compared to the existing methods, the proposed method reduces the risk of resonance frequency shift. Finally, simulations using PSCAD/EMTDC and practical experiments validate that the proposed control method offers better dynamic performance and harmonic suppression effect.关键词：power conversion system;AC grid;wide-band oscillation;frequency coupling;damping;resonance suppression2|0|0更新时间：2026-02-28
- 摘要：The multi-timescale interaction between wind turbines and the power grid in direct-drive wind power systems is prone to inducing sub-/super-synchronous oscillations, necessitating the exploration of effective suppression methods. Flywheel energy storage, with its advantages in fast dynamic power response and high charging/discharging frequency per unit time, can enhance system damping characteristics and holds potential for suppressing sub-/super-synchronous oscillations. This paper proposes an adaptive damping suppression method against sub-/super-synchronous oscillations based on flywheel energy storage. A sub-/super-synchronous oscillation adaptive damper (SSOAD) is designed and integrated into the grid-side converter of the flywheel energy storage system, leveraging its capability to rapidly absorb and release energy to achieve sub-/super-synchronous oscillation suppression. First, an overall architecture of SSOAD integrating “measurement-identification-control” functions is proposed. On this basis, a sub-/super-synchronous oscillation detection and identification method, along with an adaptive multi-channel damper, is designed to identify the number of oscillation modes and their respective frequencies. Then, a control strategy for the flywheel energy storage system is designed, including an oscillation suppression method based on current compensation and a bidirectional charging/discharging conversion control method. Finally, a simulation model of a direct-drive wind power system is built to validate the feasibility of the proposed SSOAD. The results demonstrate that the designed SSOAD not only enables real-time identification of multiple oscillation modes, but also ensures effective suppression of sub-/super-synchronous oscillations under varying operation conditions.关键词：direct-drive wind power system;sub-synchronous oscillation;super-synchronous oscillation;converter;damping suppression;flywheel energy storage2|1|0更新时间：2026-02-28
- 摘要：To address the electric power balance issues in systems caused by intraday power deviations of renewable energies, power dispatch departments require minute-level revisions to the day-ahead plans from a look-ahead perspective. Therefore, a robust decision-making method for the look-ahead dispatch in power system is proposed based on the fast identification of redundant constraints. The method improves the renewable energy accommodation rate and supply capacity of the power system in extreme operation scenarios while ensuring efficient solving in a short time. First, in the look-ahead dispatch decision-making mode, a two-stage optimization model is constructed considering the uncertainty of wind and photovoltaic power, along with the coordinated control of multiple resources such as hydro, thermal, storage, and tie-lines. The first stage considers the economy and safety of the system, while the second stage considers the renewable energy accommodation and power supply guarantee. Furthermore, considering the model complexity added by the uncertainty of renewable energy, an identification and reduction method for redundant constraints based on graph convolution neural network and long short-term memory network is proposed, followed by a robust optimization solution for the reduced look-ahead dispatch model using column and constraint generation algorithm. Finally, the effectiveness of the proposed model for the fast identification of redundant constraints is validated through numerical results in the IEEE 118-bus system, and the proposed robust decision-making method can efficiently solve look-ahead dispatch strategies in various types of scenarios.关键词：renewable energy;decision-making;extreme operation scenario;look-ahead dispatch;redundant constraint;graph convolution neural network;long short-term memory network;robust optimization3|0|0更新时间：2026-02-28
- 摘要：Low-voltage active distribution networks with a high proportion of rooftop photovoltaic face severe overvoltage issues. Simultaneously, the lack of topological structure and line parameters further complicates voltage optimization and regulation. To address this, a data-driven online voltage regulation strategy is proposed. First, a data-driven method is employed to online identify and update the parameters in the system node voltage-power equation, providing a foundation for dynamically estimating node voltages. Then, a voltage optimization and regulation model aimed at maximizing photovoltaic accommodation is established. Based on the model solution results, while controlling the photovoltaic inverters to track reactive power commands, dynamic limiting of active power output is implemented to achieve effective voltage regulation. Case results demonstrate that this strategy not only resolves the issue of node voltage estimation without an electrical model but also effectively achieves overvoltage mitigation following the principle of reactive power priority, maximizing photovoltaic accommodation and validating the effectiveness of the proposed strategy.关键词：photovoltaic;active distribution network;voltage regulation;accommodation;overvoltage mitigation3|1|0更新时间：2026-02-28
- 摘要：To address the low-carbon response delay of users caused by the transmission delay of the heating network, a low-carbon optimal scheduling method for the integrated energy system considering thermal inertia of grid and load is proposed. Firstly, the thermal inertia model and carbon flow model of the heating network are constructed based on the flow segmentation method, and the carbon pricing mechanism based on the load carbon potential distribution is designed to solve the delay problem of carbon signal transmission in the heating network. Secondly, a building thermal inertia model is established by combining the thermal comfort theory to reveal the dynamic relationship between the user thermal load adjustment and the room temperature change, and a model of heat demand price elasticity with time lag dependence is constructed accordingly. Finally, a bi-level optimization model with the objective of minimizing the operating cost of system operators and the energy cost of users is established, which is solved through coordinated iteration of the energy pricing and load response. The simulation results show that the proposed method can improve the spatiotemporal alignment between the thermal load curves of users and the peaks and valleys of renewable energy output, achieving a balance between renewable energy accommodation and user energy consumption experience.关键词：integrated energy system;transmission delay;heating network;thermal inertia;carbon flow;carbon potential;demand price elasticity;optimal scheduling2|1|0更新时间：2026-02-28
- 摘要：With the large-scale integration of intermittent renewable energy sources such as wind and photovoltaic power, the demand for operation flexibility in the power system has become increasingly prominent. High-energy-consuming industrial loads, characterized by their large capacity and high regulation potential, have become key resources for the demand-side regulation. Taking the textile industry, which is one of the six major high-energy-consuming industries, as an example, given its feature of deep coupling between energy usage and production processes, the study analyzes how this feature affects the willingness of industrial loads to participate in peak shaving or demand response, as well as its impact on production efficiency. First, based on the strongly process-driven production characteristics of the textile industry, a full-process architecture integrating the energy network structure and production procedures is proposed, revealing the deep coupling mechanism between the energy system and production links. Then, considering the characteristics of textile enterprises pursuing economic operation and the storable nature of steam, an electricity-steam coordinated scheduling model is constructed. This model aims to minimize daily operating costs while comprehensively considering process temperature requirements, the equivalent energy storage characteristics of steam, and production constraints, providing a modeling foundation for textile industry loads participating in grid interaction. Finally, the scheduling results verify the effectiveness and economy of the proposed scheduling strategy, providing a theoretical basis for industrial loads to participate in power system regulation.关键词：textile industry;industrial load;integrated energy system;scheduling;flexibility;production procedure2|2|0更新时间：2026-02-28
- 摘要：Aiming at the maintenance decision-making problem of offshore wind turbines under the influence of complex marine environments, a two-stage rolling optimization maintenance decision-making method for wind turbines is proposed. Firstly, considering the time-series correlation of multi-dimensional variables in the marine environment, an improved generative adversarial network is used to generate monthly marine environment scenarios for short-term maintenance. Then, accounting for historical seasonal variation characteristics, stochastic sampling is performed on typical monthly scenarios to form marine environment scenarios for long-term maintenance. Secondly, the reliability of turbine components and maintenance waiting time under the influence of the marine environment are considered to reflect the influence of uncertain marine environment scenarios on the maintenance efficiency of wind turbines. Subsequently, a two-stage rolling preventive maintenance model for long-term and short-term maintenance of offshore wind turbines is established to obtain the optimal maintenance strategy under the influence of uncertain marine environment conditions. Finally, simulations are conducted to validate the effectiveness of the proposed maintenance decision-making model and method, and the influence of uncertainties in marine environment scenarios on the maintenance strategy is analyzed.关键词：offshore wind turbine;marine environment;maintenance;rolling optimization;generative adversarial network2|0|0更新时间：2026-02-28
- 摘要：The instability of renewable energy power generation has exerted a significant impact on the safe and stable operation of new power systems, and the energy storage technology serves as an effective solution to address this issue. Owing to its advantages such as high power density and fast response speed, the high-temperature superconducting magnetic energy storage (HTS-SMES) demonstrates promising application potential in mitigating power fluctuations of renewable energy sources and enhancing power quality. To comprehensively and thoroughly analyze the fault characteristics of HTS-SMES after grid integration, this paper establishes a simulation model of the HTS-SMES grid-connected system based on its topological structure and control strategy. The model simulates the dynamic response processes following an AC-side short-circuit fault and a DC-side magnet quench fault on the HTS-SMES side in both charging and discharging scenarios. On this basis, the differences in fault characteristics of HTS-SMES in charging and discharging scenarios are clarified, and the primary reasons for these differences are analyzed. Finally, the functionality of the established model is validated using PSCAD/EMTDC.关键词：high-temperature;superconducting magnetic energy storage;short-circuit fault;magnet;quench fault;low-voltage ride through;power fluctuation3|1|0更新时间：2026-02-28
Basic Research
- 摘要：The site-division cascaded ultra-high voltage direct current (UHVDC) transmission system exhibits greater flexibility and complexity in connection configurations and return circuit transfer compared to conventional two-terminal UHVDC transmission systems. Based on an actual sending-end site-division cascaded UHVDC project, this paper designs a transfer strategy for the grounding modes of DC system, which satisfies the requirements for flexible commissioning and decommissioning of the sending-end low-voltage converter station. To address potential grounding mode transfer failures during ground return and metallic return operation modes, this paper proposes countermeasures involving small current step injection and short-term grounding of the receiving-end converter station, respectively. The effectiveness of the proposed control strategy is validated through experiments utilizing actual control and protection devices in conjunction with real-time digital simulation.关键词：ultra-high voltage direct current (UHVDC);site-division cascading;grounding mode;converter station;return5|1|0更新时间：2026-02-28
- 摘要：The electric energy meter, as an important data source in the low-voltage distribution network, plays a crucial role in ensuring the fairness of electricity transactions through the management of measurement anomalies. Therefore, a model of weakly-correlated measurement anomaly recognition of line loss based on neural network with variable weights is designed, whose inputs are freezing values of power and voltage on the electric energy meter, as well as partial archival information. The main part of the model is the residual neural network to calculate the measurement anomaly index. First, aimed at the accuracy degradation caused by insufficient input information, a neural network algorithm with variable weights is proposed, in which the network weights are no longer considered to remain constant after training, instead, some of them are regarded as variable weight layers formed by the superposition of several eigenstate weights. Then, through the node correlation state that is not able to be directly used as network input, the superimposing coefficients are calculated via composite density matrices with dimensions, which significantly improves the model accuracy. Finally, by using the augmented sample set for training and testing, the validity of the residual neural network recognition model with variable weights is comparatively verified. Furthermore, the model is tested and applied to the control of a high-loss distribution station area in a city in Zhejiang Province of China to confirm its detection effect in actual working conditions.关键词：distribution network;electric energy meter;measurement anomaly;residual neural network;variable weight algorithm3|1|0更新时间：2026-02-28
Engineering Application
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