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最新刊期
卷 50 ， 期 14 ， 2026
- 摘要：Under the backdrop of low-carbon transformation in global energy structures, the proportion of renewable energy generation such as wind and solar power has been continuously increasing. However, the high proportion of renewable energy integration also presents new challenges to power systems, with the phenomenon of negative electricity prices becoming increasingly prominent and even a recurring trend. This paper firstly systematically reviews the current status of negative electricity prices in multiple typical electricity markets worldwide and in China, and summarizes their key characteristics. Subsequently, based on causative factors and characteristics, negative electricity prices are classified into two categories: intrinsic and mechanism-driven negative electricity prices, with an in-depth mechanistic analysis of their causes. Furthermore, from the perspective of “source-grid-load-storage” coordination, this paper comprehensively evaluates the impacts and challenges of negative electricity prices on multiple agents at source side, grid side, user side and energy storage side. Finally, with regard to inherent negative electricity prices and mechanism-driven negative electricity prices, respectively, suggested countermeasures are proposed from the perspectives of resource allocation and market mechanisms. The research intends to provide theoretical support and decision references for facilitating renewable energy participation in electricity markets, ensuring the safe and stable operation of power systems, and promoting the sound and sustainable development of markets.关键词：negative electricity price;renewable energy;electricity market;source-grid-load-storage0|0|0更新时间：2026-08-21
- 摘要：With the large-scale integration of high proportion of renewable energy into power grids, power systems are facing security risks due to insufficient system inertia, making it necessary to establish an inertia market. However, market participants differ significantly in their capabilities to provide inertia. Maintaining an excessively high level of inertia would not only reduce profit opportunities for market participants, but also further give rise to cost allocation issues. Therefore, it is essential to develop a competitive inertia market through a fair way. First, based on the current status of renewable energy development in China, and in combination with theoretical studies and practical status of inertia markets, this paper clarifies the necessity of establishing an inertia market. On this basis, taking the adequacy of inertia as the entry point, a preliminary concept for inertia market mechanism design is proposed. By comparing inertia services with other types of ancillary services, the diversity and particularity of inertia market mechanism design are highlighted. Subsequently, a systematic analysis of the Australian market design scheme is conducted to verify the feasibility of the proposed preliminary concept. Finally, in light of China’s actual conditions, targeted suggestions are put forward for the future design of inertia markets.关键词：renewable energy;inertia;electricity market;inertia market;ancillary service0|0|0更新时间：2026-08-21
Review·Perspective
- 摘要：Configuration of grid-forming energy storage in renewable energy bases with low short-circuit ratios can effectively enhance system stability and renewable energy transmission capacity. Therefore, a decentralized configuration optimization strategy for grid-forming energy storage is proposed to balance small-signal stability and engineering economy. Firstly, based on the generalized short-circuit ratio index, the existent capacity saturation effect and mechanism of grid-forming energy storage under the single-node configuration mode are revealed, and the configuration principle for strengthening weak nodes nearby under the multi-node configuration mode is further clarified. Secondly, by comparison between centralized and decentralized configuration schemes with different numbers of location points and electrical positions, the lower limit model of the total capacity demand for grid-forming energy storage is constructed to satisfy the requirement of system stability, and an estimation method is provided. Furthermore, considering factors such as equipment type selection and station reconstruction, the initial construction and investment costs of various configuration schemes are quantified, verifying the economic advantages of the decentralized configuration scheme. Finally, the study cases are used to validate the advantages of the proposed strategy in terms of enhancing system stability and reducing investment costs.关键词：short-circuit ratio;renewable energy;grid-forming energy storage;economy;stability;decentralized configuration2|1|0更新时间：2026-08-21
- 摘要：For the selection of reactive power compensation devices in power systems, many studies have shown that the synchronous condenser provides stronger voltage support capability than the conventional static synchronous compensator (STATCOM). However, the response capability of STATCOM has been significantly improved with the development of grid-forming control techniques. Therefore, it is necessary to conduct a systematic comparison of the transient performance between the grid-forming STATCOM and the synchronous condenser to provide a reference for engineering selection. First, the principle and control of the grid-forming STATCOM are described. A transient active support strategy based on the virtual impedance is proposed to preserve the transient voltage-source characteristics of the grid-forming STATCOM. Then, the response differences between the two devices are analyzed. To eliminate the influence of system parameters and topologies, a single-machine infinite-bus system is adopted to compare their transient response capabilities. Furthermore, a high-voltage DC (HVDC) transmission system with wind power integration is established in PSCAD/EMTDC to compare the transient voltage regulation performance of the two devices. The simulation results show that, in wind power integration system scenarios, the grid-forming STATCOM using virtual impedance control and a star-connected cascaded H-bridge topology with supercapacitor energy storage has superior performance in mitigating mild voltage sags, suppressing transient overvoltages, and accelerating voltage recovery. In contrast, the synchronous condenser exhibits stronger voltage support capability under severe voltage sag conditions.关键词：wind power integration system;high-voltage direct current (HVDC) transmission;grid-forming control;static synchronous compensator (STATCOM);synchronous condenser;reactive power support;transient overvoltage;virtual impedance0|0|0更新时间：2026-08-21
- 摘要：In the weak grids, photovoltaic-storage power stations with grid-following control are prone to instability and oscillations. Integrating grid-forming (GFM) inverters in parallel helps enhance the small-signal stability of power stations. However, existing research on the ratio design of the GFM inverters only considers the capacity factor and ignores other design freedom degrees of GFM inverters, resulting in conservative configuration results. Therefore, this paper proposes a parameter design method based on partial retrofitting of inverters to grid-forming control. First, based on impedance models and stability criteria for cascaded systems, the key mechanisms for enhancing system stability after the integration of GFM inverters are clarified, and the influence of both the proportion and key filtering parameters of GFM inverters within the power station on stability is explored. Then, a configuration process for the proportion and parameters of GFM inverters is proposed to obtain the parameter domain that ensures stable system operation. Finally, the effectiveness of the proposed method is verified through case analysis.关键词：photovoltaic-storage power station;grid-following (GFL) inverter;grid-forming (GFM) inverter;small-signal stability;parameter configuration0|0|0更新时间：2026-08-21
- 摘要：Voltage-sourced grid-forming control provides technical support for the high penetration of wind power integration into the power grid. However, existing grid-forming control methods based on rotor kinetic energy extraction pose a risk of wind turbine speed instability. Furthermore, grid-side converters, limited by their output current, face challenges in maintaining DC-link voltage stability during fault ride-through (FRT), leading to difficulties in preserving their voltage-source characteristics. To address these two technical challenges, this paper proposes a supercapacitor (SC)-based voltage-source grid-forming and fault ride-through control (SGFC) method for direct-drive wind turbines. Firstly, the method combines the SC charging and discharging equations with the synchronous generator swing equation to achieve energy matching for inertia response. Additionally, it incorporates grid-side voltage-source control, enabling the perception of grid frequency variations without phase-locked loop. Secondly, a grid fault signal generation module is designed. This module autonomously switches the SC from inertia support mode to FRT mode, controlling the SC to absorb unbalanced energy from the DC side. After fault clearance, it restores the SC voltage to its neutral point. Moreover, small-signal stability analysis is employed to optimize key parameters of the SGFC. Finally, the performance of the SGFC method is evaluated under frequency and voltage disturbances through hardware-in-the-loop experiments. The results demonstrate that the SGFC method, leveraging the SC as a power-type energy storage device, comprehensively realizes the voltage-source grid-forming characteristics, inertia support, and FRT capability for direct-drive wind turbines.关键词：direct-drive wind turbine;supercapacitor (SC);grid-forming (GFM) control;inertia;fault ride-through (FRT);mode switching0|1|0更新时间：2026-08-21
- 摘要：With the accelerated construction of large-scale renewable energy bases in China, as the main voltage source of the sending-end system in the scenario where large-scale renewable energy islands are transmitted via voltage source converter based high voltage direct current (VSC-HVDC), the fault ride-through (FRT) strategy for grid-forming VSC-HVDC converter stations is critical to ensuring the safe and stable operation of the sending-end system. To effectively suppress the transient and steady-state overcurrent during fault stage and the transient overvoltage during fault recovery stage of the converter stations, while maintaining the active power transmission of the converter stations during the fault, this paper proposes a low voltage ride-through (LVRT) control strategy for grid-forming VSC-HVDC converter stations based on segmented virtual impedance method. First, the current and voltage characteristics of the sending-end converter stations during both the fault and recovery stages are analyzed. Then, aiming at the constraints of transient and steady-state current and voltage as well as LVRT guideline requirements during the fault stage, the boundary conditions that the virtual impedance needs to meet during the fault stage and fault recovery stage are derived separately. Furthermore, the optimal value of virtual impedance is determined with the objective of maximizing the active power transmission of the converter stations. Finally, a case study is carried out using a planned sending-end converter station in a project in southwest region of China to verify the effectiveness of the proposed strategy.关键词：grid-forming control;low voltage ride-through (LVRT);voltage source converter based high voltage direct current (VSC-HVDC);converter station;virtual impedance;overcurrent;transient overvoltage0|0|0更新时间：2026-08-21
- 摘要：Grid-forming inverters can enhance the stability of weak grids and serve as a key component in the construction of new power systems. Grid-forming inverters operating in voltage source mode are prone to overcurrent faults during voltage sags, and current limiting strategies for traditional current-type virtual impedance fail to rapidly suppress transient overcurrent during voltage sags. To address this issue, a fast current limiting control strategy based on voltage-type adaptive virtual impedance is proposed for grid-forming inverters. This strategy adjusts virtual impedance according to voltage sag depth rather than overcurrent magnitude, achieving effective current limiting and rapid suppression of transient current under voltage sag conditions. Meanwhile, a proportional-integral controller is adopted to adaptively regulate virtual impedance values, suppressing impedance fluctuations and improving the voltage sag ride-through capability of grid-forming inverters. Finally, the proposed method is verified on Simulink and hardware-in-the-loop simulation platforms. Compared with conventional current limiting strategies, the activation time of virtual impedance is shortened from 3.8 ms to 1.3 ms, and the peak fault current drops from 84.8 A to 55.4 A, with no virtual impedance fluctuations or power oscillations, which verifies the validity and correctness of the proposed fast current limiting control strategy.关键词：grid-forming inverter;stability;current limiting;fault ride-through;voltage sag;virtual impedance;transient surge;adaptive control0|0|0更新时间：2026-08-21
- 摘要：In power systems, asymmetries in load and line impedances give rise to voltage imbalance, while conventional grid-forming (GFM) converters lack effective negative-sequence voltage suppression capability, thereby threatening the secure operation of grid-connected equipment. To enhance the negative-sequence voltage suppression capability of GFM converters, this paper develops a negative-sequence impedance model of a GFM converter based on dual proportional-integral (PI) control, providing a quantitative characterization of its negative-sequence voltage suppression capability. On this basis, an optimization strategy based on wide-range and flexible tuning of the negative-sequence impedance is proposed. By introducing adjustable coefficients into the voltage-feedback and current-feedforward channels, the strategy enables the continuous reshaping of the negative-sequence impedance from zero to infinity, thereby significantly enhancing the negative-sequence voltage suppression capability of the GFM converter. Considering the limited capability of providing negative-sequence current by the converter, the proposed strategy adjusts the magnitude of the negative-sequence impedance to achieve coordinated optimal management and control of both voltage and current quality. Finally, the effectiveness and accuracy of the proposed strategy are validated through experiments.关键词：grid-forming converter;negative-sequence voltage;negative-sequence impedance;power quality;dual proportional-integral (PI)2|0|0更新时间：2026-08-21
Grid-forming Technology
- 摘要：The in-depth exploration and utilization of renewable energy such as wind, solar, and hydropower is a crucial approach to achieving the targets of carbon emission peaking and carbon neutrality. As a high-quality frequency regulation resource, hydropower is often integrated with wind and solar energy to form multi-energy complementary systems that support the development and utilization of new energy. However, the integrated hydro-wind-solar operation faces challenges such as ill-defined collaboration mechanisms and insufficient regulation capability. Therefore, it is urgent to further refine the complementary operation mechanisms between hydropower and new energy, as well as the methods for participation in grid frequency regulation. This paper focuses on the hydro-wind-solar coupling system under the station-level complementary development model. By establishing a minute-level hydro-wind-solar collaborative control architecture that incorporates the active power control of new energy into the control link, with the objective of minimizing system regulation costs, the proposed method optimizes the power output of hydropower and new energy units under the consideration of system reserve capacity. Subsequently, the minute-level net load deviations are optimally allocated among hydro, wind, and solar units, thereby enabling new energy to actively participate in system frequency regulation rather than undergoing passive curtailment. Meanwhile, the active power feasible region at the system interconnection node is characterized to quantify the overall adjustable capacity. A bi-level coupled optimization model for hydro-wind-solar system is then formulated to simultaneously mitigate internal new energy fluctuations and maintain sufficient margins for participating in grid automatic generation control (AGC). After receiving frequency regulation instructions from the higher-level power grid, a distributed control method is employed to facilitate rapid grid AGC response. Finally, case studies based on the real-time digital simulator (RTDS) platform validate that the proposed method can achieve integrated hydro-wind-solar collaborative operation and effective grid frequency regulation participation, providing a novel approach for the efficient and flexible complementarity in hydro-wind-solar power systems.关键词：renewable energy;hydro-wind-solar system;multi-energy complementarity;automatic generation control (AGC);collaborative operation;frequency regulation0|0|0更新时间：2026-08-21
- 摘要：The continous expansion of the grid-connected scale of wind power via flexible direct current (DC) transmission systems, the transient instability risk faced by power grids has significantly increased. This issue has become a key factor seriously limiting the large-scale wind power transmission and the flexible DC transmission capabilities. To address this issue, a fault-tolerant overvoltage control strategy for large-scale wind power transmission systems via flexible DC systems is proposed based on the detailed analysis of the transient interaction process of faults in large-scale wind power transmission systems via flexible DC systems, and the control effects between wind farms and flexible DC converter stations. By coordinately optimizing the power injection of wind farms and delaying the rectifier-side voltage recovery of the flexible DC converter station, the proposed strategy can not only provide transient voltage support during fault periods, but also participate in the fault recovery after fault clearance, thereby effectively suppressing the overvoltage during the fault recovery period. Finally, a model is built using the PSCAD/EMTDC simulation software for simulation verification. The results show that the proposed strategy can significantly improve the transient voltage stability of large-scale wind power transmission systems via flexible DC systems.关键词：wind power;flexible direct current (DC) transmission;voltage control;transient voltage stability;overvoltage suppression;fault recovery0|1|0更新时间：2026-08-21
- 摘要：The randomness of wind power poses challenges to the safe and stable operation of the power system. Accurately quantifying and forecasting uncertainty and providing reliable supply guarantee information are crucial. Regarding the probabilistic forecasting of short-term cluster power and the improvement of power supply guarantee capacity for wind power in provincial areas, a spatio-temporal pseudo-siamese diffusion probabilistic forecasting method for wind power cluster power for power supply guarantee is proposed. This method utilizes a spatio-temporal pseudo-siamese network to extract high-order spatio-temporal coupling features and generates high-fidelity random power scenarios based on a conditional diffusion framework. On this basis, a power supply guarantee capability evaluation system is constructed, which includes dimensions such as guarantee rate and longest continuous shortfall duration. This system is introduced into the model validation and optimization process, achieving model parameter optimization guided by supply guarantee indicators. Case study results on the actual wind power cluster dataset in Gansu Province, China show that the proposed method significantly reduces the continuous shortfall duration under extreme conditions while ensuring a high level of guarantee rate, providing more targeted technical support for ensuring the safe and economic operation of the power system.关键词：wind power cluster;power forecasting;short-term probabilistic forecasting;pseudo-siamese network;diffusion model;spatio-temporal feature;power supply guarantee0|0|0更新时间：2026-08-21
- 摘要：The strong uncertainty of renewable energy, combined with the increasing frequency of extreme weather, poses significant challenges to the construction of new power systems. The growing load from electric vehicles also imposes new requirements on distribution network operation. Therefore, this paper proposes a planning method for flexibility resources in distribution networks considering both normal and extreme scenarios. First, the operation characteristics of flexibility resources in electric vehicle charging stations, hydrogen storage integrated stations, fixed energy storage stations, and mobile energy storage stations are analyzed. Meanwhile, considering the requirements of both the distribution network and the transportation network on flexibility resource planning, a cloud-edge collaborative planning model for flexibility resources is established. Then, a solution network based on conditional generative adversarial network (CGAN) and deep Q-network (DQN) is developed for flexibility resource planning. CGAN and self-supervised conditional generative adversarial network (SS-CGAN) are used to generate normal and extreme scenarios, while DQN is adopted to solve and optimize the flexibility resource planning scheme. Finally, the proposed method is validated using a coupling system of the IEEE 33-bus distribution network and a 24-node transportation network. Results show that the method can effectively generate supply-demand scenarios that cover real data and achieve the flexibility resource planning within the distribution network关键词：distribution network;transportation network;extreme weather;scenario generation;flexibility resource;planning;conditional generative adversarial network (CGAN);deep Q-network (DQN)0|0|0更新时间：2026-08-21
- 摘要：With the large-scale integration of distributed photovoltaics into distribution networks, the system dynamic process exhibits multi-timescale characteristics, encompassing both millisecond-level fast fluctuations of photovoltaic inverters and minute-level evolution of grid states. To accurately track the fast and slow dynamic processes of photovoltaic inverters and distribution networks, this paper constructs a distribution network Simulink simulation system incorporating a dynamic model of photovoltaic inverters. It also proposes a multi-timescale dynamic state estimation framework and establishes two dynamic state estimation models to track dynamic changes at different timescales. Specifically, for millisecond-level state fluctuations of photovoltaic inverters, an extended Kalman filter algorithm based on an eighth-order inverter dynamic model is proposed. For minute-level power flow changes at the distribution network side, an adaptive fading unscented Kalman filter algorithm is proposed, and high-precision pseudo-measurements are constructed to achieve the fusion and unification of boundary information. Simulation results show that the proposed method can rapidly track strong system fluctuations under random noise conditions. The estimation accuracy is superior to that of traditional state estimation methods and it possesses high robustness and real-time performance.关键词：distribution network;photovoltaic inverter;state estimation;power flow;Kalman filter algorithm0|0|0更新时间：2026-08-21
- 摘要：The promotion of chargers towards ultra-fast chargers (referred to as ultra-chargers) is an important way to achieve transportation carbon emission reduction and re-electrification. With the rapid implementation of ultra-charger construction plans and projects in various cities, it will become crucial to effectively improve the convenience of electric vehicle (EV) travel while ensuring the voltage safety of medium- and low-voltage distribution networks. In response to the voltage deviation problem caused by the change in reactive voltage characteristics of the distribution network due to the widespread use of ultra-chargers, firstly, based on measurement data, this paper analyzes the load characteristics of electric vehicles in ultra-charger scenarios, and establishes an improved Monte Carlo based short-term parking model for EVs. Secondly, a queuing charging model for EVs is built with superchargers, which determines whether to adopt ultra-fast charging during parking time based on the travel information and calculates the charging load for each minute. Then, a distribution network reactive power optimization configuration model is built with the goal of minimizing annualized line loss costs and reactive power optimization annualized costs. The M-δ method is adopted to convexify the siting and sizing constraint to improve the solution efficiency. Finally, through case simulation analysis, the effectiveness of the proposed model and the economic effectiveness of the proposed solution are verified.关键词：distribution network;electric vehicle (EV);charging;improving Monte Carlo method;siting and sizing;reactive power optimization0|0|0更新时间：2026-08-21
- 摘要：As the interactions among multi-type microgrids become increasingly complex, energy scheduling has evolved into a high-dimensional, nonlinear and multi-agent decision-making process. To address this issue, this paper proposes an optimal scheduling method for multi-type microgrid hypergraph based on mean-field game. First, to effectively characterize the coupling between the strategies of individual microgrids and the energy behaviors of multi-type microgrids, a dynamic hypergraph is introduced to describe the evolution of agents’ energy behaviors, and an optimal scheduling framework is established to represent the dynamic interactions within multi-type microgrid clusters. Second, considering that the trading volume and electricity price decisions of individual microgrids are affected by the behaviors of other microgrid agents, a scheduling decision model is constructed using the mean-field game method. This model features high dimensionality, nonlinearity and multi-agent game characteristics. Then, to obtain the global optimal solution, the original problem is decomposed into two subproblems: microgrid cost minimization and individual microgrid benefit maximization. A distributed solution mechanism is developed by combining the alternating direction method of multipliers (ADMM) to achieve overall collaborative optimization. The results show that the proposed method can accurately describe the high-order interactions in the scheduling process of multi-type microgrids. In addition, the established mean-field game model improves the economic efficiency of microgrid scheduling and facilitates the participation of multi-type microgrids in market trading.关键词：mean-field game;microgrid;hypergraph;optimal scheduling;alternating direction method of multipliers (ADMM)2|1|0更新时间：2026-08-21
- 摘要：With the widespread dispersed integration of nonlinear loads in local distribution networks, harmonic issues have an extensive impact and are difficult to mitigate, leading to an increasing mitigation demand for multi-bus harmonic comprehensive compensation. In the existing comprehensive harmonic compensation technologies, the compensation current of active power filter (APF) is constrained by the system-level control cycle, resulting in insufficient dynamic response capability to nonlinear loads. Therefore, this paper proposes an optimal control technology for equivalent harmonic admittance of APFs, which balances compensation range and dynamic performance to achieve multi-bus harmonic comprehensive compensation in local distribution networks. Firstly, a multi-bus harmonic comprehensive compensation model incorporating the admittance-controlled APF is established. Subsequently, based on measured voltage values, the network impedance parameters are identified. An online optimization method for the harmonic admittance control instruction of APFs is proposed, aiming at optimizing the comprehensive compensation effect of multi-bus harmonic voltages. Finally, simulation and experiments verify the feasibility and effectiveness of the proposed optimization control technology in comprehensively compensating harmonic voltages across multiple buses in the network.关键词：distribution network;harmonic compensation;active power filter (APF);equivalent harmonic admittance;online optimization0|0|0更新时间：2026-08-21
- 摘要：The receiving-end hierarchical infeed hybrid ultra-high voltage direct current (UHVDC) transmission system possesses diverse and flexible converter control modes, which can satisfy various control objectives under multiple operating modes. Nevertheless, smooth switching among different control combinations remains a prominent issue for such systems. In this paper, considering the influences of power transmission and DC overvoltage, the applicable control combinations of the system in various fault conditions at receiving-end AC buses are analyzed and determined. To eliminate unbalanced power and improve the system fault recovery speed, an auxiliary control is adopted to regulate the power setpoints of converters. Meanwhile, to realize the smooth switching among different control combinations, a feedforward control strategy is proposed to maintain constant current inner-loop commands during converter control mode switching. Finally, simulation analysis of receiving-end AC bus faults for the hybrid UHVDC transmission system is carried out on the PSCAD/EMTDC platform. The simulation results verify the effectiveness and superiority of the proposed optimization method of control strategy.关键词：high voltage direct current (HVDC);hierarchical infeed;converter;control strategy;fault recovery0|0|0更新时间：2026-08-21
Basic Research
- 摘要：The voltage source converter based high voltage direct current (VSC-HVDC) technology has emerged as the preferred solution for large-scale transmission of offshore wind power from deep-sea areas due to its flexibility, controllability, adaptability, and environmental friendliness. As a core component of VSC-HVDC transmission system, the lightweight design of the offshore converter platform plays a crucial role in determining the economic viability of the system. However, high-voltage and large-capacity offshore converter platforms, characterized by numerous internal components and complex spatial multi-physics distributions, pose significant challenges to their compact and lightweight design. This paper reviews recent advancements in the lightweight design of offshore converter platforms, covering four key aspects: topology design of VSC-HVDC transmission system, key equipment development, multi-physics coordination, and layout optimization methods. Furthermore, future research directions are discussed to provide reference for future offshore converter platform design.关键词：offshore wind power;voltage source converter based high voltage direct current (VSC-HVDC);converter platform;lightweight design0|1|0更新时间：2026-08-21
Engineering Technology Frontier
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