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最新刊期
卷 49 ， 期 17 ， 2025
- 摘要：The main task of the new power system is to build a high proportion of renewable energy supply and consumption system, and the operation law of its source, grid, load and energy storage is closely related to meteorological changes. The operation and scheduling, planning and design, disaster prevention and reduction, and other aspects of the power grid all need to consider the influence of weather. The integration and development of the two disciplines of electricity and meteorology have become inevitable. However, currently, there is little literature that systematically reviews the key technologies and applications of numerical weather prediction of new power systems. This paper first summarizes the key technologies of numerical weather prediction from four aspects: meteorological observation, quality control, data assimilation, and numerical modeling. Secondly, typical application scenarios and methods of numerical meteorology are summarized from three aspects: source-load power prediction, wind and solar resource assessment, and power grid disaster warning. Finally, the unique requirements of the new power system for the accuracy, timeliness, and precision of numerical weather prediction are analyzed. The shortcomings of numerical weather prediction technologies in electricity demand are discussed, as well as the contradictions and promoting relationships between key technology improvements driven by demand. The key research directions for the integration and development of electricity and meteorology disciplines in the future are discussed in terms of data, mode, and platform construction.关键词：new power system;numerical weather prediction;meteorology;application scenario14|1|0更新时间：2025-09-25
- 摘要：With the promotion of the goals of carbon emission peak and carbon neutrality, the large-scale grid-connection of renewable energy generation represented by distributed photovoltaic and distributed wind power has brought great challenges to the planning and operation of distribution networks, and the distributed generation hosting capacity of distribution networks has received more and more attention. To this end, this paper summarizes the domestic and overseas research status of the corresponding assessment methods and improvement measures, and looks forward to the future research focus. Firstly, the influencing factors of the hosting capacity of distributed generation are introduced, and its typical characterization methods are described. Secondly, the results of grid-side uncertainty and source-load uncertainty which affect the hosting capacity in related studies are analyzed and summarized. Then, the relevant achievements of various active management measures in improving the hosting capacity of source, grid, load, energy storage are summarized from the perspective of mechanism. Finally, three aspects of multi-objective collaboration, multi-feeder interconnection, and multi-level collaboration in hosting capacity evaluation are prospected.关键词：distribution network;distributed generation;hosting capacity;uncertainty;assessment7|1|0更新时间：2025-09-25
Review·Perspective
- 摘要：Fractional frequency transmission provides a new option for large-scale, long-distance offshore wind power transmission by reducing the frequency and improving the line transmission capacity. Aiming at the impact of the high proportional renewable energy and power electronics equipment on the resonance stability and reliability of the system, and closing to the actual engineering needs, a fractional frequency transmission planning method for offshore wind power is proposed. Considering the economy, resonance stability, and reliability, the method makes fractional frequency grid connection scheme for offshore wind power. Firstly, the fractional frequency transmission system of offshore wind power and planning model of onshore industrial frequency power grid, resonance stability evaluation model, and operation reliability evaluation model are introduced. Secondly, taking the offshore wind power development in a coastal area of China as a case study, wind power transmission and onshore power grid expansion schemes are planed, and the engineering verification is carried out. Furthermore, the technical economy of three schemes of power frequency AC, flexible DC, and fractional frequency transmission are compared, and the optimal solution is selected. The results show that in the case scenario, the technical economy of fractional frequency transmission has certain advantages.关键词：offshore wind power;fractional frequency transmission;grid planning;resonance stability;reliability6|0|0更新时间：2025-09-25
- 摘要：To enhance the reliability and economy of high-voltage direct current (HVDC) transmission systems based on diode rectifier units (DRUs) for offshore wind power transmission, grid-forming (GFM) and grid-following (GFL) hybrid wind farms are gaining increasing attention. Regarding the capacity configuration issue of GFM-GFL wind turbines (WTs) in the hybrid wind farm, firstly, the existence of the equilibrium point and the small-signal stability of the grid-connected system of GFL wind farm through the DRU are demonstrated, and it is pointed out that the large voltage/frequency fluctuations are the key factors. Then, the operation characteristics of the grid-connected system of GFM-GFL hybrid wind farm through the DRU are analyzed, and the voltage/frequency mechanism of the GFM WT stable system is explained. Further, joint configuration methods of GFM WT and DRU reactive power compensation considering static stability and small-signal stability constraints are proposed. Finally, the validity of the proposed configuration scheme and the accuracy of the feasible region boundary are verified through the time-domain simulation model based on PSCAD/EMTDC.关键词：offshore wind power;grid-forming wind turbine (GFM WT);grid-following wind turbine (GFL WT);diode rectifier unit (DRU);high-voltage DC transmission;capacity configuration5|1|0更新时间：2025-09-25
- 摘要：Current voltage source converter based high-voltage direct current (VSC-HVDC) system has gradually become one of the main ways for the grid-connection of large-scale offshore wind power clusters. However, due to the high construction costs of converter stations and high-voltage direct current submarine cables, the economic grid-connected planning of offshore VSC-HVDC systems has always been one of the key issues in the grid-connected planning of offshore wind power clusters. Considering the low utilization rate of equipment for offshore transmission system caused by wind power fluctuations, the phenomenon of offshore wind power curtailment due to insufficient external transmission capacity in the onshore power grid under grid-connection of large-scale offshore wind power, and the flexible active-reactive power control capability of VSC stations, this paper constructs a bi-layer nested grid-connected planning model of VSC-HVDC system for offshore wind farm clusters that integrates the “N+” principle with the active-reactive power flexible operation region of the common coupling point under multiple DC integration. By optimizing the equipment selection under the “N+” principle and the siting, sizing and topology optimization of converter stations for the offshore VSC-HVDC system, from two aspects of saving investment costs in grid-connection of VSC-HVDC system and improving the energy consumption of offshore wind power by onshore power grids, the optimal life cycle benefits of offshore wind power clusters can be achieved.关键词：offshore wind power;voltage source converter based high-voltage direct current (VSC-HVDC);grid-connected planning;siting and sizing;onshore power grid6|1|0更新时间：2025-09-25
- 摘要：When the receiving-end landing point distance of the offshore wind power with modular multilevel converter based high voltage direct current (MMC-HVDC) grid-connection project is close to that of the line-commutated converter based high voltage direct current (LCC-HVDC) project, a hybrid multi-feed DC (HMIDC) transmission system is formed, but the resonant characteristics of this system are still unclear. To address this, this paper develops the transfer function calculation models for line-commutated converters (LCCs) and modular multilevel converters (MMCs) based on generalized average theory. On this basis, by adopting the harmonic impedance model of long-distance DC transmission lines considering the frequency variation distribution characteristics and relying on the typical control structures and case parameters of actual engineering, a linearized frequency-domain model of the MMC-HVDC and LCC-HVDC hybrid infeed system of offshore wind power is established. Then, the single-input single-output equivalent AC admittance characterizing the stability of the system is derived, and the potential resonance problem of the system is analyzed. The influence of controller interactions among the MMC-HVDC and LCC-HVDC transmission system of offshore wind power, flexible DC converter stations and conventional DC converter stations is explored. Additionally, the influence of DC power, tie-line length, and reactive power output of converter stations on the stability characteristics of the system is investigated. Finally, a impedance reshaping strategy based on AC feedback is proposed, and the effectiveness of the proposed controller is verified in the electromagnetic transient simulation model of PSCAD/EMTDC.关键词：offshore wind power;modular multilevel converter based high voltage direct current (MMC-HVDC);hybrid multi-infeed system;resonance;impedance reshaping;stability;generalized average theory4|0|0更新时间：2025-09-25
- 摘要：The multi-terminal flexible DC transmission system for offshore wind power can achieve power supply from multiple sources to multiple landing points. It can be transmitted to the load center through onshore DC overhead lines to improve the utilization rate of transmission corridors in coastal areas. It is an efficient and economic solution for the large-scale far-offshore wind power grid connection in the future. This paper introduces the topology and main equipment configuration scheme of the multi-terminal flexible DC transmission system for offshore wind power, and the system adaptability is introduced from the perspectives of reliability, economy and flexibility. In response to DC overhead line faults, permanent faults, and neutral line faults in the system, the technical characteristics of DC circuit breakers, half-bridge submodule converters, high-speed switches, and AC circuit breakers are fully utilized, and the detailed fault clearance schemes are given by combining the characteristics of each fault, to achieve rapid DC fault isolation and recovery of the system. Based on the PSCAD/EMTDC simulation platform, a five-terminal bipolar offshore wind power grid-connected system is built, and the feasibility of the proposed scheme is verified through steady-state operation and various DC faults.关键词：offshore wind power;flexible DC transmission;DC fault;overhead line;DC circuit breaker;half-bridge submodule converter;high-speed switch;AC circuit breaker7|1|0更新时间：2025-09-25
Key Technologies for Offshore Wind Power System
- 摘要：To address the limitations of space-time values in the time-of-use electricity trading, a dual-value theory of electric energy is proposed for the substitute power product market, in which the substitute energy is used to quantify the productive use value and the regulating energy is used to quantify the electric power balance value. Focusing on the negotiated bidding model of “regulating energy bilateral negotiation-substitute energy centralized bidding”, the operation process of the day-ahead spot market and the specific trading methods for the bilateral negotiation of regulating energy and centralized bidding of substitute energy are systematically studied. Firstly, the overall operation process of the day-ahead spot market for the substitute power product under the negotiated bidding mode and the relationships between different processes are introduced. Secondly, in response to the two stages of electricity producers forming the substitute power product by changing the initial output curves and purchasing regulating demand curves, two bilateral trading methods for the regulating energy, namely “alliance” mode and “regulating energy cloud” mode are proposed. Then, a standard bidding form for market entities is proposed for the centralized trading process of substitute energy, and a clearing model for the substitute energy market is established. The concept of substitute energy marginal rate is introduced, and a criterion for determining the optimal solution of the substitute energy market clearing model, i.e., the equal substitute energy incremental rate criterion is proposed. The settlement methods for the substitute energy market are also provided. Finally, targeting the frequent occurrence of negative electricity prices in the current electricity market, the test and analysis are conducted in the scenarios with the integration of high proportion of renewable energy. The case study not only demonstrates the operation process of the day-ahead market for the substitute power product under the negotiated bidding mode, but also indicates that the proposed bidding mode can effectively overcome the shortcomings of “price signal failure” in the time-of-use electricity trading, with advantages such as precise price signal guidance and transparent, lightweight mechanisms.关键词：electricity market;substitute power product;negotiated bidding;clearing;substitute energy marginal rate;negative electricity price8|0|0更新时间：2025-09-25
- 摘要：The dynamic security assessment (DSA) of power systems considering the operation mode and fault location requires a large number of training samples, and the structure of assessment model is complex, which has the problems of high training costs and difficulty in online updates. To solve these problems, a method for dynamic security partitioning assessment and model increment updating of power system is proposed, which reduces the complexity of the assessment model and enables online model increment updating without catastrophic forgetting. Firstly, electrical coordinates are constructed as node position features, and the Chebyshev distance is introduced to measure the difference between node position features, and the adaptive partitioning of the power grid is carried out based on the space constrained mean shift (SCMS) clustering algorithm. Secondly, the operation modes and fault location features are extracted, and the Chebyshev distance is embedded in the double-hidden-layer radial basis function neural network (RBFNN). Partitioning assessment models for various fault locations in various regions are constructed. Finally, an online model increment updating method is proposed to avoid the problem of catastrophic forgetting during the model updating process. The effectiveness of the proposed method is verified using a transient power angle stability assessment of a provincial power grid in China as an application scenario.关键词：dynamic security assessment;partitioning;electrical coordinate;Chebyshev distance;neural network5|0|0更新时间：2025-09-25
- 摘要：As a new type of condenser equipment, the energy storage doubly-fed condenser (ESDFC) not only has the strong voltage support ability of the synchronous condenser, but also can make full use of the rotor energy storage to improve the frequency response characteristics, thus providing support for the safe and stable operation of the power system with the integration of high proportion of renewable energy. First, aiming at the problem that the current active virtual inertia control methods have difficulties in balancing the steady-state constant-speed operation, transient inertia support and rotor speed self-recovery of the ESDFC, an inertia support method based on the frequency-rotor speed droop control is proposed to clarify the rotor speed regulation process during the frequency disturbance. Then, the equivalent inertia with different control parameters is evaluated by small signal modeling, and the frequency response model of the grid-connected system is constructed. The eigenvalue method is used to analyze the small signal stability, and the selection principle of the main control parameters is discussed. Finally, the effectiveness of the proposed inertia control strategy for the frequency support is verified by the grid-connected simulation case of the renewable energy station.关键词：energy storage;condenser;frequency response;rotor speed;droop control;inertia;stability8|0|0更新时间：2025-09-25
- 摘要：Motor participating in fast frequency response (FFR) is a critical measure to enhance frequency stability in independent microgrids. However, conventional motor frequency regulation methods often exhibit a gradual decline in power output after initially reaching the theoretical maximum during frequency disturbances, limiting the supporting capability for system frequency recovery. Additionally, the coordination between motor speed recovery and system frequency is paramount. If the motor speed recovery is too rapid, it may exacerbate power fluctuations, increase the burden on primary frequency regulation, and even trigger secondary frequency drops. Conversely, overly slow speed recovery compromises the effects of motor involvement in FFR. Therefore, the coordination between system frequency and motor speed must be considered when designing the control strategy to ensure the efficient FFR execution. To address this, a model predictive control (MPC)-based FFR control method for motors is proposed. The requirements for FFR control are analyzed, and a method enabling motors to track FFR power commands rapidly and accurately is adopted. A coordination control strategy between system frequency and motor speed recovery is developed, and an MPC controller which can solve optimal control commands is designed to achieve the optimal control throughout the whole FFR process for the motor. Finally, simulation experiments based on a real-time independent microgrid model demonstrate that the proposed method improves motor FFR performance and enhances microgrid frequency stability.关键词：microgrid;flexible load;motor;fast frequency response;model predictive control;frequency regulation;stability5|0|0更新时间：2025-09-25
- 摘要：The conventional modulated model predictive voltage control usually has difficulty in maintaining the stability and accuracy of the output voltage when facing parameter uncertainty and various disturbances in the LC-filtered inverter system, especially in the case of parameter mismatch, the control performance declines significantly. To address this issue, this paper proposes a Luenberger observer based modulated model-free predictive voltage control (LO-M2FPVC) strategy. This strategy mitigates the impact of system disturbances on the calculation of modulated prediction, ensuring the robustness of the inverter output voltage control. First, a parameter-free Luenberger observer is developed for the inverter to accurately identify parameter changes inside the LC-filtered inverter and other external disturbances. The observed disturbance information is then integrated into the calculation of modulated prediction, eliminating the influence of disturbances on the duration calculation of each voltage vector in modulated prediction. Finally, an experimental platform for the LC-filtered inverter is constructed to verify the effectiveness of the proposed LO-M2FPVC strategy.关键词：inverter;model predictive voltage control;model-free predictive voltage control;Luenberger observer;modulated prediction;parameter robustness6|0|0更新时间：2025-09-25
- 摘要：Limited by its energy supply form and single-port grid-connected architecture, the existing self-supplied emergency vehicles have prominent problems such as insufficient continuous power supply capability, high energy consumption, redundant capacity configuration and poor operation economic benefits. To this end, the grid-connected ports of the existing emergency vehicles are expanded; an energy-stored vehicle with soft open point (ESV-SOP) is designed with the ability of “self-supply and transfer”; and a mathematical model and its constraints are established for various working modes. Secondly, a two-layer optimal configuration model for ESV-SOP considering the joint normal-fault condition of the distribution network is proposed. In the optimal parameter configuration layer of ESV-SOP, comprehensively considering the equipment investment, the operation costs under the normal and the fault conditions in the distribution network, the optimal quantity, port capacity and energy storage battery capacity are iteratively determined by the particle swarm optimization algorithm. In the multi-scenario joint economic operation layer, based on the typical fault scenarios generated by the information entropy theory, the joint dispatching strategy of ESV-SOP under the normal and fault conditions in the distribution network is constructed. Finally, based on the IEEE 33-bus system, the effectiveness and superiority of the proposed two-layer optimal configuration method for ESV-SOP are verified, and the results show that ESV-SOP can play the roles of self-power flow regulation and load support, and improve the operation economy and reliability of the distribution network.关键词：distribution network;mobile energy storage;soft open point;configuration method;emergency management and control;economy5|0|0更新时间：2025-09-25
- 摘要：In recent years, frequent compound typhoon and waterlog disasters pose a serious threat to the power supply security of distribution networks in coastal cities. In this context, it is very important to allocate restoration resources before and after disasters in order to improve the resilience of distribution networks. Therefore, a resilience improvement method for distribution networks is proposed based on pre-disaster deployment and post-disaster dispatching of restoration resources to realize the effective cooperation of drainage, power emergency repair and mobile energy storage dispatching under compound typhoon and waterlog disaster. First, in view of the influence of compound typhoon and waterlog disaster on distribution networks and transportation networks, a distribution network-transportation network damage model under compound typhoon and waterlog disaster is established. Secondly, based on the characteristics and synergy of various restoration resources, a unified model of pre-disaster deployment and post-disaster collaborative restoration is proposed. Then, considering the pre-disaster deployment scheme and post-disaster restoration strategy, a two-stage emergency restoration framework for distribution networks under compound typhoon and waterlog disaster is designed to realize the pre-disaster and post-disaster linkage. Finally, through the coupling case of distribution network and transportation network, the effectiveness of the proposed pre-disaster deployment and post-disaster dispatching method for restoration resources is verified.关键词：typhoon;waterlog;disaster;multi-resource collaboration;resilience;distribution network;transportation network;restoration resource;mobile energy storage7|1|0更新时间：2025-09-25
- 摘要：To rapidly and accurately analyze the impact of the uncertainty of renewable energy output and the randomness of load fluctuations on the power flow distribution of AC/DC power systems, a sparse polynomial chaos expansion (SPCE) method for solving the holomorphic embedded AC/DC probabilistic power flow is proposed. Firstly, the holomorphic embedded power flow model of the AC/DC power system is constructed. Then, based on the probability distribution types of load prediction errors and renewable energy output prediction errors, the corresponding polynomial chaos expansion expressions are constructed by selecting appropriate basis functions. According to the mapping relationship between the state variables to be solved and the random input variables in the holomorphic embedded power flow model, the probability distribution of the state variables to be solved is expressed in the form of polynomial chaos expansion, and the problem of solving the state variables to be solved is transformed into the problem of solving the coefficients of the basis functions in the polynomial chaos expansion expressions of the state variables to be solved. Further, the forward-backward selection method is used to sparsely reconstruct the polynomial chaos expansion expression of the state variables to be solved, retaining the basis functions that have a significant impact on the power flow calculation results and reducing the number of basis function coefficients to be solved. Thus, the basis function coefficients can be solved based on a small number of deterministic power flow samples, and the probabilistic characteristics of the system power flow distribution can be obtained using SPCE. Finally, the accuracy and effectiveness of the proposed method are verified through the modified IEEE 14-bus and IEEE 118-bus AC/DC test systems.关键词：probabilistic power flow;polynomial chaos expansion;AC/DC power system;renewable energy4|1|0更新时间：2025-09-25
Basic Research
- 摘要：With the large-scale integration of power sources from renewable energy converter interfaces such as wind power and photovoltaic power into the grid, the equivalent inertia level of the power grid decreases, and the stability issues have become increasingly serious. To enhance the active support capability of the system in weak power grids, for the structure of grid-connected system topology based on the open-winding wound field synchronous motor (OW-WFSM) interface, the vector relationship among the converter, the motor, and the grid is analyzed. Based on the constructed system voltage vector triangle, OW-WFSM and the converter are regarded as a whole, and a novel droop control strategy of renewable energy grid-connected system based on OW-WFSM interface is proposed. The proposed control strategy performs droop control according to the vector relationship between the power factor angle and the phase and amplitude of the converter, as well as the vector relationship between the apparent power and the internal potential within the OW-WFSM. An additional power operation range expansion section is added in the control loop to achieve stable operation of the power of the renewable energy grid-connected system over the entire power range. Simulation and experimental results have verified the effectiveness of the proposed control strategy.关键词：renewable energy;active support;open-winding wound field synchronous motor (OW-WFSM);voltage vector triangle;droop control;converter;inertia5|1|0更新时间：2025-09-25
- 摘要：Under the unbalanced power grid condition, renewable energy power plants need to output negative-sequence currents to support the power grid voltage. The cascaded H-bridge static synchronous compensator (STATCOM) has been widely utilized in renewable energy power plants operating under medium- and high-voltage scenarios. Due to the lack of the common DC bus, the negative-sequence current output capability of the cascaded H-bridge STATCOM is limited. To improve the negative-sequence current compensation capability of the cascaded H-bridge STATCOM, this paper constructs a hybrid cascaded STATCOM by unraveling the common end of the three-phase cascaded H-bridge and inserting a three-phase two-level topology, to expand the negative-sequence current compensation range by taking advantage of the three-phase unbalanced active power output capability of the two-level topology. Firstly, the relationship between the unbalanced active power and the negative-sequence current of the hybrid cascaded STATCOM in the unbalanced power grid is analyzed. Two kinds of negative-sequence voltage components are superimposed on the cascaded H-bridge and the two-level circuit, respectively. The goals of transferring the unbalanced active power of the cascaded H-bridge and controlling the negative-sequence current of hybrid cascaded STATCOM can be achieved. Secondly, by constructing the constraint relationship between the two negative-sequence voltage components and the negative-sequence current compensation capacity of the hybrid cascaded STATCOM, the range of the negative-sequence current compensation of the hybrid cascaded STATCOM is calculated under unbalanced power grid conditions. The simulation and experimental results verify the feasibility of the proposed negative-sequence current control strategy.关键词：static synchronous compensator (STATCOM);negative-sequence current;negative-sequence voltage;cascaded H-bridge;hybrid topology;interphase voltage balance6|0|0更新时间：2025-09-25
- 摘要：With the wide application of power electronic technologies in the fields of renewable energy and electric vehicles, their dynamic characteristics increasingly influence the system performance. Traditional real-time simulation technologies based on ideal switch models are difficult to meet high-precision demand. To this end, a switch transient modeling and simulation method based on connectionist neural networks is proposed. A co-modeling strategy combining both system-level and transient models is employed to enhance the time-series prediction capability of the model through the introduction of time-node coupling mechanism. At the system level, the circuit network is solved using the associated discrete circuit model and nodal analysis method, and the transient model utilizes a data-driven approach to construct a connectionist neural network model to accurately describe the transient process of the switching device. The real-time simulation system is implemented on a field programmable gate array (FPGA) hardware platform, and verified through real-time simulation cases of bidirectional buck-boost converters and three-phase inverters, in which various types of switching devices are used. The comparison with offline simulation results shows that the transient model and the real-time simulation method have high accuracy and stability under multi-topology and multi-case operating conditions.关键词：power electronic switch;transient model;real-time simulation;field-programmable gate array;neural network6|0|0更新时间：2025-09-25
Application Research
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