Electric Power

Double layer rolling based optimization model for joint operation of wind-hydro- storage system

RUAN Honghua, DENG Ziqi, CHEN Feixiong, LIN Junjie

2026, 59(4): 1-11. DOI: 10.11930/j.issn.1004-9649.202504088

Asbtract ( )

PDF (1243KB) ( )

Figures and Tables | References | Related Articles | Metrics

With the gradual increase in the penetration rate of wind power and other renewable energy sources, the uncertainty of power grids operation has intensified accordingly. How to safely and efficiently exert the regulating effect of hydropower is of great significance to the stable operation of power grids. To this end, a bi-level rolling optimal scheduling method for the joint operation of wind-hydro-storage systems is proposed. First, a bi-level rolling optimal control model for wind-hydro-storage joint operation is constructed. The upper-level optimization is based on a long time scale, with the goal of minimizing the system operation cost; the lower-level optimization is based on a short time scale, aiming to minimize the system output deviation. Second, the model predictive control (MPC) method is adopted to solve the optimization model. The real-time rolling optimization of the lower level is used to feedback and correct the upper-level scheduling plan, thereby reducing the impact of uncertainty on the system. Finally, a case study is carried out on a cascade hydropower system in South China. The simulation results verify the effectiveness of the proposed method in improving energy utilization efficiency, reducing operation costs and addressing system uncertainty.

Nonparametric kernel density estimation based wind-solar-hydro-thermal-storage system operational flexibility evaluation

MI Yi, XU Xuesong, YANG Yiming, ZOU Xin

2026, 59(4): 12-23. DOI: 10.11930/j.issn.1004-9649.202508057

Asbtract ( )

PDF (1394KB) ( )

Figures and Tables | References | Related Articles | Metrics

With the rising penetration of new energy, uncertainties on both generation and load sides pose significant risks to power system stability. To scientifically assess the flexibility of a novel multi-source coupled power system (integrating wind, solar, thermal, hydro and energy storage), a collaborative analysis framework is proposed, combining interval estimation of bilateral generation-load uncertainties with stochastic production simulation. First, non-parametric kernel density estimation generates confidence intervals for new energy output and load, and extreme supply-demand scenarios are constructed to quantify such uncertainties. Second, via a hierarchical dispatching strategy, wind, photovoltaic and run-of-river hydropower are prioritized as equivalent negative loads. Considering system ramping constraints, an improved stochastic production simulation algorithm schedules thermal power unit output. Finally, reservoir-type hydropower undertakes remaining system load. In case of load shedding or new energy curtailment, energy storage devices regulate the system through charging and discharging. Case studies show non-parametric estimation effectively characterizes bilateral generation-load uncertainties. The proportions of load shedding and new energy curtailment due to insufficient system ramping capacity are 14.8% and 91.5%, respectively, indicating ramping constraints are critical to system stability. Energy storage configuration significantly enhances regulation capacity, reducing the loss of load probability (LOLP) and new energy curtailment probability by 8.6% and 34.1%, respectively.

Medium-term optimal dispatching method for wind–solar–hydro–thermal multi-energy complementary regional power system considering wind and solar power uncertainties

LU Jianyu, ZHANG Kaixuan, LI Jianhua, WANG Yue, ZHOU Yi, SHEN Jianjian

2026, 59(4): 24-34. DOI: 10.11930/j.issn.1004-9649.202506064

Asbtract ( )

PDF (1133KB) ( )

Figures and Tables | References | Related Articles | Metrics

Under the high penetration of new energy sources, the stable operation of the power grids over multiple consecutive days is increasingly affected by the volatility and uncertainty of large-scale wind and solar power output during the daytime, which exacerbates the difficulty of power supply guarantee. This paper proposes a medium-term optimal dispatching method for wind-solar-hydro-thermal multi-energy complementary regional power grids considering the uncertainty of wind and solar power generation. The covariance matrix is adopted to characterize the time-varying characteristics of the wind and solar power generation prediction errors, and the hybrid Gaussian sampling is integrated to generate the scenario set of wind and solar power output. Meanwhile, a conditional sampling strategy is utilized to retain the statistical characteristics of the prediction errors while reasonably reducing the number of scenarios. With the objectives of minimizing the sum of squares of grid-wide power shortage and curtailment as well as minimizing the thermal power operating cost, a multi-objective optimization model for wind-PV-hydro-thermal complementary operation is established. A hierarchical weight optimization method is proposed to balance the target priorities and the relative importance of each objective, thus achieving efficient solution. Simulation scheduling based on the actual data of East China Power Grid shows that, compared with conventional methods, the proposed method can reduce the overall power shortage of the system by more than 33.3%, while ensuring high reliability of grid dispatching plans. The daily maximum power shortage/curtailment only accounts for 1.3% and 1.7% of the load, respectively, which provides an effective approach for the formulation of multi-day consecutive dispatching plans of power grids under high renewable energy penetration.

Medium- and long-term optimal scheduling method for inter-basin hydro-wind-photovoltaic complementary systems based on scenario generation with improved generative adversarial network

CUI Yichen, WANG He, WANG Lili, YIN Tao, HUANG Shansong

2026, 59(4): 35-46. DOI: 10.11930/j.issn.1004-9649.202510031

Asbtract ( )

PDF (1747KB) ( )

Figures and Tables | References | Related Articles | Metrics

With the continuous increase of wind-solar penetration, how to address the volatility and uncertainty of their power output and formulate reasonable medium- and long-term scheduling strategies has become the core challenge for the efficient operation of inter-basin hydro-wind-solar hybrid systems. To this end, this study firstly proposes a wind-solar joint scenario generation method considering spatio-temporal correlation. By improving the network structure of the Wasserstein generative adversarial network (WGAN), the model can hierarchically extract the spatio-temporal coupling characteristics of wind-solar power output, and generate a representative joint scenario set. On this basis, with the objectives of maximizing the expected energy consumption of the complementary system, minimizing the curtailment and power shortage, and minimizing the loss of spilled water, an adaptive weight determination method based on feedback regulation is proposed to dynamically adjust the priority of each objective in different time periods, and a medium- and long-term multi-objective stochastic optimization model for inter-basin hydro-wind-solar hybrid systems is constructed. A simulation analysis is carried out by taking an inter-basin clean energy base in the Southwest region as an example. The results show that, compared with conventional methods, the proposed method improves the consumption level of new energy and the power supply reliability of the system while considering the utilization of water resources in basins; the comprehensive power curtailment rate and power shortage risk are reduced by 1.53 percentage points and 24.5% respectively, achieving collaborative optimization and effective balance among multiple objectives.

Evaluation of HVDC transmission capability for hydro-wind-solar hybrid power bases considering frequency and voltage support strength

WANG Xiaodi, ZHANG Lin, SU Yunche, BI Shuya, LIU Fang, WEN Yunfeng

2026, 59(4): 47-58. DOI: 10.11930/j.issn.1004-9649.202507002

Asbtract ( )

PDF (2358KB) ( )

Figures and Tables | References | Related Articles | Metrics

Large-scale hydro-wind-solar integrated power bases exhibit the fundamental characteristics of multi-energy sources, weak grid structure, and limited local loads. Thus the transmission export capability of its large-scale clean energy through HVDC connection is severely subject to system security and stability. With regards to the issue of frequency/voltage support capabilities weakened by high penetration of renewable energy, this paper develops an HVDC transmission capability evaluation model incorporating frequency and voltage support strength. Firstly, a coordinated assessment framework is established based on the analysis of the constraints limiting HVDC transmission capabilities. Next, by integrating spatio-temporal hydraulic-electric constraints of river basin cascade hydropower generation and considering complementary operation of hydro-wind-PV energy resources, a transmission capacity optimization model with the objective of maximizing delivery power is formulated via mixed-integer second-order cone programming method. Finally, security constraint frameworks covering frequency/voltage support requirements are constructed by quantifying system frequency response capability and short-circuit ratios of multiple renewable plants. Furthermore, by taking advantage of second-order cone reconstruction techniques to efficiently process nonlinear frequency constraints, a transmission capacity evaluation methodology is then formulated which balances the multi-energy complementarity and system security requirements. Case studies on modified IEEE benchmark systems are conducted to validate the model's effectiveness through multi-scenario simulations.

A quantitative evaluation method for power system inertia considering the proportion of multiple resources in operation

YAN Zhaoyang, LI Jie, LIU Shaofeng, DING Chaojie, ZHOU Tian, CHANG Kang, YANG Li

2026, 59(4): 59-69. DOI: 10.11930/j.issn.1004-9649.202509069

Asbtract ( )

PDF (1151KB) ( )

Figures and Tables | References | Related Articles | Metrics

With high-proportion new energy grid integration, power system inertia characteristics have evolved fundamentally, and traditional methods relying on synchronous units can hardly meet new-type power system needs. This paper proposes an inertia quantification method based on multi-dimensional inertia resource operation proportion: first, a multi-resource inertia assessment model (covering synchronous units, new energy, DC transmission, flexible loads and energy storage) is built, systematically analyzing various resources’ inertia support mechanisms; second, differentiated quantitative modeling is conducted for each resource’s inertia characteristics to characterize their inertia contribution under different conditions, with an innovative inertia statistical method based on capacity proportion weight proposed for comprehensive assessment of overall inertia; finally, multi-scenario verification is done via PSD-BPA and the proposed frequency response model. In the CSEE small system’s 80 MW load-shedding scenario, the steady-state frequency and maximum frequency deviation errors versus PSD-BPA measured values are only 0.023% and 8.809%.

Harmonic suppression strategy based on cross-branch enhanced VSG control

XU Tao, LI Hugang, YANG Longyu

2026, 59(4): 70-78. DOI: 10.11930/j.issn.1004-9649.202505013

Asbtract ( )

PDF (2639KB) ( )

Figures and Tables | References | Related Articles | Metrics

The multi-node distribution station area after a large number of new energy power generation equipment is connected faces the practical problem of poor current and power quality. At the same time, the deployment of grid-connected converters dominated by virtual synchronous generator (VSG) ignores the problem of current and power quality. Therefore, in order to maintain the VSG characteristics and increase the current harmonic suppression ability, this paper proposes an enhanced VSG control strategy. Firstly, the interaction mechanism of electrical angle and voltage between AC grid and VSG in multi-VSG joint operation is analyzed. Secondly, the VSG control with cross feedback branch is proposed. This method proposes a frequency-reactive power branch and a voltage-active power branch to compensate for fluctuations without affecting the inertial characteristics of the system. Finally, the IEEE-69 network simulation distribution station area is built, and 6 VSGs are set up. The experimental results show that the enhanced VSG can provide inertial and damping support for the system. The quantitative results show that compared with the traditional VSG, the total harmonic distortion of the current is reduced by 64.2%~83.8%, which can effectively suppress the influence of the harmonics generated by the traditional VSG on the distribution network.

Operation optimization strategy for highway-domain virtual power plants considering dual uncertainties of source and loads

LI Xin, SONG Jinjin

2026, 59(4): 79-93. DOI: 10.11930/j.issn.1004-9649.202509067

Asbtract ( )

PDF (2174KB) ( )

Figures and Tables | References | Related Articles | Metrics

The rapid expansion of China's highway network has exacerbated the problems of transportation energy consumption and carbon emissions. It is therefore imperative to achieve efficient local consumption of distributed energy resources in highway domains through virtual power plants (VPPs). To address the "source-load mismatch" problem caused by the volatility of distributed energy output and the randomness of electric vehicle (EV) charging demand, it is of great significance to develop an optimal operational strategy for highway-domain VPPs that account for source-load uncertainty, with the goal of reducing the VPPs' operating costs. To tackle the uncertainty in distributed energy output and EV charging demand, this paper firstly employs the Markov Chain Monte Carlo (MCMC) method to generate a multi-timescale scenario set. It then proposes a hybrid framework combining MCMC and the probability distance-based reduction method for scenario generation and reduction. Subsequently, an optimization model for highway-domain VPPs is established with the objective of minimizing its operating costs, and a smart scheduling algorithm based on constrained proximal policy optimization (C-PPO) is proposed to solve this optimization model. Case study results show that the proposed optimization scheme reduces the operating cost of the highway-domain VPPs, validating the favorable economic performance of the proposed solution.

A long-term power generation investment decision-making method considering carbon emission impacts

WENG Geping, CUI Linning, JIANG Han, REN Jiaorong, HAN Yinfeng, CHEN Hanwen

2026, 59(4): 94-104. DOI: 10.11930/j.issn.1004-9649.202401044

Asbtract ( )

PDF (2467KB) ( )

Figures and Tables | References | Related Articles | Metrics

To meet the demand for low-carbon transition of new power systems, this paper develops a long-term decision-making analysis model for power generation investment. First, the model considers the strategic decision-making of conventional price-leading generation, as well as the perfectly competitive decision-making of newly market-entering renewable generation as price-takers, to satisfy the long-term carbon emission reduction constraints. Second, a centralized quadratic programming approach based on the Nash-Gounod game is used to analyze the day-ahead electricity market prices. Then, in the proposed model, investment decisions (once a year) and production decisions (in each time period within a year) are made simultaneously, and an open-loop Gounod game model is built accordingly. Finally, the performance of the proposed method is evaluated in a simulated electricity market, where the game is tested over a period of up to 20 years, and the price and investment decisions under a series of scenarios, as well as the impacts of the number of market participants, emission limits, or emission policies, are analyzed. The results show that the application of the proposed method can achieve deep system decarbonization, which verifies its effectiveness.

Flexible combined grounding modes of large hydro-generators

WU Xiuhan, LI Chen, WEI Yang, SUN Yue, LI Guangyao, LUO Jinsong, GAO Ziwei, SHEN Hongwan, GUI Lin

2026, 59(4): 105-113. DOI: 10.11930/j.issn.1004-9649.202510035

Asbtract ( )

PDF (2398KB) ( )

Figures and Tables | References | Related Articles | Metrics

Single-phase grounding fault is the most common fault causing insulation damage to generator stator windings. The grounding transformer high-resistance grounding mode widely used in China cannot address the problem of excessive grounding fault current induced by the increase in generator-to-ground capacitive current, while the combined grounding mode has the limitation of poor parameter adaptability in its application to large hydropower stations with different unit models. This paper proposes a flexible combined grounding mode, and takes the generators of five models in a hydropower station as the research object to optimize the design of their grounding devices, which verifies the feasibility of the flexible combined grounding device. This grounding mode can not only effectively limit key indicators such as single-phase grounding fault current, but also make up the deficiency in the universal adaptabilityof grounding device parameters, significantly reduce the costs and pressures of equipment installation and spare parts purchase and storage, and is of great significance to ensuring the operational safety of generators in large hydropower stations.

Assessment of China's power sector green and low-carbon transformation efficiency from the perspective of time lag effect: based on a three-stage super-efficiency SBM-Malmquist model considering output lag

LI Lulu, HE Jiao

2026, 59(4): 114-126. DOI: 10.11930/j.issn.1004-9649.202508025

Asbtract ( )

PDF (1062KB) ( )

Figures and Tables | References | Related Articles | Metrics

The green and low-carbon transformation of China's power sector serves as a crucial underpinning for advancing Chinese modernization. Taking 30 provinces, autonomous regions and municipalities directly under the Central Government of China from 2015 to 2023 as the research sample, this paper employs a three-stage super-efficiency SBM-Malmquist index model that accounts for output lags to measure the efficiency of the green and low-carbon transformation of the power sector. The findings reveal that, based on the revised analysis of power output considering the time lag effect, the lag periods of renewable energy power consumption and the proportion of electricity in terminal energy consumption are 1 period and 3 periods respectively. Energy pricing mechanism refinement and urbanization progression have exerted a significant positive driving effect on the green and low-carbon transformation of the electric power sector, with their beneficial impacts substantially outweighing the negative inhibitory effects stemming from economic development stages and industrial structure. The external factors leads to an overestimation of the average comprehensive efficiency of green and low-carbon transformation in the power sector. Additionally, the recalibrated actual efficiency level demonstrates a spatial distribution pattern of West ＞ East ＞ Central, with notable inter-provincial differences. The total factor productivity (TFP) of the power sector's green and low-carbon transformation exhibits a fluctuating trend, and the pulling effect of technological advancements has mitigated the negative constraints caused by low technical efficiency.

Control strategy for VSC-MTDC grid connection of offshore wind farms with high penetration of renewable energy integration

ZHANG Yajun, YANG Xingang, BAO Wei, DU Zhaoxin, GAN Huichen, XIAO Huangqing

2026, 59(4): 127-139. DOI: 10.11930/j.issn.1004-9649.202509034

Asbtract ( )

PDF (1424KB) ( )

Figures and Tables | References | Related Articles | Metrics

To address the challenges of limited DC voltage dynamic performance and dynamic power deviations in grid connection of offshore wind farms via multi-terminal VSC-MTDC systems under high-penetration renewable energy integration scenarios, this paper proposes an abnormal-condition-aware master-slave coordinated hierarchical control strategy to enhance system reliability and stability. First, a coordinated control method for the primary and auxiliary converter stations is developed by integrating voltage margin and voltage droop control schemes, based on the dynamic characteristics of converter stations. Second, a dynamic hierarchical control approach is proposed, incorporating DC power fluctuation and converter station regulation capability, which can maintain the balanced active power distribution under abnormal disturbances. Third, a dynamic participation strategy and parameter tuning methodology for converter stations are established to achieve adaptive adjustment of the number of operational converter under various operating conditions, effectively suppressing the dynamic power fluctuations of converter stations and enhancing the DC voltage dynamic regulation characteristics. Finally, the effectiveness of the proposed control strategy under abnormal operating conditions is validated through a five-terminal offshore wind VSC-MTDC simulation system built on the PSCAD/EMTDC platform.

Equilibrium charging strategy for electric vehicles in residential areas based on distributed gradient projection

CAO Wangzhang, LU Yonghao, JIN Fengyuan, YANG Hao, JIN Xin, WANG Zongyi, ZHAO Boyang

2026, 59(4): 140-149. DOI: 10.11930/j.issn.1004-9649.202512027

Asbtract ( )

PDF (1169KB) ( )

Figures and Tables | References | Related Articles | Metrics

Residential charging load management is a key means to mitigate the adverse impacts of large-scale electric vehicle (EV) integration on the power grid. However, centralized management compromises users' privacy, and the autonomous response of users under time-of-use electricity prices tends to induce new load peaks. Firstly, a dynamic electricity pricing mechanism is introduced in residential communities, and an aggregative game model is constructed to guide users to spontaneously adjust their charging behaviors and avoid peak-valley reversal. Then, a distributed gradient projection algorithm is proposed to rapidly achieve the Nash equilibrium of the aggregate game, which fully protects the privacy of vehicle owners. Finally, simulation analysis is carried out based on the electricity consumption data of a residential community in southern China. The results show that the proposed method can effectively smooth the peak load caused by EV charging, and the effect is enhanced with the increase in the number of EVs. Compared with the time-of-use pricing mechanism, it can effectively avoid the emergence of new load peaks and meet the requirements of charging load management under the growing penetration of electric vehicles.

Electricity capacity market mechanisms in foreign countries and their implications for China

PANG Yuexia, ZHANG Shuyue, ZHOU Yaze, DAI Wenyi, LI Jialin, MA Yuan, LYU Yuan

2026, 59(4): 150-164. DOI: 10.11930/j.issn.1004-9649.202509021

Asbtract ( )

PDF (942KB) ( )

Figures and Tables | References | Related Articles | Metrics

With the increasing share of renewable energy integration into the grid, the utilization hours of traditional fossil fuel power units have declined. The inadequate fixed cost recovery mechanism has hindered their transformation into regulating or backup units, leading existing thermal power units to be more inclined to exit the market and further exacerbating capacity shortages in the power system during peak load periods. Against this backdrop, this paper selects three representative capacity markets—Ireland, Great Britain, and the PJM Interconnection in the United States—as case studies. It systematically examines the operation of their capacity markets and the mechanisms for allocating capacity costs, with a focus on analyzing the practical outcomes and challenges faced by each market. Furthermore, from the perspectives of institutional objectives, market structure, and the logic of balancing resource allocation, this study extracts common patterns and differentiated approaches across the three capacity markets, summarizing their adaptability under high renewable energy penetration. Finally, in light of the actual conditions of China's electricity market, this paper puts forward implications and recommendations from foreign capacity market practices for the relevant development of China in terms of market design, cost allocation, and market coordination, so as to provide a reference for advancing China's energy transition.

Table of Content