Table of Content

28 March 2024, Volume 57 Issue 3

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Special Contribution

Analysis of Power System Paradigm Shift under Energy Revolution

Qinyong ZHOU, Genzhao LI, Xiaohui QIN, Haobo SHI, Wenjing CHEN, Haoyue GONG

2024, 57(3):  1-11.  DOI: 10.11930/j.issn.1004-9649.202311115

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The essence of scientific revolution is the paradigm shift, which can be applied to the energy revolution. Under the goals of "carbon peak and carbon neutralization", the essence of energy revolution is the shift of development paradigm, that is, the transformation and upgrading paradigm from low energy density to high energy density, and the energy utilization paradigm shift from low environmental protection to high environment protection. Under the paradigm shift of energy development, the traditional power system is gradually appearing a power system with high proportion of new energy, which is facing risks such as decrease in economy, stability and adequacy, and limited development space. However, the original development paradigm, namely intensive power source development, high-voltage power grid and synchronous grid expansion cannot reduce the risks. The original paradigm will fail and the rules will gradually slack. Driven by such development factors as distributed power generation, microgrid and large-capacity energy storage, the transformation of technological innovation mode will lead to the establishment of a new development paradigm. The power system established under the new development paradigm is the new power system.

New Type Distribution Network Driven by Digital Technology

Experiment Platform of Edge Computing for Digital Distribution Networks

Mingjiang WEI, Peng LI, Hao YU, Haoran JI, Guanyu SONG, Wei XI

2024, 57(3):  12-19.  DOI: 10.11930/j.issn.1004-9649.202310041

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This paper focuses on the construction of an experimental platform for edge computing, and first builds the three-layer experimental platform architecture. Then, the functions of each physical part of the experimental platform and the communication environment are designed. Subsequently, targeting the core technical problems of software and hardware of edge computing, a specific and feasible simulation solution is proposed around the operation and control needs of distribution networks. Finally, taking edge-side local voltage control as an example, the operation scenarios are constructed based on various aspects of the experimental platform to illustrate the functional feasibility and reliability of the platform.

Optimal Operation Strategy of Data Center Aggregators for Demand Response Considering Temporal and Spatial Load Shift

Rundong GAN, Yujiang LONG, Jie TANG, Xi HE, Hongxuan LUO, Xin JIN

2024, 57(3):  20-26.  DOI: 10.11930/j.issn.1004-9649.202401079

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This paper uses aggregation technology to construct data center aggregators to participate in system demand response, and then proposes an optimal operation strategy of data center aggregators considering the demand response of load temporal and spatial shifts. First, according to the physical characteristics of the data center, the load time-space transfer demand response model is established. Then, the optimal operation model of data center aggregators was established with the goal of minimizing the operation cost of data center and maximizing the profit of data center aggregators. Finally, by using Karush-Kuhn-Tucker condition and large M method, the two-layer model is transformed into a single-layer mixed integer linear programming model. The simulation results show that the proposed optimal operation strategy can effectively improve the flexibility of the workload in the data center and promote the improvement of the operation economy of the data center.

Economic and Technological Optimization of Hybrid Rural Microgrid with Wind, PV, Biogas, Storage, AC, and DC

Hu TAN, Xiaoliang WANG, Tingting XU, Ke ZHAO, Lianchao SU, Wenyu ZHANG, Zheng XIN

2024, 57(3):  27-33.  DOI: 10.11930/j.issn.1004-9649.202401017

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This article establishes a microgrid AC/DC hybrid system model based on wind, solar, and biogas storage. Under the conditions of meeting the reliability of system power supply, multi-objective optimization is carried out with the highest utilization rate of new energy, the best economic cost, and the smallest carbon emissions. The optimal economic and technological configuration of the microgrid energy system under certain climatic conditions is studied.

Accurate Estimation Method of Customer Baseline Load for Continuous Participation of Industrial Users in Demand Response

Heng LIANG, Geng HUANG, Bin HOU, Xi YANG, Xiaohu LUO, Da ZHANG

2024, 57(3):  34-42.  DOI: 10.11930/j.issn.1004-9649.202312036

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A computational method combining K-means cluster analysis with long- and short-term memory neural network algorithm is proposed, and transfer learning is carried out by industrial homogeneous group information to further optimize the estimation effect. Accurate estimation of industrial customer power baseline load under long-term continuous response is realized, and the accuracy of the demand response effect evaluation of industrial customers is improved. The effectiveness of the method is verified by the load data of industrial customers participating in demand response practice collected by the city-level virtual power plant platform.

Coordinated Optimization of Active and Reactive Power of Active Distribution Network Based on Safety Reinforcement Learning

Hao JIAO, Yanyan YIN, Chen WU, Jian LIU, Chunlei XU, Xian XU, Guoqiang SUN

2024, 57(3):  43-50.  DOI: 10.11930/j.issn.1004-9649.202311065

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A safe reinforcement learning method based on offline strategies is proposed. Through offline training of a large amount of historical operating data of the distribution network, it gets rid of the traditional optimization method. Dependence on complete and accurate models. First, combined with the distribution network parameter information, an active and reactive power optimization model based on the constrained Markov decision process (CMDP) was established; then, a new safety reinforcement learning method was designed based on the original dual optimization method. The cost function is minimized while maximizing future discount rewards; finally, simulations are performed on power distribution system. The simulation results show that the proposed method can online generate a dispatching strategy that satisfies complex constraints and has economic benefits based on real-time observation information of the distribution network.

Reactive Power Optimization Control for Renewable Energy in Distribution Networks Considering Active Power Uncertainties

Jingzhong ZHANG, Fei MENG, Yang SUN, Huixia YU

2024, 57(3):  51-59.  DOI: 10.11930/j.issn.1004-9649.202310053

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A dual-layer robust optimization control method based on the droop principle of reactive power and voltage is proposed for renewable energy in distribution networks, considering active power uncertainties. First, in the reference-point optimization layer, the typical control quantities that affect the reactive power distribution in the power system are optimized with the objective of minimizing the overall cost over the multi-period, such as the static reactive power compensation devices, the coordinated control instructions of voltage regulating transformers, and the reactive power and port voltage reference values for renewable energy. Secondly, in the slope optimization layer, based on the column-and-constraint generation (C&CG) algorithm framework, the main problem model of slope instruction optimization and the sub-problem model of extreme scenarios set filtering are established. The results demonstrate that the proposed optimization control method can not only effectively adapt to the random fluctuations of renewable energy generation output but also maximize the utilization of reactive power capacity of grid-connected converters. It can optimize the system network losses and the operational cost of voltage regulation devices and enhance the operation reliability of power systems.

Power System

Single Terminal Transient Protection Scheme Based on Fuzzy Multi-criteria Fusion

Meiling LUO, Zixiao LI, Tao ZHENG, Xiaojun YU, Jianyun WU, Haibin XIE

2024, 57(3):  60-72.  DOI: 10.11930/j.issn.1004-9649.202306105

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The existing single-terminal transient protection schemes rely solely on single fault feature for fault identification, which leads to the poor identification reliability. This paper thus proposes a novel single-terminal transient protection scheme based on fuzzy multi-criteria fusion to achieve the complementation of the advantages of different single-terminal transient protection schemes through fuzzy multi-criteria fusion. Firstly, the characteristics and action sensitive regions of three single-terminal transient protection schemes, which are based on the ratio of high- and low-frequency transient energy, the arrival time difference of fault initial zero-mode/line-mode voltage traveling wave and the polarity relationship of initial line mode voltage traveling wave, are analyzed, and the fuzzy membership functions of corresponding criteria are constructed. Secondly, based on the advantages and disadvantages of different transient protection schemes, the above three single-terminal transient protection schemes are integrated based on fuzzy logic to achieve fault zone discrimination. Finally, based on a large number of simulation using PSCAD/EMTDC, the three transient protection schemes mentioned above and the proposed novel scheme is compared in terms of adaptability under different fault locations, different bus stray capacitance, different transition resistance and different weight coefficients, which has verified the effectiveness of the proposed novel scheme.

Centralized Control Strategy for Hybrid Microgrid Based on Layered Event Triggering

Yiming LI, Qi HE, Hailiang WANG, Hao ZHONG, Hui MA, Yuehua HUANG

2024, 57(3):  73-82.  DOI: 10.11930/j.issn.1004-9649.202305073

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A hierarchical event-triggered control strategy involving the microgrid central control (MGCC) is proposed to address the issues of strong dependence on central controllers, high communication demand, and poor disturbance regulation ability in centralized control of hybrid microgrid, which effectively reduces the redundant communication in distributed clusters and the computational burden on central controllers, and improves the reliability of strategy. The proposed strategy divides the control system into two layers. The device layer is the local control layer, which adopts the distributed collaborative control. The designed local controller can locally control and update the output status, achieving decentralized and autonomous operation of the hybrid microgrid. In addition, a microgrid control layer is established in the control layer, and an event-triggered strategy is introduced to coordinate MGCC to obtain the global information of the hybrid microgrid and issue predefined control instructions to the local controllers, achieving the flexible scheduling of "source-grid-load-storage", especially in response to grid oscillations caused by unexpected events. Finally, a hybrid microgrid model is built using the Matlab for simulation and the Stateflow module is used to realize the event-triggered strategy, It is verified that the proposed control strategy can reduce the system communication traffic by 56.4% while meeting the reliability and stability of grid connection/island mode.

Two-stage Frequency Regulation Method for Energy Storage Coordinated with Thermal Power Unit Based on Weight Coefficient Correction

Yibin WANG, Feixiong CHEN, Zhenguo SHAO, Shuling ZHANG, Weijun ZHANG, Zhicheng LI

2024, 57(3):  83-94.  DOI: 10.11930/j.issn.1004-9649.202303041

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With the large-scale uncertain renewable energy connected to the grid, the frequency characteristics of the power grid are increasingly complex. Plagued by long response times and the inability to accurately track frequency regulation commands, traditional thermal power units call for urgent improvement in the performance of its participation in frequency regulation of automatic generation control (AGC) of thermal power by use of energy storage. Therefore, firstly, the mathematical model of frequency regulation performance index is established according to frequency regulation assessment rules. Besides, considering the output characteristics of the energy storage system, combined with the improved analytic hierarchy process to correct the weight coefficient of the frequency regulation sub index, the first-stage optimization model aiming at the optimal AGC performance is constructed. On this basis, in order to reduce the limit crossing and storage depth charging & discharging cases at the state of charge (SOC), the second-stage optimization model is constructed in order to minimize the SOC deviation. The simulation verification shows that the two-stage frequency regulation method proposed in this paper can improve the frequency regulation performance and benefits of the system of energy storage coordinated with thermal power unit, while reducing the energy storage in-depth charging & discharging cases and working life loss, thus improving the sustainability of frequency regulation auxiliary service of energy storage.

Standardization Research on SF₆ Mixed Gas and Eco-Friendly Alternative Gas Equipment

Yanmiao HE, Yin HUANG, Xianglian YAN, Zhibing LI

2024, 57(3):  95-102.  DOI: 10.11930/j.issn.1004-9649.202303133

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In order to support the "dual carbon" goals, adapt to the requirements of limiting the use of SF₆ gas, and enhance the environmental friendliness of power grid equipment, research on the standardization of SF₆ mixed gas and eco-friendly alternative gas equipment is conducted. Based on the current status of eco-friendly gas equipment research and application, the technical standards of SF₆/N₂ mixed gas equipment were reviewed. A standardization framework was established covering equipment materials, operation and maintenance, test and detection, instruments and meters. For eco-friendly alternative gas C₄F₇N equipment replacing SF₆, a standardization framework was constructed, including gas performance detection technology and method, equipment operation and maintenance, test and detection, and recycling. Based on this, a standard system of SF₆ mixed gas and eco-friendly alternative gas equipment was preliminarily proposed, consisting of six sub-branches consistent with the standard system of GIS equipment in power industry, reflecting the research direction of eco-friendly gas equipment standardization.

Neural Network-based CF₄ and SF₆/CF₄ Detection in High Altitude and Extreme Cold Regions

Rukuo MA, Jie DONG, Yatian WANG, Guoxin YI, Xianghao DING, Le MA

2024, 57(3):  103-112.  DOI: 10.11930/j.issn.1004-9649.202310033

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In extreme cold regions, the need to carry multiple instruments to meet the demands for detecting varying concentration levels of CF₄ gas within SF₆ gas leads to inefficient field operations and high costs for instrument acquisition. To overcome this, an SF₆ gas CF₄ concentration detector utilizing pyroelectric detection technology was initially developed, capable of automatically switching among different ranges by selecting appropriate amplification resistances. Subsequently, two neural network models for temperature-pressure collaborative compensation, BP and PSO-BP, were introduced. Data for model predictions were supported by an effective simulated experimental platform, with results indicating the PSO-BP neural network's superiority over the BP network. The PSO-BP neural network's temperature-pressure collaborative compensation model was then embedded within the multi-range detection instrument for CF₄ gas concentration. Simulation experiments demonstrated that the instrument maintains a detection error and repeatability within ±2% and 1.6% across small and large ranges, and within ±0.5% and 0.2% for mixed ratio ranges, respectively, under varying temperatures and pressures. This technological advancement significantly enhances maintenance operations within the power grids of cold regions.

Multi-objective Collaborative Optimization Control Method of Composite Function Grid Connected Inverters Considering Variable Weight Hybrid Decision Evaluation

Fan YANG, Shuiping WEI, Yi REN, Zilong CHEN, Jian LE

2024, 57(3):  113-125.  DOI: 10.11930/j.issn.1004-9649.202310052

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Multi-functional grid connected inverter (MFGCI) has the ability to solve various power quality problems in the distribution network while fulfilling the power output task simultaneously, but this ability is often limited by its compensation capacity that can be used for power quality management. Based on the control structure of MFGCI, this paper provides the current compensation order and grid connection tracking current order without phase-locked loop(PLL). A multi-objective collaborative optimization method based on variable weight mixed decision evaluation is proposed to better adapt to the fluctuations in power quality indicators caused by nonlinear load integration and uncertainty of new energy. A multi-objective function is constructed to achieve the best power quality compensation effect and the minimum required compensation capacity. Based on update mechanism from the multi-objective artificial hummingbird algorithm (MOAHA), an optimization algorithm is employed to solve the optimal capacity allocation coefficient for compensating various power quality problems. The correctness and effectiveness of the proposed method are verified through simulations in various scenarios.

Impacts of Insulation Barrier on Air Gap Discharge Spectral Characteristics and the Charge Evolution Mechanism

Yanhui WEI, Liankang ZHANG, Fengyuan XU, Yanze HAN, Yuanwei ZHU, Guochang LI

2024, 57(3):  126-134.  DOI: 10.11930/j.issn.1004-9649.202310071

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Investigating the discharge patterns and detection methodologies for rod-to-plate gap discharges within spatially constrained power equipment, such as switchgear, is critically important. The study delved into the distribution of discharge spectra within a "rod electrode-insulating barrier-ground electrode" system across various barrier materials and positions. Utilizing a surface potentiometer, the study analyzed the distribution characteristics of trap energy levels on the insulating barrier's surface post-discharge. A simulation model of an insulating system of identical dimensions was established to examine the influence of introducing an insulating barrier on electron density and electric field distribution, thereby elucidating the discharge mechanism. The research findings indicate that incorporating an insulating barrier significantly elevates the system's breakdown voltage, with a potential increase of up to 1.6 times. Discharge spectral characteristics vary with the barrier material; while epoxy resin barriers exhibit higher overall discharge spectral intensities, polyester boards show slightly greater intensities at wavelengths of 309.25 nm and 589.05 nm. Moreover, the spacing between electrodes markedly affects the discharge spectrum, with a clear presence of residual charge on the barrier surfaces. Epoxy resin demonstrates higher charge accumulation compared to polyester, impacting breakdown voltage more substantially. Simulation results further reveal that alterations in barrier materials not only affect the amplitude of the breakdown voltage but also modify the physical motion of micro-particles, consequently altering the discharge spectrum. This research provides theoretical and practical guidance for spectral discharge monitoring and insulation condition assessment within electrical equipment.

Application of Message Compliance Detection and Intrusion Blocking Technology in Remote Operation and Maintenance System of Relay Protection

Jiang YU, Honghui GAO, Zebing SHI, Weiwei JIANG, Fangying WU, Qingcai ZHAN, Rui ZHANG

2024, 57(3):  135-143, 151.  DOI: 10.11930/j.issn.1004-9649.202302015

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In the remote operation and maintenance of relay protection, there are network intrusion risks at every stage of data transmission. Existing security measures have not effectively addressed business layer risks, and some issues such as delayed risk response still exist. Therefore, a message compliance detection method and intrusion blocking technology have been proposed. By analyzing the objects, formats, business logic, and behavioral patterns of messages, a library of message compliance rules and a strategy for blocking non-compliant messages are established. Finally, modules for blocking non-compliant messages and an "emergency blocking" control module are designed and developed. The simulation testing results indicate that the proposed technology consistently blocks abnormal messages of different types as expected. This technology can effectively prevent the illegal intrusion attacks, thereby enhancing the security and stability of the remote operation and maintenance for relay protection.

New Energy

A Grid-based Numerical Weather Prediction Method for Multi-output Prediction of Regional Photovoltaic Power

Wenhua ZHAN, Jianfeng CHE, Bo WANG, Yu DING

2024, 57(3):  144-151.  DOI: 10.11930/j.issn.1004-9649.202305029

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The short-term power prediction of regional photovoltaic (PV) is one of the important bases for the provincial and above power grid control center to make power generation plans and improve the photovoltaic consumption. In essence, short-term photovoltaic power prediction is to build a mapping model between numerical weather prediction and actual power. In order to improve the prediction accuracy, the grid-based numerical weather prediction and residual network were used in this paper to establish a multi-output prediction model of regional photovoltaic, and fully explore the correlation between the distribution of meteorological resources and the power of each photovoltaic power station in the regional photovoltaic space, thus identifying the grid-based numerical weather prediction as input and the power of each photovoltaic power station in the region as output. The simulation was carried out by use of actual operation data. The results showed that the proposed method was superior to the existing proven methods in predicting the power and total power of each photovoltaic power station.

Capacity Allocation Method of Key Equipment in PV System Applied in Office Buildings

Lei ZHANG, Weidong XIAO, Chunbing JIANG, Yao LIU, Shaojie LI, Ji ZHANG

2024, 57(3):  152-159, 169.  DOI: 10.11930/j.issn.1004-9649.202305114

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With the goal of carbon peak and carbon neutrality, the photovoltaics, energy storage, direct current, and flexibility (PEDF) system applied in buildings is developing rapidly. The photovoltaic output in urban office buildings is generally lower than the building electricity load. In view of the two optimization objectives of improving the system load supply rate and the smoothness of the electricity curve, this paper studies the equipment capacity allocation methods of various main devices in the PEDF system. In addition, the coordinated configuration and regulation of different internal resources are analyzed, so as to give full play to the flexible capabilities of energy storage and electric vehicles, improve the overall performance of the system, and provide a reference for the subsequent development of the PEDF system in office buildings. The results show that the configuration of the PEDF system in the building can greatly improve the system's self-sufficiency rate and power smoothness and reduce the AC/DC capacity configuration. While increasing the system's flexible adjustment ability, the charging pile for electric vehicles may bring a new peak power load. The energy storage capacity of about 0.2 times the daily load can achieve more than 90% photovoltaic consumption, effectively improving the power curve stability and reducing the AC/DC capacity by 29.1%.

Performance Investigation of PEDF System Applied in Rural Areas

Chaoliang WANG, Tao XIAO, Shaojie LI, Ji ZHANG

2024, 57(3):  160-169.  DOI: 10.11930/j.issn.1004-9649.202303094

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Photovoltaics, energy storage, direct current, and flexibility (PEDF), a new building power distribution system, is an important way to "carbon peak and carbon neutralization". Amid the vigorous commitment to distributed photovoltaic pilots based on county seats, the utilization mode of photovoltaic and system capacity allocation in rural residential buildings need to be further explored. Based on the utilization mode of roof PV, this paper proposes two topologies of PEDF systems for rural residential buildings, self-priority and public PV. The system performance of different topologies with various photovoltaic and energy storage capacity configurations is compared and analyzed from technological and economical perspectives. A simulation of a distribution station composed of 18 rural households from a village in Beijing shows that the public PV system is suitable for high PV installed capacity. The load satisfaction rate can be increased by 0.3-1.9%, and the annual net income by CNY 17,000. While the self-priority PV system is suitable for low PV installed capacity. The load satisfaction rate and photovoltaic consumption rate can be increased by 1.0~3.0 percentage points and 0.6~2.7 percentage points, respectively. In the actual project, the system optimization selection can be combined with the investment operator, and the regulation and storage capacity of the flexible resources in the buildings can be fully used to improve the system stability and cost-effectiveness, which can help construct the new power system mainly fueled by renewable energy.

Stability Analysis of LCC-HVDC with PV Station at the Receiving End

Yuqing ZHOU, Dahu LI, Wei YAO, Qihang ZONG, Hongyu ZHOU, Jinyu WEN

2024, 57(3):  170-182.  DOI: 10.11930/j.issn.1004-9649.202305006

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A new type of receiving-end power system with high proportion of new energy and HVDC has been formed in Hubei. In the scenario where the PV station is located near the HVDC receiving-end converter station, the sub-synchronous oscillation characteristics of power electronic devices and the interactions between the sub-systems are still to be analyzed. This paper used eigenvalue analysis method to explore the influence of the massive infeed of PV stations. Firstly, with a small signal analysis model of HVDC with PV station established, this paper has confirmed that the infeed of PV stations has a significant influence on the system stability. The interaction characteristics between subsystems were further observed through the dominant mode, and the feasible region of photovoltaic control parameters set, with a view to lower risks of sub-synchronous oscillation in the system. Finally, this paper defined the subsystem participation degree and measured the influence of operational parameters on the sub-synchronous interaction between the systems. It is concluded that the interaction between the PV plant and the DC system is stronger in the case of low grid strength and high light intensity at the receiving end. When designing a PV plant for grid connection, a conductor with a small impedance ratio should be selected to reduce the distance of the PV grid connection line. This conclusion can provide a theoretical basis for photovoltaic grid-connected design.

Risk Assessment of Clean and Low-Carbon Energy Transformation Considering Superimposed Scenario of Multiple Factors

Yinan WANG, Jing LU, Xingtong CHEN, Hongcai DAI

2024, 57(3):  183-189.  DOI: 10.11930/j.issn.1004-9649.202309122

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At present, China's clean and low-carbon energy transformation mainly faces four risks: sustainable supply, sociality, geography, and sanctions. This article establishes a risk assessment model for clean and low-carbon energy transformation and arranges 11 superposed scenarios of risk factors according to the combinations of "superposition of two factors, three factors, and all factors". Based on the analytic hierarchy process, the probability and impact degree of various scenarios in clean and low-carbon energy transformation are studied. On this basis, power grid enterprises are suggested as backbone enterprises serving clean and low-carbon energy transformation and promoting new power system construction. It is necessary to moderately advance the construction of power grids and the development of regulatory resources, promote the construction of risk warning, policy dynamic evaluation, and key raw materials for clean and low-carbon energy transformation, as well as research and development reserve mechanisms of "bottleneck" technology, and focus on preventing the impact of dual endogenous risks and dual external risks.

Offshore Wind Farm Wake Deflection Control Based on Adaptive Wind Condition Prediction Error

Jie YAN, Jialin YANG, Hangyu WANG, Jiaoyang LU, Yongqian LIU, Lei ZHANG

2024, 57(3):  190-196.  DOI: 10.11930/j.issn.1004-9649.202303020

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Wind farm wake deflection control is an important tool to reduce the wake effect and improve the total power generation. The wind prediction is an important input to the wind farm wake deflection control, and its error has a huge impact on the actual control effect, even leading to a "decrease instead of an increase" in the overall power generation, which greatly limits the engineering application of wind farm wake deflection control technology. Therefore, this paper explores the impact of minute-level wind speed and wind direction prediction errors on the wind farm wake deflection control effect of an offshore wind farm, and proposes an offshore wind farm wake deflection control based on adaptive wind condition prediction error and a control model based on deep neural network. The results show that the total power generation of the proposed method is improved by 1.77% compared with the conventional wind farm wake deflection control method without wind prediction error adaption.

Technology and Economics

Optimization of Power Grid Business Portfolio Investment Considering Coupling Effects

Yongli WANG, Ziben MA, Yumeng QIN, Yanchao LU, Yuan LIN

2024, 57(3):  197-205.  DOI: 10.11930/j.issn.1004-9649.202301026

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Power grid business is in a critical period of transformation from traditional business to emerging business. Due to the diversity of grid business development, the interplay between businesses should be considered to accurately quantify the investment value of businesses. This paper analyzes the coupling effect between businesses, constructs an evaluation system of business coupling effects to quantify the degree of grid business coupling through Choquet fuzzy integral, constructs an evaluation system of grid business investment value suitable for the new environment of future development, and constructs an optimization model of grid business portfolio investment taking into account the coupling effects. In the case study, the portfolio investment value, covering the comprehensive energy business, energy storage business and electric vehicle business, is 2.024, ranking the highest, among which, the basic investment value of business is 1.87 and the coupling investment value is 0.154. The case study verifies the necessity to consider the grid business coupling and the applicability of the investment optimization model. The results of this study can provide a support for the grid company to make the grid business portfolio investment decision.

Economic Evaluation Method and Parameter Optimization for Third-Generation Nuclear Power in China

Juanjuan GUO, Di SHEN, Pu TONG, Kun YAN, Xiaofan ZHANG, Fang HE

2024, 57(3):  206-212, 223.  DOI: 10.11930/j.issn.1004-9649.202302059

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As the clean and low-carbon energy, the nuclear power has become more and more important in achieving the dual carbon target. "The economic evaluation guidelines of the nuclear power plant construction project" (NB/T 20048-2011) is the main basis for economic evaluation of the nuclear power construction projects, but it has not been revised since its release in 2011. At present, the profound changes of nuclear power technology, industrial policies and market environment bring about new requirements for the 2011-edition standard. This paper proposes the contents and parameters that need to be optimized and adjusted in the 2011-edition standard from four aspects of economic evaluation parameters, nuclear-related costs, electricity market reform, and maintenance cost division. Moreover, the electricity price level before and after the parameter adjustment are calculated using the financial analysis method. Finally, a sensitivity analysis is made on four parameters including economic evaluation period, load factor, the extraction proportion of retirement fund, and the amortization period of the first furnace charge. The average generation cost decreases by 5% after parameter adjustment, and the economic period and load factor have more obvious impact on decreasing generation cost.

The Regulation Mechanism of Electricity Market on Load Side Resources Based on the Economic Person Hypothesis

Zhiyuan GAO, Weijin ZHUANG, Jian GENG, Feng LI, Bike XUE, Xiaolei YANG, Keju BAI

2024, 57(3):  213-223.  DOI: 10.11930/j.issn.1004-9649.202309108

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In order to make full use of the load-side regulation capacity, it is necessary to conduct an in-depth research on the regulation mechanism of the market-oriented mechanism on the load side. Based on the different regulatory purposes and signal sources for different types of loads in the market, the market-oriented regulatory role is generally divided into two categories: electricity price regulation and interactive regulation. Based on the assumption of economic man in classical economics, the mechanisms of electricity price regulation and interactive regulation for different types of loads are studied in terms of cost, benefits, and other factors. Furthermore, the differences and connections between electricity price regulation and interactive regulation are qualitatively analyzed and quantitatively compared. Case study results show that the electricity price regulation always works as ordinary market through pursuit of surplus maximization on the load side, and the interactive regulation is a kind of market-oriented tool that market operators use on demand to pursue social welfare maximization, and the action mechanism of the two is quite different, but also interrelated.

Generation Technology

The Influence of the Air-coal Ratio on Transient Characteristics of the Ultra-supercritical Power Unit during the Load Cycling Processes

Yong ZHANG, Chaoqiang YIN, Yugang LIU, Bin ZHANG, Chunhong MO, Chaoyang WANG

2024, 57(3):  224-232.  DOI: 10.11930/j.issn.1004-9649.202302026

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In order to study the influence of the air-coal ratio on the peak regulating characteristics of a coal-fired unit during load cycling transients, a dynamic model of a double-reheat ultra-supercritical coal-fired power plant with 660MW was established. The influence of the air-coal ratio on the live and reheat steam temperatures, the flowrates of the desuperheating water and the transient energy consumption was studied. A control scheme of air - coal ratio considering the steam temperature control effect and operational efficiency under different load cycling rates was proposed. The results show that, during the load cycling transient processes, a larger air-coal ratio benefits the stabilization of the live and reheat steam temperatures, while the average coal consumption rate of power during the transient process is higher. When the load cycling rate is equal to or less than 1%/min, a smaller air-coal ratio is preferred to reduce the average coal consumption by 1.2 g/(kW·h) during the load cycling transient process. When the load cycling rate is between 2%/min and 3%/min, a higher air-coal ratio is preferred to ensure that the deviations of the live and reheat steam temperatures can be controlled within 10℃．