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- Abstract：Since the goal of "having CO2 emissions peak before 2030 and achieving carbon neutrality before 2060" was put forward, the ninth meeting of the Central Finance and Economics Committee has further proposed the basic ideas and main measures to achieve this goal, especially implementing renewable energy substitution actions, deepening the reform of the power system and building new power systems with new energy as the main power source. These measures will inevitably lead to major adjustments in the generation mix. On the other hand, various negative events in the electricity markets around the world occurred one after another in recent years, which has attracted widespread attention from all the world. The reasons for these events are highly related to the defects of generation mix and electricity market design. On basis of the introduction and cause analysis of typical accidents in the global electricity markets in recent years, this paper focused on the safety risks and diversification of electricity value caused by the changes in generation mix, analyzed the challenges faced by the electricity market designs, and proposed preliminary solutions. Electricity pricing and electricity market design should be based on the law of electricity value. In the context of large-scale integration of renewable energy, electricity not only has capacity value and energy value in traditional electricity markets, but also has various other values such as flexibility, security and resilience, which makes the problem more complicated. This paper carried out a preliminary analysis of these issues.Keywords：electricity market;law of value;generation mix;flexibility46|11|0<HTML><DownloadPDF> <Meta-XML>Updated：2025-07-04
- Abstract：On February 15 and 16, 2021, a winter storm swept across Texas, causing a destroying rotating blackout. The blackout has affected about 4.5 million residents, and the price on spot power market soared sharply, resulting in a great damage on the economic and social order. On February 24, the Electric Reliability Council of Texas (ERCOT) released its first report of the blackout incident. Based on the report, a brief overview of Texas power grid and the development process of the whole blackout event were introduced firstly. Then, this paper analyzed the causes in detail. Finally, some suggestions on how to construct China power gird with the goal of achieving "carbon peak, carbon neutral" were proposed.Keywords：power grid;Texas' rotating blackout;new energy power generation;incident analysis;power market152|6|0<HTML><DownloadPDF> <Meta-XML>Updated：2025-07-04
- Abstract：In China, the power system has been developed toward the direction of high penetration of renewable energy plus high penetration of power electronic equipment (double high), which results in major challenges in the structure of power and grid. Generator excitation system control technologies have great significance in keeping the safe and stable operation of power systems, and the improvement of its performance is one of the most economical and effective means to deal with the above challenges. This paper reviewed the development history of excitation system control technology and pointed out the technical challenges brought by "double high" power system. Furthermore, the key techniques for mining and improving the network-related performance of excitation system were proposed, including performance test in laboratory, field test and evaluation, refine simulation modeling of excitation system control, additional stability control, auxiliary control strategy optimization, etc. Finally, the research focus and development direction of excitation system control technology in the future were prospected.Keywords：excitation system;automatic voltage regulator;synchronous generator;power electronic dominated source;source-grid coordination75|4|0<HTML><DownloadPDF> <Meta-XML>Updated：2025-07-04
- Abstract：With the gradual deepening reform of the power system and the gradual improvement of the power market trading mechanism, it provides a new opportunity for the development of energy storage technology, and the energy storage technology presents a good trend of diversified development. The establishment of an auxiliary service compensation mechanism has accelerated the penetration of energy storage systems in the auxiliary service field. The auxiliary service market has become one of the main application directions of energy storage technology. The participation mechanism was investigated, the status of energy storage technology in auxiliary services were researched, and the application scenarios and main research directions of energy storage technology in power system auxiliary services were summarized. At the same time, combined with the construction of the ubiquitous power internet of things, the business model of energy storage participating in auxiliary services in China was discussed.Keywords：ubiquitous power internet of things;energy storage;auxiliary service;business model42|4|0<HTML><DownloadPDF> <Meta-XML>Updated：2025-07-04
- Abstract：With the increasing integration scale of electric vehicles, their impact on the operation and control of the power system cannot be ignored. As a controllable load, the charging and discharging control of electric vehicles can effectively weaken the adverse effects brought by the charging load, and can also play a role of peak-shaving and valley-filling, and promote the consumption of new energy, which will become an important means of power system operation control. The factors to be considered in charging load modeling were firstly given, and the methods for establishing electric vehicle load forecasting models were summarized. Then, the feasible methods of electric vehicle participating in power grid dispatching were reviewed, and the characteristics of different methods were revealed. At the same time, in order to promote the willingness of electric vehicles to participate in dispatching, the architecture and methods of using blockchain to complete electric vehicle power trading were introduced. Finally, the unsolved problems and possible research directions were discussed.Keywords：electric vehicle;charging load;intelligent control;blockchain;power system98|5|0<HTML><DownloadPDF> <Meta-XML>Updated：2025-07-04
- Abstract：In order to reduce the fluctuation of DC microgrid bus voltage, a bidirectional Buck-Boost converter control strategy based on active disturbance rejection control (ADRC) was proposed. The control method of DC bus voltage outer loop and DC converter inductance current inner loop was used to realize the bidirectional flow of energy between the DC microgrid and the energy storage system. It was further proposed to observe the total output disturbance based on the extended state observer (ESO), including the change of load current and bus voltage. Before the load disturbance current affects the final output of the DC bus voltage of the system, the disturbance information was actively extract from the input signal inductance current or the output signal bus voltage of the controlled object in the outer loop. Then, the control signal was used to eliminate the disturbance information as soon as possible, which reduces the influence on the controlled quantity, and further suppresses the voltage fluctuation and impact of the transient DC bus. Therefore, the bus voltage can quickly recover to the normal working state when the bus voltage fluctuates. The correctness of the proposed control strategy was verified by simulation. The simulation results show that the energy storage system can achieve bidirectional energy transfer through the control strategy. In addition, when the bus generates power fluctuations and current shocks, the energy storage system can stabilize the DC bus voltage and improve the system the reliability.Keywords：DC microgrid;bidirectional Buck-Boost converter;bus voltage fluctuation;active disturbance rejection controller (ADRC)86|8|0<HTML><DownloadPDF> <Meta-XML>Updated：2025-07-04
- Abstract：A large number of photovoltaic grid-connection brings many harmonic resonance problems to the power grid. A joint model including photovoltaic converter and grid equivalent impedance was established for the photovoltaic converter resonance problem. The s-domain model of photovoltaic converter impedance and grid impedance was derived. The photovoltaic output current contains not only the voltage frequency component but also the resonant component of the photovoltaic impedance by using the inverse Laplace transform. The stochastic subspace method was used to analyze the modal components of photovoltaic grid-connection points and currents. The impedance modes of photovoltaic converters were extracted according to the difference between the two modes. Finally, the effectiveness of the proposed method was verified by simulation and experimental data analysis.Keywords：photovoltaic;converter;equivalent impedance of power grid;resonance;stochastic subspace;mode38|5|0<HTML><DownloadPDF> <Meta-XML>Updated：2025-07-04
Energy Internet
- Abstract：As a secondary energy, hydrogen energy will play an important role in the future energy system dominated by renewable energy because of its green, flexible and wide-ranging characteristics. The core of large-scale development of hydrogen energy industry is to realize low-cost and efficient raw material source, storage and transportation. Therefore, a review was made on the key technologies of how to truly realize the clean and efficient utilization of hydrogen energy in the aspects of hydrogen production from renewable energy electrolyzed water and hydrogen storage and transportation. The ideas and progress were summarized in the development of hydrogen energy in Europe and Japan as the leading countries for hydrogen energy utilization, and also the cost factors of hydrogen energy were discussed. The development trend of hydrogen energy in China was analyzed, and the development prospect of China's hydrogen energy industry in the future was also put forward, the suggestions were as follows: establishing a sound legal and policy system; paying attention to the development of hydrogen supply and storage and transportation; actively exploring and developing various ways of hydrogen energy utilization.Keywords：carbon neutrality;hydrogen energy;renewable energy;water electrolysis;hydrogen storage and transportation;hydrogen-natural gas mixtures231|20|0<HTML><DownloadPDF> <Meta-XML>Updated：2025-07-04
- Abstract：In view of the thermal management of power batteries, the new liquid-cooling structure of 18650 cylindrical lithium ion battery array and its cooling effect were studied. An immersion cooling method combined with a checkerboard topology shunt structure was proposed. And by combining the shape and array arrangement of the lithium ion battery, a simple and reasonable immersion cooling topology based on the battery array was formed. Under this new cooling structure, the single model and module model of the battery array were established. Through the numerical simulation, the temperature distribution of the single and module models at every moment was analyzed, and the feasibility of replacing the module model with the single one was verified. On the basis of ensuring the calculation accuracy of the single model, numerical simulations on the layout of the inlet and outlet of the cooling channel were carried out. The results show that the same-side arrangement and the different-side one are almost the same in the pressure drop, but the same-side arrangement is superior to the different-side arrangement in terms of cooling effect. Moreover, with the increase of the heat generation of the battery and the extension of the heating time, the advantages of the arrangement of the inlets and outlets on the same side are more obvious.Keywords：lithium ion battery;thermal management;manifold;immersion cooling;numerical simulation33|4|0<HTML><DownloadPDF> <Meta-XML>Updated：2025-07-04
- Abstract：Based on the finite volume method in computational fluid dynamics, the performance of the trough solar thermal power collector with Al2O3/Syltherm800 oil nanofluid as heat transfer fluid was studied. A three-dimension model of the vacuum collector was established, optical simulation and heat transfer numerical simulation were carried out and verified by experiments. Under the condition of non-uniform heat flux distribution, the influence of inlet temperature and inlet velocity on the heat transfer performance of the trough collector with nanofluid was studied. The simulation results show that the heat transfer performance and heat efficiency of the trough collector are improved with the increase of Al2O3 volume fraction. The heat transfer performance of the collector is greatly influenced by the inlet temperature and the inlet velocity. With the increase of inlet temperature and the decrease of inlet velocity, the influence of the nanofluid on the heat transfer performance increases gradually.Keywords：solar thermal power generation;trough collector;nanofluid;heat transfer performance43|4|0<HTML><DownloadPDF> <Meta-XML>Updated：2025-07-04
- Abstract：As a heat storage method with high heat storage density, long storage time and long transportation distance, the chemical heat storage has been widely studied in recent years. This article firstly summarized the basic principles and research progress of several existing solid-gas two-phase chemical heat storage reaction systems, mainly involving the metal hydroxide reaction, metal oxide reaction, carbonate reaction, and hydration salt reaction. Then, according to the moving state of solid phase reactant in the reactor, the reactor was divided into three types: the fixed bed reactor, fluidized bed reactor and moving bed reactor. Moreover, their research progress was summarized respectively. Finally, based on the current deficiencies in the research of chemical heat storage, the future development trend of chemical heat storage was analyzed. At present, the storage still needs further research, and there are still technical difficulties in strengthening and matching the chemical reaction rate and heat transfer. The cyclic stability of chemical heat storage under long-term operation condition still needs to be further explored.Keywords：solar thermal power generation;thermochemical heat storage;heat storage material;reactor29|4|0<HTML><DownloadPDF> <Meta-XML>Updated：2025-07-04
New and Renewable Energy
- Abstract：During the operation of a power plant, there is a periodic phenomenon of mist eliminator resistance rising and scaling, which results in the partial collapse of the mist eliminator. In order to solve this problem, the gas-liquid two-phase flow field in the desulfurization tower was simulated by numerical simulation method, and the condition of flue gas carrying spray droplets at the bottom of the mist eliminator was further studied, as affected by the varying heights (2.0-3.5m) from the top spray layer center to the bottom and the different misting drop sizes (1500-2500μm) of the particular nozzles. The results show that with the increase of the distance from the mist eliminator to the spray layer, the mass concentration of spray drops decreases, and the flow field inside the desulphurization tower becomes more uniform. The quantitative data were obtained by numerical simulation, which can provide a diagnostic thought and optimization basis for domestic coal-fired power plants with similar phenomena such as mist eliminator blocking and collapsing.Keywords：desulphurization tower;flow field simulation;mist eliminator;spray layer33|5|0<HTML><DownloadPDF> <Meta-XML>Updated：2025-07-04
- Abstract：To optimize the gasification performance of Shell gasifier, the balance model of Shell entrained-flow pulverized coal gasification process was established by using Aspen Plus software. Four modules were mainly investigated, including pyrolysis, combustion, gasification, cold gas chilling and sensible heat recovery of waste heat boiler. The impacts of oxygen/coal ratio and steam/coal ratio on the gasification performance of Shell gasifier were investigated. The results show that with the increase of oxygen/coal ratio, the concentration of H2 and CH4 decreases, the concentration of CO2 increases slowly and then increases rapidly. The concentration of CO and cold gas efficiency increase first and then decrease. With the increase of steam/coal ratio, the concentration of H2 and CO2 increases, the concentration of CO and CH4 decreases, the efficiency of cold gas increases rapidly and then decreases slowly. The optimal ratio of oxygen/coal and steam/coal of Shenfu coal is 0.86 and 0.05 respectively.Keywords：coalgasification;Shell gasifier;entrained-flow bed;sensible heat recovery;oxygen/coal ratio;steam/coal ratio46|5|0<HTML><DownloadPDF> <Meta-XML>Updated：2025-07-04
- Abstract：Supercritical CO2 cycle has a high cold end temperature. Optimizing the cold end temperature plays an important role in improving the cycle efficiency. In order to obtain the best annual average efficiency, it is necessary to introduce artificial refrigeration to make the supercritical CO2 cycle run at a more optimized cold end temperature. For the supercritical CO2 recompression cycle with parameters of 550℃/20MPa, the annual average cycle efficiency under different cold end temperature of 5 to 35℃, with the combination of natural cooling and artificial refrigeration was analyzed by thermodynamic method, and the feasibility and economic analysis of the cold end temperature optimization method were studied as well. The annual average efficiency of the unit can be improved by choosing the optimal cold end temperature and combining natural cooling with artificial refrigeration. For northern China, the cold end temperature optimization method has better feasibility. The artificial refrigeration increases the investment of unit equipment, but the improvement of operation efficiency brings more power generation revenue and moreover increases the net income of the unit during its life cycle.Keywords：supercritical CO2 cycle;cold end optimization;cycle efficiency;economy24|5|0<HTML><DownloadPDF> <Meta-XML>Updated：2025-07-04
- Abstract：Through the coal quality analysis and comparison between semi-coke powder and design anthracite, the systematic analysis was taken to research the feasibility of semi-coke blending on a 600MW anthracite "W" flame boiler. The results show that it is technically feasible to blend semi-coke in this power plant. The limit of blending semi-coke is up to 3 coal mills controlled-by the load capacity. Considering the extremely strong abrasion characteristics of semi-coke, anti-wear reform is necessary to carry out on related equipment and components such as coal mills, pulverized coal separators, pulverized coal pipelines, burners and other equipment and components before blending, the perform subsequent operation and maintenance are very important either. The thermal efficiency of the boiler will not be reduced by blending of semi-coke, and due to the substantial reduction of the comprehensive dust content and sulfur content of the fuel, the blending will bring great environmental benefits and economic benefits. When the difference between semi-coke and coal is less than 220 yuan/ton, the blending semi-coke has profit, and the smaller the difference, the greater the profit.Keywords：semi-coke;anthracite;"W"flame boiler;blending30|10|0<HTML><DownloadPDF> <Meta-XML>Updated：2025-07-04
Research on the Method of Depth Peaking at Full Load of Supercritical Circulating Fluidized Bed Unit
Abstract：With the expansion of installed capacity of new energy power generation, the thermal power market has been severely squeezed. To meet the needs of grid flexibility, thermal power plants are required to undertake the task of deep peak shaving. Circulating fluidized bed units can be used without shutdown. It takes a supercritical 350MW circulating fluidized bed unit in a power plant in Shanxi Province as the research object. Two kinds of deep peak shaving methods of supercritical circulating fluidized bed unit's typical steam-water systems were analyzed. Some problems that might be encountered during operation were analyzed. Corresponding prevention and control measures were provided. Finally, the analysis shows that the supercritical circulating fluidized bed unit can use two typical steam-water systems to achieve full load deep peak shaving. The investment of adding boiler water circulating pump system is large, and the operation is complex. The investment of adding water storage tank to deaerator pipeline is small, and the operation is simple. However, when the boiler water circulating pump system is added to participate in full load deep peak shaving, the stability of each system is better.Keywords：supercritical circulating fluidized bed unit;depth peaking;separator;water storage tank;deaerator38|4|0<HTML><DownloadPDF> <Meta-XML>Updated：2025-07-04- Abstract：The low-pressure economizer installed in the tail flue of coal burning boiler can reduce temperature of boiler discharge smoke, thus saving energy and reducing consumption. There are many factors affecting the energy saving effect of low-pressure economizer, which makes the performance evaluation and analysis uncertain. Performance evaluation test of energy saving effect of low-pressure economizer was carried out on a 220 MW unit. Under 4 electrical loads, a total of 24 conditions were tested with different operating modes and operating parameters of the low-pressure economizer. Using thermal performance test method, and the fitted curve of steam turbine main steam flow with energy saving effect, the energy saving effect of low-pressure economizer had been calculated. Under main steam flow corresponding to 4 electrical loads, the energy saving effect was 116.8, 96.7, 108.2 and 99.1kJ/(kW·h), respectively. By changing operating parameters of the low-pressure economizer, variation range of energy saving effect under different electric load conditions was obtained. According to heat balance equation and heat transfer equation, design heat transfer amount and actual heat exchange amount of the low-pressure economizer were calculated. The impact of operating parameters of low-pressure economizer on energy saving was calculated by using the equivalent enthalpy drop method. Under 220MW test condition, the test value of energy saving effect was 116.8kJ/(kW·h), and was 190.97kJ/(kW·h) after parameter being modified.Keywords：turbine unit;low-pressure economizer;performance test;energy saving effect;energy saving evaluation30|5|0<HTML><DownloadPDF> <Meta-XML>Updated：2025-07-04
Power Generation and Enviromental Protection
