Objectives Under the background of the “dual carbon” strategic goal, the demand for flexible regulation resources in the power system has significantly increased after the large-scale integration of new energy generation into the grid. At present, the coal-fired power is the main flexible resource on the power side with the ability to scale up peak shaving. Since 2016, the major domestic power generation companies have implemented a certain scale of flexibility transformation of coal-fired power units. Therefore, it is necessary to summarize and analyze the problems existing in the actual operation and maintenance of the unit after flexibility transformation. Methods The technical route, investment cost and actual operation of several coal-fired power units with flexible transformation in a company were statistically analyzed. Results After the flexibility improvement and transformation of the active coal-fired power generation unit, the minimum power generation output of the advanced unit can be reduced to 18%P_e (P_e is rated load) level, the load change rate with 20%P_e~30%P_e can reach 1.8%P_e/min, and an average unit capacity investment is 101 yuan/kW. In addition, under flexible operating conditions, the coal consumption of coal-fired power units after the transformation has significantly increased. Conclusions Suggestions are put forward for the operation, maintenance and further work of coal-fired power units under flexible operating conditions. The research results provide reference and inspiration for the flexibility improvement and transformation of existing coal-fired power units.

Objectives Under the background of the “double-carbon” target, thermal power is facing great pressure to reduce emissions. Thermal power carbon footprint evaluation can directly show the greenhouse gas emissions of thermal power and help tap the potential of carbon reduction. Therefore, the research status of thermal power carbon footprint assessment was reviewed. Methods This paper introduced the main standards and methods for thermal power footprint evaluation, and summarized the thermal power footprint evaluation process. The differences in the evaluation process were reviewed and some suggestions were given. The life cycle is divided into upstream, core and downstream. According to the high concentration of carbon emissions in the core links, the carbon footprint of the construction, decommissioning and power transmission of coal-fired power plants can be ignored in some cases. Conclusions The life cycle of different types of thermal power generation is similar, but the carbon footprint of waste incineration power generation does not include the acquisition process of domestic waste. Regardless of the form of thermal power, in the absence of measured emission factors, it is recommended that the emission factors select the default values of the published standards, literature and databases at home and abroad.

Objectives The absorption and regeneration properties of different formulations of methyldiethanolamine (MDEA) mixed with different diamines were studied. Methods In the simulated flue gas environment with 12% CO₂ and 88% N₂, MDEA was used as the main agent, while ethylenediamine (EDA), 1,3-diaminopropane (DAP), N-methyl-1,3-propanediamine (MAPA), aminoethylethano-lamine (AEEA), N,N-dimethylethylenediamine (DMEDA) and 3-dimethylaminopropylamine (DMPDA) were added as activators, respectively. Under a total amine concentration of 40%, the chemical absorbent was configured with mass ratios of main agent to activator of 1∶1, 2∶1 and 3∶1, respectively. The absorption rate, regeneration rate and circulation capacity of different absorbers were determined by comparing bubble absorption and oil bath regeneration experiments. Results MDEA-EDA system has the best absorption property when the mass ratio of MDEA to EDA is 1∶1. The MDEA-DMEDA system has the best regeneration property when the mass ratio of MDEA to DMEDA is 2∶1, with a circulation capacity reaching 1.7 mol/kg. The overall properties of MDEA-AEEA system are optimized when the mass ratio of MDEA to AEEA is 1∶1, with a cycle capacity reaching 1.49 mol/kg. Conclusions The research results can provide a theoretical basis for the formulation optimization of mixed amine solutions in industry.

Objectives The effectiveness of cooling technology directly influences the performance and lifespan of gas turbine blades operating in high-temperature, and high-pressure environments. The research status of swirl cooling technology was reviewed, aiming to summarize and evaluate its application in enhancing cooling efficiency and reducing thermal stress, and systematically analyze the basic principle and performance of swirl cooling technology. Methods The review focused on the design of swirl cooling channels, the combined use of swirl and film cooling, and the impact of rotational conditions on heat transfer performance. Results The swirl cooling technology significantly improves blade cooling efficiency and reduces thermal stress concentration. Specifically, reasonable design of swirl cooling channel can achieve uniform distribution of cooling fluid, enhance the cooling effect and prolong the service life of the blade. Conclusions The application of swirl cooling technology in gas turbine blade cooling has broad prospects. Future research should continue to explore the optimized design of swirl cooling technology and its performance under various operating conditions. Additionally, the combination with advanced manufacturing technologies, such as additive manufacturing, can further enhance the design complexity and cooling efficiency of swirl cooling channels, providing reliable support for the efficient and stable operation of gas turbines.

Objectives The accurate measurement of CO₂ emission is of great significance for carbon reduction and the operation of carbon market. Continuous monitoring technology is an important means of measuring carbon emissions from flue gas of thermal power units. Compared with the accounting method, it has the advantages of less human intervention, high automation, and strong timeliness.The research progress and application status of continuous monitoring technology for carbon emissions was reviewed, aiming to provide reference for the power generation industry to establish a more perfect carbon emission measurement method system and carbon emission data management system. Methods The research progress of CO₂ concentration monitoring technology and flow monitoring technology in flue gas was emphasized. The current application status of continuous carbon emission monitoring technology in thermal power plants in the United States, the European Union and China was analyzed. The comparative research situation between continuous monitoring method and accounting method was discussed. Conclusions The technical challenge faced by continuous carbon emission monitoring technology is the accurate monitoring of flue gas flow rate. There are great differences in the magnitude and accuracy of carbon emissions obtained by continuous monitoring and accounting methods. Based on the current situation of continuous monitoring of carbon emissions in China, it is recommended to improve the relevant policies and standard system as soon as possible, conduct in-depth technological research, and expand technological applications.

Objectives In order to master the deep peak shaving capability of supercritical circulating fluidized bed units and scientifically participate in the auxiliary service market, it is necessary to conduct in-depth research on the deep peak shaving performance of existing units. Methods From the three dimensions of safety, economy and environmental protection, 40% and 30% of rated load continuous trial operation, boiler combustion optimization adjustment, boiler efficiency and steam turbine heat consumption rate performance tests were carried out, respectively.More than 10 optimization measures such as single pump operation of feed water pump, pressure curve optimization, boiler oxygen amount, bed pressure adjustment, etc., were implemented. Results The continuous operation of 30% rated load for 12 consecutive days was realized, 40% and 30% rated load depth peak-monasizing the peaks affected coal consumption by about 52%, 72 g/(kW·h), respectively. Conclusions The 350 MW supercritical circulating fluidized bed unit has good deep peak shaving ability. There is no need to transform 30% rated load conditions, and inject oil to stabilize combustion and maintain high efficiency of the boiler. Monitoring parameters for the steam turbine generator unit body, thermal system and auxiliary equipment are normal. The main flue gas pollutants are ultra-low emission.

Objectives The high-efficiency internal cooling technology of turbine blade is crucial for improving the thermal efficiency of gas turbine. As an important component of the gas turbine, it is essential to conduct research on the cooling performance of rotor blade. Due to significant effect of Coriolis force, buoyancy force, and channel structure on the cooling performance of rotating internal channel of turbine blade, this paper summarized the research status and development trends of rotating internal cooling channel based on these effect factors. Methods A new structural design of rotating internal cooling channels was introduced, and a new rotating internal cooling channel structure suitable for double-walled blade configurations was proposed. Conclusions Double-sided enhanced U-shaped channels can utilize the enhanced heat transfer effect of Coriolis force, resulting in better cooling performance than traditional rotating U-shaped channels. There is a broad room for improvement in the internal cooling of gas turbine rotor blades.

Objectives Compressed air energy storage (CAES) is a new type of energy storage system that utilizes the mutual conversion of electrical energy and compressed air potential energy to balance the fluctuation of power grid. The accumulation of relevant experience in the construction and operation of CAES power station is of great significance to the development of CAES technology. In view of the low efficiency of information transfer between the designer and the site, the difficulty of construction control, and the difficulty of overall project process supervision, a whole-process intelligent system suitable for CAES power station was proposed. Methods Firstly, the construction process of CAES power station was analyzed and its engineering characteristics were found out. Secondly, based on the whole process from design to operation and maintenance of CAES power station, the whole process intelligent construction system of CAES power station was constructed in space and time dimensions. Finally, in the design stage, the key techniques such as forward design drawing were proposed. In the stage of equipment manufacturing, the key technologies such as virtual pre-assembly of equipment were proposed. In the construction stage, the key technologies such as 5D construction management were proposed. In the operation and maintenance stage, the key technologies such as data delivery oriented to operation and maintenance were proposed. Results The verification results of a 300 MW CAES demonstration project show that the construction of the whole process intelligent system of CAES power station is reasonable, and the application of key equipment and software provides technical support for the project. Conclusions Through the intelligent system of the whole process of CAES power station and its key technologies, the interworking chain of each stage of power station construction is opened, and the information management of the whole life cycle of CAES power station is realized.

Objectives With the continuous development of China's new power system, there is a growing integration of new energy sources such as photovoltaic and wind power into the grid. However, this integration has also led to an increase in intelligent control equipment and nonlinear loads, resulting in more complex power quality issues. In order to enhance the power supply quality of the entire power grid and achieve economic operation and efficient development, it is crucial to conduct a scientific and rational quantitative evaluation of power quality. Methods Starting from three aspects of power quality evaluation indicators, weighting methods and evaluation models, the comprehensive power quality evaluation methods were systematically summarized and compared, and the research status of comprehensive power quality evaluation methods was summarized. On this basis, the shortcomings and problems that need to be solved of various existing comprehensive power quality assessment methods were summarized, and the possible research directions in this field were prospected. Conclusions Although many results have been achieved in the research on comprehensive evaluation of power quality at home and abroad, each method has its own advantages and disadvantages, there are still a series of important neglected problems that need to be solved in this field.

Objectives The natural draft cooling towers with flue gas injection (NDCT-FGI) is a crucial retrofitting technique for enhancing the efficiency of thermal power plants. However, its operational impacts on existing systems are significant and cannot be overlooked. Therefore, the current status of NDCT-FGI technology and its problems in operation were analyzed, and the countermeasures were put forward. Methods Through comprehensive analysis of the existing research, the causes and formation mechanism of environmental impact, cooling tower corrosion, and deterioration of circulating cooling water quality caused by the technical transformation of NDCT-FGI were discussed. Results The protective distance can be reasonably set by the simulation results of flue gas emission trajectory and pollutant landing concentration by computational fluid dynamics (CFD). Installation of baffles at the tower top can prevent flue gas washdown during the extreme weather conditions. Different anticorrosive coatings are recommended for various parts of the cooling tower to extend its service life. To control and optimize cooling water quality, the advanced water treatment techniques are necessary for optimizing chemical dosing, and the management of effluent and makeup water must be carefully controlled to ensure operational sustainability. Conclusions By implementing appropriate and effective countermeasures, the negative impacts of NDCT-FGI retrofitting can be mitigated, thereby enhancing both the environmental and economic benefits for thermal power plants.

Objectives Under the background of the “dual carbon” target, the safety and economic problems of peak shaving caused by the construction of high wind power penetration system are urgent to be solved. Methods By using the solution of peak shaving and valley filling of battery energy storage system, a peak shaving optimization control method for zinc-bromine flow battery (ZBB) energy storage taking into account both technology and economy was proposed. According to the actual battery device, the structure analysis and the mathematical model construction of ZBB energy storage were carried out. Considering the technical effects of peak shaving, and taking the minimum standard deviation of load curve after peak shaving as the objective function, a bidirectional optimization control strategy for energy storage considering peak shaving effects was proposed. On this basis, according to the time of use (TOU) policy of the power grid, taking the technical and economic optimization as the objective function, an economic model of energy storage peak shaving based on the TOU price mechanism was proposed, and the optimal power timing results for energy storage were obtained. Finally, taking the load and wind power data of a certain area in Northeast China as an example, the effectiveness of the proposed strategy was verified by comparison. Results Compared with the original load, the proposed strategy reduces the daily average load peak-valley difference and peak-valley difference rate by 35.973% and 34.205%, respectively, and improves the peak shaving economic optimization by 5.582%. In addition, the problem of wind curtailment in the power grid is alleviated. Conclusions The proposed strategy achieves a certain peak shaving effect while maintaining a good peak shaving economy throughout its life cycle.

Objectives As an important support for the new power system, hydrogen gas turbines can help reduce carbon emissions and are conducive to grid peak regulation. They are the focus of technological innovation in the global future strategic emerging industries. Many key issues faced by hydrogen blending gas turbine power generation technology from demonstration to commercialization, need to be solved. Methods H-class gas turbines were taken as the research object, and the strategic planning and demonstration projects of hydrogen blending gas turbine power generation in China and abroad were introduced, and the technology routes of H-class gas turbines of major gas turbine manufacturers were compared. The analysis and suggestion was made from four aspects for the scale application of future hydrogen blending gas turbine power generation technology, including hydrogen source, system transformation, emission impact and hydrogen blending power generation cost. Results Renewable energy electrolysis of water to produce hydrogen will be the main source of hydrogen blending gas turbine power generation. In addition, the development of new dry low nitrogen oxide burners, which are suitable for unstable combustion of hydrogen blending, will be the key direction for future hydrogen blending gas turbine system transformation. The higher the hydrogen volume percentage is, the greater the CO₂ emission reduction is. However, the NO _x emission is on an upward trend. Moreover, there is a risk of exceeding the standard value, and the future cost of hydrogen blending gas turbine power generation can reach the same level as the cost of natural gas power generation. Conclusions With the reduction of the cost of large-scale renewable energy hydrogen production, and the implementation of carbon tax and the maturity of hydrogen blending power generation technology, the gas turbine hydrogen blending power generation will gradually enter large-scale application.

Objectives Liquid storage and transportation is one of the effective ways to realize large-scale and long-distance storage and transportation of hydrogen and ensure the large-scale application of hydrogen energy. At present, there is relatively little research on the preparation, storage, transportation, and refueling of liquid hydrogen in China. Therefore, the current development status analysis of key technologies in these fields was conducted. Methods The advantages and disadvantages of high pressure gaseous storage, liquid hydrogen storage and solid hydrogen storage technologies were compared. The main liquefaction methods, liquid hydrogen storage insulation technologies and key materials in the process of liquid hydrogen preparation were reviewed. The characteristics of different transportation modes and equipments of liquid hydrogen were analyzed. The construction of liquid hydrogen hydrogenation station was combed, and the liquid hydrogen filling technologies were compared. The main application fields and industrialization modes of liquid hydrogen were expounded, and a statistical analysis of the patent technologies of liquid hydrogen storage and transportation in China in recent years was carried. Results The “neck-stuck” difficulties faced by the development of liquid hydrogen storage and transportation in China and the urgent need for technical research directions were proposed. Conclusions The results can provide reference for the key technology research and equipment development of liquid hydrogen.

Objectives In order to solve the shortcomings of the traditional preventive maintenance method of air preheater in large thermal power unit, a general mode of predictive maintenance based on digital twin was proposed, and the digital twin system of air preheater was constructed based on digital twin technology. Methods The proposed system included physical entity of rotary air preheater, real-time data acquisition and analysis module, digital twin model construction module, thermal parameter state monitoring, rotor thermal field video and thermal deformation visualization and ash accumulation prediction module. By the real-time acquisition of temperature parameter state and video data, and through the temperature field, video image, air leakage calculation and other modules, the calculation of thermal parameters and the prediction of ash accumulation were realized. At the same time, the 3D configuration screen was used to display data in real time, continuously optimize the accuracy of thermal parameter calculation and ash accumulation prediction, and realize the automatic optimization of soot-blowing strategy. Results The proposed scheme realizes the state monitoring and dynamic control of the thermal calculation process of the air preheater, and solves the problem that the ash accumulation factor of the rotary air preheater in the existing power station affects the safe and reliable operation of the thermal power unit. Conclusions Through engineering testing of actual units, the proposed scheme effectively improves the operation and maintenance efficiency of the air preheater of thermal power units, verifies the feasibility of the proposed method, and provides technical support for the development of smart power plant systems in future.

Objectives In order to promote the efficient utilization of energy storage and user-side resources and improve the level of clean energy consumption, a multi-area interconnected integrated energy system planning model considering cloud energy storage was proposed. Methods On the basis of establishing the energy router model of the regional integrated energy system, a virtual energy router model considering electricity/heat/gas cloud energy storage was proposed. Aiming at the problem that cloud energy storage and integrated energy system belong to different investment entities, considering the limitation of the investment return period of cloud energy storage, a dual-subject two-stage planning model was proposed. In the first stage, the grid, equipment capacity and cloud energy storage price were planned. In the second stage, the operation strategy of the integrated energy system was optimized. Aiming at the high complexity of multi-energy flow grid planning, a pre-screening algorithm based on minimum spanning tree was proposed. Results The example analysis results of a three-park integrated energy system planning show that the proposed model is helpful to improve energy efficiency, reduce carbon emissions, and improve the economic benefits of interconnected integrated energy systems. Conclusions The research reveals the potential of collaborative planning between cloud energy storage and multi-area integrated energy systems, and provides reference for the in-depth application and commercial promotion of multi-type energy storage in the energy field.

Objectives Battery energy storage system is one of the effective means to ensure the reliability of photovoltaic (PV) power generation system and improve the utilization rate of PV power generation. However, there are some problems in the PV-energy storage power station, such as the difficulty of power fluctuation suppression and the unreasonable configuration of energy storage capacity. In order to solve these problems, relevant research was carried out. Methods For energy-based battery energy storage, the characteristics of scheduling mode and autonomous mode were analyzed, and a power-limited suppression strategy of PV-energy storage system based on energy storage operation in scheduling mode was proposed to realize power suppression and reduce the frequency of energy storage charge/discharge switching. The optimization objective of minimizing abandoned power losses in the PV-energy storage system was established, with constraints such as the probability of power fluctuation exceeding the limit. An algorithm was used to solve and optimize the energy storage configuration. Taking the 50 MW Sangzhuzi PV-energy storage power station in Langming, Tibet as an example, the effectiveness of the proposed grid-connected power suppression strategy was validated. Results The proposed grid-connected power suppression strategy can reduce the probability of power fluctuation exceeding the limit from 25.64% to 6.41% without increasing the frequency of energy storage charge/discharge switching. When the probability of grid-connected power fluctuation exceeding the limit is 5%, the optimal configuration for the energy storage system of the power station is determined to be 14.5 MW/94 MW⋅h. Conclusions The proposed power fluctuation suppression strategy and energy storage optimization configuration method can provide technical reference for the optimal design and operation of grid-connected PV-energy storage system.

Objectives Calculate the carbon emission efficiency of listed thermal power companies, compare and analyze the reasons why the efficiency ranks at the bottom and the top driving factors, group thermal power companies according to different conditions, and explore the influencing factors of efficiency differences. Methods Based on the improved three-stage undesirable-slack based measure (SBM)-data envelopment analysis (DEA) model to more accurately measure the total-factor carbon emission efficiency of China listed thermal power companies during 2016-2022. Results The carbon emission efficiency of listed thermal power companies rises annually and lowers when the effects of the external environment are taken into account. The increasing environmental subsidies from government may lead to excessive investment of capital, personnel and coal consumption in the thermal power companies. The increasing in regional R&D investment has a beneficial impact on company assets, personnel, and coal consumption. The most effective utilization of company assets and employees management will be promoted by a better regional economic level, but wasteful consumption of coal for power generation will occur. Conclusions The listed thermal power companies with central control, low coal consumption rate and carbon emissions trading have higher technology gap rate and better overall carbon emission efficiency.

Objectives Deep peak regulation of coal-fired boilers is crucial to the stability of the future power system dominated by new energy, but there is a lack of performance and engineering applications on deep peak regulation of 1 000 MW ultra-supercritical coal-fired boilers. In order to improve the deep peak regulation capacity of 1 000 MW coal-fired boilers, a 1 000 MW coal-fired unit of a power plant is selected to carry out a wide-load high-efficiency research. Methods Focusing on the unit load depth peak regulation load of 340 MW, the low-load stable combustion experiment and the denitrification side inlet flue gas test were carried out. In addition, the main operating parameters of the boiler, the temperature distribution of the furnace and the combustion adjustment test on the boiler side were analyzed. The combustion optimization adjustment experiment was carried out on this basis. Results 1 000 MW unit has a deep peak regulation capacity of 34% rated power. The flue gas temperatures of selective catalytic reduction (SCR) denitrification inlet are basically 320-350 ℃, which meet the flue gas temperature requirements higher than 300 ℃. After the optimization and adjustment of the boiler, the modified thermal efficiency of the boiler is 94.09% (increased by 0.94%), and the coal consumption for power supply is reduced by 3.27 g/(kW⋅h). The NO _x at the inlet of SCR denitrification is basically 180-260 mg/m³ (decreased by about 30 mg/m³), and meet the requirements of less than 300 mg/m³. Conclusions The research results are helpful to improve the safety, economy and environmental properties of low-load operation of 1 000 MW coal-fired thermal power units.

Objectives The mechanism of the impact of carbon capture technology on the peaking capacity of coal-fired power plants was analyzed, and the impact on the carbon capture technology on the power generation efficiency of coal-fired power plants was quantified. Methods A typical coal-fired power plant was used as an example, and a post-combustion carbon capture scheme was selected. The simulation model of the conventional coal-fired thermal power unit and the carbon capture power plant was constructed by EBSILON software. The operation interval of the carbon capture power plant was derived. A comparative analysis of the operation of the carbon capture power plant and the conventional coal-fired power plant was conducted, and the variation in peaking performance was investigated. Results The equivalent output power of the carbon capture power plant decreased by 1%-2%, the net output power decreased by 20%-30%, and the net efficiency of the whole field decreased by 8%-10% compared with the conventional coal-fired power plant. Conclusions The addition of a carbon capture system allows the plant to gain greater downward peaking depth and faster peaking response, although it reduces efficiency.

Objectives The inlet temperature of gas turbine has far exceeded the allowable temperature of the blade material, so it is very important to develop more efficient turbine cooling technology, especially the film cooling technology. The film cooling in the central region of the turbine blade is usually supplied by the crossflow ribbed passage. Therefore, the research progress of the film cooling in the crossflow ribbed passage in recent years was reviewed. Methods The variations in film cooling performance under different coolant supply modes were introduced. The impacts of rib angle, rib shape, relative position of film holes and ribs, and Reynolds number at the inlet of the crossflow channel on flow and film cooling performance were summarized. The research progress of film cooling hole shape design under the condition of crossflow ribbed cooling air was concluded. Results The internal cooling structures within the crossflow ribbed passage and the Reynolds number at the entrance of the crossflow channel exert significant influences on film cooling performance, while the distribution of cooling effectiveness at the hole outlet downstream is altered during crossflow intake. Moreover, the flow at the hole entrance is influenced by both the relative position of the hole and rib as well as changes in Reynolds number. The asymmetrical spanwise cooling hole and the hole insensitive to the crossflow can enhance the film cooling performance. Conclusions In order to further promote the development of film cooling technology in the crossflow ribbed passage, it is recommended to thoroughly study the relationship between film cooling performance and all influencing factors, and to optimize the design of special film cooling hole suitable for crossflow ribbed inlet.

Objectives Driven by the dual carbon goal and the accelerated transformation of China’s energy structure, the scale of the wind power industry continues to grow rapidly, and there is an urgent need to reduce costs and increase efficiency to cope with the pressure of grid parity. The cost of collector lines accounts for a relatively large proportion of investment, and there is considerable space for optimization. In order to reduce the investment cost, an improved fuzzy C-means (FCM) clustering algorithm was proposed. Methods The improved FCM clustering algorithm was used to divide the collector circuit of onshore wind farm. The algorithm comprehensively considered the azimuth angle and the Euclidean distance to ensure that the lines between the circuits were not crossed, and the adjacent units were gathered to the same circuit. The correction factor of the distance from the machine position to the cluster center was introduced, and the circuit capacity was limited by adjusting the distance correction factor. On the basis of circuit division, the dynamic Prim algorithm was used to optimize the line selection of each circuit. Finally, the effectiveness of the method was verified by an example of an onshore wind farm. Results Compared with the clustering method only considering the azimuth angle, the improved FCM algorithm considering azimuth angle and spacing has better optimization effect. The total cost of single-circuit and double-circuit collection lines is reduced by 2.6% and 5.4%, respectively. Conclusions The proposed algorithm can effectively reduce the total cost of collector lines, and has certain application value. It can provide a reference for the design of wind farm collector lines.

Objectives As the proportion of renewable energy in power grids increases year by year, the volatility and uncertainty of the grid are significantly heightened, posing challenges to the safe operation of distribution networks. To address the issue of distributed network reconfiguration in high-proportion renewable energy grids, this paper proposed an online rolling optimization framework. Methods The framework utilized a distributed consensus protocol to obtain network topology and node operation information. It can enable automatic reconfiguration in the event of N-1 and N-2 line failures, allowing the distribution network to automatically restore normal operation without the need for additional external triggering signals, thus ensuring economic operation of the grid. Additionally, a rolling optimization method was employed to handle grid fluctuations caused by the high proportion of renewable energy, and generative adversarial network (GAN) technology was used to generate new data, which combined with historical data. It can help to achieve high-precision forecasting of grid operation data. Results The proposed method can achieve automatic economic optimization and self-healing in normal, single-point failure, and two-point failure scenarios. Conclusions This method provides an effective solution for ensuring the safe operation of distributed networks in high-proportion renewable energy grids.

Objectives With the intervention of new energy, the uncertainty and volatility problems of new energy output have been shown. In order to make up for the shortcomings of new energy output, thermal power units have assumed the role of peak regulation. In order to improve the peak-load capacity of thermal power units, the peak-load characteristics were studied. Methods Firstly, a 350 MW heating unit was taken as the analysis object. The simulation software was used to build the thermal system model, and the accuracy of the model was verified. Secondly, with the heat storage system as the auxiliary system, the peak-load capacity of the unit under the condition of meeting the heating demand was studied, and the influence of energy storage units such as heat storage on the peak-load capacity of the unit was analyzed. Finally, the heuristic particle swarm optimization algorithm was used to optimize the operation strategy of the storage tank, and the optimal operation mode of the storage tank changing with the heat load was obtained. Results The peak regulation and heating capacity of the unit can be effectively improved by coupling the storage water tank with the unit, and the operation mode can be determined according to the actual heat load data to maximize the benefit. Conclusions This method has guiding significance to the operation strategy of the unit.

Objectives With the implementation of the national “Dual Carbon Strategy” (carbon peak and carbon neutrality), it is anticipated that the existing coating structures may not meet the requirements of future gas turbine thermal protection coatings. The concept of a new type of environmental/thermal barrier coating (E/TBC) structure with high temperature corrosion resistance has been proposed to meet the demand for thermal protection coatings in hybrid hydrogen combustion engines. Methods The development history and research status of thermal barrier coating (TBC), environmental barrier coating (EBC), thermal/environmental barrier coating (T/EBC) and thermal and environmental barrier coating (TEBC) were reviewed and analyzed from the perspective of thermal protection coating materials and coating structures. Moreover, the gap between the above coating structures and the requirementsof thermal protection coating for mixed hydrogen gas turbines was investigated. Results It is reasonable to superimpose the function of EBC onto the thermal protection coating of current mixed hydrogen gas turbines, thereby forming a new type of E/TBC structure with high temperature corrosion resistance on the high-temperature alloy substrate. Conclusions Through the preliminary test, it is proved that the new E/TBC structure is suitable for the thermal protection coating requirements of mixed hydrogen gas turbine against high temperature water oxygen corrosion, and it is pointed out that the theory and application research of this new E/TBC thermal protection coating should be vigorously carried out.

Objectives This research aims to investigate the operational mechanism of a coal gasifier within an integrated gasification combined cycle (IGCC) power plant, with a focus on analyzing and optimizing key operational parameters. Methods A steady-state thermodynamic model of the gasifier was developed using Aspen Plus. The model’s accuracy was validated by comparing its simulation results with published data. A sensitivity analysis was then conducted to assess the impact of key gasifier parameters. Results The thermodynamic model demonstrates the suitability for simulating steady-state coal gasification processes. The model exhibits high accuracy, simplified structure, and efficient computational performance. Conclusions The sensitivity analysis reveals that the oxygen-to-coal ratio holds the most significant influence on the coal gasification process. Both insufficient and excessive oxygen levels result in a reduction of syngas active ingredient production. The optimal oxygen-to-coal ratio for the Shell gasifier model is determined to be approximately 0.85. Water-to-coal ratio also plays a critical role in the gasification process. When sufficient energy is present within the gasifier, increasing the water input leads to higher water content in the syngas, potentially increasing hydrogen concentration. However, excessive water input under energy-constrained conditions can decrease the effective composition of the syngas.

Objectives With the widespread integration of renewable energy, the uncertainty of power flow in distribution networks with neutral points grounded through small resistors has made the setting of traditional three-stage current protection increasingly complex, and reduced its sensitivity and reliability. To solve the above issues, a new type of current protection based on positive sequence sudden-change variable current phasor trajectory identification was proposed. Methods Firstly, the magnitude and distribution characteristics of the positive sequence sudden-change variable current upstream and downstream of the fault point were analyzed. Secondly, using the affinity clustering algorithm, the defined “main fault path” based on the clustering results was identified. Finally, a novel searching method was proposed to identify the source of the positive sequence sudden-change variable, which was the last level feeder located on the main fault path, as the faulted feeder. Results Simulation research based on PSCAD shows that the proposed protection method can adapt to various fault conditions, is immune to the integration of renewable energy, and has high sensitivity and reliability. Conclusions The research findings are helpful to enhance the operational safety of distribution networks with neutral points grounded through small resistors, and improve the efficiency of fault detection.

Objectives Compressed air energy storage is a type of energy storage technology with large capacity, long cycle, low cost and high efficiency. Due to the strict requirements of gas storage chambers, gaseous compressed air energy storage cannot be widely promoted and applied in multiple scenarios and on a large scale. Therefore, a non-supplementary combustion liquid compressed air energy storage system was proposed. Methods A theoretical calculation model was constructed to conduct sensitivity analysis on key parameters such as compressor interstage temperature, number of compressor stages, and turbine inlet temperature within the system. The results were compared with those of a non-supplementary combustion gaseous compressed air energy storage system. Results Too low or too high interstage temperature in compressors will restrict the improvement of electric-electric conversion efficiency of the system. The number of compressor stages is positively correlated with compressor power consumption, and negatively correlated with the turbine power generation. Under the same inlet pressure, the higher the inlet air temperature of the turbine is, the larger the power generation is, and the higher the electric-electric conversion efficiency is. Compared with the non-supplementary combustion gaseous energy storage system, the density of non-supplementary combustion liquid energy storage system is increased by 3.7 times, and the volume of the storage chamber is decreased by 9/10. Conclusions The non-supplementary combustion liquid compressed air energy storage system effectively solves the problem of gas storage chambers, enabling compressed air energy storage technology to be promoted and applied in multiple scenarios and on a large scale. It is of great significance for deep peak shaving of thermal power units and large-scale energy storage in power grids.

Objectives The localization of core components of heavy-duty gas turbines holds significant importance for technological innovation, industrial upgrading, and even national security. As a typical hot-end component of heavy-duty gas turbines, the performance of the turbine first-stage rotor blade directly determines the efficiency and reliability of the gas turbine. Therefore, the structure of the first-stage turbine blades of a certain heavy-duty gas turbine was optimized. Methods By increasing the number of bamboo nodes in the blade body, the blade cooling hole structure was optimized, and the thermal barrier coating was used to improve the blade coating. The temperature, stress distribution and aerodynamic efficiency of the blades before and after optimization under the service condition of the blade were compared and analyzed by fluid calculation and finite element calculation. Results Heat transfer efficiency inside the blade is enhanced by optimization of turbulent structure. Under the condition of the same inlet pressure of the cooling air, the surface temperature of the optimized blade is reduced by more than 50 ℃. Since the shape of the blade is not changed, there is little influence on the aerodynamic efficiency. Compared with the blades without optimization, the maximum equivalent stress and equivalent total strain of the optimized blade during service are significantly reduced. Conclusions By optimizing the cooling structure and upgrading the protective coatings, the reliability of the blades in high-temperature can be significantly improved. The research results provide a theoretical basis for the localization of gas turbines.

Objectives The wet flue gas desulphurization of coal-fired power plants generates a large amount of wastewater containing heavy metals, the removal of heavy metals from wastewater by coupling of limestone and sodium metaaluminate precipitation and activated carbon adsorption were studied. Methods The optimized feed ratio, temperature, and pH value for the precipitation method were obtained, and the experimental parameters for the type of adsorbent and adsorption layer height were optimized. Based on this, engineering tests were conducted on the 300 MW unit of Sanhe coal-fired power plant. Field experiments were conducted with an additional precipitator feeder and adsorption device, and effect was investigated. Results The optimal feeding rate is 160 kg/h, the flow rate is 1 m³/h, and the adsorption height is 10 cm. Under the experimental conditions, the overall heavy metal removal efficiency is significantly improved. Compared with the heavy metal content in the original export of the power plant, the removal efficiency of lead, chromium, copper, and nickel from the export increase by 33.24%, 81.93%, 35.22%, and 57.52%, respectively, after installing a mixed precipitation and adsorption device. Conclusions The method of coupling of limestone and sodium metaaluminate precipitation and activated carbon adsorption can effectively promote the removal of heavy metals from desulfurization wastewater, providing guidance for the deep removal of heavy metals in the wastewater from coal-fired power plants.

Objectives Considering the difference of primary frequency regulation ability of wind turbines under different wind conditions in wind farms, the evaluation method of frequency regulation capability of wind turbines was optimized on the basis of sag control and inertia control strategy. Methods An improved multi-unit frequency modulation reference power cooperative control strategy was proposed. Results The introduction of multi-unit cooperative control method can effectively improve the distribution of frequency modulation reference power among units, thus effectively adjust the degree of each unit participating in the primary frequency regulation of the system. An improved cooperative control strategy was introduced on the basis of inertia control and sag control. According to the operation state of the unit under the actual wind condition, the reference power of the unit which can effectively participate in the primary frequency modulation was evaluated. The introduction of frequency modulation capability coefficient can realize the energy distribution of the reference value of frequency modulation power among units. Conclusions The cooperative control strategy can effectively protect the speed of wind turbine and improve the frequency response of power grid.

Objectives Distributed photovoltaic power prediction is of great significance for the operation and scheduling of photovoltaic power plants. Point prediction methods are difficult to comprehensively describe the uncertainty of distributed photovoltaic power. This article proposed a distributed photovoltaic power interval prediction model based on complete ensemble empirical mode decomposition with adaptive noise (CEEMDAN) and sparrow search algorithm optimized least squares support vector machine (SSA-LSSVM). Methods Firstly, the photovoltaic sequence was broken down into multimodal components through CEEMDAN, and then the high-frequency non-stationary components obtained from the first decomposition were decomposed twice. Secondly, sample entropy (SE) was used to reconstruct all components into trend and oscillation components. Then, the point prediction values of the two components were obtained through SSA-LSSVM. Finally, the probability density estimation was performed on the point prediction error of the oscillation component, and the stacked point prediction value was used to obtain the overall prediction interval result. Results The interval prediction model proposed in this paper has higher interval coverage and narrower average interval width. Conclusions Adding secondary modal decomposition to distributed photovoltaic power data processing and combining sample entropy to reconstruct its sub-sequences can effectively reduce the complexity of the original prediction components and improve the accuracy of model prediction.

Objectives In order to make the small independent power supply unit provide more flexible and stable power supply, a photovoltaic-piezoelectric composite independent power supply system was designed, and its performance in actual operation was analyzed. Methods Considering the power supply scenarios such as bus stations, the output characteristics model of piezoelectric ceramics and photovoltaic cells was established, the system configuration of photovoltaic-piezoelectric outdoor independent power supply unit was designed, and the power output and system stability under typical daily, typical annual and long-term operating conditions were analyzed. For the system design with or without piezoelectric ceramics, the reliability rate of power supply, curtailment power and power generation cost of the system were analyzed. Results After adding piezoelectric ceramics, the reliability rate of the system is 99.18%, the power generation cost is 1.399 yuan/(kW⋅h), and the annual curtailment power is 161.24 kW⋅h. Compared with the system without piezoelectric ceramics, the reliability rate is increased by 0.12%, the cost is increased by 0.8%, and the curtailment power is reduced by 18.6%. Conclusions After the addition of piezoelectric ceramics, although the power generation cost of the system increases slightly, the reliability of the system power supply is improved and the curtailment power is reduced. With the reduction of the cost of piezoelectric ceramics and the development of technology, the photovoltaic-piezoelectric composite independent power supply system will have a better application prospect in special scenarios.

Objectives The preliminary research device of magnetic confinement deuterium-deuterium fusion neutron source is a novel neutron source preliminary research device based on field-reversed configuration (FRC) cascade magnetic compression. It aims to leverage the experiences from the first-phase construction to enhance system design, significantly improve plasma parameters, and further expand research on magnetic compression fusion, laying the foundation for achieving a large-volume high-flux fusion neutron source in the third phase. Methods The preliminary research device control system optimized and reconstructed the control framework, provided safety interlocking, pulse control and comprehensive data services, coordinated and integrated each service into the automated discharge process through integrated control, and added a number of resources to expand applications and DevOps tool. Results Through the reconfiguration design, the comprehensive performance of the control system in terms of safety, stability and efficiency had been significantly improved. The safety interlock system ensured the safety of personnel and equipment during the experiment process, the pulse control system achieved high-precision timing control, the comprehensive data service provided full process support from data collection to analysis, and resource expansion applications and DevOps tools further improved the system flexibility and operation and maintenance efficiency. Conclusions By optimizing the control framework and introducing advanced operation and maintenance tools, the design can better meet the needs of complex device structure and precise discharge flow, and provide an efficient control system construction plan for the subsequent long-term cooperation construction of the magnetically confined deuterium fusion neutron source preliminary research device.

Objectives Timely and accurate detection of power facilities is very important to ensure the reliability of energy supply. However, a single sensor has certain limitations in the detection of power facilities. Therefore, a multi-scale feature heterogeneous image fusion algorithm based on saliency detection was proposed. Methods Firstly, the edge guidance network was used to extract the salient target from the infrared image to generate the salient target mask. Secondly, a specific loss function was established in each region, and the salient target mask was used to guide the network for feature extraction. Finally, a directional heterogeneous fusion method based on feature hierarchy was proposed, which combined the depth features of different scales to minimize information loss. Results Subjective and objective experiments on the TNO dataset show that the algorithm is superior to other methods in most evaluation indicators, which verifies the effectiveness of its application in the field of power facilities detection. Conclusions The algorithm effectively solves the problems of low detection rate and information loss, and makes the detection of power facilities more comprehensive and accurate. It is of great significance to improve the accuracy and diagnostic efficiency of power equipment fault detection.

Objectives A portable solid oxide fuel cell (SOFC) system includes a gas supply module, a fuel processing module, an SOFC power generation module, a thermal management module, an exhaust treatment module and a control module. There is a complex coupling relationship between the fuel processing module and the SOFC power generation module. Clarifying the coupling characteristics between them is crucial for improving system performance and operating time. Methods The effects of temperature, the carbon-to-oxygen ratio and other factors on the performance of catalytic partial oxidation (CPOx) of propane with Rh as catalyst were analyzed, and the coupling performance of CPOx and SOFC stack was further tested. Results With the increasing of fuel flow rate, the reforming efficiency first increases and then decreases. The most suitable flow rate is 100 or 150 mL/min. An increase in temperature can continuously improve the reforming efficiency, but the improvement in reforming efficiency at high temperatures caused by an increase in temperature gradually decreases. The optimal C/O ratio obtained from the experiment is 1.0. Under the optimal operating conditions, the output power of SOFC stack reaches 8.38 W. Conclusions Under the conditions of propane flow rate of 150 min^-1, carbon and oxygen mole fraction ratio of 1.0, and operating temperature of 800 ℃, the coupling performance between SOFC stack and CPOx is the best, the portable propane power generation system can generate 150 W of power with a volume of 12 L.

Objectives The advanced exergoeconomics analysis method based on exergetic analysis development can refine the economic costs of splitting system components and deeply explore the underlying reasons for the formation of economic costs. Methods Combining advanced exergetic analysis, advanced exergoeconomics analysis method is used to split the costs of the components in the gas-steam combined cycle power generation system into endogenous, exogenous, avoidable and unavoidable costs, and calculate them. Results Under the design conditions, the avoidable loss in the combustion chamber in the combined cycle power system is the largest, which is 28.41 MW, accounting for 26.55% of the combustion chamber loss. Based on the results of the analysis, different improvement measures are proposed for the turbine to reduce the endogenous and exogenous losses of the system. The largest share of the annualized cost of the system is the endogenous avoidable portion, and the bottom-cycle improvement is prioritized highest for the high-pressure cylinder, followed by the low-pressure cylinder. The exogenous share of annualized costs in the combined cycle power system is 80.59%, of which the exogenous avoidable portion is 40.04%. Conclusions The findings of the study can provide the system with a multifaceted energy efficiency evaluation perspective and an improvement direction to optimize the cost.

Objectives The operating state under the condition of high-pressure turbine damage will have a certain impact on the performance and vibration of the gas turbine. At present, the means to accurately assess whether the whole machine can continue to be in service was relatively lacking. Therefore, the research on the influence of the tip groove wear and block shedding of the high-pressure turbine rotor blade on the aerodynamic performance and vibration deformation had been carried out. Methods Using the three-dimensional numerical simulation method, based on the original tip groove structure of the blade, the influence of five different tip groove damage shapes on typical aerodynamic performance and vibration characteristics of the high pressure turbine was simulated and analyzed. Results The damage of the blade tip groove on the pressure side with falling block, suction side with falling block, trailing edge with falling block, pressure side and trailing edge with falling blocks simultaneous, or pressure side, suction side and trailing edge with falling blocks simultaneous of rotor blades cause an efficiency decrease of 0.44%, 1.6%, 0.03%, 0.67%, and 3.2%, respectively. Different blade squealer tip shapes have a smaller impact on the vibration deformation of the rotor blade, while trailing edge with falling block reduces the deformation of the rotor blade. Conclusions Based on the analysis results of comprehensive performance and vibration, rotor blades with falling blocks at pressure side, trailing edge, or both can continue to be used. However, it is not recommended to use rotor blades with falling blocks at suction side or pressure side, suction side and trailing edge.

Objectives The demand for energy in outdoor work and survival is increasing, and there are some significant shortcomings in the existing conventional energy supply methods, such as the need to carry a large amount of fuel for conventional generators and heavy weight of cells. Solar photovoltaic/thermal (PV/T) technology can effectively solve the problem of lack of energy for outdoor survival and field work. However, most of the existing PV/T collectors are rigid structures with large weight and are not easy to carry. Methods A light and thin PV/T module based on the combination of a Cu(In,Ga)Se₂(CIGS) thin film battery and a piece of capillary network were proposed. The energy collection performance of the module and the impact of water flow rate on the photoelectric and photothermal conversion efficiency of the module were studied experimentally. Results Under the typical Shanghai climate conditions, the all-day electrical efficiency and thermal efficiency of the module are 13.04% and 22.50%, respectively. Under experimental conditions with an average irradiance of 760 ‍W/m², the optimal energy collection performance of this PV/T is achieved when the water flow rate is 2.1 ‍L/min. The cooling water in the capillary network can effectively reduce the cell temperature (by 10 ℃) and improve the energy utilization efficiency (by 23.94%). Conclusions The module has the characteristics of high power density, light weight and flexibility, and can be used for energy supply during outdoor work and survival, providing a new idea for the design of outdoor energy equipment.

Objectives With the annual increase in the generation of solid waste, traditional treatment methods have struggled to meet the increasingly stringent environmental requirements and the demands for resource recycling. In order to realize the efficient utilization of solid waste resources, a combined medical waste-waste tire resource utilization system based on gasification and pyrolysis was proposed. Methods The system fully combined the advantages of plasma gasification and pyrolysis technologies, coupling the medical waste plasma gasification power generation technology with tire pyrolysis technology. The syngas obtained from the gasification and pyrolysis processes was utilized together as the fuel of a gas turbine. At the same time, the high-temperature flue gas produced by the gas turbine provided the heat source for tire pyrolysis, after which the flue gas heat was recovered by a waste heat boiler. While harmlessly treating the medical waste-waste tires, the gradient utilization of energy was realized. The energy analysis and economic analysis of the proposed system were carried out under the condition of fixed feed rate. Results The system is able to achieve a total energy output of 23.59 MW, with a total energy utilization efficiency of 52.56%, which is much higher than the efficiency of conventional waste-to-energy generation. The system has good economic returns, and can realize a relative net present value of 727.978 1 million yuan in a 20-year life cycle, and the dynamic payback cycle is only 3.13 years. Conclusions The research results provide a new technical path for the efficient co-processing of solid waste resources.