In order to explore the influence of type Ⅰ and type Ⅱ boundaries in the weld of TP347H/12Cr1MoV dissimilar metal welded joint after high temperature aging treatment on the microstructure and properties of the joint, CALPHAD method was employed, and Thermo-Calc software was utilized to study the equilibrium phase composition and precipitate behavior of the welded joints. The simulation results from Thermo-Calc software indicate that, under the same temperature at 600-800 ℃, the carbon activity in each alloy decreases in the order of 12Cr1MoV, weld, and TP347H. Considering the activity factor, the direction of carbon migration is from 12Cr1MoV to the weld at first and then to TP347H, which is consistent with the actual results of carbon migration. Additionally, the TP347H/12Cr1MoV welded joint was subjected to isothermal aging treatment at 650 ℃ for 1 500 h, then the microstructures and precipitate characteristics of type Ⅰ and type Ⅱ boundaries were analysed using metallographic microstructure observation, scanning electron microscopy, and energy dispersive spectroscopy. Results show that, the weld microstructure consists of a mixture of cellular and dendritic crystals. The solidification mode of the weld in the TP347H/12Cr1MoV welded joint is primarily the austenitic A-type solidification mode. After aging treatment, Cr-rich and Nb-rich phases appear in type Ⅰ and type Ⅱ boundaries of TP347H and weld interface.

A simulation method for the condensate water throttling dynamic process in coal-fired units based on Dymola software was proposed. For a 350 MW supercritical unit, a dynamic simulation of the condensation water throttling process under automatic generation control (AGC) condition was conducted. The dynamic process and primary control and regulation model of the coal-fired unit was developed, and the accuracy of the model was verified. By simulating the impact of the condensate water throttling on the dynamic characteristics of the coal-fired unit, the response rates of the coordinated control system (CCS) lifting and lowering loads of 90% and 75% thermal heat acceptance (THA) conditions were compared with those of the traditional CCS lifting and lowering loads under the condensate water throttling conditions. The simulation results indicate that the CCS involving condensate water throttling can respond quickly to the lifting and lowering load commands, and the load response rate of the unit is significantly higher than that in the traditional coordinated case. Additionally, the condensate water throttling process has minimal effects on the main steam and reheated steam temperature/pressure of the unit.

The deformation of the high-medium pressure inner cylinder of a supercritical 660 MW unit steam turbine under working conditions was analysed and calculated using the finite element method. The radial deformation at different axial positions of the cylinder was obtained, and improvement and optimization measures were proposed. The analysis results show that under steady-state operating conditions, the radial deformation of the cylinder exhibits a vertical elliptical shape in the middle section and more flattened ellipses at both ends, with higher ellipticity at the ends. After analysing the causes of deformation and adopting improvement measures, the radial deformation ellipticity of the cylinder is significantly reduced. The maximum reduction in ellipticity is 60% in the high-pressure section and 90% in the medium-pressure section. The maximum ellipticity is reduced from -1.47 mm to -0.34 mm. The improvement is evident and beneficial for the design and adjustment of the steam seal clearance.

To solve the problem that the negative pressure of gas turbine lubricating oil tank in existing units needed to be adjusted frequently, a scheme was proposed for optimizing the transformation of gas turbine lubricating oil exhaust fan by variable frequency conversion, and investigations were conducted on the remote adjustment effect of the negative pressure of lubricating oil tank in gas turbine within full load range. Operation data show that the negative pressure can be flexibly and accurately controlled within the specified value range after the variable frequency conversion, thus reducing the fire risk of gas turbine, improving the stability of lubricating oil exhaust system, reducing the power consumption rate of the plant, and achieving the purpose of energy saving and consumption reduction.

The electronic weighing coal feeder is an important auxiliary equipment in thermal power plants. Once a fault occurs, it will seriously affect the operation of the entire unit. The evaluation method of equipment health status can accurately reflect the status of the coal feeder and predict the future status of the equipment. By analysing the functions and common failures of the coal feeder, a health status evaluation model for the coal feeder was established. Combined with an expert knowledge base, a quantitative model integrating deviation and fluctuation indicators was proposed, and a comprehensive weighting method was used to calculate the health index of coal feeder equipment. Taking the CS2024 coal feeder as an example for testing and analysis, the results show that this method has high accuracy, practical value, and guiding significance in practical applications, and can provide a reference for the subsequent health status evaluation of electronic weighing coal feeders.

Taking a waste heat retrofit project of a 1 000 MW coal-fired unit in southern China as an example, and combining heat pump and air preheater bypass waste heat utilization technology, the waste heat in flue gas was deeply coupled with the waste heat in closed-loop cooling water to maximize the utilization of low-grade waste heat in closed-loop cooling water. Under design condition, the net coal consumption rate can be reduced by 3.87 g/(kW·h), with 0.25 g/(kW·h) of savings attributed to the waste heat in closed-loop cooling water. Under winter condition, the net coal consumption rate can be reduced by 3.16 g/(kW·h), with 1.34 g/(kW·h) of savings attributed to the waste heat in closed-loop cooling water. The static payback period for this retrofit scheme is 2.1 years. The economic performance of the unit can be effectively improved by utilizing low-grade waste heat to replace the high-grade steam thermal energy of steam air heater.

Focusing on medium-temperature and medium-pressure superheated steam power generation technology, the working principles and characteristics of two currently more mature technologies were introduced in detail. Taking a low-concentration gas oxidation device that produces superheated steam as the research object, specific plans were developed using these two power generation technologies, and a comparative analysis was conducted from both economic and technical perspectives. The research results show that plan 1 is superior to plan 2 in terms of technical feasibility, economic cost, and comprehensive benefit, and it is more suitable for application in the field of superheated steam power generation of low-concentration gas oxidation devices. The findings can serve as a reference for the equipment selection and technologies application.

Based on the business application scenarios of the electric power design industry， the digital and intelligent upgrading paths of the industry were deeply analyzed. Firstly， the significance of the artificial intelligence （AI） leadership system and the plan for its establishment were elaborated. Secondly， the AI multi-application scenarios covering administrative office work， business management， design production， and customer service were built according to the characteristics of the enterprise. Through the application of AI， enterprises can comprehensively enhance design quality and work efficiency. In the technical implementation aspect， the principles， characteristics and typical applications of the current mainstream large model modes were analyzed， and the selection and implementation principles for electric power design enterprises were given. A systematic AI technology application framework is conducive to improving the design quality and efficiency of enterprises， and has reference significance for the digital transformation and upgrading of the traditional electric power design industry.

Based on the gas turbine performance model and combined with field temperature data and gas turbine performance test data, an economic model was established to predict the monthly and hourly variations of the unit output power, exhaust temperature and fuel flow rate more accurately. Through calculations using the economic model, the average monthly revenue of the entire project after replacing natural gas with membrane separation tail gas is approximately 48.523 2 million yuan, indicating significant economic benefits. Replacing natural gas with membrane separation tail gas as fuel not only achieves efficient operation of gas turbines, but also ensures the green utilization of membrane separation tail gas.

The impact of adopting an integrated steam chamber structure in the cylinder on stiffness and flange sealing was discussed. Through finite element calculations and analyses, compared with the conventional independent steam chamber structure, the integrated design can not only significantly reduce the deformation of the cylinder upper arch, avoid the friction between the steam chamber seal and the rotor during operation, but also reduce the deformation of the opening at the upper cylinder steam chamber, and solve the problem of performance reduction of the flange sealing caused by deformation. Cylinders with an integrated steam chamber structure can meet the requirements for long-term, efficient, and safe operation of the unit and also provide an engineering example for designing steam turbines with higher extraction steam pressures.

The finite element method was employed to simulate the working condition of the high-pressure and intermediate-pressure integrated inner casing of a 660 MW supercritical unit steam turbine under hydrostatic test conditions. The hydrostatic test plan and the bolt tightening force requirements were determined. Moreover, the hot-tightening nut rotation angle during installation was derived through practical application, forming a complete design and analysis process for the hydrostatic test of high-parameter cylinders. Through optimized design, the plan ensures the structural strength safety of the cylinders while effectively meeting the sealing requirements of the hydrostatic test. The research results provide a reference for the hydrostatic test of other high-parameter units.

During the pyrolysis process of large-sized biomass particles, significant temperature gradients develop within the particles, which have an important impact on the heat transfer and reaction processes. Centimeter-scale biomass spheres were used as the research subject. Numerical simulations were conducted to investigate the effects of heating gas flow rate, temperature, and particle diameter on the internal temperature distribution, heat transfer characteristics, and weight loss rate/reaction time during pyrolysis. Results show that the temperature distribution along the particle diameter in the flow direction is U-shaped. Compared with the flow rate and temperature of the heating gas, the particle size has a more significant influence on the pyrolysis process. The pyrolysis time required for a particle with a diameter of 30 mm is 10.31 times that of a particle with a diameter of 5 mm. A weight loss model for particle pyrolysis based on back propagation (BP) neural network was established, which can effectively reduce computational costs while accurately predicting the heat transfer and reaction characteristics during the pyrolysis process. This approach is importance for the control of the pyrolysis process and the design of pyrolysis reactors.

After the major overhaul of a 350 MW steam turbine unit， abnormal vibration occurred at both ends of the steam turbine shaft system. By analyzing the vibration mechanism through spectrum analysis and adjusting the data through experiments， it is found that the high and medium pressure rotors produce unstable vibration under the combined action of steam flow disturbance force and unbalanced centrifugal force. The vibration value is reduced through fine dynamic balance adjustment. Due to insufficient stiffness of the end bearing， the rotor of the exciter undergoes a vibration step change under the influence of unbalanced excitation force. By increasing the load on the end bearing and reducing the unbalanced excitation force， the unstable vibration problem of the exciter rotor is effectively solved.

With the development of large steam turbine generator sets towards greater capacity，the lubricating oil system，as a key auxiliary system，faces new challenges in terms of reliability. The common issues in the commissioning process of the lubricating oil system were systematically analyzed， including low oil pressure， delayed interlocking of oil pumps， lag in pressure signals， and abnormal system vibration. In response to these issues，system improvements were carried out through measures such as optimizing the starting mode of the direct current oil pump，improving the high-level oil supply system，enhancing the pressure measurement system，and applying intelligent vibration control. The practical application effect of a 530 MW unit shows that after the improvement，the minimum oil pressure of the system increases by 132%，the dynamic response time shortens by 40%，and the amplitude of pressure fluctuation decreases by 37.5%.

To systematically solve the overtemperature problem of the converters in aged wind turbine generator sets， taking a 1.5 MW wind turbine generator set that has been in operation for more than 10 years as an example， a cooling system renovation plan was proposed based on the existing main defects and faults of the converter system of this type of wind turbine generator set， combined with the cooling and heat dissipation methods. Through the comparison and analysis of the measured data of the unit before and after the renovation， it is confirmed that the renovation measures can effectively reduce the operating temperature of the frequency converter， significantly reduce the frequency of faults， and significantly improve the operational reliability of the wind turbine generator set. Practice experience has proved that the two-phase flow heat dissipation technology applied in the renovation is mature， reliable， and economically viable.

Under the dual carbon policy framework， the new power system introduces new flexibility requirements for coal-fired power units，including rapid start-stop operations and deep peak regulation. During deep peak regulation，the rapid load fluctuations of units lead to substantial variations in water-steam flow rates and steam parameters. This significantly complicates the maintenance of water-steam quality control and increases the risks of stress corrosion fatigue on thermal equipment，thereby threatening the safe and stable operation of the units. A systematic analysis was conducted on how the deep peak regulation process affects steam-water parameters and quality control，as well as corrosion and scaling in thermal equipment，and the underlying causes of these issues were examined. Six major problems were summarized，including inadequate feedwater control and increased steam carryover，corrosion and scaling of the furnace heating surfaces and hydrodynamic instability，abnormal fluctuations in steam temperature，intensified water erosion of the final stage blades of the steam turbine，excessive dissolved oxygen in condensate water and feedwater，and lagging regulation of the chemical dosing system. The proposed multi-dimensional risk prevention measures provide theoretical guidance and practical reference for the optimal control of water-steam systems in coal-fired power enterprises during deep peak regulation operations.

With the development of thermal power units towards higher parameters and larger capacities，the amount of data that needs to be monitored during the operation of turbo-generator set is increasing. The widely used expert diagnosis systems have severely impacted fault discrimination accuracy. To address this problem，a new steam turbine fault diagnosis method based on deep learning technology was proposed. Firstly，the original signals were reconstructed and output by using the autoencoder network. Secondly，the convolutional neural network（CNN）was employed to reduce the number of input parameters in the fully connected layers through convolution and pooling operations，while extracting data features and combining them into deeper，higher-dimensional data. Finally，the fully connected layers were used for output prediction and classification. Engineering application results demonstrate that this method can adaptively extract features of different fault locations and types in steam turbine systems under various operating conditions，accurately identifying equipment health status. Its discrimination accuracy is significantly higher than that of the currently widely used expert diagnosis systems.

Aiming at the problems of low initial discharge field strength and easy occurrence of corona in stator coil bars and windings under high-altitude conditions，the research on the anti-corona performance of stator coil bars and windings was conducted. Firstly，the impact of different altitudes on the initial discharge field strength at the end of stator coil bars was analyzed. Secondly，the key parameter ranges of anti-corona materials，the basic requirements for the optimization design of anti-corona structures，the field strength distribution at the corners of stator coil bar conductors，and the equipotential layer treatment technology in the slot section of conductors were introduced. Finally， anti-corona technologies for the end of stator windings were presented，and the influence of the ground clearance at the end of stator windings on end discharge was analyzed. The research results indicate that the anti-corona technologies for individual stator coil bars and stator windings have laid a solid foundation for enhancing the anti-corona performance of stator coil bars and windings in high-altitude impulse hydrogenerator units.

In order to achieve the economic evaluation and decision-making guidance of peak regulation in the operation mode of cogeneration units coupled with electric boilers，a peak regulation decision-making model for the unit was established. Through big data tools such as data mining technology and back propagation （BP） neural network，a prediction model for energy consumption indicators of cogeneration units was constructed to achieve precise calculation of various cost and revenue indicators of the unit revenue model. Meanwhile，an economic evaluation method for peak regulation of thermal power units was proposed. It comprehensively considered the coupled operation modes such as peak regulation，steam extraction heating，and electric boilers. By calculating the revenue of the full-load operation in real time，it provided guidance for peak regulation decisions based on the optimal operating income. The results show that when the heat load is higher than the critical value，the operation mode of giving priority to starting the electric boiler of the unit is more economical. The critical heat load of the unit is determined by the ratio of the unit price of standard coal to the heat price. During the heating period，to maximize the revenue of the electric boiler，the unit should operate below the critical heat load. The critical peak regulation compensation correction coefficient of the unit is mainly affected by the heat load and the non-peak regulation allocation electricity price. Referring to this coefficient to guide the peak regulation decision-making of the cogeneration units can maximize the operating income of the unit.

To address the hydrodynamic instability and combustion disturbances of a 600 MW supercritical oncethrough boiler at Ligang power plant during deep peak regulation down to 20% rated load，a hydrodynamic calculation model for the water wall and a coupled simulation platform for the combustion system were established based on the actual boiler structure and operational parameters. Through the combination of numerical simulations and field tests， the mass velocity distribution characteristics，wall temperature deviation，and pulsation risks under low-load conditions were quantitatively analyzed. A dynamic control strategy based on the optimization of coal mill combinations was proposed. The results show that adopting the mid-upper coal mill combination（B+C+D）with a staged air distribution strategy can reduce the water wall mass velocity deviation to 18.7%. The research findings provide a theoretical basis for the deep peak regulation of supercritical units.

To further enhance the peak regulation capability and reduce fuel costs of coal-fired power plants， achieving multi-coal types compartmentalized storage and flexible blending， a 650 MW ultra-supercritical coal-fired unit was taken as the research subject to study the rapid switching technology of high/low calorific-value coals in raw coal bunkers， which was suitable for fast load changes in high-parameter coal-fired units. Meanwhile， based on the actual production and operation of the case unit， a comparative analysis was conducted on various schemes， including partition plate， shrimp-shaped outer bunker， conduit connection between two raw coal bunkers， and parallel screw conveyor bunker separation. Simulation software was also used to assist in the scheme design. Results show that the conduit connection between two raw coal bunkers scheme enables rapid switching of high/low calorific-value coals in the coal feeder， meeting the requirements for efficient and economical operation of the system.

Establishing an accurate and efficient integrated energy system model on the source side of thermal power plants is crucial for optimizing the system management process and improving the safety and economy of operation，and is an important reference for the planning and transformation of thermal power plants. A digital twin operation and maintenance model of the integrated energy system on the source side of thermal power plants based on feedforward neural networks was proposed. This system took the thermal power unit as the core，coupled three types of renewable energy，namely biomass gasification，waste gasification and dried sludge，at the input end，and supplied four types of energy products，namely cold，heat，steam and electricity，at the output end. The feedforward neural network was trained using the computational data provided by the physical model，and its optimal hyperparameters were calculated. The corresponding neural network model was constructed，and finally a digital twin model was formed. Through comparison and verification with the physical model，it is found that this digital twin model has good calculation accuracy and high calculation efficiency，and can complete the prediction within milliseconds.

In order to optimize the control effect of the boiler fans in cogeneration power plants and improve the combustion efficiency and energy efficiency level，a frequency prediction model suitable for boiler fans was developed. Two prediction models were constructed using the fan performance method and the boiler operating condition method， and the two models were verified based on the actual data. The results show that the boiler operating condition method has higher accuracy in fan frequency prediction compared with the fan performance method. The frequency prediction relative errors of the primary fan and the secondary fan have decreased to 0.03% and 0.39%，respectively. Therefore， the prediction model established by the boiler operating condition method can provide more reliable fan frequency prediction results for the operators of cogeneration power plants，which is conducive to achieving the optimal control of boiler fans operation，reducing fan energy consumption，and improving the overall production efficiency of cogeneration power plants.

The CAP1000 unit is a representative of advanced pressurized water reactor nuclear power technology independently developed in China. The overspeed protection system of its steam turbine is the core to ensure the safe operation of the unit. To identify an optimal solution，the traditional "mechanical and electrical overspeed" scheme and the innovative "dual electrical overspeed" scheme were compared，and an analysis was conducted from the aspects of technical compliance，safety redundancy，operation and maintenance efficiency，and economy，supported by a case study. The results demonstrate that upgrading from mechanical overspeed protection to independent electrical overspeed protection conforms to the technical trends and relevant standards of the nuclear power industry. It enhances protection response speed，simplifies operation and maintenance，and delivers both safety and economic benefits. The research findings can serve as a reference for the design and retrofit of CAP1000 units.

In order to enhance the competitive advantage of industrial steam turbines in the thermoelectric field， increasing the pressure in the turbine impeller chamber can effectively improve the internal efficiency of the entire machine. However，the increase of impeller chamber pressure poses higher requirements for the strength and low cycle fatigue life of the high pressure inner cylinder. Therefore，the finite element method and the theory of low cycle fatigue life were adopted to analyze the strength and low cycle fatigue life of the high pressure inner cylinder. The research results show that stress concentrations are prone to appearance at the connection points of the inner cylinder structure and the areas with sudden shape changes，leading to fatigue damage. The research results can provide a theoretical basis for the design and optimization of the inner cylinder of industrial steam turbines.

Experimental study was carried out to investigate the effect of H₂O on the mercury removal performance of modified rice straw coke under conventional combustion conditions. Experiments were conducted to get rice straw coke particles prepared from rice straw in Jiangsu region and modified by chemical impregnation of NH₄Cl combined with HNO₃. A fixed-bed experimental platform was utilized to simulate the flue gas environment of coalfired power plants，through which the mercury removal effect of the modified rice straw coke was tested. The results show that the addition of H₂O inhibits the mercury removal effect of modified rice straw coke under conventional combustion atmosphere（composed of N₂ and 6% O₂）. Further analysis reveals that the increase of H₂O concentration leads to a gradual decrease of mercury adsorption，and the mercury adsorption forms on the surface of coke samples are mainly Hg⁰ and HgO under the H₂O-containing atmosphere，without changing the main adsorption forms. However，H₂O dissociates the oxidizable OH，weakens the Hg⁰ competitive adsorption，and provides additional electrons for the reduction of Hg²⁺. Excessive H₂O concentration will exacerbate the segregation of Hg⁰ and CO₂， leading to the decomposition of unstable oxidation products such as HgCl₂，thus inhibiting the overall Hg removal effect of the adsorbent.

Under special operating conditions， such as in the event of a condensate system accident or condensate throttling for primary frequency regulation of the unit， the deaerator water level may drop. Blindly and rapidly replenishing condensate when the deaerator water level is low can lead to a rapid decrease in deaerator pressure， resulting in insufficient net positive suction head （NPSH） available for the feedwater pump. By simplifying the transient mass-energy balance calculation model of the deaerator， the calculation formula for the conservative maximum condensate flow rate allowed to prevent insufficient NPSH of the feedwater pump was obtained. The calculation results using design parameters are consistent with the parameter variation laws of deaerator simulation modeling and transient calculation. Based on this， a deaerator water level control method was proposed to prevent insufficient NPSH for the feedwater pump by limiting the condensate flow rate. The method has been verified through experiments and can ensure that the NPSH of the feedwater pump is always sufficient.

In the long-term operation of the pulverized coal pipelines in the No. 4 ultra-supercritical unit of a power plant， frequent issues such as support and hanger failure， crossarm deformation， and pulverized coal leakage posed serious safety risks to the unit. The causes of abnormal pipeline expansion were studied through on-site cold and hot state inspection of supports and hangers， disassembly analysis of bellows compensators， and stress simulation calculation using CAESAR Ⅱ software. The results show that improper installation and vibration of the V-type compensator at the coal mill outlet cause the hanger unloading. The bellows compensator at the burner inlet fails due to pulverized coal blockage and hardening of aluminosilicate fibers， unable to compensate for the thermal expansion of the boiler， causing the rigid hanger of the crossarm to be overloaded and deformed. By repairing the blockage in the inner cavity of the compensator， optimizing the pre-tension amount and adjusting the force on the hanger， the abnormal problems of the pulverized coal pipeline， as well as the overloading and complete unloading of the hanger， are successfully solved， providing an important reference for the design， installation and maintenance of the pulverized coal pipeline and its supports and hangers in coal-fired boilers.

With the rapid development of steam turbine technology and the continuous emergence of various new types of steam turbine generator sets， the traditional frame-type foundation has been continuously optimized into a complex foundation with irregular structure. It is difficult to establish a concise and reasonable mechanical model and carry out a correct dynamic analysis for this kind of irregular space structure with multiple mass points and degrees of freedom. Taking the 9F-class gas generator set as an example， based on the vibration response characteristics of components such as the foundation base plate， column pier， and frame under the action of horizontal radial， axial， and vertical disturbing forces， four basic vibration modes with single mass points and single degrees of freedom were established by applying the principle of structural dynamics. Simple dynamic analysis and vibration verification were carried out， and the theoretical calculation values were verified with the on-site measured data. The research results prove that the dynamic analysis and vibration calculation method for the complex foundation of this large-scale power machine is reasonable and feasible， and has certain reference value.

To address the problem of poor drainage of high pressure heaters under deep peak regulation conditions， taking a 650 MW unit as the research object and combining the operating characteristics of high pressure heaters during deep peak regulation of the unit， an optimized drainage system for high pressure heaters based on a booster pump was proposed. This system adds a drainage bypass to the original normal drainage pipeline， uses a booster pump to overcome the water level pressure difference between the high pressure heater and the deaerator， and realizes the automatic switching of the drainage pipeline at low loads through the coordination of valve groups， meeting the requirements for normal operation of high pressure heaters drainage under deep peak regulation.

In order to ensure the safe operation of the generating set， a detailed analysis was conducted on the typical corrosion problems of two waste heat boilers in a gas-fired power plant. Specific types of corrosion included low-temperature corrosion， erosion corrosion， corrosion under insulation layer， uniform dissolved oxygen corrosion， atmospheric oxygen corrosion and stress corrosion. The results show that the main causes of corrosion include low-pressure recirculation system not being put into operation， the outer protection of the insulation layer not being tight， internal leakage of the valve， impurities in the pipeline， small curvature radius of the elbow， moisture in the equipment after the furnace is shut down， rainwater seeping into the insulation layer， and the pipe material being sensitive to stress corrosion. Therefore， effective corrosion prevention and control measures are proposed to ensure the safe operation of the equipment throughout its service life.

In order to consume green electricity and promote the construction of low carbon industrial parks， a system integration solution of "green electricity-energy storage-heating" based on molten salt energy storage technology was proposed. By constructing a molten salt energy storage system， the renewable energy consumption capacity can be effectively improved， while significantly reducing the carbon emissions of industrial parks. Based on the current situation of using thermal power plants to supply steam for an industrial park， a design was conducted using an electric heating molten salt energy storage system. The economy of using the molten salt energy storage system was evaluated by analyzing equipment selection and system operation. The results show that this scheme is expected to reduce the annual heating cost by 22% and the annual carbon emissions by approximately 3 241 t of the park. The molten salt energy storage system provides a replicable solution for building low carbon energy systems in industrial parks， and has important practical value for promoting energy structure adjustment in the industrial field.

The full life cycle aging management of nuclear power plants is a key task for the "Hualong One" nuclear power units. In order to effectively manage the aging issues of the "Hualong One" nuclear power units， it is necessary to retain material aging samples for concrete and cables. By analyzing the failure mechanisms of concrete and cable materials and combining with the actual operating conditions of the nuclear power plant， the concrete in the reactor pressure vessel pit area and the top of the outer dome of the containment vessel， and the cables in the steam generator， pressure stabilizer， and main steam pipeline room were finally selected for sample retention， forming a list of aging samples for concrete and cables. The implementation nodes for the regular inspection of subsequent aging management were planned， and finally the problems encountered during the implementation of the retained samples were summarized.

Yaw deviation of wind turbines is commonly observed in operational wind farms， and the lack of appropriate measurement methods hinders accurate deviation assessment， preventing turbines from achieving optimal performance. To address the issue of static yaw deviation in wind turbine generator system， a quantitative analysis method based on operating condition segmentation and bidirectional binning was proposed. Utilizing big data technology and feature models， the method conducted both qualitative and quantitative analyses of historical operational data to achieve precise identification and quantification of static yaw deviation. Based on the operation data of a wind farm， support vector regression （SVR） was used for data preprocessing， and the yaw deviation was quantitatively evaluated by combining the operating condition segmentation and bidirectional binning method of wind speed and power. Results show that this method can effectively identify the yaw static deviation of wind turbine generator system， providing quantitative input for the yaw correction control and power curve optimization of wind farms， thereby providing effective support for improving the operation and maintenance efficiency of wind farms.

A 2×600 MW unit in a power plant employs a dual-tower series desulfurization technology. During operation， the oxidation air ducts inside the tower frequently broke， resulting in a deterioration of the slurry quality in the absorption tower and difficulties in gypsum dewatering. Field inspection and analysis revealed that insufficient mechanical strength and improper support arrangement were the primary causes of duct failure. Based on an in-depth analysis of the corrosive environment inside the tower， the differences in performance and price among three commonly used stainless steels for desulfurization were analyzed. It is recommended to replace the material of the oxidation air duct with 2205 duplex stainless steel， which has high strength and excellent corrosion resistance， to meet the performance requirements and achieve a higher cost-effectiveness. Increasing the wall thickness of the air duct and optimizing its fixation method can effectively reduce stress concentration and prevent the deformation of the air duct. The transformation has achieved remarkable results， providing valuable reference experience for similar upgrades.

In order to solve the problem of reheat steam temperature deviation during the comprehensive upgrading and transformation for a unit，the inter-tube panel flow distribution curve of the high-temperature reheater before the transformation was obtained through mathematical modeling. Combined with the measured values of the operating wall temperature，the heat exchange deviation on the flue gas side was calculated. Under the new transformation boundary，based on the known deviation of the flue gas side，the structural form of the header was renovated and optimized，and the optimization plan was determined. Results show that a high heat-transfer zone exists slightly right of the furnace center because of the residual swirl at the furnace exit and the size of the imaginary circle. By reducing the temperature rise amplitude of the high-temperature reheaters and adjusting the positions of the radial inlet and outlet tees，the temperature deviation level of the reheat steam can be significantly reduced，achieving the transformation goal.

To address the limitations of existing methods in handling non-stationary data and extracting salient features for monitoring ash blockage in rotary air preheaters of power station boilers， a hybrid differential pressure prediction model that integrates variational mode decomposition （VMD）， convolutional neural network （CNN）， bidirectional long short-term memory （BiLSTM）， and frequency-enhanced channel attention mechanism （FECAM） was proposed. To further improve the decomposition quality of VMD， the goose optimization algorithm （GOOSE） was employed to adaptively optimize the number of modes and the penalty factor， thereby enhancing the model’s ability to suppress noise interference. Experimental validation using real-world operational data from a coal-fired power plant demonstrates that the proposed model reduces root mean square error （RMSE）， mean absolute error （MAE）， and mean absolute percentage error （MAPE） by 42.93%， 43.58%， and 44.72%， respectively， in single-step forecasting compared to the baseline BiLSTM model. Additionally， the model exhibits superior robustness and predictive stability in multi-step forecasting tasks， outperforming other time series prediction models.

In photovoltaic power stations，high-power string inverters often employ forced air cooling as a heat dissipation method to control the operating temperature of the equipment. During actual operation，the air inlets of these inverters are prone to being blocked by dust， willow catkins and other impurities in the surrounding environment，which can lead to thermal failure. To address this issue，a numerical simulation method was adopted for analysis and research. A numerical model with engineering accuracy was constructed，and based on the simulation results，a self-cleaning solution that takes into account the heat dissipation performance was designed. The results show that this solution not only ensures the heat dissipation performance of the inverter under normal operation but also has strong self-cleaning ability for the air inlets. Field test results have verified the feasibility and actual operation effect of the solution，providing an efficient solution for the problem of air inlet blockage in in-service inverters in photovoltaic power stations and having significant application reference value.

Theoretical modeling and simulation analyses of primary frequency control for the digital electric hydraulic control system （DEH） of 1 000 MWclass thermal power generating units were carried out. Firstly， an electro-hydraulic servo system model considering nonlinear factors was established. Secondly， a variable-parameter steam turbine model was proposed， in which the error does not change with the variation of the operating point of the unit load. A DEH optimization model considering nonlinear factors and the influence of load changes was established. This model is more consistent with the actual operating characteristics of deep peak regulation units and can maintain good accuracy and consistency within a wide range of deep peak regulation load intervals. A Simulink simulation model was established for a 1 000 MW class unit to analyze its primary frequency control performance under deep peak regulation conditions， and the results were compared with the unit’s actual test data， validating the accuracy of the established primary frequency control model.

Under deep peak regulation operations， the primary air temperature of a subcritical 300 MW lignite-fired boiler in the eastern part of Inner Mongolia was relatively low， resulting in insufficient drying capacity of the pulverizing system and adversely affecting the combustion process inside the furnace. Therefore， a retrofit plan was proposed to install a steam heater in the primary air duct of the air preheater to increase the hot primary air temperature. The results show that the scheme can increase the primary air temperature by at least 35 ℃， and the effect of temperature improvement is remarkable under deep peak regulation operations. The technology can also optimize the distribution of air volume in the furnace and improve the boiler thermal efficiency.