Currently， the design of fuel cells mainly aims to meet the usage requirements in plains， and there are relatively few studies on their output performance in high-altitude areas. To broaden the application scenarios of fuel cells， a model was constructed based on Simulink. Through simulation calculations， the quantitative impact of altitude variations from 0 to 3 000 meters on fuel cell parameters， such as single-cell voltage， efficiency， and net output power was analyzed. Meanwhile， the variation patterns of the air compressor operating points at different altitudes were also examined. The results indicate that as altitude increases， on the one hand， the single-cell voltage， efficiency， and net output power of the fuel cell system all decrease. This decline is particularly pronounced at high current densities， where the maximum net output power drops by over 50%. On the other hand， the air compressor operating point continuously shifts towards the upper left region of its map. At 2 000 meters altitude and a low current density of 0.3 A/cm²， the operating point enters the surge range. At a high current density of 1.5 A/cm²， the pressure ratio of the operating point exceeds the effective range， indicating insufficient air supply capability from the compressor. To address these issues， optimization measures for enhancing fuel cell performance in plateau regions were proposed. This research establishes a theoretical foundation for promoting the application of fuel cells in high-altitude， low-pressure areas.

A systematic analysis and research were conducted on the flow characteristics of the hydraulic actuator of the gas fuel control valve of a gas turbine. By establishing a finite element model of the hydraulic cylinder fluid domain and the valve group actuator， the flow characteristics of the two internal chambers and the inlet and outlet sections of the hydraulic cylinder were calculated. The flow field of the hydraulic cylinder was used as the boundary condition required by the actuator to analyse its static characteristics under the influence of the flow field， resulting in pressure cloud diagrams， velocity cloud diagrams， and flow streamlines. Results show that， the internal flow field pressure of the hydraulic cylinder is much lower than the material strength of the cylinder body， piston， and piston rod. Moreover， the maximum stress experienced by the actuator， piston rod， front and rear end caps， and the connection with the cylinder body is all below the material yield limit， indicating that the design meets the requirements. The research results can provide a theoretical basis for the design of the actuator and have important engineering application value.

A finite element model of in-service rigid hangers was established， and pre-stressed modal analysis was conducted to obtain the corresponding relationship between the first-order natural frequency of the rigid hanger and the applied load. Based on this relationship， the quantitative load measurement of in-service rigid hangers was indirectly achieved by measuring the natural frequency. Under the condition of no axial force， the accuracy of the finite element analysis method for solving the natural frequency was verified by comparing the finite element solution of the natural frequency with the analytical solution. In addition， a load uniformity adjustment strategy was proposed， which can control the load non-uniformity of the furnace-top rigid hangers within 5%， thereby significantly enhancing the capability for safe operation of the unit.

Numerical simulations were conducted on a 330 MW tangential coal-fired boiler burning high-alkali coal to predict the combustion characteristics and the easily corroded positions of the heating surface under different imaginary circle diameters and air distribution methods conditions. The results show that when the imaginary circle diameter is 800-1 000 mm，with the increase of the diameter，the area of the high-temperature zone shows a trend of first increasing，then decreasing and then increasing again，and the combustion reaction is enhanced. When the imaginary circle diameter further increases，the risk of the water cooled wall corrosion increases. Compared with the reference condition of uniform air distribution，increasing the air volume of the lower nozzle is conducive to the thorough mixing and combustion of fuel. In the air distribution method of reducing the air volume at the bottom layer，the diameter of the tangent circle at the center of the bottom layer increases. The upper layer area has sufficient oxygen，and the combustion is more complete. The overall temperature of the furnace is higher than that under other conditions. Furthermore，CO is mainly distributed in the high-temperature area. The CO content in the middle layer of the burner area is higher under the air distribution method of reducing the air volume of the middle nozzle. The wall area between the bottom and the top separated overfire air （SOFA） is prone to high-temperature corrosion caused by SO₂.

The variation characteristics of the primary and secondary air velocities at the burner outlet of a four-corner tangential firing boiler under deep peak regulation conditions were studied， and based on this， the variation law of the aerodynamic field in the furnace was analysed. Results show that under low-load conditions， the organizing ability of the secondary air flow to the aerodynamic field is significantly reduced， and the combustion state within the furnace is characterized by slow flow and mixing， resulting in a loose combustion mode that is not conducive to stable combustion at low loads. To address these issues， a transformation technical scheme was proposed to effectively increase the secondary air velocity at the burner outlet under low loads. This scheme has significant value for engineering implementation.

A study was conducted on the heat load deviation problem of a 1 000 MW ultra-supercritical double tangential circular boiler to reveal its causes and propose a comprehensive governance strategy. The research shows that the heat load deviation is mainly caused by the “hot corner” formed in the overlapping area of the combustion side tangential circles， uneven distribution of primary air velocity and pulverized coal concentration， secondary air volume deviation， instability of working fluid flow in the vertical water wall， and burner installation angle deviation. Among them， the distributed control system （DCS） value of the secondary air volume is opposite to the actual value， which aggravates the high-temperature phenomenon in the rear wall area. Under low-load conditions， the hydrodynamic instability further expands the imbalance of the heat load distribution. Therefore， a series of control measures were formulated： optimizing the combustion system， differentially adjusting the secondary air dampers， correcting the burner installation angle， and optimizing the size of the throttle orifice ring at the water wall inlet. After comprehensive governance， the secondary air volume distribution on the front and rear walls tends to be balanced， the number of over-temperature occurrences in the water wall is reduced by 54.1%， the wall temperature change rate is significantly reduced， and the flue gas temperature deviation between the front and rear walls is basically eliminated. The research results prove that the comprehensive governance strategy is effective in improving the heat load distribution and enhancing the boiler safety and operation stability.

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 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.

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.

An off-grid wind-solar-diesel-storage hybrid power generation system applied at the ash disposal management station of a power plant was introduced， covering its basic composition， working principle and the characteristics of the main equipment. This power generation system comprehensively takes into account local natural conditions， wind and solar resources， electricity demand and the characteristics of energy storage system， and selects a more reasonable capacity configuration. While ensuring the continuity and rationality of power supply， it effectively improves the utilization rate of wind and solar energy. The system provides a low-cost and highly reliable power source. Through the self-generation and self-use mode， it fully meets the living and production electricity needs of the ash disposal management station and has achieved good application results. It is suitable for ash disposal management stations of power plants located in remote areas without power supply.

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.