国网上海市电力公司

[Objectives]In order to effectively improve the energy storage characteristics and system efficiency of compressed air energy storage(CAES)systems,the performance of each component and their coupling characteristics are modeled and analyzed.[Methods]In this study,for CAES systems,the standard thermal resistance method is applied to take into account the transfer characteristics of the heat exchange components.Combined with the gas storage device and the work component model,this study establishes a comprehensive thermodynamic model integrating heat transfer,gas storage,and work coupling,along with an energy and exergy analysis model.The influence of the mass flow rate of energy storage and release on the system performance during compression and expansion is evaluated.The pattern of influence of the relationship between the maximum gas storage pressure and volume of the gas storage reservoir on the system energy storage efficiency and energy storage density is revealed.[Results]With the increase of the mass flow rate of energy storage and release,the total energy consumption of the compressor first decreases and then increases,and the output work of the expander first increases and then decreases.When the mass rates of energy storage and release are 1.2 and 1.3,respectively,the system efficiency reaches the maximum value of 53.65％.In addition,the exergy loss of the first-stage compression and expander in the system is the largest,and the exergy loss of the oil-gas heat exchanger and the compressor accounts for 69％of the total exergy loss of the system.[Conclusions]The established model and the research findings provide important guidance for CAES operational strategy.

With the continuous increase in the penetration rate of distributed photovoltaics,traditional photovoltaic modeling methods are no longer able to meet modeling needs.To establish a model for large-scale regional distribu-ted photovoltaic systems and study their operational characteristics,a dynamic clustering multi-machine equivalent modeling method for distributed photovoltaic power generation systems is proposed.Firstly,representative feature points of the fault curve are selected as clustering indicators.Then,based on the improved FCM(fuzzy-C means)clustering algorithm,the distributed photovoltaic systems in the region are clustered using the selected feature points as indicators.Subsequently,the parameters design of the equivalent model is carried out.For control parameters that are difficult to obtain,a multi-objective optimization algorithm based on NSGA-II(non-dominated sorting genet-ic algorithm II)and principal component analysis is used to identify them.Other parameters are obtained using ca-pacity weighting method.Thus a multi-machine equivalent model for regional distributed photovoltaic systems is constructed.Finally,the feasibility and accuracy of the proposed equivalent modeling scheme of distributed photo-voltaic equivalent model is significantly improved using Simulink simulation tools.

[Objective]Under China's"dual carbon"goals,as energy decarbonization accelerates and renewable energy deployment enters a fast-growth phase,low-probability but high-risk extreme weather poses significant challenges to the safe and reliable operation of new power systems with high renewable energy penetration.Flexible power resources—such as electric vehicles and distributed generation—offer solutions to enhance system resilience during extreme weather.[Methods]This paper outlines the conceptual characteristics of power system resilience and examines the impact of extreme weather on new power systems.It reviews the resilience research of new power systems under extreme weather from three aspects:system component modeling under extreme weather,system resilience analysis methods,and resilience indicator frameworks.Furthermore,by analyzing the adjustable capacity of flexible power resources during extreme weather,the paper proposes strategies for enhancing the resilience of new power systems considering flexibility and extreme weather from four perspectives(generation,grid,load,and storage),and across three stages(prevention,emergency control,and rapid power restoration).[Results]Finally,the paper identifies research directions on the resilience of new power systems with flexible resources under extreme weather,aiming to establish a closed-loop risk management and resilience enhancement framework,and provide a theoretical basis for ensuring power supply during extreme weather.

To address performance degradation caused by detector temperature fluctuations in a dual-chan-nel infrared imaging system for sulfur hexafluoride(SF6)gas leak detection,this study developed an active temperature control module based on a Thermoelectric Cooler(TEC)to enhance its stability.The opti-mal spatial layout of the TEC was determined by combining experimental measurements with thermal field simulations,and a closed-loop control system governed by a PID algorithm was implemented.Compara-tive experiments demonstrated that the integrated control module significantly enhances the system perfor-mance.Regarding imaging quality,the steady-state standard deviation of the grayscale value is reduced by 40.87%,the linearity error is decreased from 7.253 4%to 0.660 4%,and the Noise Equivalent Temper-ature Difference(NETD)is improved by 19.35%,from 14.379 mK to 11.597 mK.In the SF6 gas detec-tion application,the average relative contrast,signal-to-noise ratio,and gas pixel ratio are increased by 123%,56%,and 77%,respectively.This enhancement method effectively suppresses the adverse ef-fects of temperature fluctuations,substantially improving SF6 gas detection capability while enhancing the fundamental imaging quality,and validating a feasible technical pathway for developing high-performance,low-cost portable gas leak detection instruments.

Aluminum sheaths of high-voltage(HV)cables are susceptible to localized damage induced by the combined effects of environmen-tal corrosion and mechanical stress during long-term service,posing a severe threat to the safe and reliable operation of power grids.According-ly,efficient and reliable in-situ repair techniques are urgently needed.To solve the problem that traditional hot brazing often causes thermal damage to insulation layers during in-situ repair of HV cable aluminum sheaths,cold spray solid-state additive manufacturing(CSAM)has be-come an optimal adternative owing to its superior low-temperature solid-state deposition characteristics.Particle impact velocity is the core pa-rameter determining the deposition and repair quality of cold spray.However,the corrugated curved structure commonly adopted in HV cable aluminum sheaths severely disrupts the distribution of the supersonic flow field,significantly affecting the kinetic behavior of particles.In this study,a three-dimensional numerical model was established based on a coupled computational fluid dynamics-discrete phase model(CFD-DPM)method.The shock wave evolution characteristics on both flat and corrugated curved substrates were comparatively investigated.The velocity attenuation of 5-45 μm particles passing through the shock waves under normal incidence was quantitatively characterized,and com-parative deposition experiments using powders with different classified size fractions were conducted.Simulation results revealed that in the near-wall region of the curved substrate,influenced by shock waves,gas velocity gradients increased sharply;particle velocities decreased most markedly when the particle size was below 15 μm.Experimental results demonstrated that by removing fine powders(optimizing the particle size range to 15-45 μm)and synergistically adjusting the carrier gas pressure to 0.65 MPa,the adverse effects of shock waves were effectively mitigated,yielding denser coatings.By revealing the kinetic energy dissipation mechanism of particles during cold spray onto curved substrates,this study confirmed the feasibility of improving the repair quality of corrugated aluminum sheaths through particle size gradient optimization,providing theoretical support for the development of in-situ repair processes for power equipment.