Investigating Load Regulation Characteristics of a Wind-PV-Coal Storage Multi-Power Generation System

There is a growing need to explore the potential of coal-fired power plants(CFPPs)to enhance the utilization rate of wind power(wind)and photovoltaic power(PV)in the green energy field.This study developed a load regulation model for a multi-power generation system comprising wind,PV,and coal energy storage using realworld data.The power supply process was divided into eight fundamental load regulation scenarios,elucidating the influence of each scenario on load regulation.Within the framework of the multi-power generation system with the wind(50 MW)and PV(50 MW)alongside a CFPP(330 MW),a lithium-iron phosphate energy storage system(LIPBESS)was integrated to improve the system’s load regulation flexibility.The energy storage operation strategy was formulated based on the charging and discharging priority of the LIPBESS for each basic scenario and the charging and discharging load calculation method of LIPBESS auxiliary regulation.Through optimization using the particle swarm algorithm,the optimal capacity of LIPBESS was determined to be within the 5.24-4.88 MWh range.From an economic perspective,the LIPBESS operating with CFPP as the regulating power source was 49.1% lower in capacity compared to the renewable energy-based storage mode.

An Investigation of Battery Energy Storage Aided Wind-Coal Integrated Energy System

This paper studies the feasibility of a supply-side wind-coal integrated energy system.Based on grid-side data,the load regulation model of coal-fired power and the wind-coal integrated energy system model are established.According to the simulation results,the reasons why the wind-coal combined power supply is difficult to meet the grid-side demand are revealedthrough scenario analysis.Basedon thewind-coal combinedoperation,a wind-coalstorage integrated energy system was proposed by adding lithium-iron phosphate battery energy storage system(LIPBESS)to adjust the load of the system.According to the four load adjustment scenarios of grid-side instructions of the wind-coal system,the difficulty of load adjustment in each scenario is analyzed.Based on the priority degree of LIPBESS charge/discharge in four scenarios at different time periods,the operation mode of two charges and two discharges per day was developed.Based on the independent operation level of coal-fired power,after the addition of LIPBESS(5.5 MWh),the average qualified rate of multi-power operation in March and June reached the level of independent operation of coal-fired power,while the average qualified rate of the remaining months was only 5.4%different from that of independent operation of coal-fired power.Compared with the wind storage mode,the energy storage capacity and investment cost of wind-coal-storage integrated energy system are reduced by 54.2%and 53.7%,respectively.

Partial Surface Damper to Suppress Vibration for Thin Walled Plate Milling

The material removal rate and required work- piece surface quality of thin-walled structure milling are greatly limited due to its severe vibration, which is directly associated with the dynamic characteristics of the system. Therefore, the suppression of vibration is an unavoidable problem during milling. A novel partial surface damping method is proposed to modify the mode of the thin walled cantilever plate and to suppress vibration during milling. Based on classical plate theory, the design criterion is analyzed and configuration of the partial surface damper is introduced, in which viscoelastic plate and constraining plate are attached to the surface of the plate to increase the system＇s natural frequency and loss factor. In order to obtain the energy expression of the cutting system, the Ritz method is used to describe the unknown displacements. Then, with Lagrange＇s equation, the natural frequency and loss factor are calculated. In addition, the plate is divided into a finite number of square elements, and the regulation of treated position is studied based on theoretic and experimental analysis. The milling tests are conducted to verify its damping performance and the experimentalresults show that with treatment of partial surface damper, the deformation of the hare plate is reduced from 0.27 mm to 0.1 mm, while the vibration amplitude of the bare plate is reduced from 0.08 mm to 0.01 mm. The proposed research provides the instruction to design partial surface damper.

KH550-SiO_(2)/polyimide insulating paper preparation and characterisation

Oil-paper insulation material is an essential component for oil-filled transformers,and polyimide(PI)insulation paper is a novel material in the field of electricity.The improvement of insulation class for insulation paper has gained significant attention in recent years.In this study,SiO_(2)nanoparticles were modified with a silane coupling agent(KH550),and the KH550-SiO_(2)was added to the fibre membrane through in situ poly-merisation.The chemical composition and microcosmic characteristics of the PI porous fibre membrane were characterised using FT-IR and SEM FT-IR and SEM.Conse-quently,the dielectric constant of the composite paper was reduced to 2.3 upon adding 3 wt%of KH550-SiO_(2),and the dielectric strength reached its maximum value of 85 kV/mm.The results demonstrate that the insulation performance of the KH550-SiO_(2)/PI composite was significantly improved due to the incorporation of nano-SiO_(2).This establishes an efficient approach for achieving excellent electrical and thermal properties in practical applications using the KH550-SiO_(2)/PI fibre membrane.

A novel stability prediction approach for thin-walled component milling considering material removing process

The milling stability of thin-walled components is an important issue in the aviation manufacturing industry, which greatly limits the removal rate of a workpiece. However, for a thin-walled workpiece, the dynamic characteristics vary at different positions. In addition, the removed part also has influence on determining the modal parameters of the workpiece. Thus,the milling stability is also time-variant. In this work, in order to investigate the time variation of a workpiece＇s dynamic characteristics, a new computational model is firstly derived by dividing the workpiece into a removed part and a remaining part with the Ritz method. Then, an updated frequency response function is obtained by Lagrange＇s equation and the corresponding modal parameters are extracted. Finally, multi-mode stability lobes are plotted by the different quadrature method and its accuracy is verified by experiments. The proposed method improves the computational efficiency to predict the time-varying characteristics of a thin-walled workpiece.

Mesenchymal stromal cells alleviate acute respiratory distress syndrome through the cholinergic anti-inflammatory pathway

Mesenchymal stromal cells(MSCs)have been considered a promising alternative for treatment of acute respiratory distress syndrome(ARDS).However,there is significant heterogeneity in their therapeutic efficacy,largely owing to the incomplete understanding of the mechanisms underlying the therapeutic activities of MSCs.Here,we hypothesize that the cholinergic antiinflammatory pathway(CAP),which is recognized as a neuroimmunological pathway,may be involved in the therapeutic mechanisms by which MSCs mitigate ARDS.Using lipopolysaccharide(LPS)and bacterial lung inflammation models,we found that inflammatory cell infiltration and Evans blue leakage were reduced and that the expression levels of choline acetyltransferase(ChAT)and vesicular acetylcholine transporter(VAChT)in lung tissue were significantly increased 6 hours after MSC infusion.When the vagus nerve was blocked orα7 nicotinic acetylcholine(ACh)receptor(α7nAChR)-knockout mice were used,the therapeutic effects of MSCs were significantly reduced,suggesting that the CAP may play an important role in the effects of MSCs in ARDS treatment.Our results further showed that MSC-derived prostaglandin E2(PGE2)likely promoted ACh synthesis and release.Additionally,based on the efficacy of nAChR andα7nAChR agonists,we found that lobeline,the nicotinic cholinergic receptor excitation stimulant,may attenuate pulmonary inflammation and alleviate respiratory symptoms of ARDS patients in a clinical study(ChiCTR2100047403).In summary,we reveal a previously unrecognized MSC-mediated mechanism of CAP activation as the means by which MSCs alleviate ARDS-like syndrome,providing insight into the clinical translation of MSCs or CAP-related strategies for the treatment of patients with ARDS.