分析了现行功率因数考核办法的不足之处,并提出了详细的改善方案。基于江苏省全网无功考核用户的完整统计信息,以未达标用户数和未达标无功电量为关键优化指标,权衡先进性和可行性,提出了功率因数考核指标优化提升方案;结合理论和算例分...分析了现行功率因数考核办法的不足之处,并提出了详细的改善方案。基于江苏省全网无功考核用户的完整统计信息,以未达标用户数和未达标无功电量为关键优化指标,权衡先进性和可行性,提出了功率因数考核指标优化提升方案;结合理论和算例分析,提出了按峰谷平3个时段进行无功考核的考核周期改善方案,并指出有必要将50~100 k VA用户纳入无功考核范围;详细分析了考核指标提升对电网企业和电力用户综合效益的影响,建立了无功电价对用户投资回收期的影响模型。算例结果表明,在实现综合效益合理再分配的前提下,新考核指标具备技术经济可行性。展开更多
Since its first discovery in 2017,evaporation-induced electricity has attracted extensive attention and shown significant advantages in green energy conversion.While the streaming potential-related electrokinetic effe...Since its first discovery in 2017,evaporation-induced electricity has attracted extensive attention and shown significant advantages in green energy conversion.While the streaming potential-related electrokinetic effect has been intensively explored and widely recognized as the underlying mechanism,the role of coupling between water molecules and charge carriers in the material remains elusive.Here we show through carefully designed experiments that the streaming potential effect indeed plays a role but can only contribute about half to the total water-evaporation-induced voltage occurring within the partially-wetted region of the carbon black film where the solid-liquid-gas three-phase interface exists.It is also shown that water evaporation from carboxyl and amino-functionalized carbon black films produces opposite voltage signals.Detailed first-principles calculations unveil that the adsorption of water molecules can lead to reversed charge transfer in the carboxyl and amino-functionalized carbon substrates.Finally,an evaporation-driven charge transport mechanism is proposed for the induced electricity mediated by the coupling between water molecules and charge carriers in the material.The results reveal the important role of direct interaction between water molecules and materials,deepening our understanding of the mechanism for evaporation-induced hydrovoltaic effect beyond streaming potential.展开更多
Electricity and magnetism and electromagnetic induction are phenomena that can be perceived by people. But their interpretation and theoretical study took a long time. The theoretical research on electricity began wit...Electricity and magnetism and electromagnetic induction are phenomena that can be perceived by people. But their interpretation and theoretical study took a long time. The theoretical research on electricity began with the discovery of Coulomb’s law in 1785, while the theoretical research on magnetism began with the discovery of Oersted’s Law in 1820. From the 1850s to the 1870s, Maxwell summarized a set of theoretical equations for electromagnetism based on some laws of predecessors. However, this set of equations contains a few statistical relationships and empirical concepts, so it is difficult to explain the physical nature of electromagnetic phenomena and principles. This paper explained that the macro phenomenon of electricity is the separation of unlike charges of new electrons produced by the orthogonal collision of old particles under the action of external forces. The physical nature of magnetism is the potential energy (magnetic energy) and information associated with the overall orientation of the moving electrons solidly recorded in the material. The physical principle of electromagnetic induction describes how change in electric current intensity generates change in magnetic intensity and vice versa through orthogonal interaction of ordered electrons. This theoretical interpretation does not require the concepts of traditional electromagnetic forces, electromagnetic fields, magnetic moments, and magnetic domains.展开更多
Capacity allocation and energy management strategies for energy storage are critical to the safety and economical operation of microgrids.In this paper,an improved energymanagement strategy based on real-time electric...Capacity allocation and energy management strategies for energy storage are critical to the safety and economical operation of microgrids.In this paper,an improved energymanagement strategy based on real-time electricity price combined with state of charge is proposed to optimize the economic operation of wind and solar microgrids,and the optimal allocation of energy storage capacity is carried out by using this strategy.Firstly,the structure and model of microgrid are analyzed,and the outputmodel of wind power,photovoltaic and energy storage is established.Then,considering the interactive power cost between the microgrid and the main grid and the charge-discharge penalty cost of energy storage,an optimization objective function is established,and an improved energy management strategy is proposed on this basis.Finally,a physicalmodel is built inMATLAB/Simulink for simulation verification,and the energy management strategy is compared and analyzed on sunny and rainy days.The initial configuration cost function of energy storage is added to optimize the allocation of energy storage capacity.The simulation results show that the improved energy management strategy can make the battery charge-discharge response to real-time electricity price and state of charge better than the traditional strategy on sunny or rainy days,reduce the interactive power cost between the microgrid system and the power grid.After analyzing the change of energy storage power with cost,we obtain the best energy storage capacity and energy storage power.展开更多
The emergence of prosumers in distribution systems has enabled competitive electricity markets to transition from traditional hierarchical structures to more decentralized models such as peer-to-peer(P2P)and community...The emergence of prosumers in distribution systems has enabled competitive electricity markets to transition from traditional hierarchical structures to more decentralized models such as peer-to-peer(P2P)and community-based(CB)energy transaction markets.However,the network usage charge(NUC)that prosumers pay to the electric power utility for network services is not adjusted to suit these energy transactions,which causes a reduction in revenue streams of the utility.In this study,we propose an NUC calculation method for P2P and CB transactions to address holistically economic and technical issues in transactive energy markets and distribution system operations,respectively.Based on the Nash bargaining(NB)theory,we formulate an NB problem for P2P and CB transactions to solve the conflicts of interest among prosumers,where the problem is further decomposed into two convex subproblems of social welfare maximization and payment bargaining.We then build the NUC calculation model by coupling the NB model and AC optimal power flow model.We also employ the Shapley value to allocate the NUC to consumers fairly for the NUC model of CB transactions.Finally,numerical studies on IEEE 15-bus and 123-bus distribution systems demonstrate the effectiveness of the proposed NUC calculation method for P2P and CB transactions.展开更多
为了改善生物基锦纶56(PA56)静电严重,可纺性差的缺陷,对PA56短纤维进行抗静电处理并优化梳理工艺。采用手持式静电仪监测了纤维在梳理过程中纤维喂入处、出口处和成卷处的静电势变化,以探究PA56短纤维梳理工艺参数与梳理效果的关系。...为了改善生物基锦纶56(PA56)静电严重,可纺性差的缺陷,对PA56短纤维进行抗静电处理并优化梳理工艺。采用手持式静电仪监测了纤维在梳理过程中纤维喂入处、出口处和成卷处的静电势变化,以探究PA56短纤维梳理工艺参数与梳理效果的关系。结果表明:手持式静电仪可以准确测量纤维表面静电荷,未处理的PA56短纤产生的静电荷多,静电势大,达到+21.2 k V,此时纤维网搭接不连续且堆积在道夫前。经过抗静电处理的PA56纤维在梳理机各个位置的静电电势处于较低水平(≤+0.28 k V),能形成完整均匀的纤维网并且能连续地传递到储棉辊上形成棉卷。棉网出口处的静电释放能力是保证PA56成网质量的关键。PA56纤维梳理优化工艺为:锡林转速500 r/min,锡林、刺辊线速比2.4。展开更多
文摘分析了现行功率因数考核办法的不足之处,并提出了详细的改善方案。基于江苏省全网无功考核用户的完整统计信息,以未达标用户数和未达标无功电量为关键优化指标,权衡先进性和可行性,提出了功率因数考核指标优化提升方案;结合理论和算例分析,提出了按峰谷平3个时段进行无功考核的考核周期改善方案,并指出有必要将50~100 k VA用户纳入无功考核范围;详细分析了考核指标提升对电网企业和电力用户综合效益的影响,建立了无功电价对用户投资回收期的影响模型。算例结果表明,在实现综合效益合理再分配的前提下,新考核指标具备技术经济可行性。
基金the National and Jiangsu Province NSF(T2293691,BK20212008)of ChinaNational Key Research and Development Program of China(2019YFA0705400)+2 种基金the Research Fund of State Key Laboratory of Mechanics and Control of Mechanical Structures(MCMS-I-0422K01)the Fundamental Research Funds for the Central Universities(NJ2022002)the Fund of Prospective Layout of Scientific Research for NUAA(Nanjing University of Aeronautics and Astronautics).
文摘Since its first discovery in 2017,evaporation-induced electricity has attracted extensive attention and shown significant advantages in green energy conversion.While the streaming potential-related electrokinetic effect has been intensively explored and widely recognized as the underlying mechanism,the role of coupling between water molecules and charge carriers in the material remains elusive.Here we show through carefully designed experiments that the streaming potential effect indeed plays a role but can only contribute about half to the total water-evaporation-induced voltage occurring within the partially-wetted region of the carbon black film where the solid-liquid-gas three-phase interface exists.It is also shown that water evaporation from carboxyl and amino-functionalized carbon black films produces opposite voltage signals.Detailed first-principles calculations unveil that the adsorption of water molecules can lead to reversed charge transfer in the carboxyl and amino-functionalized carbon substrates.Finally,an evaporation-driven charge transport mechanism is proposed for the induced electricity mediated by the coupling between water molecules and charge carriers in the material.The results reveal the important role of direct interaction between water molecules and materials,deepening our understanding of the mechanism for evaporation-induced hydrovoltaic effect beyond streaming potential.
文摘Electricity and magnetism and electromagnetic induction are phenomena that can be perceived by people. But their interpretation and theoretical study took a long time. The theoretical research on electricity began with the discovery of Coulomb’s law in 1785, while the theoretical research on magnetism began with the discovery of Oersted’s Law in 1820. From the 1850s to the 1870s, Maxwell summarized a set of theoretical equations for electromagnetism based on some laws of predecessors. However, this set of equations contains a few statistical relationships and empirical concepts, so it is difficult to explain the physical nature of electromagnetic phenomena and principles. This paper explained that the macro phenomenon of electricity is the separation of unlike charges of new electrons produced by the orthogonal collision of old particles under the action of external forces. The physical nature of magnetism is the potential energy (magnetic energy) and information associated with the overall orientation of the moving electrons solidly recorded in the material. The physical principle of electromagnetic induction describes how change in electric current intensity generates change in magnetic intensity and vice versa through orthogonal interaction of ordered electrons. This theoretical interpretation does not require the concepts of traditional electromagnetic forces, electromagnetic fields, magnetic moments, and magnetic domains.
基金a phased achievement of Gansu Province’s Major Science and Technology Project(W22KJ2722005)“Research on Optimal Configuration and Operation Strategy of Energy Storage under“New Energy+Energy Storage”Mode”.
文摘Capacity allocation and energy management strategies for energy storage are critical to the safety and economical operation of microgrids.In this paper,an improved energymanagement strategy based on real-time electricity price combined with state of charge is proposed to optimize the economic operation of wind and solar microgrids,and the optimal allocation of energy storage capacity is carried out by using this strategy.Firstly,the structure and model of microgrid are analyzed,and the outputmodel of wind power,photovoltaic and energy storage is established.Then,considering the interactive power cost between the microgrid and the main grid and the charge-discharge penalty cost of energy storage,an optimization objective function is established,and an improved energy management strategy is proposed on this basis.Finally,a physicalmodel is built inMATLAB/Simulink for simulation verification,and the energy management strategy is compared and analyzed on sunny and rainy days.The initial configuration cost function of energy storage is added to optimize the allocation of energy storage capacity.The simulation results show that the improved energy management strategy can make the battery charge-discharge response to real-time electricity price and state of charge better than the traditional strategy on sunny or rainy days,reduce the interactive power cost between the microgrid system and the power grid.After analyzing the change of energy storage power with cost,we obtain the best energy storage capacity and energy storage power.
基金supported in part by the Foundation of State Key Laboratory of Alternate Electrical Power System with Renewable Energy Sources(No.LAPS22015)in part by Shanghai Science and Technology Development Funds(No.22YF1429500)。
文摘The emergence of prosumers in distribution systems has enabled competitive electricity markets to transition from traditional hierarchical structures to more decentralized models such as peer-to-peer(P2P)and community-based(CB)energy transaction markets.However,the network usage charge(NUC)that prosumers pay to the electric power utility for network services is not adjusted to suit these energy transactions,which causes a reduction in revenue streams of the utility.In this study,we propose an NUC calculation method for P2P and CB transactions to address holistically economic and technical issues in transactive energy markets and distribution system operations,respectively.Based on the Nash bargaining(NB)theory,we formulate an NB problem for P2P and CB transactions to solve the conflicts of interest among prosumers,where the problem is further decomposed into two convex subproblems of social welfare maximization and payment bargaining.We then build the NUC calculation model by coupling the NB model and AC optimal power flow model.We also employ the Shapley value to allocate the NUC to consumers fairly for the NUC model of CB transactions.Finally,numerical studies on IEEE 15-bus and 123-bus distribution systems demonstrate the effectiveness of the proposed NUC calculation method for P2P and CB transactions.
文摘为了改善生物基锦纶56(PA56)静电严重,可纺性差的缺陷,对PA56短纤维进行抗静电处理并优化梳理工艺。采用手持式静电仪监测了纤维在梳理过程中纤维喂入处、出口处和成卷处的静电势变化,以探究PA56短纤维梳理工艺参数与梳理效果的关系。结果表明:手持式静电仪可以准确测量纤维表面静电荷,未处理的PA56短纤产生的静电荷多,静电势大,达到+21.2 k V,此时纤维网搭接不连续且堆积在道夫前。经过抗静电处理的PA56纤维在梳理机各个位置的静电电势处于较低水平(≤+0.28 k V),能形成完整均匀的纤维网并且能连续地传递到储棉辊上形成棉卷。棉网出口处的静电释放能力是保证PA56成网质量的关键。PA56纤维梳理优化工艺为:锡林转速500 r/min,锡林、刺辊线速比2.4。
