Optimal configuration of islanded microgrid capacity considering energy utilization and power supply reliabilityGong, Wei; Wang, Xihuai
doi: 10.1088/1742-6596/2993/1/012015pmid: N/A
The inherent periodicity, randomness, and volatility of renewable energy sources such as ocean energy pose substantial challenges to the energy supply stability and self-sufficiency of isolated island microgrids. This paper aims to determine the optimal capacity and evaluate the techno-economic benefits of independent microgrids on remote islands in the East China Sea. Specifically, considering a hybrid energy microgrid system comprising photovoltaic panels, wind turbines, marine power generation devices, battery energy storage systems, and diesel generators. The optimal configuration of this model is determined using an enhanced sparrow search algorithm, with constraints ensuring stable microgrid operation and maximizing the utilization rate of renewable energy resources. The objective is to achieve the lowest annual comprehensive cost. The results of the example verify that the improved algorithm optimizes the microgrid configuration and controls the renewable energy reduction rate and annual power shortage rate at 1.93% and 2.42%, respectively.
Research on fast transient overvoltage suppression measures in 750kV GISJiang, Longyun
doi: 10.1088/1742-6596/2993/1/012062pmid: N/A
The isolation switch in gas-insulated switchgear (GIS) will generate rapid transient overvoltage VFTO during opening and closing, which will cause great harm to the GIS itself and adjacent equipment. In order to solve the problem of rapid transient overvoltage in GIS, the electromagnetic transient program (ATP-EMTP) was used to simulate and calculate two measures to suppress rapid transient overvoltage: installing a zinc oxide arrester (MOA) and installing a closing resistor. The research results indicate that firstly, the zinc oxide arrester (MOA) installed only on the transformer side can, to some extent, limit overvoltage, but the main suppression effect is reflected in the equipment near the MOA, and the suppression effect is relatively small for electrical equipment far away from the MOA such as isolation switches, CTs, etc. Secondly, after installing a 500Ω closing resistor, the VFTO level of GIS internal and external equipment, such as transformers, CTs, and other electrical devices, was effectively suppressed, with amplitudes below 1000kV and wavefront steepness reduced.
Lab testing cycle research of gasoline light duty vehicle for real-driving emissionsZhang, Qingmao; Ren, Xiangfei; Wan, Dong; Wang, Jiangwei; Wu, Xiangke; Chen, Chu; Chen, Shengdian; Ji, Hongyu; Chen, Jiahao; Ren, Peng
doi: 10.1088/1742-6596/2993/1/012070pmid: N/A
In line with the China 6B emissions regulation, Real Driving Emissions (RDE) have been introduced as an additional type of approval requirement. This aims to account for the influence of road profiles, ambient conditions, traffic situations, and driving behavior. However, the RDE testing procedure imposes stringent requirements, leading to high experimental costs and increased risks of failure. To address these challenges, this study utilizes a standardized random test procedure alongside the maximum 95th percentile of the v•A pos cycles to assess RDE emissions on a chassis dynamometer. The World Harmonized Light-Duty Test Cycle (WLTC) and real-world on-road driving conditions serve as comparative references. Additionally, cold start performance is evaluated across these various test cycles to provide a comprehensive analysis of emission characteristics.
Experimental research on the thermal runaway of lithium-iron-phosphate batteries under high-speed impact conditionRan Li, Aona
doi: 10.1088/1742-6596/2993/1/012029pmid: N/A
With the rapid development of the new energy vehicle industry, the safety of power lithium-iron batteries has garnered significant attention. In this article, a 50 Ah square lithium-iron phosphate battery is used as the research object for a high-speed impact test. Through the self-designed high-speed impact test device of the lithium-ion battery, the piston is powered by high-pressure gas to impact the 50 Ah square lithium-iron phosphate battery, and the gas pressure is changed to simulate the impact of different speeds on the battery. We analyze the electric heating response of the battery under different impact conditions, study the impact speed, impact depth, punch shape, and state of charge on the impact safety of the battery, using the battery voltage and temperature changes after impact to describe the thermal runaway risk of the battery. The results show that the higher the impact velocity and the deeper the impact depth do not necessarily lead to a greater risk. There is a critical impact velocity and critical impact depth that make the risk of thermal runaway of the impact greatest. When the spherical punch hits the battery, the larger the punch diameter is, the faster the battery temperature rises and the higher the peak temperature is. When the sharp object destroys the battery, it is easier to cause thermal runaway, and the risk of thermal runaway is greater. With the increase of the battery’s state of charge, the risk of battery thermal runaway increases. This study supplemented research on the different factors affecting the thermal runaway risk of lithium-iron-phosphate batteries under the condition of high-speed impact and provided effective support for the safety research of lithium-iron-phosphate batteries.
Maximum power tracking of wave energy generation system based on improved sparrow search algorithmLan, Ying; Huang, Jiayu
doi: 10.1088/1742-6596/2993/1/012011pmid: N/A
The sparrow search algorithm (SSA) has emerged as a promising swarm intelligence optimization technique, particularly in the context of maximum power point tracking (MPPT) for wave energy generation systems. It has demonstrated significant potential in optimizing power capture efficiency. Building on this foundation, this paper introduces an enhanced variant of the SSA, termed the Firefly Search Perturbation-based Sparrow Search Algorithm (FSSA). By integrating firefly search perturbation, the proposed FSSA aims to further improve the optimization capabilities of the original SSA. Simulation results indicate that FSSA effectively mitigates the risk of the wave energy generation system becoming trapped in local maxima, thereby enhancing its overall energy capture efficiency.
MKConvLFormer: A streaming speech recognition algorithm for power grid semantic environmentsXie, Zhihua; Wu, Huijuan; Chen, Xiang; Wei, Wenqi
doi: 10.1088/1742-6596/2993/1/012067pmid: N/A
The power grid dispatching system is a critical component in the development of the power industry and the technological innovation of smart grids. However, as smart grid systems expand, the traditional approach to managing and dispatching the grid through telephone communication is no longer sufficient to meet the growing data processing demands of smart grids. Consequently, this paper introduces an algorithm named MKConvLFormer (multi-scale residual convolutional neural network and Linformer). The MKConvLFormer is a streaming speech recognition algorithm designed for the semantic environment of the power grid, which utilizes the transformer model to extract features and incorporates a multi-scale convolutional neural network within the transformer architecture to enhance its feature extraction capabilities. Additionally, this research leverages the low-rank property of matrices to reduce the computational complexity of the existing self-attention mechanism, aiming for efficient and accurate recognition of streaming speech within the power grid semantic environment. Experimental results indicate that the MKConvLFormer model demonstrates superior speech recognition performance on the AISHELL-1 and THCHS-30 datasets.
Adjustable resource assessment and optimal scheduling method for electric vehicles considering cross-station mutual aidWang, Yang; Yan, Dazhi; Xu, Xiaolong; Gao, Peng; Yang, Hao; Zhao, Yingjie
doi: 10.1088/1742-6596/2993/1/012036pmid: N/A
Electric vehicles (EVs), as a new type of dispatchable resource in distribution networks, can help local new energy consumption and enhance grid security. In this paper, a method for evaluating and optimizing the dispatching of adjustable resources of electric vehicles considering cross-station mutual aid is proposed. Firstly, a Long Short-Term Memory (LSTM) network model is used to predict the power demand of charging posts and the number of Evs, then a consumer psychology model is constructed to evaluate the adjustable resources of EVs by considering the extra time and cost factors of cross-station charging. Then a scheduling model considering cross-station support for EVs is built. Through the case study, the effectiveness of the method in guaranteeing grid security and enhancing the level of new energy consumption is verified.
Applicability analysis of equivalent circuit model parameter identification method for lithium-ion batteriesQin, Taichun; Shao, Hua; Zhou, Yuege; Zhao, Guangming
doi: 10.1088/1742-6596/2993/1/012077pmid: N/A
The equivalent circuit model (ECM) of lithium-ion batteries is commonly utilized for state of charge (SOC) online estimation. In recent years, researchers have proposed different ECM identification methods according to their own needs, so the application scenarios of each method are different. The ECM identification consists of two steps: (1) obtaining the open circuit voltage curve and (2) obtaining the parameters of ECM. Since the OCV curve acquisition process is common, the difference between these estimation methods lies in the different parameter estimation methods. Since high dynamic profiles and low dynamic profiles have different influences on parameter estimation, this paper analyzes three modeling methods for SOC estimation are compared. Finally, the selection basis of ECM identification is provided.
Heating furnace scheduling with grey wolf optimizationRao, Chen; Zhang, Jianxin
doi: 10.1088/1742-6596/2993/1/012018pmid: N/A
To achieve energy-saving goals in the steel industry, this paper first analyzes the characteristics of billets and considers the impact of shape and size on heating time. Based on the billet heating specifications, an energy-efficient scheduling model is established with the furnace charging capacity difference rate and maximum completion time as the objective functions. An improved Grey Wolf Optimizer (GWO) algorithm, combined with real-valued encoding, is designed to solve this objective function. The model and algorithm’s effectiveness is verified through case studies. The results of the application examples show that the working time of each heating furnace is reduced by 12, 21, and 30 minutes, respectively. Compared to five other optimization algorithms, the improved GWO algorithm demonstrates superior performance. This model and algorithm meet the practical furnace charging requirements, improve furnace utilization, shorten the working time, and achieve energy-saving goals under specific production conditions, which is of significant importance for energy efficiency in steel enterprises.
Heat transfer characteristics of a round block impervious graphite heat exchangerRen, Bin
doi: 10.1088/1742-6596/2993/1/012016pmid: N/A
The round block graphite heat exchanger is one of the three most popular types of impervious graphite heat exchangers with a market share of 50%. The heat transfer characteristic was experimentally studied. First, the effects of velocities of cold and hot medium on overall heat transfer coefficient were studied. Second, distributions of thermal resistance of hot medium, cold medium, graphite, and resin were illustrated. Finally, the Nusselt numbers for the shell and tube side were individually formulated based on the Reynolds and Prandtl number. The result shows that the overall heat transfer coefficients rose as the velocities of the cold and hot mediums increased. The thermal resistance of cold medium was the dominant one because of leakage flow and corresponding deteriorative heat transfer. In addition, thermal resistance of resin is slightly higher than that of the wall indicating that the thickness of the resin layer is relatively large. The experimental values of shell-side heat transfer coefficient are much less than the theoretical ones with a maximum error of 44%. The experimental numbers of tube-side heat transfer coefficient are equal to theoretical values.