Global Energy Interconnection最新文献

{"title":"Improved combustion stability of biogas at different CO2 concentrations using inhomogeneous partially premixed stratified flames","authors":"Mohy Saad Mansour ,&nbsp;Maged Kiriakos ,&nbsp;Lili Hao ,&nbsp;Mohamed Amr Serag-Eldin","doi":"10.1016/j.gloei.2024.08.008","DOIUrl":"10.1016/j.gloei.2024.08.008","url":null,"abstract":"<div><p>Biogas is a renewable and clean energy source that plays an important role in the current environment of low- carbon transition. If high-content CO₂ in biogas can be separated, transformed, and utilized, it not only realizes high-value utilization of biogas but also promotes carbon reduction in the biogas field. To improve the combustion stability of biogas, an inhomogeneous, partially premixed stratified (IPPS) combustion model was adopted in this study. The thermal flame structure and stability were investigated for a wide range of mixture inhomogeneities, turbulence levels, CO₂ concentrations, air-to-fuel velocity ratios, and combustion energies in a concentric flow slot burner (CFSB). A fine-wire thermocouple is used to resolve the thermal flame structure. The flame size was reduced by increasing the CO₂ concentration and the flames became lighter blue. The flame temperature also decreased with increase in CO₂ concentration. Flame stability was reduced by increasing the CO₂ concentration. However, at a certain level of mixture inhomogeneity, the concentration of CO₂ in the IPPS mode did not affect the stability. Accordingly, the IPPS mode of combustion should be suitable for the combustion and stabilization of biogas. This should support the design of highly stabilized biogas turbulent flames independent of CO₂ concentration. The data show that the lower stability conditions are partially due to the change in fuel combustion energy, which is characterized by the Wobbe index (WI). In addition, at a certain level of mixture inhomogeneity, the effect of the WI on flame stability becomes dominant.</p></div>","PeriodicalId":36174,"journal":{"name":"Global Energy Interconnection","volume":"7 4","pages":"Pages 486-502"},"PeriodicalIF":1.9,"publicationDate":"2024-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2096511724000689/pdf?md5=5a3e3030e3ebeff05b20d88b39630d78&pid=1-s2.0-S2096511724000689-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142095118","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Dynamic optimal allocation of energy storage systems integrated within photovoltaic based on a dual timescale dynamics model","authors":"Kecun Li ,&nbsp;Zhenyu Huang ,&nbsp;Youbo Liu ,&nbsp;Yaser Qudaih ,&nbsp;Junyong Liu","doi":"10.1016/j.gloei.2024.08.005","DOIUrl":"10.1016/j.gloei.2024.08.005","url":null,"abstract":"<div><p>Energy storage systems (ESSs) operate as independent market participants and collaborate with photovoltaic (PV) generation units to enhance the flexible power supply capabilities of PV units. However, the dynamic variations in the profitability of ESSs in the electricity market are yet to be fully understood. This study introduces a dual-timescale dynamics model that integrates a spot market clearing (SMC) model into a system dynamics (SD) model to investigate the profit-aware capacity growth of ESSs and compares the profitability of independent energy storage systems (IESSs) with that of an ESS integrated within a PV (PV-ESS). Furthermore, this study aims to ascertain the optimal allocation of the PV-ESS. First, SD and SMC models were set up. Second, the SMC model simulated on an hourly timescale was incorporated into the SD model as a subsystem, a dual-timescale model was constructed. Finally, a development simulation and profitability analysis was conducted from 2022 to 2040 to reveal the dynamic optimal range of PV-ESS allocation. Additionally, negative electricity prices were considered during clearing processes. The simulation results revealed differences in profitability and capacity growth between IESS and PV-ESS, helping grid investors and policymakers to determine the boundaries of ESSs and dynamic optimal allocation of PV-ESSs.</p></div>","PeriodicalId":36174,"journal":{"name":"Global Energy Interconnection","volume":"7 4","pages":"Pages 415-428"},"PeriodicalIF":1.9,"publicationDate":"2024-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2096511724000653/pdf?md5=9794bcf15f3b9eeb9ab23745acbe57bf&pid=1-s2.0-S2096511724000653-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142095113","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Impact of the carbon market on investment benefits of power-grid enterprises in China: A system dynamics analysis","authors":"Wanning Mao ,&nbsp;Liang Hu ,&nbsp;Wenjuan Niu ,&nbsp;Xiaorong Sun ,&nbsp;Lili Hao ,&nbsp;Abimbola Susan Ajagun","doi":"10.1016/j.gloei.2024.08.007","DOIUrl":"10.1016/j.gloei.2024.08.007","url":null,"abstract":"<div><p>The power grid, as the hub connecting the power supply and consumption sides, plays an important role in achieving carbon neutrality in China. In emerging carbon markets, assessing the investment benefits of power-grid enterprises is essential. Thus, studying the impact of the carbon market on the investment and operation of power- grid enterprises is key to ensuring their efficient operation. Notably, few studies have examined the interaction between the carbon and electricity markets using system dynamics models, highlighting a research gap in this area. This study investigates the impact of the carbon market on the investment of power-grid enterprises using a novel evaluation system based on a system dynamics model that considers carbon-emissions from an established carbon-emission accounting model. First, an index system for benefit evaluation was constructed from six aspects: financing ability, economic benefit, reliability, social responsibility, user satisfaction, and carbon-emissions. A system dynamics model was then developed to reflect the causal feedback relationship between the impact of the carbon market on the investment and operation of power-grid enterprises. The simulation results of a provincial power-grid enterprise analyze comprehensive investment evaluation benefits over a 10-year period and the impact of carbon emissions on the investment and operation of power-grid enterprises. This study provides guidelines for the benign development of power-grid enterprises within the context of the carbon market.</p></div>","PeriodicalId":36174,"journal":{"name":"Global Energy Interconnection","volume":"7 4","pages":"Pages 402-414"},"PeriodicalIF":1.9,"publicationDate":"2024-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2096511724000677/pdf?md5=d86f88524de60b4f81c75ab936888189&pid=1-s2.0-S2096511724000677-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142095051","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Optimized scheduling of integrated energy systems for low carbon economy considering carbon transaction costs","authors":"Chao Liu ,&nbsp;Weiru Wang ,&nbsp;Jing Li ,&nbsp;Xinyuan Liu ,&nbsp;Yongning Chi","doi":"10.1016/j.gloei.2024.08.010","DOIUrl":"10.1016/j.gloei.2024.08.010","url":null,"abstract":"<div><p>With the introduction of the “dual carbon” goal and the continuous promotion of low-carbon development, the integrated energy system (IES) has gradually become an effective way to save energy and reduce emissions. This study proposes a low-carbon economic optimization scheduling model for an IES that considers carbon trading costs. With the goal of minimizing the total operating cost of the IES and considering the transferable and curtailable characteristics of the electric and thermal flexible loads, an optimal scheduling model of the IES that considers the cost of carbon trading and flexible loads on the user side was established. The role of flexible loads in improving the economy of an energy system was investigated using examples, and the rationality and effectiveness of the study were verified through a comparative analysis of different scenarios. The results showed that the total cost of the system in different scenarios was reduced by 18.04%, 9.1%, 3.35%, and 7.03%, respectively, whereas the total carbon emissions of the system were reduced by 65.28%, 20.63%, 3.85%, and 18.03%, respectively, when the carbon trading cost and demand-side flexible electric and thermal load responses were considered simultaneously. Flexible electrical and thermal loads did not have the same impact on the system performance. In the analyzed case, the total cost and carbon emissions of the system when only the flexible electrical load response was considered were lower than those when only the flexible thermal load response was taken into account. Photovoltaics have an excess of carbon trading credits and can profit from selling them, whereas other devices have an excess of carbon trading and need to buy carbon credits.</p></div>","PeriodicalId":36174,"journal":{"name":"Global Energy Interconnection","volume":"7 4","pages":"Pages 377-390"},"PeriodicalIF":1.9,"publicationDate":"2024-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2096511724000707/pdf?md5=cdfba3c7d664931949b8ff15d4a5c2ed&pid=1-s2.0-S2096511724000707-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142095111","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A coordinated operation method of wind-PV-hydrogen- storage multi-agent energy system","authors":"Tengfei Ma ,&nbsp;Wei Pei ,&nbsp;Yanhong Yang ,&nbsp;Hao Xiao ,&nbsp;Chenghong Tang ,&nbsp;Weiqi Hua","doi":"10.1016/j.gloei.2024.08.001","DOIUrl":"10.1016/j.gloei.2024.08.001","url":null,"abstract":"<div><p>Wind-photovoltaic (PV)-hydrogen-storage multi-agent energy systems are expected to play an important role in promoting renewable power utilization and decarbonization. In this study, a coordinated operation method was proposed for a wind-PV- hydrogen-storage multi-agent energy system. First, a coordinated operation model was formulated for each agent considering peer-to-peer power trading. Second, a coordinated operation interactive framework for a multi-agent energy system was proposed based on the theory of the alternating direction method of multipliers. Third, a distributed interactive algorithm was proposed to protect the privacy of each agent and solve coordinated operation strategies. Finally, the effectiveness of the proposed coordinated operation method was tested on multi-agent energy systems with different structures, and the operational revenues of the wind power, PV, hydrogen, and energy storage agents of the proposed coordinated operation model were improved by approximately 59.19%, 233.28%, 16.75%, and 145.56%, respectively, compared with the independent operation model.</p></div>","PeriodicalId":36174,"journal":{"name":"Global Energy Interconnection","volume":"7 4","pages":"Pages 446-461"},"PeriodicalIF":1.9,"publicationDate":"2024-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2096511724000616/pdf?md5=be0b794cfe0219254fefd67e4d340f6c&pid=1-s2.0-S2096511724000616-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142095115","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Generation of input spectrum for electrolysis stack degradation test applied to wind power PEM hydrogen production","authors":"Yanhui Xu ,&nbsp;Guanlin Li ,&nbsp;Yuyuan Gui ,&nbsp;Zhengmao Li","doi":"10.1016/j.gloei.2024.08.006","DOIUrl":"10.1016/j.gloei.2024.08.006","url":null,"abstract":"<div><p>Hydrogen production by proton exchange membrane electrolysis has good fluctuation adaptability, making it suitable for hydrogen production by electrolysis in fluctuating power sources such as wind power. However, current research on the durability of proton exchange membrane electrolyzers is insufficient. Studying the typical operating conditions of wind power electrolysis for hydrogen production can provide boundary conditions for performance and degradation tests of electrolysis stacks. In this study, the operating condition spectrum of an electrolysis stack degradation test cycle was proposed. Based on the rate of change of the wind farm output power and the time-averaged peak-valley difference, a fluctuation output power sample set was formed. The characteristic quantities that played an important role in the degradation of the electrolysis stack were selected. Dimensionality reduction of the operating data was performed using principal component analysis. Clustering analysis of the data segments was completed using an improved Gaussian mixture clustering algorithm. Taking the annual output power data of wind farms in Northwest China with a sampling rate of 1 min as an example, the cyclic operating condition spectrum of the proton-exchange membrane electrolysis stack degradation test was constructed. After preliminary simulation analysis, the typical operating condition proposed in this paper effectively reflects the impact of the original curve on the performance degradation of the electrolysis stack. This study provides a method for evaluating the degradation characteristics and system efficiency of an electrolysis stack due to fluctuations in renewable energy.</p></div>","PeriodicalId":36174,"journal":{"name":"Global Energy Interconnection","volume":"7 4","pages":"Pages 462-474"},"PeriodicalIF":1.9,"publicationDate":"2024-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2096511724000665/pdf?md5=51b59c89b74af8f5169221718325b4db&pid=1-s2.0-S2096511724000665-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142095116","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A novel cascaded H-bridge photovoltaic inverter with flexible arc suppression function","authors":"Junyi Tang,&nbsp;Wei Gao","doi":"10.1016/j.gloei.2024.08.002","DOIUrl":"10.1016/j.gloei.2024.08.002","url":null,"abstract":"<div><p>This paper presents a novel approach that simultaneously enables photovoltaic (PV) inversion and flexible arc suppression during single-phase grounding faults. Inverters compensate for ground currents through an arc-elimination function, while outputting a PV direct current (DC) power supply. This method effectively reduces the residual grounding current. To reduce the dependence of the arc-suppression performance on accurate compensation current-injection models, an adaptive fuzzy neural network imitating a sliding mode controller was designed. An online adaptive adjustment law for network parameters was developed, based on the Lyapunov stability theorem, to improve the robustness of the inverter to fault and connection locations. Furthermore, a new arc-suppression control exit strategy is proposed to allow a zero- sequence voltage amplitude to quickly and smoothly track a target value by controlling the nonlinear decrease in current and reducing the regulation time. Simulation results showed that the proposed method can effectively achieve fast arc suppression and reduce the fault impact current in single-phase grounding faults. Compared to other methods, the proposed method can generate a lower residual grounding current and maintain good arc-suppression performance under different transition resistances and fault locations.</p></div>","PeriodicalId":36174,"journal":{"name":"Global Energy Interconnection","volume":"7 4","pages":"Pages 513-527"},"PeriodicalIF":1.9,"publicationDate":"2024-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2096511724000628/pdf?md5=016f43233e70698519f8ef08713a0188&pid=1-s2.0-S2096511724000628-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142095025","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Consideration of the influence of supports in modeling the electromagnetic fields of 25 kV traction networks under emergency conditions","authors":"Konstantin Suslov ,&nbsp;Andrey Kryukov ,&nbsp;Ekaterina Voronina ,&nbsp;Pavel Ilyushin","doi":"10.1016/j.gloei.2024.08.004","DOIUrl":"10.1016/j.gloei.2024.08.004","url":null,"abstract":"<div><p>Single-phase 25 kV traction networks of electrified alternating current (AC) railways create electromagnetic fields (EMFs) with significant levels of intensity. The most intense magnetic fields occur when short circuits exist between the contact wire and rails or ground. Despite the short duration of exposure, they can adversely affect electronic devices and induce significant voltages in adjacent power lines, which is dangerous for operating personnel. Although numerous investigations have focused on modeling the EMF of traction networks and power lines, the challenge of determining the three-dimensional electromagnetic fields near metal supports during the flow of a short-circuit current through them is yet to be resolved. In this case, the field has a complex spatial structure that significantly complicates the calculations of intensities. This study proposes a methodology, algorithms, software, and digital models for determining the EMF in the described emergency scenarios. During the modeling process, the objects being studied were represented by segments of thin wires to analyze the distribution of the electric charge and calculate the intensities of the electric and magnetic fields. This approach was implemented in the Fazonord software, and the modeling results show a substantial increase in EMF levels close to the support, with a noticeable decrease in the levels as the distance from it increases. The procedure implemented in the commercial software Fazonord is universal and can be used to determine electromagnetic fields at any electrical power facility that includes live parts of limited length. Based on the proposed procedure, the EMF near the supports of overhead power lines and traction networks of various designs could be determined, the EMF levels at substations can be calculated, and the influence of metal structures located near traction networks, such as pedestrian crossings at railway stations, can be considered.</p></div>","PeriodicalId":36174,"journal":{"name":"Global Energy Interconnection","volume":"7 4","pages":"Pages 528-540"},"PeriodicalIF":1.9,"publicationDate":"2024-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2096511724000641/pdf?md5=aec14698b5c2c5d56839d91da7ef39b9&pid=1-s2.0-S2096511724000641-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142095026","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Modeling load distribution for rural photovoltaic grid areas using image recognition","authors":"Ning Zhou,&nbsp;Bowen Shang,&nbsp;Jinshuai Zhang,&nbsp;Mingming Xu","doi":"10.1016/j.gloei.2024.06.002","DOIUrl":"https://doi.org/10.1016/j.gloei.2024.06.002","url":null,"abstract":"<div><p>Expanding photovoltaic (PV) resources in rural-grid areas is an essential means to augment the share of solar energy in the energy landscape, aligning with the “carbon peaking and carbon neutrality” objectives. However, rural power grids often lack digitalization; thus, the load distribution within these areas is not fully known. This hinders the calculation of the available PV capacity and deduction of node voltages. This study proposes a load-distribution modeling approach based on remote-sensing image recognition in pursuit of a scientific framework for developing distributed PV resources in rural grid areas. First, houses in remote-sensing images are accurately recognized using deep-learning techniques based on the YOLOv5 model. The distribution of the houses is then used to estimate the load distribution in the grid area. Next, equally spaced and clustered distribution models are used to adaptively determine the location of the nodes and load power in the distribution lines. Finally, by calculating the connectivity matrix of the nodes, a minimum spanning tree is extracted, the topology of the network is constructed, and the node parameters of the load-distribution model are calculated. The proposed scheme is implemented in a software package and its efficacy is demonstrated by analyzing typical remote-sensing images of rural grid areas. The results underscore the ability of the proposed approach to effectively discern the distribution-line structure and compute the node parameters, thereby offering vital support for determining PV access capability.</p></div>","PeriodicalId":36174,"journal":{"name":"Global Energy Interconnection","volume":"7 3","pages":"Pages 270-283"},"PeriodicalIF":1.9,"publicationDate":"2024-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2096511724000410/pdf?md5=1e9a34705fc1550ee22ec7209638ba18&pid=1-s2.0-S2096511724000410-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141480936","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Online identification and extraction method of regional large-scale adjustable load-aggregation characteristics","authors":"Siwei Li ,&nbsp;Liang Yue ,&nbsp;Xiangyu Kong ,&nbsp;Chengshan Wang","doi":"10.1016/j.gloei.2024.06.004","DOIUrl":"https://doi.org/10.1016/j.gloei.2024.06.004","url":null,"abstract":"<div><p>This article introduces the concept of load aggregation, which involves a comprehensive analysis of loads to acquire their external characteristics for the purpose of modeling and analyzing power systems. The online identification method is a computer-involved approach for data collection, processing, and system identification, commonly used for adaptive control and prediction. This paper proposes a method for dynamically aggregating large-scale adjustable loads to support high proportions of new energy integration, aiming to study the aggregation characteristics of regional large-scale adjustable loads using online identification techniques and feature extraction methods. The experiment selected 300 central air conditioners as the research subject and analyzed their regulation characteristics, economic efficiency, and comfort. The experimental results show that as the adjustment time of the air conditioner increases from 5 minutes to 35 minutes, the stable adjustment quantity during the adjustment period decreases from 28.46 to 3.57, indicating that air conditioning loads can be controlled over a long period and have better adjustment effects in the short term. Overall, the experimental results of this paper demonstrate that analyzing the aggregation characteristics of regional large-scale adjustable loads using online identification techniques and feature extraction algorithms is effective.</p></div>","PeriodicalId":36174,"journal":{"name":"Global Energy Interconnection","volume":"7 3","pages":"Pages 313-323"},"PeriodicalIF":1.9,"publicationDate":"2024-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2096511724000434/pdf?md5=f879b90415d9ddcb452fdaa01f1894f9&pid=1-s2.0-S2096511724000434-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141480947","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}