高密度球形LiFePO4的合成及性能

通过控制结晶法制备球形前驱体FePO_4·xH_2O,经过预烧得到高密度的FePO_4,与Li_2CO_3和葡萄糖均匀混合,采用碳热还原法合成锂离子蓄电池正极材料球形磷酸铁锂(LiFePO_4)。用X光衍射和扫描电镜分析对FePO_4和LiFePO_4的结构进行了表征。充放电测试表明LiFePO_4具有3.4V放电电压平台,在0.1mA/cm2电流密度条件下,首次充电比容量为146.9mAh/g,放电比容量为129.7mAh/g。该球形LiFePO4粉末的振实密度高达1.8g/cm3,首次放电比容量高达233.5mAh/cm3,远高于一般非球形LiFePO_4正极材料。     

球形Ni(OH)2表面覆钴及其性能

为了提高球形Ni(OH)2的电化学性能,在球形Ni(OH)2表面喷涂钴盐溶液,通过烘干、碱化等工序后得到的覆钴球形Ni(OH)2,对它进行了XRD、粉末微电极循环伏安模拟充放电实验,并制备成样品电池进行测试.包覆3.0%钴的材料导电性好,振实密度为2.05g/ml,制成的电极1 C放电比容量为260 mAh/g,10 C放电比容量为228 mAh/g.     

Li_(1.2)Ni_(0.13)Co_(0.13)Mn_(0.54)O_2正极材料的制备及性能

采用共沉淀法合成了球形Ni0.13Co0.13Mn0.54(OH)1.6前驱体,与锂结合生成Li1.2Ni0.13Co0.13Mn0.54O2正极材料。采用X射线衍射(XRD)、电子扫描电镜(SEM)、循环伏安测试(CV)、交流阻抗测试(EIS)和充放电测试对Li1.2Ni0.13Co0.13Mn0.54O2正极材料进行了表征。结果表明,所合成的材料具有球形形貌,粒度分布均匀,振实密度达2.1 g/cm3,材料0.2 C首次放电比容量280.9 mAh/g,1 C首次放电比容量237.1 mAh/g,循环50次后1 C容量保持率92.5%,表现出优异的电化学性能。     

锂二次电池正极材料的液相合成

研究了用液相法合成锂离子电池正极材料LiCoO2的制备工艺、结构和性能。研究表明,液相法合成的LiCoO2首次充电容量160mAh／g,放电容量145mAh／g,充放电效率为90．6％。另外,采用本工艺合成的LiCoO2正极活性材料性能稳定,工艺简单、操作方便,适合批量生产。     

球形正极材料LiNi0.75Co0.2Mg0.05O2的合成及表征

用控制结晶法合成球形材料Ni0.75Co0.2Mg0.05(OH)2与LiOH·H2O混合后,在750℃氧气气氛中焙烧得到LiNi0.75-Co0.2Mg0.05O2.电镜扫描(SEM)结果显示,焙烧后的材料保持了原有的球形形貌.X射线衍射光谱(XRD)和能量色散谱显微分析(EDS)显示,掺镁后的样品晶型结构好,所得产物成分均一.电化学测试表明,LiNi0.75Co0.2Mg0.05O2材料表现出优良的电化学性能,其首次充电比容量达到271 mAh/g,首次放电比容量达到217.7 mAh/g,循环50次后放电比容量仍能保持211.7 mAh/g,仅衰减了3%(3.0～4.3 V,0.2 C).结果表明,镁的掺入减少了材料的阳离子混排,大大提高了循环性能,抑制了充放电过程中的相变和电池阻抗的增加.     

高镍三元正极材料LiNi0.8Co0.1Mn0.1O2的合成与电化学性能研究

采用高温固相法在不同条件下合成了一系列球形LiNi0.8Co0.1Mn0.1O2正极材料,并通过XRD、SEM、TEM、EDS等表征手段对其物相结构、形貌以及电化学性能进行了研究.结果表明,Li/Me(摩尔比)为1.07时合成的正极材料结晶良好,结构稳定,以0.2 C倍率在2.8～4.3 V电压范围内的首次放电比容量为200.4 mAh/g,首次充放电效率为86.7％,1 C放电比容量为189.5 mAh/g,50次循环之后的放电比容量为178.3 mAh/g,此时容量保持率高达94.1％.继续循环至100次比容量还有145.7 mAh/g,容量保持率为76.9％.     

不同形貌LiMn2O4的电化学及Li+扩散性能

合成了球形和立方体形貌的MnCO3前驱体,再用熔融浸渍和程序升温法煅烧,得到两种LiMn2O4正极材料.XRD和SEM分析表明:两种LiMn2O4均为纯净立方尖晶石型,颗粒形貌保持完好.球形材料的性能优于立方体形材料,在3.50～4.30 V充放电,0.1C首次放电比容量为133.4 mAh/g,5.0C平均放电比容量...     

碳热还原法合成高密度球形LiFePO_4/C

通过水热-碳热还原法,合成了高密度球形LiFePO_4/C材料。通过扫描电子显微镜(SEM)和振实密度测试发现,LiFePO_4/C的振实密度得到显著提高,达到1.553g/cm~3。通过恒流充放电测试表明,适当的碳包覆能改善LiFePO_4材料的电化学性能。在0.1C下,2.5~4.2V进行充放电,首次放电比容量为137.63mAh/g,10C时放电比容量维持在76.71mAh/g左右。     

LiFePO4正极材料的熔盐-碳热还原法合成

采用熔盐-碳热还原法制备了LiFePO4正极材料。采用X射线衍射(XRD)、扫描电镜(SEM)、交流阻抗(EIS)和充放电测试对粉末样品进行了表征。结果表明,合成材料具有完整的橄榄石结构,颗粒粒径约1μm且粒度分布均匀,材料0.2 C首次放电比容量为156.4 mAh/g,1 C首次放电比容量为141.2 mAh/g,循环50次后1 C比容量增至141.7mAh/g,表现出优异的电化学性能。     

碳酸盐共沉淀法制备LiNi0.5Co0.3Mn0.2O2及其性能

以化学共沉淀法制备出的球形Ni0.5Co0.3Mn0.2CO3前驱体,合成了振实密度高达2.60 g/cm3的球形正极材料LiNi0.5Co0.3Mn0.2O2.研究表明,LiNi0.5Co0.3Mn0.2O2为10 μm左右的球形粉体,为纯相的α-NaFeO2层状结构.在2.7～4.3V,0.2 C倍率进行充放电,LiNi0.5Co0.3Mn0.2O2的首次放电比容量170.2 mAh/g,50次循环后容量保持率为94.3%;在2.7～4.6 V,在0.2 C倍率下放电,首次放电比容量为191.8 mAh/g,循环50次后容量保持率为90.5%.LiNi0.5Co0.3Mn0.2O2的首次循环伏安测试结果和交流阻抗测试结果进一步表明材料具有良好的电化学性能.     

追求卓越绩效提升客户满意度

本文主要介绍了电力体制改革后，电力行业仍然存在的运营特点，申明不应只看到电力行业公益性、基础性的特殊性质，裹足不前，而应通过提高电能质量、追求卓越绩效来提升服务水平的观点。     

Detection of energy theft and defective smart meters in smart grids using linear regression

The utility providers are estimated to lose billions of dollars annually due to energy theft. Although the implementation of smart grids offers technical and social advantages, the smart meters deployed in smart grids are susceptible to more attacks and network intrusions by energy thieves as compared to conventional mechanical meters. To mitigate non-technical losses due to electricity thefts and inaccurate smart meters readings, utility providers are leveraging on the energy consumption data collected from the advanced metering infrastructure implemented in smart grids to identify possible defective smart meters and abnormal consumers’ consumption patterns. In this paper, we design two linear regression-based algorithms to study consumers’ energy utilization behavior and evaluate their anomaly coefficients so as to combat energy theft caused by meter tampering and detect defective smart meters. Categorical variables and detection coefficients are also introduced in the model to identify the periods and locations of energy frauds as well as faulty smart meters. Simulations are conducted and the results show that the proposed algorithms can successfully detect all the fraudulent consumers and discover faulty smart meters in a neighborhood area network.     

Coordinating self-healing control of bulk power transmission system based on a hierarchical top-down strategy

Top-down power system restoration following a widespread blackout begins with energization of the backbone transmission network. All interconnected regions will be restored as a whole, which needs collaboration of multiple operators. The parallel control and integrated restoration planning issues have to be addressed. In order to conduct an efficient top-down restoration process and guarantee the operational security, a hierarchical coordination mechanism and an online decision support system-based self-healing approach are proposed. Considering the multiple decision-making problems involved, an associated bi-level optimization model is built, which integrates the planning problems of backbone reconfiguration, sub-transmission system restoration, and non-black-start units start-up. Then, a solution methodology is developed to provide online decisions based on the model. Simulation results of Shandong Power System in China show that the restoration performance is significantly improved using the proposed control approach. Additionally, the decision method is proved to be efficient enough for online applications.     

默勒"easy"用于地铁低压配电系统

将综合控制继电器”easy”应用于广州地铁1#残变电所单母残分段联络断路器的备用电源自投装置中，可提高配电系统的可靠性。     

城市电网"N-1"准则实现途径

城市电网框架功能的不断完善，是保证电网安全稳定运行与社会经济同步发展的基本条件。建立层次清晰、结构简单、接线规范、冗余度合理、技术适度超前的电网框架，实现城市电网“Ｎ－１”准则。     

高职院校顶岗实习管理工作绩效评价研究

镇江市高等专科学校以实现实践教学目标为导向,突出系部的责任驱动和利益驱动双重管理,对其顶岗实习工作做出基本判断,探索出一套科学合理、定性与定量结合、易于操作的工作绩效评价标准、指标体系和操作流程,与实习单位密切合作,促进了学校人才培养工作水平的提高和学生的可持续发展,有一定的应用推广价值.     

基于以太网的电站监控系统的研究与应用

介绍了一种基于以太网实现对电站"三遥"控制的远程监控系统.给出了系统结构、工作原理,着重论述了利用以太网实现电站远程通信的方法.该方法已在产品中得到了应用.实践证明:使用方便,性能可靠.     

Grid synchronization and control of distributed generation unit with flexible load compensation capabilities using multi-output LMS-filter

This paper deals with grid synchronization and control of single-phase voltage source inverter in distributed generation (DG) systems using a multi-output adaptive filter. Besides the active power injection, the proposed control enables the inverter to compensate load harmonic and reactive currents based on the capacity of inverter. The currents to be compensated are obtained using a multi-output adaptive filter structure that operates on the principle of variable step size (VSS) least mean squares (LMS) algorithm. The main objective of VSS-LMS filter is to decompose the load current into harmonic and reactive current components and compute their RMS values. The currents extracted by the VSS-LMS filter are used in developing a flexible compensation based on load compensation factors. The load compensation factors are calculated based on the remaining capacity of the inverter and priority. Harmonic currents compensation is given first priority over the reactive currents. In addition to harmonic currents detection, the same VSS-LMS filter is used in developing a phase locked loop unit for synchronizing the inverter with fundamental point of common coupling (PCC) voltage. Synchronizing the DG inverter with fundamental PCC voltage would make the proposed control algorithm insensitive to grid voltage harmonics and frequency fluctuations. The feasibility and the efficacy of the proposed control algorithm are demonstrated using hardware-in-the-loop (HIL) based experiments.     

柔性交流输电技术在智能电网中的应用

智能电网对输变电系统提出了灵活调节、高效输送、稳定可靠的要求。柔性交流输电技术为智能电网提供了解决方案。文中对各种类型的FACTS设备进行了简要的介绍,对可能在智能电网中应用的四种综合型FACTS设备进行了重点阐述,介绍了其基本结构和工作原理,分析了各种设备的优点及不足。总体上讲,FACTS技术为交流输电网提供快速、连续和精确的控制手段以及优化潮流的能力,同时能够保证系统稳定性。从我国电网智能电网的发展而言,采用经济有效的、相应的FACTS技术,充分发挥智能电网的潜力已成为必然趋势。     

广播电视播出电源可靠性保证的应用与探讨

论述不间断电源系统———UPS首选配置作为动力第四路后备电源 ,其技术的控制原理与应用 ,及重要意义。