基于无线通信的防窃电系统设计

有效遏制窃电行为具有重大意义,但目前缺乏可靠实用的防窃电手段。在介绍窃电危害性、窃电方式和目前防治窃电技术措施的基础上,提出了一种基于无线通信技术的防窃电实时监控系统;介绍了系统结构、工作原理及功能;最后举例说明了具体应用。该系统能够准确、实时地检测出窃电,且运行稳定可靠。     

基于GSM网络的防窃电实时监控系统方案探讨

在介绍窃电危害性、窃电手法及目前防治窃电技术措施的基础上,探讨了一种基于全球移动通信系统GSM(Global System for Mobile communication)网络的防窃电实时监控系统的设计方案、系统组成和工作原理。介绍了系统中窃电行为识别与诊断的软件流程,分析了系统的技术特点。指出了该系统能快速发现窃电,从而防止窃电行为。     

一种新型防窃电装置的设计

有效遏制窃电行为具有重大意义,但目前缺乏可靠实用的防窃电手段。介绍了一种新型防窃电装置,该装置直接采集用户一次侧用电信息,作为判断窃电的依据,对该装置的功能及设计方法进行了说明,并详细说明介绍了从高压侧获取电源的方法。最后给出了防窃电实例证明该装置的实用性。     

一种新型防窃电装置的设计

有效遏制窃电行为具有重大意义,但目前缺乏可靠实用的防窃电手段.介绍了一种新型防窃电装置,该装置直接采集用户一次侧用电信息,作为判断窃电的依据,对该装置的功能及设计方法进行了说明,并详细说明介绍了从高压侧获取电源的方法.最后给出了防窃电实例证明该装置的实用性.     

电力远程智能管理信息系统应用于用电监测与反窃电系统的方案

在介绍窃电危害性、窃电手法及目前防治窃电技术措施的基础上,提出一种基于电力远程智能管理信息系统应用于用电监测与反窃电系统的设计方案、系统组成和工作原理。介绍了系统中窃电行为识别与诊断方法,分析了系统的技术特点。指出该系统能及时捕获窃电和提高反窃电速度,从而防止窃电行为。     

配变监控系统的防窃电功能实现

介绍一种应用在低压配电网中具有反窃电功能的基于移动GPRS的配变监控系统。在硬件上是通过ADE 7758反窃电数据采集模块实现防窃电。配变远方终端软件采用C语言编程,主站采用VC 6.0进行编程。通过功率比较法和电量比较法,实现对实时数据的处理和防窃电。利用配变监控系统的实时特性,在配变监控系统中开发防窃电功能,相比采用防窃电电能表防窃电,具有快速侦察窃电、实时告警提示等优点。该系统已经在实际中使用,实践表明其投资少,效果良好。     

无线防窃电系统研制及应用

通过分析目前防窃电工作所面临的困难,引出无线防窃电系统。进一步介绍了无线防窃电系统的组成和关键技术并详细介绍了无线防窃电系统主要功能的实现原理。通过现场运行,介绍了无线防窃电系统在电网挂网运行的应用实例。     

一种新型配变监控系统防窃电功能的研究与实现

针对当前配电网的实际运行环境,介绍一种应用在低压配电网中的基于移动GPRS无线通信的新型配变监控系统。详细介绍了该配变监控系统中防窃电功能的实现和工作原理。利用配变监控系统的实时特性,在配变监控系统中开发防窃电功能,比采用防窃电电能表防窃电,具有快速侦察窃电,实时告警提示等优点,可操作性强,可行性高,效果良好。该系统集多种功能为一体,具有配变监测、防窃电、计量、通讯等功能,具有投资少,管理方便等优点,特别适合于当前的配电网改造工程,在实践中具有广阔的应用前景。     

一种新型配变监控系统防窃电功能的研究与实现

针对当前配电网的实际运行环境,介绍一种应用在低压配电网中的基于移动GPRS无线通信的新型配变监控系统.详细介绍了该配变监控系统中防窃电功能的实现和工作原理.利用配变监控系统的实时特性,在配变监控系统中开发防窃电功能,比采用防窃电电能表防窃电,具有快速侦察窃电,实时告警提示等优点,可操作性强,可行性高,效果良好.该系统集多种功能为一体,具有配变监测、防窃电、计量、通讯等功能,具有投资少,管理方便等优点,特别适合于当前的配电网改造工程,在实践中具有广阔的应用前景.     

智能防窃电管理信息平台的应用

介绍智能防窃电管理平台的系统构架、设计思路,以及关键功能的实现方案,对专用变压器用户监测和数据建模,从海量数据中快速甄别定位重点监测用户中可能出现的窃电时间、窃电方式、窃电地点等信息,实现了从被动防窃电到主动式防窃电、智能化防窃电的飞跃,有利于及时、准确、有效地定位及处理各种窃电行为。     

Ferroelectric behaviors of sandwich structured PbZr0.52 Ti0.48O3/Pb(Mg1/3Ta2/3)0.7Ti0.3O3/PbZr0.52Ti0.48O3 thin film

Sandwich structured PbZr_0.52Ti_0.48O₃/Pb(Mg_1/3 Ta_2/3)_0.7Ti_0.3O₃/PbZr_0.52Ti_0.48O₃ (PZT/PMTT/PZT) thin films have been successfully synthesized via a combined route involving sol-gel and RF magnetron sputtering. Insertion of the PMTT interlayer effectively suppressed formation of the heterogeneous “rosette” structure of PZT thin film when deposited onto Pt/Ti/SiO₂/Si substrate. While both remanent polarization and coercive field were lowered for the sandwich structured films, the coercive field was reduced more significantly. Such sandwich structured films exhibit improved fatigue behavior and the relative permittivity can not be simply described as a series connection of individual components of perovskite layers.     

1865140型(LiMn2O4+LiNi1/3Co1/3Mn1/3O2)/Li4Ti5O12电池的性能

使用锰酸锂(LiMn2O4)、镍钴锰酸锂(LiNi1/3 Co1/3Mn1/3O2)混合正极材料和钛酸锂(Li4 Ti5 O12)负极材料,制备了中倍率1865140型锂离子电池.制备的电池在12 min内可充满电池容量的80％以上,且电池表面温度不超过35℃;在室温下以2.00 C循环1 200次,容量保持率高于91％;在高温55℃下以1.00 C循环1 000次,容量保持率高于82％.FreedomCAR混合脉冲功率特性表明:在放电深度(DOD) 10％ ～ 70％内、10s脉冲充放电状态下,电池的阻抗都在9 mΩ以下;50％DOD时的10s放电比功率为372 W/kg,充电比功率为520 W/kg.     

YBa2Cu3O7

Some background information on superconducting ceramics is given, and the history of yttrium barium copper oxide (YBCO) is discussed. The crystal structure of superconducting YBCO is described. The production and extraction methods of bulk samples of YBCO are detailed. Different theories of superconductivity in YBCO are addressed, and applications of YBCO superconductors are discussed     

Electromechanical Properties and Morphotropic Phase Boundary of Na0.5Bi0.5TiO3-K0.5Bi0.5TiO3-BaTiO3 Lead-free Piezoelectric Ceramics

The crystal structure and electromechanical properties of two ternary ceramic Na_0.5Bi_0.5TiO₃- K_0.5Bi_0.5TiO₃-BaTiO₃ (NBT-KBT-BT) systems were investigated. A gradual change in crystalline structure and microstructure with the increase of KBT and BT concentrations were observed. It was ascertained that the rhombohedral-tetragonal morphtropic phase boundary (MPB) lies in the range of 0.024 ≰ x ≰ 0.030 for (1–5x) NBT-4x KBT-x BT system and 0.025 ≰ y ≰ 0.035 for (1 − 3y) NBT—2y KBT—y BT system at room temperature. The piezoelectric constant d₃₃ and electromechanical coupling factor k_p of the ceramics attain a maximum value of 150 pC/N and 0.298, respectively. The MPB phase diagram of NBT-KBT-BT ternary system was determined by phase analysis of XRD patterns from calcined specimens. The ferroelectric properties of the (1 − 5x) NBT—4x KBT—x BT system have been characterized. The ternary system ceramics have relatively high Curie temperature T_c.     

混合动力电动车用高效双向直流变换器的设计

针对传统以蓄电池为动力的电动车存在的问题,提出以超级电容加双向DC-DC变换器为辅助动力源的方案。该方案在弥补蓄电池缺陷的同时,提高了整个系统的能源利用效率,并增加了电动车的续驶里程。在简要介绍了超级电容储能系统的基础上,主要研究和设计了系统中的核心部件—双向DC-DC变换器,分析了双向DC-DC变换器的工作模式和控制策略,并对双向变换器进行了软开关分析。Matlab仿真所得的相应波形验证了方案的有效性。     

Textured ferroelectric SrBi2Nb2O9 phase obtained by melt-quenching the SrBi2B2O7-Nb2O5 system and its anisotropic dielectric and pyroelectric properties

Textured SrBi₂Nb₂O₉ ceramics were obtained by quenching the melts of SrBi₂B₂O₇-Nb₂O₅ in equimolar ratio. The as-quenched samples were crystalline comprising 40% c-oriented grains. The influence of the post heat-treatment temperature on the orientation factor (f) and microstructure was studied using x-ray powder diffraction (XRD) and Scanning electron microscopy (SEM). The orientation factor was found to increase with increasing post heat-treatment temperature and reached a maximum value of 65% for the samples heated at 700°C for 10 h. Relative density and the grain-size of the partially grain oriented ceramics were found to increase with an increase in the heat-treatment temperature. The effect of texturing yielded anisotropy in the dielectric and pyroelectric properties. The dielectric constant ( e_r^￠ ( ^) = 114 ) \left( {\varepsilon_r^{\prime } \left( \bot \right) = 114} \right) and the pyroelectric coefficient (p(┴) = −0.07 nC cm⁻² °C⁻¹) along the direction perpendicular to the melt pressing axis were superior to that of the direction parallel ((e_r^￠ ( ||) = 93 \varepsilon_r^{\prime } \left( \parallel \right) = 93 ) (p(||) = −0.02 nC cm⁻² °C⁻¹)) (c-axis of the grain) to the pressing axis at room temperature.     

高温固相法合成Li0.98M0.02Fe0.95V0.05PO4/C的电化学性能

通过高温固相法合成锂离子电池正极材料Li0.98M0.02Fe0.95V0.05PO4/C(M=Mg、Ti、Al、Ni、Zr、Mo和Mn),用XRD、循环伏安(CV)、电化学阻抗谱(EIS)和恒流充放电等方法研究了产物的性能.金属掺杂后的材料,首次充放电比容量均高于未掺杂的纯相材料.在室温下,掺杂Mg的材料在4.2～2.4 V充放电,0.1C首次放电比容量可达154.1 mAh/g,且高倍率充放电比容量高于纯相材料,循环性能稳定,具有较好的电化学性能.     

用于多表集抄系统的自适应M-BUS主机电路设计

针对国家电网的电、水、气、热多表集抄,提出了一种自适应的MBUS主机电路,通过调整LDO的反馈电阻来实现对M-BUS总线电平的控制,使用电容来采样、锁存总线电流数值,自动适应外部总线电流的变化,从而完成对从机数据的收发。文中详细阐述了主机电路的收发原理,并结合实际应用的特点,实现了与主控电路的光电隔离。现场应用表明,该电路抗干扰能力强、可靠性高、带负载能力强。     

Studies on Electrical Properties and Magnetoelectric Effect of (x)Ni0.8Cu0.2Fe2O4 + (1?x)Ba0.8Pb0.2Ti0.8Zr0.2O3 Composites

Materials consisting of piezomagnetic and piezoelectric phases viz. Ni_0.8Cu_0.2Fe₂O₄ and Ba_0.8Pb_0.2 Ti_0.8Zr_0.2O₃ have been prepared by standard ceramic method. The presence of two phases in the composites has been confirmed by XRD. Variation of the dielectric constant with frequency in the range 100–1 MHz has been studied at room temperature and the variation of dielectric constant with temperature at set frequencies (1 kHz, 10 kHz, 100 kHz and 1 MHz) has been studied. The dielectric relaxation was observed for the compositions with tetragonal structure whereas normal behaviour was observed for cubic structure. All the samples have shown linear magnetoelectric conversion in the presence of a static magnetic field. The dc resistivity (ρ_DC) was studied as a function of temperature in the range 300–773^∘K. The variation of resistivity with temperature shows metal/seconductor behaviour.     

TiO2包覆LiNi1/3Co1/3Mn1/3O2的高温与高倍率性能

用载体转移工艺制备TiO2包覆的LiNi1/3Co1/3Mn1/3O2(TZ-NC M)材料,产物为层状α-NaFeO2结构,TiO2均匀包覆在LiNi1/3Co1/3Mn1/3O2(NCM)的表面.在2.8～4.3 V循环,TZ-NCM的5.0 C首次放电比容量为111.8 mAh/g;在55℃下以1.0 C循环50次,TZ-NCM的放电比容量为151.0 mAh/g.包覆TiO2能提高高倍率性能、高温稳定性和循环性能.