气隙结构对特高压并联电抗器铁芯振动的影响

以气隙个数和气隙位置对特高压并联电抗器铁芯振动的影响为主要研究对象,在分析特高压并联电抗器铁芯振动机制的基础上,指出了麦克斯韦力和磁致伸缩力的矢量和是影响铁芯振动强度的主要原因;系统分析了铁芯气隙可能存在的结构型式,搭建了具有不同气隙个数和气隙位置的特高压并联电抗器铁芯的真型仿真模型,并采用多物理场有限元仿真计算的方法,得到了气隙结构对特高压并联电抗器铁芯振动的影响规律。研究结果表明,在研究范围内(气隙个数为15~25),特高压并联电抗器铁芯气隙个数越少则振动强度越弱;气隙位置越靠近底轭则振动越强,越靠近铁芯柱3/4高度中心则振动越弱。在此基础上提出一种特高压并联电抗器铁芯减振设计方案,与现有铁芯设计方案相比该方案能够使铁芯振动位移均方根减小18.925%。     

LARGE AREA PIEZOELECTRIC ACTUATORS USING METAL FOIL SUBSTRATES WITH Pb(Zrx,Ti1 - x)O3 THIN FILMS

ABSTRACT

We report on the deposition of Pb(Zr_x,Ti_{1 - x})O₃ (PZT) thin films by chemical solution deposition (CSD) on stainless steel foils. The electrical characterization proves good ferroelectric properties with a remnant polarization of 38 μ C/cm². Since PZT is also piezoelectric the 35 μ m and 50 μ m thick metal foils are used to make piezoelectric actuated cantilever beams of several millimeter lengths. Actuated with 10–30 V a displacement up to 32 μ m was measured in quasi-static mode. In resonance mode the displacement increases several times at the same driving voltage.     

LAGRANGE MULTIPLIERS FOR THE INTERMEDIATE METALLIC REGIONS IN THE COMPUTATION OF THE POTENTIAL DISTRIBUTION OF INSULATOR CHAINS BY FEM

ABSTRACT

It is very important to predict the behaviour of the high voltage insulators at the operating conditions from the point of improving of the design and practical selection of the insulator type. Therefore, it is necessary to compute the potential and electric field distributions and to determine the critical regions forced much more by the electric field. In case the insulator surface is clean or the pollution film at the surface is dry, a little capacitive current flows and the solution of the problem results in a capacitive potential distribution.

In the numerical computational methods of potential distribution of insulator chains, it requires to insert into the resulting equation system as boundary conditions of the intermediate metallic zones that connect two units that have the same potential at every point. In this work, the potential distribution of clean insulator chains have been computed using the Finite Element Method (FEM). The metallic zones between the units have been taken into account as equipotential surfaces by Lagrange Multipliers. The computed results were compared with experimental results obtained by using the Conducting Paper Method and good agreement was observed.     

适于深层次CNN的配电网过电压数据集建立方法

随着人工智能算法的快速发展,在配网过电压识别中层数较少的卷积神经网络已得到应用。深层次网络有较高的识别率,但需要大量数据样本,目前已有数据集数据量不足,不能满足深层级网络训练所需。为此提出了一种满足深层次网络训练所需的配电网过电压数据集建立方法。首先利用电磁暂态仿真软件EMTPworks仿真10 kV配网5种典型的过电压并且编辑相应的JavaScript脚本,通过改变故障初相角、过渡电阻、线路长度等参数产生16 272个数据。然后将三相过电压一维信号进行连续小波变换,得到相应二维时频图,并根据原始信号的特征自动标记二维时频图,从而建立了完整的配电网过电压数据集。最后利用卷积神经网络（CNN）对5类过电压信号数据的有效性进行验证。结果表明,构造的数据集数据规模大,有效性高,能够满足深层次网络需要。     

一种基于集成SoC芯片的中低压配电网故障监测系统

故障监测一直是电网安全运行的有力保障,而传统电缆线路繁多、分布复杂、信道传输环境恶劣,变压器、电气柜等状态监测手段不足,始终存在泄漏电流,这些问题均导致故障定位准确性、实时性差,局部放电类型日趋复杂。针对中低压配电网中日益复杂的故障监测问题,文章基于智能配电终端(DSU)在配电网中的应用,提出了一种基于集成SoC芯片的故障监测系统,系统中以芯片集成了剩余电流检测、无线通信、GIS等技术,并加入IRIG-B码对时技术,依托终端的边缘计算能力及云平台对采集信息进行计算分析,判断是否引起故障及故障类型,进而实现对故障点实时定位、报警。芯片集成改善了目前故障检测的实时性及智能终端设备难以普及的经济性。     

新型的电缆局部放电在线监测系统研究

城市电网中因电缆沟电缆故障起火的事件时有发生,电缆绝缘劣化是电缆发生故障的重要原因,局部放电(简称局放)是电缆绝缘缺陷的表征,也是导致其绝缘劣化的主要原因之一。一直以来手持局放仪巡检电缆线路是诊断电缆绝缘状态的重要方法,为降低工作人员手持局放仪巡线的繁琐程度,研究了一种新型的电缆局放在线监测系统,该系统中使用高频电流传感器耦合流过电缆接头接地引下线的高频脉冲电流信号,并通过新型局部放电采集器将局放综合信息上传至局放监测主机,完成局放信号的实时在线监测。与传统的局放采集器相比新型局放采集器搭载了电力人工智能芯片,实现了局放信号处理的边缘计算,极大地缓解了庞大安装数量级下局放监测主机的压力,最后在现场测试中应用了该系统,并验证了该系统的可行性。