为更有效地监测电抗器的工作状态,提出一种基于振动参数图像融合灰度共生矩阵的电抗器机械状态辨识方法.首先对电抗器施加不同大小的电压、预紧力以模拟不同工况,在采用工作变形分析的基础上,利用灰度共生矩阵提取不同工况下工作变形分析云图的纹理特征,引入能够定量表征电抗器振动情况的振型相关系数,进而得到电抗器振动参数结合工作变形分析灰度图纹理特征的融合特征矩阵,最后利用支持向量机实现电抗器的状态辨识.通过模拟绕组松动故障试验,将所提方法与单一基于灰度共生矩阵的常规辨识方法进行比较,实验结果表明:所提方法能够有效地提取电抗器振动信号特征参量,且诊断精度相较于常规方法有明显提升,准确率可达93.6％.

Aiming to fulfill the need for noise monitoring of a power grid, a self-powered system was established in this study for noise monitoring sensors of power equipment. Specifically, the self-powered system is a wireless vibrational energy transduction and storage system that has low power consumption and does not require a power supply. It includes a transducer module, a circuit conditioning module, and an energy storage module. In particular, the piezoelectric sheet was designed based on the vibration characteristics of power equipment and a zinc oxide nanowire array was selected as the material of the transducer module, which converts vibrational power used by the power equipment into electrical energy. An LTC 3588-1 chip was adopted for the circuit conditioning module to rectify the electrical energy collected. Meanwhile, lithium batteries were employed for the energy storage module. Through preliminary experimental research, the system demonstrates good energy transduction and storage functions. Regarding the technical characteristics of this self-powered system, the respective installation and maintenance are convenient. Further, such vibrational energy harvesting technology uses the vibration of the power equipment itself as an energy source; thus, it has potential in applications in which obtaining light energy and replacing batteries are difficult.

准确快速计算高压输电线路的宽频电磁散射特性是研究其对周边通信设施无源干扰影响的重要基础与前提.然而,当前提出的基于等间隔均匀采样模型参数估计(MBPE)技术的快速求解方法存在稳健性差、计算精度低等问题.为此,文中通过引入一种新的MBPE技术和构建一种自适应频点采样方法,提出了一种稳定性强、计算精度高的高压输电线路宽频散射场快速重构方法.以IEEE研究频段和调幅广播收音台站工作频段为例,分别建立高压输电线路无源干扰的直线模型及线面混合模型,并利用矩量法求解自适应采样频点对应的散射场函数信息,以此基于Thiele连分式有理函数对各频段散射场进行插值,从而实现高压输电线路宽频散射场的准确快速求解.结果表明:传统均匀采样MBPE技术稳健性差、计算精度低,全局平均误差高达25.63％,而所提自适应MBPE技术仅为9.08％,因而其相比于传统MBPE技术具有可靠性高、通同性强等优点.

绕组松动是变压器常见故障之一,对变压器的安全运行产生巨大威胁.故对其进行精准的监测,对提高电力系统的安全稳定性具有十分重要的意义.基于声信号的变压器绕组松动检测,由于其具有无损检测和不需停运变压器等优点,成为近年来研究的热点.但声信号检测存在故障特征提前复杂和易受噪声干扰等缺陷,限制了其工程应用.该文提出了一种基于声信号听觉谱特征和支持向量机的变压器绕组松动识别方法.首先,将采集的声信号进行去均值和消除趋势项的预处理,以减小信号采集环境和传感器性能对所采集信号的影响;然后,将预处理后的声信号输入到多特征频率分析的听觉外周模型,经过中耳滤波器滤波、基底膜模型选频、外毛细胞模型放大、内毛细胞模型换能作用后,输出内毛细胞电压信号,实现多个特征频率听觉信号的提取,以此构成听觉谱,并在听觉谱基础上提取多种统计特征;最后,每种特征分别使用遗传算法优化的支持向量机进行识别试验,以验证提取特征的有效性.为进一步提高识别准确率,融合多种统计特征构成特征向量并进行测试,以此确定最优融合特征.研究表明,该文所建立的变压器绕组状态检测方法可以有效地应用于变压器故障诊断和监测中.

利用共振型声学超表面吸声是近年来噪声控制的研究热点,然而其狭窄的吸收峰限制了进一步应用.针对电磁噪声在中低频噪声峰分布呈现倍数关系的特点,基于Visco?Thermal长直管吸声原理设计了六棱柱状的共面迷宫腔声学超表面单元结构,厚度仅为波长的1/137,可以用一种结构实现对多个噪声峰值的吸收.利用不同单元结构的并联,实现了对更多噪声峰值的覆盖.以变压器噪声为例,用并联的共面迷宫腔声学超表面结构实现对800 Hz以下所有整数阶谐频噪声的吸收,分析了结构参数对吸声效果的影响规律并进行了原理性实验验证.

为了研究新型电力系统下负载因素对S13-M400/10配电变压器振动噪声特性的影响,文中在半消声室中搭建了振动噪声试验平台探究了该变压器的整体模态及其散热片的振动噪声特性,研究了谐波、不平衡负载、过励磁、过载等因素对于该变压器振动噪声特性的影响.研究结果表明,S13?M400/10配电变压器整体模态频谱复杂,固有频率较多;散热片的振动比相邻的油箱箱体部分振动更强烈;三相不平衡负载中不平衡相为B相时振动、噪声小于不平衡相为A相和C相时的振动、噪声;5次谐波下该变压器振动噪声剧增;过励磁状态下变压器的A计权声压级约以17 dB(A)/kV的速率增长,振动剧增;当二倍额定负载时,变压器基频振动幅值提高3～4倍,但变压器噪声变化幅度小于1 dB(A).文中研究结果对于变压器测点布置及振动控制具有参考意义.

This article is mainly aimed at defining and verifying whether the project involves environmentally sensitive areas in the process of environmental intelligent survey, calculating the position coordinate information of the target GPS position in the aerial image map under the condition of Gaussian projection, and further calculating the four corners of the image and the position of other target points under the WGS84 coordinate system. First of all, based on the POS data information of aerial equipment, this paper calculates the corresponding Gaussian projection and POS data information, then the pseudo-position information of image center coordinates is further calculated; Second, Based on the coordinates information of gauss projection, this paper calculates the heading open angle and side open angle of the camera, then calculate the width and height of the image for pose correction, and finally get the coordinate position of the corrected image center point. Finally, the GPS positions of other target points can be calculated by pixel coordinates of images, and the calculated results are pasted on Google earth for precision comparison. Experimental results show that the proposed method can accurately calculate the GPS positions of targets in aerial images.

With the continuous development of science and technology, the capacity of data is also showing a geometric increase. Therefore, this paper mainly studies how to store query, change, and replace a large number of geographic images. The text uses SQL server platform and ArcGIS geographic software processing platform. It solves the problem of processing limit exceeding the database in the face of massive database, insufficient network bandwidth compared with massive images, slow image display speed, storage problem of massive image data, and so on.

The radio interference generation mechanism of AC-DC parallel transmission lines is different from that of conventional lines, so that the prediction model is either too rough and leads to large errors, or too complicated to be mastered by engineers. In order to take into account the accuracy of radio interference solution and engineering practicability, an error back-propagation feedforward neural network model combined with gray correlation theory is proposed. First, the gray theory screening of multiple impact indicators of radio interference, and then the indicators that have a real impact on radio interference as input variables, the BP neural network fitting algorithm is used to predict the radio interference. Validation combined with the actual measured radio interference samples of the AC-DC parallel transmission lines that have been put into operation, the results show that compared with the traditional algorithm, the prediction accuracy of the BP neural network prediction model is improved by 14.6%.

交直流并行输电线路无线电干扰的产生机理与常规线路不同,以至于其预测模型要么过于粗略而误差过大,要么过于复杂而不易被工程人员掌握.为兼顾无线电干扰求解准确性与工程实用性,提出了一种结合灰色关联度理论的误差反向传播前馈神经网络模型.首先,对影响无线电干扰的17个影响指标进行灰色理论筛选,然后将得到的对无线电干扰有切实影响的指标作为输入变量,以无线电干扰为输出变量,通过BP神经网络拟合算法进行无线电干扰预测.结合已投入运行的交直流并行输电线路实测无线电干扰样本进行验证,结果表明,相较于传统算法,采用BP神经网络预测模型的预测精度提高了13.58％.

The electromagnetic environment under AC-DC parallel lines has become one of the main considerations in lines design. In this paper, the influence of temperature on the mixed ion flow field under AC-DC parallel lines is studied, the influence mechanism of temperature on the mixed ion flow field is analyzed, and the size of the mixed ion flow field at different temperatures is calculated. The results show that when the temperature increases from 0°C to 25°C, the corona intensity of the line and the ion mobility increases, which makes the mixed ion flow field and the mixed ion current density under the line increase by 12.8% and 14.75% respectively.

In order to study the complex electromagnetic environment under the AC and DC parallel transmission lines, the hybrid ionized field characteristics under different line structures are studied. The influence of DC line pole spacing, AC and DC parallel spacing, AC line voltage level and other factors on the hybrid ionized field are considered. The results show that the influence of the DC line polar distance on the hybrid ionized field is negligible, and the change of the AC and DC parallel spacing in different ranges has different effects on the hybrid ionized field, and with the increase of the AC line voltage level, it will reduce the hybrid ionized field under the line.

由于线路间耦合效应,交直流并行线路产生的无线电干扰与单独线路不同.为研究交直流并行输电线路无线电干扰与温湿度的相关性,建立了无线电干扰与气象自动化同步测量系统,开展了长达1年的监测.由于数据量巨大且存在随机误差,采用了Pauta准则进行离群值处理,并通过计算处理后的数据,分析了无线电干扰与温湿度之间的相关性.结果 表明,好天气条件下,交直流并行输电线路无线电干扰大体上与温度呈微弱的正相关性,与湿度呈较强的负相关性.通过组合单点数据的分析结果,得到不同季节好天气条件下交直流并行输电线路无线电干扰的横向分布规律,为并行线路无线电干扰的分析提供了支撑.

随着电网的不断建设,交直流输电线路同走廊并行架设已在多处出现.目前,交直流混合电磁环境监测多以单点离散测量为主,无法实现横向分布的连续实时测量.通过建立工频电场、无线电干扰、合成电场等测量设备沿同一路径的分布式实时数据采集系统,实现交直流并行线路电磁环境移动式横向分布测量及数据的动态管理,并以典型合成电场数据为例,研究了垂直于线路走廊155 m的横向断面合成电场分布趋势.结果 表明,实测数据与仿真计算结果趋势较吻合,为交直流并行线路合成电场研究提供了参考.

Abstract Along with the social and economic development and continuous increasing of electrical load, power distribution network has its scale continuously expanded, and more and more distribution transformers go deep into the urban residential areas, leading to increasingly serious vibration and noise problems. Relying on a typical 35 kV distribution transformer, a vibration mode test was done on the tank structure of the distribution transformer, and PolyLSCF fitting method was adopted to obtain the first 10-order modal shape in this paper. Meanwhile, finite element model was built for distribution transformer tank, and contrastive analysis were done in combination with the measured data to obtain the rules of influence on vibration mode of distribution transformer by tank wall thickness. The vibration characteristics acquired by measured mode of distribution transformer are consistent with those obtained by numerical simulation, and the central vibration amplitude of the tank is the maximum. Along with the increase of wall thickness, the low-order mode of the tank structure shows insignificant change, and high-order mode frequency reduces, thus providing measured data reference for optimizing the tank structure of distribution transformer.

特高压交直流线路并行条件下的混合电场形成机理复杂,现有算法难以准确且高效地进行求解,从而制约了交直流线路并行工程的建设与推广.为兼顾特高压交直流并行线路混合电场求解的准确性和工程实用性,提出了一种适合工程应用的简化处理方法.该方法以特高压交直流并行线路中交流线路与直流线路之间的相互影响为基础,将任一时刻的交流导线视为电压值为交流电压瞬时值的直流导线,从而将交直流并行问题简化为多回直流线路的电场问题,并在地面合成场强解析计算模型的基础上发展出了一种新的交直流并行线路混合电场解析计算模型,适用于工程简化计算.以河南省沁阳市±800 kV天中线与1000 kV长南Ⅰ线并行线路为例,通过实验和仿真的方法对算法进行验证.结果表明,计算结果与实地测量结果误差最大值为17.04％,误差最小值为4％,平均误差为8.2％.

户外变电站(换流站)的降噪措施以隔声罩、隔声屏障为主,其主要构成材料为"碳钢、玻璃棉和岩棉".电力火灾主要以绝缘油和高聚物燃烧为主,升温速度及最高温度均高于纤维类火灾,对材料影响更为严酷.电力火灾下,矿物棉类材料会发生热缩、粉化,对于消防基本无影响,但钢结构及镀锌钢板即使在1000℃时仍有强度,虽然软化变形,但不会直接断裂,仍阻碍灭火工作."高温熔落式颗粒板""基于热塑性PA6材料的高温可熔落结构"两种隔声罩改进方式改善了消防条件,其最终服役性能还需在应用中进一步积累试验数据.变电设备的本体低噪声化将是电工装备技术发展的最终趋势.

滤波电抗器是换流站中噪声的主要来源之一.本文以干式空心电抗器为研究对象,利用多频率复合加载实验研究了其在谐波激励下噪声特性,并提出了基于频响函数的噪声预估方法.研究结果表明:在复合频率电流激励下,干式空心电抗器的主要噪声频率分量为所加电流频率的二倍频以及相互之间的差频与和频;电抗器受电磁力作用振动辐射噪声的物理过程可被视作线性系统,在多频加载下相应频率的噪声分布与单频加载时近似相同.在此基础上提出了基于频响函数干式空心电抗器噪声预估方法,并对其进行了实验验证,结果表明声功率误差较小,平均声功率级误差为0.2 dB.

提出一种基于无网格径向点插值法的混合离子流场求解算法,实现了对交直流并行线路离子流场的精确求解.利用多项式的径向点插值法对传统无网格法的形函数进行修改,使形函数在待施加边界约束条件的点处满足Kronecker-δ函数性质,以符合直接施加边界约束条件的要求;再结合交流线路对混合离子流场的影响因素,得到混合离子流场和离子流密度值;最后,以500 kV博塔线和±800 kV天中线在武陟段的并行线路为例进行仿真计算与实验测量分析.结果表明,采用所提算法可将离子流密度的相对误差缩减至4.5％,将离子流场的相对误差缩减至24％.

干式空心电抗器在变电站运行中发挥着重要作用.为了有效控制电抗器噪声的环境影响,该文利用特征系统实现方法,针对通电作用下的电抗器模态特性进行了试验分析.结果 表明,干式空心电抗器的前5阶固有频率出现在其通电运行状态的作用频率中,并可能成为其在通电运行条件下发生噪声增强和设备损坏的重要原因,该研究将为改进其设备共振问题提供重要依据.