In-situ diagnostics of HV outdoor insulators using laser-induced fluorescence spectroscopy

A new method for remote and non-intrusive diagnostics and surveillance of high-voltage insulators and insulation materials is presented, in particular pertinent to outdoor insulation. The method is based on laser-induced fluorescence (LIF) spectroscopy. The relationship between the LIF-spectrum and different materials and surface characteristics of silicone rubber samples are studied. These characteristics include hydrophobicity, filler content and biological growth. Furthermore, real insulators that have been naturally aged have also been studied. We conclude that laser-induced fluorescence has a significant potential to become a highly useful technique for contact-free and non-intrusive monitoring of the status of insulator materials in high-voltage systems.     

模拟电路故障诊断的邻近支持向量机集成方法

提出了基于非对称AdaBoost算法与邻近支持向量机的模拟电路集成故障诊断方法。该方法采用非对称AdaBoost解决邻近支持向量机处理多分类问题出现的数据不平衡问题,提高邻近支持向量机的分类准确率;利用高斯变异策略自适应选择核函数及正则化因子,提高集成邻近支持向量机的个体间差异性;最后获得分类精度高和泛化性能好的分类器。通过对模拟电路的故障诊断实验,验证了该方法的鲁棒性和可行性。诊断结果表明本文方法具有故障定位准确和泛化性好的特点。     

传感器非线性校正的遗传支持向量机方法

针对传感器非线性校正中现有的较为常用的神经网络法的不足和支持向量机参数难确定的问题,提出了一种遗传算法和支持向量机相结合的方法,阐述了支持向量机的非线性校正原理和遗传算法优化支持向量机参数的实现过程,并分别采用BP神经网络法和遗传支持向量机方法对压力传感器进行非线性校正.实验结果表明: BP神经网络法使得传感器的最大相...     

基于支持向量机的随钻测量

针对目前随钻测量的需要,提出了一种基于支持向量机预测的随钻测量方法.与传统随钻测量方法相比该方法能够预测提示井下钻头需要待钻进的地理方位位置,为司钻人员下一步的施工钻进提供方位信息.通过现场试验数据测试,结果表明,该方法能够预测提示井下定向钻进过程中的定向方位信息,大幅度节省钻进施工时间.     

Optimization of HV electrode systems by neural networks using a newlearning method

To avoid a large number of iterations, optimization of electrode shapes has been done by artificial neural networks (NN). Two practical examples have been considered, an axisymmetric single-phase GIS bus termination and an axisymmetric transformer shield ring. The shape of the electrodes has been taken as quarter-ellipse or half-ellipse because an ellipse has more flexibility than a circle. For NN, the so-called resilient propagation algorithm, learning faster than the standard back-propagation algorithm, has been employed. The training sets as well as the test sets of NN have been prepared by charge simulation method     

采用模糊支持向量机的模拟电路故障诊断新方法

为了解决模拟电路故障诊断复杂多样难于辨识的问题,有效提高分类的准确度,提出了一种模拟电路故障诊断的新方法。首先对采集的信号进行时-频域联合特征提取并采用新的模糊隶属度函数确定训练样本的隶属度,消除噪声和野点对故障诊断的影响;然后将训练集输入模糊支持向量机分类方法训练获得故障诊断模型;最后将测试集输入训练好的模糊支持向量机分类模型,实现对不同故障类型的识别。将该方法应用于CTSV滤波电路进行故障诊断仿真实验,结果显示该方法不仅能正确分类单故障而且能有效分类多故障,平均故障诊断率达到98.2%,为模拟电路故障诊断开辟新的途径。     

一种基于多类支持向量机的故障诊断算法

主要研究了多类支持向量机算法,及其在多类故障诊断问题中的运用.考虑到传统"一对一"算法和"一对多"算法的局限,提出了基于遗传算法的决策树支持向量机,利用遗传算法的全局随机搜索性能来构造决策树.根据样本数据的分布,遗传算法的适应度函数定义为两个子类集聚类中心之间的距离,使得在决策树的每一个节点最可分类别尽可能分开.通过对三个数据集进行仿真分析,表明该算法的性能优于两个传统算法,具有更高的推广能力,验证了算法的有效性.     

基于Hilbert-Huang变换和最小二乘支持向量机的电力市场出清电价预测

随着世界各国电力工业改革的发展趋势,我国于20世纪90年代也开始了以打破垄断、引入竞争、放松管制为目标的电力市场化改革。如何合理制定相应的运营模式以及怎样根据电力市场的相关历史数据准确的预测出未来的市场出清电价,对于市场中的各个参与者都具有十分重要的意义。而实际电力市场的出清电价数据具有很强的非平稳性,Hilbert-Huang变换是分析处理非平稳性信号数据非常有效的方法,本文应用Hilbert-Huang变换首先对电力市场出清电价数据进行平稳化处理,然后运用最小二乘支持向量机（LS-SVM）对处理后的数据进行预测。预测结果表明,此模型显著的提高了出清电价预测的精度。     

Flashover of discontinuous pollution layer on HV insulators

This paper deals with discontinuous pollution layers deposited on the insulator surface. Two zones are known to form: a clean (dry) zone and a polluted (wetted) zone. The influence of the length and position of the dry zone on the leakage current and the arc length are investigated. These were made on a plane experimental model under ac voltage. Two configurations were studied: pollution deposited near the HV electrode, and pollution deposited near the ground electrode. This study was made using pollution layers with different conductivities. Based on the experimental results, a theoretical model allowing us to calculate the gap impedance, the transferred (gap) voltage and the leakage current was established. This model enables to predict the pollution severity based on the sample's equivalent impedance     

Optimal locality preserving least square support vector machine

In this paper, a novel least square support vector machine (LSSVM), termed as optimal locality preserving LSSVM (OLP-LSSVM) is proposed. By integrating structural risk minimization and locality preserving criterion in a unified framework, the resulting separating hyperplane is not only in accordance with the structural risk minimization principle but also be sensitive to the manifold structure of data points. The proposed model can be solved efficiently by alternating optimization method. Experimental results on several public available benchmark datasets show the feasibility and effectiveness of the proposed method.     

基于支持向量机模型的环境音分类研究

音频分类是提取音频结构和内容语义的重要手段,是基于内容的音频、视频检索和分析的基础.支持向量机(SVM)是一种有效的统计学习方法.本文提出了一种基于SVM的音频分类算法.将环境音分为6类:车鸣声,钟声,风声,冰块声,机床声和雨声.特征抽取是音频分类的基础.本文从帧层次上深入分析了不同类音频之间的区别性特征,包括频域能量,子带能量,过零率,频率中心,带宽,基音频率及MFCC(Mel-Frequency Cepstral Coefficients).实验结果表明,支持向量机模型的环境音分类性能较好,最优分类精度达到97.73%.     

A new flashover dynamic model of polluted HV insulators

In this work, a model based on field criterion has been developed to represent the flashover phenomenon, which occurs due to surface pollution on high voltage insulators, under ac voltage. The values of potential and electric field on an insulator surface have been determined using the finite element method (FEM). The open model of the insulator has been used for calculating the resistance in series with the arc, in addition to the values of the leakage current and the arc gradient. As a new approach, this dynamic model uses Lagrange multipliers for the solution of the pollution flashover problem. Both the impedance and the electric field criterion have been used for the propagation of arc on the surface. A computer program called NFDM (new flashover dynamic model) has been developed to achieve this. The results obtained from the program have been compared with theoretical and experimental results of other researchers.     

有向无环图的多类支持向量机分类算法

为研究基于有向无环图的支持向量机分类算法以及在故障诊断问题中的应用,考虑到有向无环图的结构运算相当于一个表操作,且分类结果依赖于有向无环图中节点的排列顺序,提出一种分类算法,该算法引入基于类分布的类间分离性测度,估计各类训练数据间的分布性质,建立初始操作表单,将样本所有可能的类别按照一定顺序排列在表单中,从而重新组合有...     

One airport detection method based on support vector machine

This paper proposes a novel airport detection method, which integrates the texture features and shape features of the airport. Eight texture features, such as the mean of the region, the deviation of the region, the smoothness of the region, the skewness of a histogram, the uniformity of the region, the randomness of the region, the mean of the gradient image and the deviation of the gradient image, are used to represent the features of the region. In this method, first the long lines are detected and the regions where the lines locate are segmented. Second, support vector machine (SVM) based on Gaussian kernel is used as a classifier which discriminates the runway from other candidate regions. Experimental results show that the error rate of the proposed method is lower than those of conventional methods which detect airport only by the shape feature of runway. The detection accuracy of the proposed method is nearly ten times higher than that of Liu’s methods, and the method has favorable speed for a real-time system. __________ Translated from Journal of Xi’an Jiaotong University, 2006, 40(6): 709–713 [译自: 西安交通大学学报]     

基于支持向量机的电晕放电模式识别方法

应用自回归（Autoregression,简称AR）模型提取电晕放电信号的AR模型参数作为信号特征量,利用支持向量机（Support Vector Machine,简称SVM）作为分类器对放电模型进行识别,重点分析了核函数和支持向量机参数对分类器的影响。结果表明,AR模型参数作为信号特征量,并与支持向量机结合对电晕放电信号进行识别是有效的。     

高压输电线路合成绝缘子断裂机理研究

本文探讨了常见的合成绝缘子破坏形式和断裂机理 ,并分析了广东省 5 0 0 k V惠汕线合成绝缘子断串事故的原因 ,提出了生产和应用的改进措施     

提高高压支柱瓷绝缘子运行可靠性的建议

近几年来 ,国家电力公司系统高压支柱瓷绝缘子折断、开裂事故接连发生 ,给电力系统的正常运行和人身安全带来危害。国家电力公司对此高度重视 ,组织小组对高压支柱瓷绝缘子事故情况进行了调查。在各网省公司积极配合下 ,提出了“高压支柱瓷绝缘子事故情况的调查报告” ,并随国家电力公司部门文件“发输电输 [2 0 0 2 ]116号”下发。结合本次调查情况及体会 ,本文对提高高压支柱瓷绝缘子的运行可靠性谈点看法 ,其观点也适用于其它电力设备。1　适当增大设计裕度首先 ,设计一般都是按现行的手册、标准及规范进行。随着技术进步 ,产品的结构工…     

Numerical design of HV insulators based on charge accumulation invacuum

A MCS (Monte Carlo simulation) method of charge accumulation based on the SEEA (secondary emission electron avalanche) mechanism is applied to the design of effective corrugation on an insulator surface used in vacuum. The electric field distribution on the cathode in the vicinity of a triple junction is analyzed taking the SEEA charge accumulation into account. Considerable relaxation of field strength takes places due to negative charge accumulation with appropriate corrugation. The flashover voltage obtained experimentally increases as the field strength decreases. The results of the MCS agree well with experiment     

基于支持向量机的锅炉煤质预测模型

通过基于统计学习理论的支持向量机建模和机理性的分析及推导,给出了2种不同的电厂锅炉煤质预测模型,并结合现场试验数据,给出2种方法不同的预测结果及评价.验证了支持向量机建模对于火力发电厂煤质监测具有较高的应用价值.     

基于惩罚加权支持向量机回归的径流预测模型

径流预测是水文科学研究的重要内容。针对径流时间序列的特性,本文尝试建立了一种惩罚加权支持向量机回归的径流预测模型。通过与BP神经网络和标准支持向量机的结果进行比较,表明该模型预测精度更高,可以用于河川径流的中长期预测。