期刊文献+
共找到14篇文章
< 1 >
每页显示 20 50 100
基于测量波阻抗的母线保护新方法 被引量:6
1
作者 陈洋 黄纯 +1 位作者 陈为熙 魏荣进 《电网技术》 EI CSCD 北大核心 2012年第5期198-203,共6页
为避免电流互感器饱和对母线保护的影响,提出一种基于测量波阻抗的母线保护新方法:对母线区内、外故障的情况进行了理论分析,当发生母线区内故障时,所有线路的测量波阻抗的极性均为负,幅值近似相等;当母线发生区外线路故障时,故障线路... 为避免电流互感器饱和对母线保护的影响,提出一种基于测量波阻抗的母线保护新方法:对母线区内、外故障的情况进行了理论分析,当发生母线区内故障时,所有线路的测量波阻抗的极性均为负,幅值近似相等;当母线发生区外线路故障时,故障线路的测量波阻抗的极性为正,且其幅值远小于非故障线路的测量波阻抗的幅值;通过对母线上各线路的测量波阻抗的极性和幅值进行比较即能判断母线故障类型。此外,还对该母线保护新方法的实现方案进行了探讨,得到了可行的保护实现方案。理论分析及EMTP仿真表明,基于测量波阻抗的母线保护方法基本不受故障类型、故障过渡电阻、故障距离和故障初始角的影响,且能体现行波的本质,保护方法可靠、有效。 展开更多
关键词 母线保护 测量波阻抗 行波 模量变换 小波变 电磁暂态程序
下载PDF
一种基于行波法的新型线路故障定位装置的研制 被引量:6
2
作者 李畅 赵晶 陈岭 《广东电力》 2006年第5期42-45,共4页
传统的阻抗法进行故障定位,难以克服过渡电阻等因素的影响。随着行波法的优点被日趋认识,基于行波法的故障定位装置已成为主流。为此,提出了一种基于行波法的单端故障定位装置的开发思路,并详细介绍了该装置硬件、软件的设计工作及故障... 传统的阻抗法进行故障定位,难以克服过渡电阻等因素的影响。随着行波法的优点被日趋认识,基于行波法的故障定位装置已成为主流。为此,提出了一种基于行波法的单端故障定位装置的开发思路,并详细介绍了该装置硬件、软件的设计工作及故障定位方法的研究。 展开更多
关键词 行波 故障定位 模量变换 小波
下载PDF
平行多导线系统波过程分析再探讨──有损系统的分析与求解 被引量:1
3
作者 李泽 《电气电子教学学报》 1997年第3期22-26,共5页
本文先在无损平行多导线系统分析的基础上,对有损系统进行模量变换解耦,得到模量上相互独立的有损平行多导线系统,再利用单根有损线计算波过程的特征线法─—Bergeron分析模式,求得每个模型变量,最后经反变换求得实际系统的解。
关键词 有损平行多导线系统 模量变换 Bergeron 波过程
下载PDF
平行多导线系统波过程的分析与求解
4
作者 李泽 《电工教学》 1997年第1期22-26,共5页
本文用麦克斯韦电场和磁场方程推导出平行多导线系统的矩阵波动方程。经模量变换将系统电压、电流向量化为一组新的电压、电流模型变量,再利用求单根导线波过程的方法对每个模型变量求解,最后经反变换求的实际系统的电压、电流向量。
关键词 平行多导线系统 波动方程 模量变换 波过程
下载PDF
一种基于行波法的新型线路故障定位装置研制 被引量:2
5
作者 方力谦 李静 《广东电力》 2009年第6期33-36,56,共5页
鉴于采用传统的阻抗法进行故障定位难以克服过渡电阻等因素的影响,提出了一种基于行波法的单端故障定位装置。详细论述了该装置硬件、软件的设计工作,提出了一种基于小波的暂态信息分析方法,以及基于模量变换的定位算法。由于装置中高达... 鉴于采用传统的阻抗法进行故障定位难以克服过渡电阻等因素的影响,提出了一种基于行波法的单端故障定位装置。详细论述了该装置硬件、软件的设计工作,提出了一种基于小波的暂态信息分析方法,以及基于模量变换的定位算法。由于装置中高达120MHz的高速数据采集板的使用,单端故障定位也能够满足输电线路故障定位的要求,并且由于单端装置设备更简单,还具有向配电网故障定位装置发展的优势。 展开更多
关键词 行波 故障定位 模量变换 小波
下载PDF
Calculation of earth pressure based on disturbed state concept theory 被引量:4
6
作者 朱剑锋 徐日庆 +1 位作者 李昕睿 陈页开 《Journal of Central South University》 SCIE EI CAS 2011年第4期1240-1247,共8页
The theoretical formulations of Coulomb and Rankine still remain as the fundamental approaches to the analysis of most gravity-type retaining wall,with the assumption that sufficient lateral yield will occur to mobili... The theoretical formulations of Coulomb and Rankine still remain as the fundamental approaches to the analysis of most gravity-type retaining wall,with the assumption that sufficient lateral yield will occur to mobilize fully limited conditions behind the wall.The effects of the magnitude of wall movements and different wall-movement modes are not taken into consideration.The disturbance of backfill is considered to be related to the wall movement under translation mode.On the basis of disturbed state concept(DSC),a general disturbance function was proposed which ranged from-1 to 1.The disturbance variables could be determined from the measured wall movements.A novel approach that related to disturbed degree and the mobilized internal frictional angle of the backfill was also derived.A calculation method benefited from Rankine's theory and the proposed approach was established to predict the magnitude and distribution of earth pressure from the cohesionless backfill under translation mode.The predicted results,including the magnitude and distribution of earth pressure,show good agreement with those of the model test and the finite element method.In addition,the disturbance parameter b was also discussed. 展开更多
关键词 disturbed state concept disturbance function translation mode earth pressure cohesionless soil
下载PDF
Risk-based water quality decision-making under small data using Bayesian network 被引量:3
7
作者 张庆庆 许月萍 +1 位作者 田烨 张徐杰 《Journal of Central South University》 SCIE EI CAS 2012年第11期3215-3224,共10页
A knowledge-based network for Section Yidong Bridge,Dongyang River,one tributary of Qiantang River,Zhejiang Province,China,is established in order to model water quality in areas under small data.Then,based on normal ... A knowledge-based network for Section Yidong Bridge,Dongyang River,one tributary of Qiantang River,Zhejiang Province,China,is established in order to model water quality in areas under small data.Then,based on normal transformation of variables with routine monitoring data and normal assumption of variables without routine monitoring data,a conditional linear Gaussian Bayesian network is constructed.A "two-constraint selection" procedure is proposed to estimate potential parameter values under small data.Among all potential parameter values,the ones that are most probable are selected as the "representatives".Finally,the risks of pollutant concentration exceeding national water quality standards are calculated and pollution reduction decisions for decision-making reference are proposed.The final results show that conditional linear Gaussian Bayesian network and "two-constraint selection" procedure are very useful in evaluating risks when there is limited data and can help managers to make sound decisions under small data. 展开更多
关键词 water quality risk pollution reduction decisions Bayesian network conditional linear Gaussian Model small data
下载PDF
Various Methods for Constructing Auto-Bcklund Transformations for a Generalized Variable-Coefficient Korteweg-de Vries Model from Plasmas and Fluid Dynamics
8
作者 ZHANG Chun-Yi GAO Yi-Tian +5 位作者 XU Tao LI Li-Li SUN Fu-Wei LI Juan MENG Xiang-Hua WEI Guang-Mei 《Communications in Theoretical Physics》 SCIE CAS CSCD 2008年第3期673-678,共6页
In this paper, under the Painleve-integrable condition, the auto-Biicklund transformations in different forms for a variable-coefficient Korteweg-de Vries model with physical interests are obtained through various met... In this paper, under the Painleve-integrable condition, the auto-Biicklund transformations in different forms for a variable-coefficient Korteweg-de Vries model with physical interests are obtained through various methods including the Hirota method, truncated Painleve expansion method, extendedvariable-coefficient balancing-act method, and Lax pair. Additionally, the compatibility for the truncated Painleve expansion method and extended variable-coetfficient balancing-act method is testified. 展开更多
关键词 variable-coefficient Korteweg-de truncated Painleve expansion Schwarzian derivative-scattering Vries models auto-Backlund transformation Hirota method method extended variable-coefficient balancing-act method method Lax pair
下载PDF
Linear Transformation Theory of Quantum Field Operators and Its Applications
9
作者 MALei 《Communications in Theoretical Physics》 SCIE CAS CSCD 2003年第3期291-294,共4页
We extend the linear quantum transformation theory to the case of quantum field operators. The corresponding general transformation expressions of CPT transformations and gauge field transformations are considered as ... We extend the linear quantum transformation theory to the case of quantum field operators. The corresponding general transformation expressions of CPT transformations and gauge field transformations are considered as its applications. 展开更多
关键词 linear quantum transformation CPT transformations gauge field transformations
下载PDF
Numerical simulation and validation of ocean waves measured by an Along-Track Interferometric Synthetic Aperture Radar
10
作者 张彪 何宜军 Paris W.VACHON 《Chinese Journal of Oceanology and Limnology》 SCIE CAS CSCD 2008年第1期1-8,共8页
A new nonlinear integral transform of ocean wave spectra into Along-Track Interferometric Synthetic Aperture Radar (ATI-SAR) image spectra is described. ATI-SAR phase image spectra are calculated for various sea sta... A new nonlinear integral transform of ocean wave spectra into Along-Track Interferometric Synthetic Aperture Radar (ATI-SAR) image spectra is described. ATI-SAR phase image spectra are calculated for various sea states and radar configurations based on the nonlinear integral transform. The numerical simulations show that the slant range to velocity ratio (R/V), significant wave height to ocean wavelength ratio (Hi2), the baseline (2B) and incident angle (0) affect ATI-SAR imaging. The ATI-SAR imaging theory is validated by means of Two X-band, HH-polarized ATI-SAR phase images of ocean waves and eight C-band, HH-polarized ATI-SAR phase image spectra of ocean waves. It is shown that ATI-SAR phase image spectra are in agreement with those calculated by forward mapping in situ directional wave spectra collected simultaneously with available ATI-SAR observations. ATI-SAR spectral correlation coefficients between observed and simulated are greater than 0.6 and are not sensitive to the degree of nonlinearity. However, the ATI-SARoPhase image spectral turns towards the range direction, even if the real ocean wave direction is 30. It is also shown that the ATI-SAR imaging mechanism is significantly affected by the degree of velocity bunching nonlinearity, especially for high values of R/V and H/2. 展开更多
关键词 ATI-SAR nonlinear integral transform numerical simulation VALIDATION
下载PDF
B-SPLINE-BASED SVM MODEL AND ITS APPLICATIONS TO OIL WATER-FLOODED STATUS IDENTIFICATION
11
作者 Shang Fuhua Zhao Tiejun Yi Xiongying 《Journal of Electronics(China)》 2007年第2期245-250,共6页
A method of B-spline transform for signal feature extraction is developed. With the B-spline, the log-signal space is mapped into the vector space. An efficient algorithm based on Support Vector Machine (SVM ) to auto... A method of B-spline transform for signal feature extraction is developed. With the B-spline, the log-signal space is mapped into the vector space. An efficient algorithm based on Support Vector Machine (SVM ) to automatically identify the water-flooded status of oil-saturated stratum is described. The experiments show that this algorithm can improve the performances for the identification and the generalization in the case of a limited set of samples. 展开更多
关键词 Feature extraction B-spline transform Support Vector Machine (SVM) Water-flooded status
下载PDF
Digital Acousto-optic Matrix Computer
12
作者 SHI Yong-ji, WU Xin,ZOU Hong-wen ((Luoyang Technology College, Louyang 471003,CHN) 《Semiconductor Photonics and Technology》 CAS 1999年第2期74-81,共8页
Acousto-optic system for performing basic operations of vector-matrix multiplication with digital(16-bit)accuracy are described.The system comprised of two multi-transducer Bragg cells that can perform at least 1×... Acousto-optic system for performing basic operations of vector-matrix multiplication with digital(16-bit)accuracy are described.The system comprised of two multi-transducer Bragg cells that can perform at least 1×10 8 operation/s of basic vector-matrix multiplication with digital (16-bit ) accuracy and which is simple and compact. 展开更多
关键词 Acousto-optic Device Acousto-optic Processor Analog Convolution Inner Product Multi-transducer Bragg Cell Vector-matrix Multiplication CLC number:TP302.1 Document code:A
下载PDF
ANALYTICAL SOLUTION WITH SYSTEM METHOD FOR THE MODEL OF ROCK STRATA MOVEMENT AS COMPLEX LAMINATED PLATES
13
作者 赵晓东 宋振骐 《Journal of Coal Science & Engineering(China)》 1999年第2期39-45,共7页
Starting from the basic equation of elastic mechanics, without any additional hypotheses of displacement or stress model, just introducing state space and state equation, the model of rock strata movement as complex l... Starting from the basic equation of elastic mechanics, without any additional hypotheses of displacement or stress model, just introducing state space and state equation, the model of rock strata movement as complex laminated plates is presented. In addition, using displacement as a basic unknown quantity, the accurate analytical series solution for the problem of strata movement induced by extraction of horizontal seam is worked out when crosswise isotropic elastic layers are in sliding contact condition. A new approach is put forward to solve the complicated system of mining subsidence. 展开更多
关键词 strata movement complex laminated plate state space state equation
全文增补中
Tracking with nonlinear measurement model by coordinate rotation transformation 被引量:5
14
作者 ZENG Tao LI Chun Xia +1 位作者 LIU Quan Hua CHEN Xin Liang 《Science China(Technological Sciences)》 SCIE EI CAS 2014年第12期2396-2406,共11页
A new filtering method is proposed to accurately estimate target state via decreasing the nonlinearity between radar polar measurements(or spherical measurements in three-dimensional(3D) radar) and target position in ... A new filtering method is proposed to accurately estimate target state via decreasing the nonlinearity between radar polar measurements(or spherical measurements in three-dimensional(3D) radar) and target position in Cartesian coordinate. The degree of linearity is quantified here by utilizing correlation coefficient and Taylor series expansion. With the proposed method, the original measurements are converted from polar or spherical coordinate to a carefully chosen Cartesian coordinate system that is obtained by coordinate rotation transformation to maximize the linearity degree of the conversion function from polar/spherical to Cartesian coordinate. Then the target state is filtered along each axis of the chosen Cartesian coordinate. This method is compared with extended Kalman filter(EKF), Converted Measurement Kalman filter(CMKF), unscented Kalman filter(UKF) as well as Decoupled Converted Measurement Kalman filter(DECMKF). This new method provides highly accurate position and velocity with consistent estimation. 展开更多
关键词 target tracking Kalman filtering nonlinear filtering decoupled NONLINEARITY
原文传递
上一页 1 下一页 到第
使用帮助 返回顶部