Wide-area multiple line-outages detection in power complex networks

Multiple line outages (MLOs) are common in blackouts, the detection of MLOs are very important for the robusty and securety of power grid. Many insightful methods have been reported to handle with line outage detection, but few of them focus on the detection of MLOs that happen in a short period of time. To deal with this promblem, based on the complex network theory, some novel algorithms are developed by using phasor measurement units (PMUs) information. By invoking virtual adaptive observers, the presented algorithms monitor the connectivity status between buses, which make the algorithms tolerant to the interaction effects between the multiple line outages. Besides, the proposed algorithms also address the reconstruction of the real-time adjacency matrix of the power transmission networks. Simulation results demonstrate the effectiveness of the presented algorithms.     

Fault Location for Single-Circuit Line Based on Bus-Impedance Matrix Utilizing Voltage Measurements

Diverse transmission line fault location algorithms have been proposed in the past depending on measurements available. Existing algorithms usually require measurements captured from buses of a faulted line. By taking advantage of the bus-impedance matrix technique, this paper presents a possible fault location approach for single-circuit lines utilizing only voltage measurements from one or two buses, which may be distant from the faulted line. With the addition of a fictitious bus where the fault occurs, the transfer impedances of this bus and other buses are revealed as a function of the fault location. Based on the relationship between the bus voltage change due to fault and the transfer impedance, the fault location can be derived. Shunt capacitance of the line is ignored first and then fully considered based on distributed parameter line model. Electromagnetic transients program simulation studies have shown quite encouraging results.     

Comparative analysis of passive algorithms in adaptive control

Representative passive adaptive algorithms have been developed with a wide variety of applications. However, to the best of our knowledge, the attempt to unify or to compare them has not been clearly established in literature. In this article, we provide a passive adaptive framework which encompasses all those algorithms including the recently developed proportional‐integral (PI) adaptive scheme. A comparative analysis among performances of the passive algorithms is carried out by means of simulations considering the problem of passivity‐based adaptive tracking control of a simple pendulum. In addition, passivity property for PI algorithm is rigorously shown in case of linear parametrization. Copyright © 2013 John Wiley & Sons, Ltd.     

三种小电流接地系统选线算法及其仿真验证

针对小电流系统发生单相故障时单一选线法存在着一定动作死区问题,提出了相关系数选线算法、小波包多频带选线算法和小波包单频带极性选线算法。基于PSCAD/EMTD的35 kV系统模型的大量仿真数据显示,这三种选线算法不受各种过渡电阻、故障电压初始角和故障点位置的影响,能够正确选线。     

Boundary conditions in TLM diffusion modelling

The connection algorithms used in transmission‐line matrix (TLM) modelling of diffusion processes for describing boundary conditions in both link‐line and link‐resistor nodal configurations have been derived. The new algorithms regarding the inhomogeneous Robin condition enhance the capability of the TLM method in simulating thermal or particle diffusion phenomena. A number of boundary treatments in the existing literature have been found to be special cases of our results. The Dirichlet‐type boundary condition is also discussed. TLM numerical results using the new algorithms, particularly with the link‐resistor model for achieving signal synchronization, are shown to be in excellent agreement with the available analytical solutions. Copyright © 2006 John Wiley & Sons, Ltd.     

Online Optimal Transmission Line Parameter Estimation for Relaying Applications

Transmission line protective relaying algorithms usually require transmission line parameters as inputs and thus accuracy of line parameters plays a pivotal role in ensuring the reliable performance of relaying algorithms. Online estimation of line parameters is highly desirable and various methods have been proposed in the past. These methods perform well when the measurements utilized are accurate; they may yield erroneous results when the measurements contain considerable errors. Based on nonlinear optimal estimation theory, this paper puts forward an optimal estimator for deriving the positive sequence line parameters, capable of detecting and identifying the bad measurement data, minimizing the impacts of the measurement errors and thus significantly improving the estimation accuracy. The solution is based on the distributed parameter line model and thus fully considers the effects of shunt capacitances of the line. Case studies based on simulated data are presented for demonstrating the effectiveness of the new approach.      

修正的潜在结构正交投影的过程监控

近年来,质量相关的故障诊断受到学界的广泛关注。目前存在多种基于后处理的故障诊断算法,但是,进一步的研究发现,当质量无关的故障幅度增强时,这些后处理算法会逐渐失去功能,除此之外,后处理算法在实践中会产生很大的计算量。为了进一步解决上述算法的弊端,采取一种预处理、建模、后处理的结构,并提出修正的潜在结构正交投影算法。对比之前的算法,该方法对质量相关的故障更具实用性,同时减少了模型所需潜在变量的数目,与之前算法相比,计算量更低,数值示例和田纳西-伊士曼过程用来验证该方法的有效性。     

电力系统长,中,短期能源调度管理系统的研究

本文研究电力系统长、中、短期能源调度管理系统。长期调度系统中提出了包括经济性及可靠性的目标函数，水、火电厂的发电计划和检修计划统一优化，提出了闭环求解的算法，同时考虑了负荷、机组可用率及天然来水的随机性。中期及短期的调度系统有详细的数学模型，且适合我国的各种特殊运行情况。此外长、中期调度计划均可完成滚动计算，直到下一月或下一年。相应的实用软件已用于实际电网，实践证明，此系统的模型和算法是实用和有效的。     

基于改进RL模型的串联补偿线路单相接地 故障测距新算法

基于RL模型算法的测距式继电器是我国最早开发成功并获得广泛应用的微机线路保护继电器,但其直接应用在串联电容补偿线路中具有一定的局限性。基于此,针对常见的单相接地故障类型,给出了一种基于改进RL模型的串联补偿线路故障测距算法。该算法考虑了故障过程中MOV动作及串联电容对线路实际阻抗值的影响。与传统的串联补偿线路故障定位方法相比,该算法无需判断串联补偿装置是否在故障回路中,也无需知道串联补偿装置的相关参数和其具体工作状态,就能简单准确地实现串联补偿线路的故障测距。EMTDC/PSCAD和Matlab仿真计算结果表明,所提出的算法能够获得比传统算法更加准确的测距结果。     

房颤智能检测中的心电特征选择和机器学习

房颤是最常见的心律失常疾病,因其临床诊断率低而促进了实时自动检测算法的发展.但大多算法缺乏模型或数据库间的对比,难以评判模型的优劣.为此考虑选择3种机器学习算法(支持向量机、随机森林、逻辑回归)构建3个独立的房颤检测模型.3种模型分别在MIT-BIH房颤数据库上训练,并在3个独立数据库上进行测试和对比,同时进一步分析特...     

Line protection based on the differential equation algorithm using mutual coupling

The application of the distance protection for distribution systems is increasingly more frequent. However, the distance relaying algorithms employed are designed for single lines without considering mutual coupling between parallel lines. Mutual coupling affects the accuracy of the results. In this work, the behavior of the conventional differential equation algorithm (DEA) is analyzed for its accuracy in the estimation of the fault distance. The response time, the variation of the line parameters, the fault inception angle, the presence of erroneous samples and the mutual coupling are considered in the study. These results are compared with those obtained using the Fourier algorithm. In both algorithms, the errors are significant when mutual coupling is present, reaching 12.59% for fault at the end of the line. In this paper, a new distance relaying called DEA with mutual coupling (DEAMC) has been presented. The new algorithm is an improvement to the DEA algorithm that takes into account the coupling effect in the analytical equations. The DEAMC response has been compared with the conventional algorithms results. The results show that the new algorithm improves the accuracy when mutual coupling is present. The DEAMC algorithm reduces the error to 1.93% for fault at the end of the line.     

带散射体的电力系统多级传输线高频耦合模型

高频电磁场会与架空输电线路产生耦合,一旦高频电磁场的波长小于传输线的高度,经典传输线理论就不再适用。传统的全波数值算法虽然可以解决这一问题,但它的求解效率不高,需要消耗大量的时间与计算资源。此外,电力系统输电线路往往有多个垂直端,线路布局复杂。为了解决这些问题,本文提出了一种理论有效的方法来解决有损耗地面上方带有散射体的电力系统多级传输线的高频电磁场耦合问题。采用计算效率高的渐近法,并在渐近法中引入散射体的概念,以考虑更复杂的电路结构。最后用数值算例验证了该方法的准确性和有效性。     

Performance analysis of microcomputer based differential protectionof UHV lines under selective phase switching

The effects of primary and residual faults, as well as of couplings of the neighboring phases or lines, on the sensitivity of operation and threshold settings of microcomputer-based differential protection of UHV lines were investigated. The microcomputer-based differential protection appears to have poor performance when applied to uncompensated lines employing selective pole switching. A computer-based method which, for improved accuracy, utilizes the ABCD generalized line constants has been developed and used to deduce a set of analytical expressions for computing the residual fault currents, recovery voltages, and coupling effects of neighboring lines under varying isolated and connected fault conditions. The performance analysis and digital simulation of UHV lines ranging from 345 kV through 1500 kV have revealed that the residual faults, recovery voltages, and coupling of neighboring lines are rather large and have an adverse effect on the performance, sensitivity of operation, and threshold settings of differential protection and other protection algorithms. A microcomputer-based single-equation algorithm, independent of fault types, for per-phase differential protection without restraint is described. Shunt inductive and capacitive compensation has been proposed for improved performance     

Optimal Estimate of Transmission Line Fault Location Considering Measurement Errors

Various transmission line fault location algorithms have been proposed in the past depending on the measurements available. These algorithms perform well when the measurements utilized are accurate; they may yield erroneous results when the measurements contain considerable errors. In some cases, there are redundant measurements available for fault location purposes, and it may be possible to design an optimal estimator for the fault location based on nonlinear estimation theories. This paper aims at proposing a possible method for deriving an optimal estimate of the fault location that is capable of detecting and identifying the bad measurement data, minimizing the impacts of the measurement errors and thus significantly improving the fault location accuracy. The solution is based on the distributed parameter line model and thus fully considers the effects of shut capacitances of the line. Since field data are not available, case studies based on simulated data are presented for demonstrating the effectiveness of the new method.     

输电线路检修计划的优化算法综述

目前人工编制检修计划的方法,无法综合考虑输电线路检修的可靠性和经济性,而优化算法可以实现两者的平衡。该文综述了国内外输电线路检修计划优化算法的研究现状,介绍了该算法的两种类型即输电与发电联合和输电线路单独编制检修计划的优化算法。前者重点介绍了基于Benders分解的算法和灵敏度分析法,后者主要有基于Benders分解和基于可靠性评估的两种算法。对四种算法分析比较后,提出今后的研究方向应为从实用化的角度改进算法的计算效率和收敛性。     

A visual package for educating preparatory transmission line series compensation

Transmission of electric power over great distances imposes very severe economical and technical limitations. Series compensation techniques are found to be very effective in overcoming such economical and technical limitations, especially transmission line compensation using series capacitors, which has gained special interest among researchers because of its cost effectiveness. This work provides two series compensation algorithms for a student and presents a user-friendly software package developed in Visual Basic for the study of transmission line series compensation.     

同塔架设平行双回线的跨线故障精确测距算法

本文首次提出了用单端检测参数进行同塔架设平行双回线跨线故障测距计算的一整套算法。尤其是当发生不含同名相跨线接地故障和各种非对称型跨线不接地故障时的测距算法,其测距精度可以不受对端系统阻抗变化、过渡电阻和负荷电流的影响。所有测距算法均经过计算机的数字仿真试验,其结果令人十分满意。     

EMS/DTS一体化系统中若干地调特色模型和算法

传统的EMS/DTS都是面向网(省)调开发的,因此需要依据地区电网的网络结构和管理职能的特点开发具有地调特色的EMS/DTS。文中面向地区电网,研究了若干地调特色模型和算法。其中主变优化功能通过计算调度员潮流分别能够得到实时和阶段性的优化运行方案;消弧线圈自动整定不但能够分区域给出消弧线圈挡位的调整方案,而且还满足考虑自动装置“N-1”校验的整定方法;DTS中基于逻辑判断的继电保护仿真通过网络拓扑实现了对辐射网中保护动作以及低压系统单相接地故障的准确模拟。以上这些模型和算法已在实际地调EMS/DTS中在线应用。