小电流接地系统单相接地故障选线测距和定位的新技术

按照小电流接地系统单相接地故障的特点，本文提出了通过检测注入信号的路径和特征来实验现选线，测距和定位的“Ｓ注入法”选线，测距和定位新原理，导出了有关的公式和算法，研制了相应的装置，并已在较大范围内推广应用。     

单端测试故障定位灵敏度分析

分支线路单端测试故障定位方法要求故障测试数据准确,实际系统发生故障时数据测试左不仅对故障」一位产生偏差,而且也将对分支线路真伪故障的识别产生影响。通过理论分析提出：起端相位测试偏差是故障定位准确性和真伪故障识别的关键。     

基于免疫学的在线故障检测算法的研究及应用

受人体免疫机理的启示提出了一种适合于故障诊断的算法一疫苗算法。建立了疫苗算法的数学模型，介绍了算法的实现过程。该算法通过重采样方法，利用少量样本即可获得表征某一故障类型所需的样本，当一未知故障出现时系统自动获得该故障类型特征，并给出信息供专家分析，以便下次该故障再次出现时给出应答，具有边检测边学习，不断动态调整的功能。最后通过对电机的故障检测验证了本算法的优越性和有效性，检测结果表明准确率达到95％。     

高压输电线路行波测距的行波波速确定方法

行波故障测距系统中的行波波速测量的准确性在一定程度上影响了行波测距的精度,文章在对影响行波波速测量准确性的因素、行波波速对测距精度的影响及现有行波波速测量方法进行分析的基础上,提出线路区外故障时利用取端行波测距系统本身测量行波波速,实现了行波波速的在线测量和调整.理论分析和实测数据均表明,该方法实现简单,对提高行波故障测距精度有一定的效果.     

两起典型变压器故障的分析与处理

基于两起典型变压器故障，提出了预防变压器短路损坏事故的综合措施。     

合成绝缘子故障的红外热像在线检测

文章介绍了用红外热像测温跟踪缺陷合成绝缘子的状况以及对其的电气试验情况，合成绝缘子运行中发热是因为内部界面缺陷局部放电引起的。对运行中同类型的合成绝缘子进行了普查，发现存在过热缺陷的合成绝缘子缺陷率高达20％以上。最后，文章分析了合成绝缘子产生界面缺陷的原因，指出2年一次的红外定期热像测温可以检测和监测此类界面缺陷。     

变压器经受短路冲击后继续运行的决策

简要介绍了变压器经受短路冲击后如何运行的几个决策实例,提出了受短路冲击变压器是否投入运行的几个决策依据。     

变压器经受短路冲击后经纬运行的决策

简要介绍了变压器经受短路冲击后如何运行的向几个决策实例,提出了受短路冲击变压器是否投入运行的几个决策依据.     

一起220kV变压器短路故障的诊断与分析

对一起220kV变压器出口短路故障进行了分析与诊断。     

基于电磁暂态三相三柱变压器内部故障仿真模型的研究

介绍了三相三柱变压器内部故障模型的建立过程,并对三相三柱变压器进行了仿真.     

基于相量测量的输电线路故障测距新算法

提出了一种新的基于相量测量的输电线路故障测距的自适应算法,对于单回线和同杆双回线均适用.该算法利用输电线路两端的电压和电流相量并采用集中参数模型对∏型等值线路的正序参数进行了在线计算以用于故障测距,解决了线路参数在运行过程中的不确定性问题.为了实现双端测距,通过故障前后线路两端的采样数据获取突变量,并采用对称分量和六序分量分别计算了单回线和同杆双回线的等效系统阻抗.大量的EMTP仿真计算结果和实际系统数据验证结果表明,该测距算法能适应系统运行方式的变化,不受故障点过渡电阻、故障类型、故障距离等因素的影响,具有很高的测距精度.     

三峡水电站短路电流水平及限制措施分析

本文根据对三峡水电站不同线接方式，不同故障型式下短路电流的计算，分析了几条限制短路电流的措施，可供大型水电站限制短路电流参考。     

基于改进谱分析法的大功率可控整流电路故障在线诊断系统

该文研究了一种便于在实时系统中实现的可控整流电路故障诊断方法。论文将3只以内的晶闸管故障按整流波形的畸变规律分为11类，115种故障元。选择4个特殊“面积”表达式描述电压波形，并建立了以此为基础的12维故障模式向量。通过对模式向量的逻辑处理，将其转化为由常数构成的12维简单时间序列向量。对新的模式向量进行DFT处理，得出了以三维特征向量表达的诊断定位算法，改进了现有的谱分析故障诊断方法。最后在研制的DSP实时诊断系统上实验。结果表明该方法能快速准确地诊断出各种故障。     

k-NN based fault detection andclassification methods for powertransmission systems

This paper deals with two new methods, based on k-NN algorithm, for fault detection and classification in distance protection. In these methods, by finding the distance between each sample and its fifth nearest neighbor in a predefault window, the fault occurrence time and the faulty phases are determined. The maximum value of the distances in case of detection and classification procedures is compared with pre-defined threshold values. The main advantages of these methods are: simplicity, low calculation burden, acceptable accuracy, and speed. The performance of the proposed scheme is tested on a typical system in MATLAB Simulink. Various possible fault types in different fault resistances, fault inception angles, fault locations, short circuit levels, X/R ratios, source load angles are simulated. In addition, the performance of similar six well-known classification techniques is compared with the proposed classification method using plenty of simulation data     

Multi objective optimal allocation of fault current limiters in power system

Transmission systems, connection of distributed generation to the grid are increased due to increase in power demands. This fact causes the increase in short circuit level of power networks. The occurrence of fault in such networks leads to large short circuit currents throughout the system, which may exceed the rating of existing circuit breakers and can damage system equipment. There are some approaches to reduce this fault current such as power network reinforcement and utilization of fault current limiter (FCLs) in power systems. Power system reinforcement is too difficult if not impractical. Therefore, the utilization of FCLs can provide an effective way to suppress fault currents. The effectiveness of FCL depends on the number of FCLs and their installation location. In this paper, a novel approach is presented to determine the optimal number and location of FCLs to improve the power network reliability and fault current reduction based on different conflicting objective functions. IEEE 39 BUS system and IEEE 57 BUS system are considered to evaluate the effectiveness and feasibility of the proposed method. The objective functions considered for the optimal allocation are reliability of power system, economic impact and short circuit current reduction. Unlike what has been previously done in literature, in this paper Pareto based optimization algorithms, namely non-dominated sorting algorithm, multiobjective particle swarm optimization and multiobjective evolutionary algorithm based on decomposition, are utilized to deal with this problem. The use of these methods made it possible to obtain the Pareto optimal front in which these objective functions are optimized simultaneously.     

k-NN based fault detection and classification methods for power transmission systems

This paper deals with two new methods, based on k-NN algorithm, for fault detection and classification in distance protection. In these methods, by finding the distance between each sample and its fifth nearest neighbor in a predefault window, the fault occurrence time and the faulty phases are determined. The maximum value of the distances in case of detection and classification procedures is compared with pre-defined threshold values. The main advantages of these methods are: simplicity, low calculation burden, acceptable accuracy, and speed. The performance of the proposed scheme is tested on a typical system in MATLAB Simulink. Various possible fault types in different fault resistances, fault inception angles, fault locations, short circuit levels, X/R ratios, source load angles are simulated. In addition, the performance of similar six well-known classification techniques is compared with the proposed classification method using plenty of simulation data     

基于瞬时功率信号频谱分析的鼠笼式异步电动机转子故障在线诊断方法

该文介绍了一种基于瞬时功率频谱分析的鼠笼式异步电动机转子故障监测与诊断方法。采集定子某两个端子之间的线电压和对应的线电流，由二者的乘积即可构成瞬时功率信号。理论分析表明，与常见的基于定子线电流频谱分析方法相比，使用瞬时功率信号能避免基波电流对故障特征成分的影响，更好地突出故障特征，分离复合故障。这些都有益于对故障程度的量化，和诊断规则的建立。通过对样机进行断条和偏心故障设置，多种故障情况下的实验结果也证实了上述结论。     

基于径向基函数网络的高压断路器在线监测和故障诊断

介绍了一种高压断路器在线检测和故障诊断的方法。由于高压断路器出现机械故障不仅会引起振动冲击事件的时间漂移,还会引起时域波形中一些波峰幅值的变化。基于径向基函数（RBF）网络理论,将健康振动信号和断路器实际振动信号波峰幅值之差形成的残差以及波峰幅值发生的时间区段作为断路器故障诊断的特征参数,来判别断路器是否发生故障及其故障类型。在实际工程应用中,可以将断路器正常工作时的动静触头接触时产生的振动信号记录下来,存入用于巡回检测的微机系统。用RBF网络预测器的输出与预先给定的阈值进行比较,实现故障的自动诊断。对模拟故障信号进行了仿真实验,仿真结果表明：RBF网络在线学习只需1组样本,因而其收敛速度比BP网络的收敛速度快,更适合于断路器在线检测。该方法还具有精度高和鲁棒性的特点,是一种比较有效的方法。     

干式变压器快速温度保护研究

本文中作者利用温升加速度算法,研究了干式变压器在短路故障和正常工作状态时温升的加速度,得出了判别变压器故障的判据。     

利用测量电流互感器实现配电网故障电流检测的新方法

提出一种利用测量电流互感器（TA）进行过流故障,故障电流幅值及故障方向检测的新算法。故障检测利用了TA饱和时二次输出电流的间断角,而根据TA在上下半周饱和前的有效信息进行故障电流幅值和方向的计算,电流幅值的估算采用了最小二乘法,可以滤除衰减直流分量和谐波,方向的计算利用了电压,电流故障分量间的相位关系,同时了以上算法基于采样值的实现方法。