故障分析

Usually, distribution networks operate in arborescence mode, so in the simulation of fault analysis the impact of faulty switch element on system reliability is apportioned to failure consequences of adjacent sections that connect to switch, and then an equivalent analytical model considering switch fault is proposed. Thus, not having to conduct the reliability analysis of switch element singly, the impact of switch element fault on system reliability can be calculated. Applying the proposed algorithm in RBTS-BDS6 system, RBTS-BUS4 system and actual medium-voltage distribution network to conduct reliability assessment, the results show that the proposed algorithm is superior in speed and possesses efficiency and engineering practicality.

配电网常具有树状运行特点，在故障解析模拟时，将开关元件故障对系统可靠性的影响分摊到连接开关的相邻分块的故障后果中，进而提出计及开关故障的可靠性等值解析模型，不需单独进行开关元件故障的可靠性分析即可计算其对系统可靠性的影响，应用该算法对RBTS-BUS6和RBTS-BUS4系统及实际中压配电网进行了可靠性评估，结果表明该算法有较明显的速度优势，具有高效性和工程实用性。

The fault arc characteritie of EHV transmission lines is investigated, the fault arc EMTDC model is set up, and the result of simulation confirms to the result of experiment.

考虑到EHV电网故障带有电弧的特点，利用电力暂态信号小波分析方法的研究结果，首次提出基于小波分析的EHV输电线路单端量暂态保护机理和实现方案，该保护原理能够实时检测EHV电网线路故障，区分区内外故障。

Besides protection maloperation model, this paper thought over other dependent outage models such as stuck breaker, component-group outage, station-originated outage and common cause outage; the article chose initial system state of cascading failure by using of function group decomposition technique and event tree analysis, provided simplification principle and processing method of continual fault process analysis, then proposed one new probabilistic risk assessment method for cascading failure.

该文在分析中考虑了保护误动、断路器拒动、元件组停运、电站相关停运、共因停运等相关停运模型，利用功能组分解技术和事件树分析法，选择连锁故障的初始系统状态，提出简化相继故障过程分析的依据和处理方法，进而提出一种新的连锁故障概率风险评价方法。

Aiming at the characteristic of network fault,MM* model and Fault Tree Analysis are introduced into network fault diagnosis modeling.An algorithm is proposed which analyzes and diagnoses network fault,extracts the minimum cut sets quantificationally with Fault Tree Analysis,then detects and orients network fault with MM* model by testing the geminate nodes selected from minimum cut sets.

针对网络故障特点，将MM*模型和FTA方法引入网络故障诊断建模中，设计了一种用FTA方法进行网络故障的系统分析与诊断，并定量求解出所有故障可能的最小割集，然后用MM*模型从最小割集中选取测试点对进行单点故障检测与定位的网络故障诊断算法。

In order to solve the fault location problem, this paper analyzes the electric structure of automatic blocking and continuous power transmission line, investigating the transient characteristics of traveling waves generated by different fault in the lines on the basis of traveling wave theory. The results show that transient process of earth fault and short fault in neutral noneffective grounding systems produce aerial mode component of traveling waves with steadyparameters.

为了解决自闭/贯通线路故障自动定位问题，分析了自闭/贯通线路电气结构的特殊性，以行波理论为基础研究了接地故障和相间短路故障产生的暂态电压、电流行波特征，发现接地故障和相间短路故障都存在参数比较稳定的行波线模分量。

And based on the analysis on the relationship of the positive and the negative sequence impedance,also the positive and negative fault component current under simple and duplicate fault conditions,a cross-country fault identifier is proposed in this paper.

同时通过对线路发生单纯性故障与跨线故障情况下的正、负序故障分量阻抗关系和正、负序故障分量电流幅值关系的分析，提出了一种判别电力系统发生跨线故障的判别元件。

The Hilbert amplitude envelope of the stator current includes the low frequency of fault characteristic, thus it can reduce the signal length by resample the Hilbert amplitude envelope of the stator current by downsampling, which can avoid spectrum aliasing. Then it can reduce the computation time of the MUSIC Method for the spectrum analysis to the resampled signals for the given bandwidth. Meanwhile combining continuous subdivision Fourier transform and rotor slot harmonics based slip estimation it can in advance estimate the concrete values of the fault characteristic frequency, and then inquiry purposely the fault feature component information in the stator current spectrum in order to accomplish the broken rotor bar fault with high sensitivity and h reliability, which eliminates adverse effect of issuable false peaks to the fault detection and formed a novel scheme to detect broken rotor bar fault.

定子电流Hilbert幅值包络信号包含了低频的故障特征频率调制信号，故通过对定子电流Hilbert幅值包络信号进行降采样率重采样、减少分析信号长度，可避免低频段频谱混叠，再对减少的重采样数据进行具有超分辨率的MUSIC低频段估计，可大大降低MUSIC算法频谱估计时间；运用连续细化傅里叶变换和转子齿槽谐波转差率估计技术，可预知故障特征频率精确值，从而可有目的地查询故障分量，消除MUSIC虚假波峰对故障检测混淆的影响，大大提高了故障检测的灵敏度和可靠性，以此形成异步电动机转子断条故障检测新方法。

The method of object-oriented power network topology analysis based on compartment knowledge has been put out. Contingency aggregate and pre-screening method are combined to applied in automatic contingency selection. Contingency performance index has been modified in view of contingency probability. The programme such as contingency aggregate and contingency screening has been compiled.

提出基于间隔知识的面向对象结线分析方法；把预想故障集合和预筛选结合起来运用于预想故障自动选择，结合故障概率对故障行为指标进行修正，开发了预想故障集合和故障扫描等程序。

Secondly, in spite of the reliability of software and control system, the mechanical system reliability of automatic yarn evenness tester is researched using FTA, and fault trees of each unit and system are established by analyzing its structure and function. According to system reliability theory and events probability, the mechanical system fault tree is analyzed by means of qualitative analysis and quantitative calculation, the system weak parts are found , and the ways are put forward to improve the mechanical system reliability.

其次，在不考虑软件及控制系统可靠性的情况下，利用故障树分析的方法，对全自动条干仪机械系统可靠性进行了分析研究，通过对其结构、功能的分析，建立了单个单元的故障树和系统的故障树；并根据系统可靠性的原理和事件发生的概率，进行了定性分析和定量计算，找出了系统的薄弱环节，提出了提高机械系统可靠性的途径。

After observing the physical course of the single-phase grounding of transmission line, analyzing by the wavelet transformation the transient signals sampled during the fault period from the moment that single-phased grounding occurs to the moment that line breakers work, we can distinguish temporary fault from permanent one through the wave form.

本文提出了一种不同于现有故障类型判别的思路，通过考察线路单相接地故障的物理过程，利用小波变换理论分析处理线路单相瞬时性故障和永久性故障在故障发生后断路器开断前时间段的暂态信号，通过波形识别区分两种故障。

Cynanchum Lingtai apricot production in the average weight 65 grams, the brightly-colored fruit, juicy rich, sweet-sour taste, sweet from the nucleolus, when the late Qing Dynasty famous Shaanxi, Gansu provinces, the Qing imperial court Tongzhi tribute for years.

灵台生产的牛心杏平均单果重65克，果实色泽鲜艳，汁多味浓，甜酸适口，离核仁甜，清末时就驰名陕、甘两省，清同治年间曾为朝廷贡品。

Chenopodium album,Solanum nigrum, and Amaranthus retroflexus were very susceptible to the herbicides. Polygonum persicaria and Abutilon theophrasti were relatively less susceptible to the herbicides, and Lycopersicon esculentum was not susceptible to it. The relationship between reduction rates of weed biomass and PPM values of weed leaves 2,4, and 6 days after treatment was established.

供试的6种杂草对该混剂的敏感性存在显著差异：红心藜Chenopodium album、龙葵Solanum nigrum和反枝苋Amaranthus retroflexus对该混剂最敏感，ED90值分别为47.65、71.67和29.17g/hm2；春蓼Polygonum persicaria和苘麻Abutilon theophrasti敏感，ED90值分别为96.91、114.20g/hm2；而番茄不敏感。