有故障

At present,the analytic tools used for the power signals in microcomputer protection include FFT,Kalman filter and finitely shock response filter,etc.They are effective to analyze stationary signals but localizable for unstationary signals analysis.Especially it is difficult to identify nonlinear fault,e.g,the nonlinear high impedance short trouble is along-term unsolved problem of power system.

目前，用于微机保护中的电力信号分析工具有FFT、Kalman滤波器、有限冲激响应滤波器等，它们对于平稳信号的分析是高效的，但在分析非平稳信号中有其局限性；尤其对非线性故障识别困难，如探测高阻抗非线性短路故障便是电力系统一个长期没有很好解决的问题。

By means of analyzing the difference between HVDC transmission line and traditional HVAC transmission lines, it is proved that it is not suitable to apply superposition principle to the power grid containing HVDC transmission lines, thus following conclusions are obtained: in the place near to HVDC transmission line the fundamental frequency fault component element should be not adopted; and there is definite relation between the maloperation of directional comparison pilot protection applied in practical project and the adoption of fundamental frequency fault component element.

通过分析HVDC的特性与传统交流系统的不同，证明叠加原理不能应用在含有HVDC的系统中，从而得出结论：在HVDC附近不应该采用工频故障分量元件，实际工程中的纵联方向保护误动作与使用工频故障分量元件有一定关系。

Risk and maneuverability analysis on engineering design is widely used to conduct security appraisal abroad. The potential risks might be caused by technical parameter deviation, failure and faulty operation of facilities and pipelines in the system were normally analyzed along with the reason why deviation and faulty operation occurred. The acceptable risk was then appraised according to the results, reasons and designed protective facilities. Later, the security countermeasures and solutions were brought forward purposively to further modify and refurbish the security design and operation management.

国外广泛应用危险与可操作性分析对工程设计进行安全评价，分析系统中装置、设备、管道的个别部分工艺参数偏离、故障或误操作引起的潜在危险，分析偏离、故障出现的原因，根据后果、原因和已设计的保护装置，评估可接受的风险，并有针对性地提出安全对策和措施，用以指导修改、完善工程的安全设计和操作管理。

It is shown that by using ECT,both the sensitivity and reliability of the relay protection are improved,and the operation property of conventional two-stage percentage restraint differential protection is meliorated.

以线路光纤纵差保护为例，利用实验数据分析了采用ECT后纵差保护的性能，指出采用ECT后保护在区外故障可靠性、区内故障灵敏度方面有显著提高，继而改进了传统的二段式比率制动差动保护动作特性。

The results are significant to improving design and Selection of large pump units, reducing failure frequency, diagnosing and obviating failures exactly in time, reducing maintenance and repair time and costs, and ensuring maintenance quality.

成果对改进大型水泵机组的设计选型，减少故障发生，及时准确诊断和排除故障，缩短维修时间，降低维修费用，确保维修质量有重大意义。

Many of the mills and processing plants use 480 V distribution , with 2300 V for very large secondaries are often delta-connected so that plant operations may continue even if one phase becomes grounded , but these systems are always equipped with ground-indicating lights , and usually have special fault-tracing equipment so that phase-to-ground faults can be detected and isolated.

很多的纺织厂和加工厂使用480 v的分布，与2300年第五非常大的中级往往三角洲连接，使植物的行动可能会继续，即使一个阶段，成为接地，但这些系统都是配备的地面显示灯，和通常有特殊故障追踪设备，使第一阶段到接地故障可检测和孤立。

If global air-failure and valve is kept as FC, steam to reboiler will fail close , reflux will fail open , hence likely that safety valve will not blow.

如果整体气源中断，而阀门保持FC，到再沸器的蒸汽将故障关闭，回流将故障打开，因此安全阀有可能不会打开泄放。

Moreover, second-winding current waveform of a current transformer is calculated under the transient current of the typical short-circuit fault by numerical method. The analysis shows that the relevant protection equipment may refuse to trip when the fault current is extra high. It will result in the maloperation of protective relays for loss of their selectivity, and cause other protective relays to operate beyond range, and extend the scope of shutdown of power supply.

在这些回路出口处发生相间直接短路等严重故障时，流过相应TA一次侧的故障电流可能达到TA额定工作电流的100倍以上，大大超过了保护用TA的10%误差容许倍数，将使TA严重饱和，从而影响相关的保护设备的动作性能，因此有必要对在这种特大电流作用下的TA的传变特性做一些探讨，以分析其对继电保护装置动作特性的影响及应采取的措施。

When a fault of the rotor bar of an frequency converter has taken place,the characteristic signal components of the currents will be added into the stator current.

在实际使用中，转子导条断裂是常见的导致变频机故障的重要因素之一，统计表明，大约有10%的故障是由转子断条与端环断裂引起的。

Since this phenomenon is common in the current network fault management, it is very necessary to find an effective solution for solving the above problem.

由于以上现象在当前的网络故障管理中普遍存在，因此有必要寻找一种能够有效地解决上述问题的网络故障诊断模型和方法。

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。