有故障

Based on varying process of generator terminal parameters after excitation fault, shortages of excitation protective principle of static stability boundary and asynchronous impedance boundary are analyzed. It proposed that excitation fault research relates to large-disturbance stability. Because dynamic power-angle character of generator after excitation fault is non-sinusoidal, there are differences between dynamic power-angle character and static state power-angle character. So it isn't ideal to protective operation result based on small-disturbance stability and static stability boundary criterion. At the same time, it proposed that asynchronous boundary impedance criterion is a constant reactive power circle moving adown j Xd′. It can ensure complete loss-of-excitation generator measuring impedance enter into the circle, but can't ensure the other condition measuring impedance including impossible losing synchronism enter. So loss-of-excitation protection would be maloperation when system voltage drops short and recovers or generator rejects load.③Based on stability principle, it puts forward setting conditions and calculation method of generator loss-of-excitation protection by direct measuring power-angle.

以励磁故障后发电机端的相关参数的变化为基础，通过对以静稳定边界和异步阻抗边界作判据的两类三种现行励磁保护在原理上存在的缺陷分析，发现：励磁故障是一个大干扰稳定性问题，励磁故障后的发电机的动态功角特性与静态功角特性有很大的差异，已远非正弦曲线，因此基于小干扰稳定性原理、以静稳定边界作判据的保护必然动作不理想；异步边界阻抗判据是一个下移j Xd′的等无功阻抗圆，它可以保证完全失磁后的发电机测量阻抗能进入该阻抗圆，但不能保证完全失磁之外的其它状态不会进入该阻抗圆，因此在系统电压短时下降或发电机突然甩负荷等情况下可能启动该保护使之误动。

This paper introduces hardware and software design of data acquisition system in mine crusher fault diagnosis.

本文以该设备故障诊断为研究对象，介绍了在破碎机故障诊断系统中数据采集子系统的软硬件设计方案，对破碎机故障诊断系统的开发有一定的作用。

On the basis of the analysis to the short circuit malfunction in domestic underground high voltage power network the paper deeply studied the relevant protection principle and the approach for improving the sensitivity and reliability of short circuit protection in underground high voltage power network designed the new type computerizable protection scheme of selective and rapid short circuit in underground high voltage power network with computer communication and logic identification technology Computer .

在分析我国井下高压电网短路故障的基础上，深入研究相关的保护原理及提高井下高压电网短路保护灵敏度和可靠性的方法，设计出新型的利用计算机通信与逻辑识别技术的井下高压电网微机选择性速断短路保护方案，将微机保护应用于煤矿井下高压电网，通过多机通信，逻辑判断判定线路故障段，从而做到快速的，有选择性的切断故障线路，避免煤矿井下高压电网因越级跳闸而造成大面积停电。

Dirt in the tube accounts for 29.79%, rubber gasbag, tubing aging 5.85%, others 3.19%.

示值管内有污物的故障占总检定台件数的29.79%，气囊、胶管、胶球漏气老化故障占总检定台件数的5.85%，其他的故障占总检定台件数的3.19%。

However, most of previous FDA protocols only take into account simple network with single faulty component.

目前，大部分FDA协议还是只考虑单一故障组件的简单网络，而对于实际的分布式应用、故障节点和故障链路并存的系统假设更加有意义。

Simulation results prove that so long as both busbar stray capacitance and sampling frequency satisfy a certain condition, the proposed scheme can judge the fault accurately under various fault conditions. The proposed scheme possesses good selectivity and strong ability of anti-transition resistance, besides, it is more sensitive to the fault occurred at the end of transmission line.

仿真试验表明，只要母线杂散电容和采样频率满足一定的条件，该方法在各种故障条件下均能准确判断故障，具有很好的选择性，并且有很强的抗过渡电阻能力，对末端短路故障的反应灵敏度更高。

By the theoretical analysis of the subminiature breakdown of full flow during the test of the variable pump of constant voltage,we can find the reason of the breakdown and take measure to fix it.

通过对恒压式变量泵在试验中出现全流量超小故障的理论分析，找出了故障原因，并有针对性地采取了排除措施，即(1)减小弹簧刚度，(2)弹簧材料改为高温稳定性较好的材料，并经48小时加载荷压缩处理，(3)在试验中严格控制零流量压力公差，使故障有效排除，从而从根本上解决了生产中的疑难问题。

The misaction and nonaction of protection can bring the immeasurable loss for power plant and power system .So the fault analysis of the unit have been a problem for a long time that worker have to face. However some recorder of unit can only matriculate the waveform such as the analysis and calculate of electric parameter that the worker want to know , find the cause of fault correctly, analysis and appraise the action of protection and automechanism.

发变组作为电力系统中重要的电力设备，尤其是大型机组，同时配套有大量不同工作原理的保护，运行工况复杂，相对事故率较高，故障种类多，故障原因各异，故障的分析、判断更加困难，对机组的安全和稳定运行极其重要，保护装置的拒动或误动，都会给发电厂或电力系统带来不可估量的损失。

The frequency changer Surpasses the voltage fail safe is the frequencychanger middle DC voltage after achieved the degree of hazard adoptsprotective measures, this is a big flaw which the frequency changerdesigns, causes this breakdown reason in the frequency changer actualmovement many, may adopt the measure are also more, when processesthis kind of breakdown must analyze the clear breakdown reason, haspointed takes the corresponding measure to process.

变频器过电压故障保护是变频器中间直流电压达到危险程度后采取的保护措施，这是变频器设计上的一大缺陷，在变频器实际运行中引起此故障的原因较多，可以采取的措施也较多，在处理此类故障时要分析清楚故障原因，有针对性的采取相应的措施去处理。

The frequency changer Surpasses the voltage fail safe is the frequencychanger middle DC voltage after achieved the degree of hazard adoptsprotective measures, this is a big flaw which the frequency changerdesigns, causes this breakdown reason in the frequency changer actualmovement many, may adopt the measure are also more, when processesthis kind of breakdown must analyze the clear breakdown reason, haspointed takes the corresponding measure to process.

摘 要：摘要变频器过电压故障保护是变频器中间直流电压达到危险程度后采取的保护措施，这是变频器设计上的一大缺陷，在变频器实际运行中引起此故障的原因较多，可以采取的措施也较多，在处理此类故障时要分析清楚故障原因，有针对性的采取相应的措施去处理。关键词变频器电动机整流 Abstract ：The frequenc。。

Since historical times,England ,where the early inhabitants were Celts, has been conquered three times .

从有历史以来，英国，在此地早期居住的是凯尔特人，已经被征服了三次。

Bluetooth OBEX File Transfer Enables the sending and receiving of files on your phone via Bluetooth.

蓝牙OBEX文件移动允许经过蓝牙传送和接受文件。。。。