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一种高压电动机综合保护装置的研究 总被引:1,自引:0,他引:1
针对目前高压电机故障频繁及其保护存在的问题,根据对称分量法,提出并设计了一种基于检测正序、负序、空序、零序电流分量的电动机综合保护装置,该装置应用于大中型异步电动机及同步电动机,效果明显,运行可靠。 相似文献
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文章介绍了电机保护的一些理论和电机故障检测方法。使用对称分量法,基于STM32设计了一个微机电机保护装置,可以智能检测电机工作状态,并显示电机主要的电气参数。介绍了装置的主要硬件组成及各组成部分实现的功能,结合软件流程图,分析了装置的内部运行原理。 相似文献
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通过对某厂一起其他故障引起负序电流保护事故的分析,分析了电动机负序电流的产生原因和对保护的影响,同时对高压电动机的微机保护装置其负序过流保护定值的整定方法进行了探讨和改进,根据该厂6kV高压电动机具体系统和设备参数对负序保护进行了定值优化. 相似文献
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1.电动机为电感性负载,虽说启动过程很短,但启动电流比正常额定工作电流大许多。因此,选择电动机回路熔断器、熔丝时一定要考虑到启动电流大这一重要因素,选择印能保证电动机启动时熔丝不会熔断,而运行时又能对短路等故障起到保护作用的合适熔断器、熔丝,太大或太小都会直接影响电动机正常工作。 相似文献
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与交流电动机相比,直流电动机结构复杂,成本高,运行维护困难。但是直流电动机具有良好的调速性能、较大的起动转矩和过载能力强等许多优点,因此在许多行业中仍有应用。文章介绍了一种利用单片机控制的PWM调速装置实现小功率赢流电动机调速的方法,具体详述了电路的设计思想、电路的组成以及工作原理。 相似文献
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Uluyol O. Kyusung Kim Nwadiogbu E.O. 《IEEE transactions on systems, man and cybernetics. Part C, Applications and reviews》2006,36(4):476-484
In this paper, we present a synergistic approach to startup fault detection and diagnosis (FDD) in gas turbine engines. The method employs statistics, signal processing, and soft computing techniques in a complementary manner to address fault detection at transient conditions. Traditional turbine engine FDD methods are based on engine data collected at steady-state conditions. However, incipient faults are difficult to diagnose using steady-state engine data; only engine faults that are fairly developed can be detected using conventional methods. Because incipient engine component faults are often manifest in the engine startup characteristics, we present a method to characterize the engine transient startup. Engine sensor data during engine startup are recorded in time series format. The sensor profiles corresponding to "good" and "bad" engine startups are sampled using the bootstrap technique. A feature vector is extracted in two steps, and signal processing is followed by the feature vector selection. In the signal processing step, principal component analysis (PCA) is applied to reduce the samples consisting of sensor profiles into a smaller set. In the feature vector selection step, a cost function is defined, and important discriminating features for fault diagnosis are distilled from the PCA output vector. The features obtained from this step are then classified using neural-network-based methods. The "leave-one-out" approach to cross validation is applied to obtain an objective evaluation of the neural network training. The proposed FDD method is evaluated using actual engine startup data, and the results are presented. 相似文献
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A new two-terminal switching device based on an a-Si:H n-i-δp-i-n symmetrical structure is investigated. The current through the device arises from thermionic emission of electrons over the triangular barrier lowered by the applied voltage. The key role of the thickness and of the doping level of the central δp layer on the electrical behavior of the device is analyzed in detail by a numerical model. The current-voltage characteristic of an optimized device exhibits an ON/OFF current ratio, taken at 3 and 1 V, respectively, of six orders of magnitude with a nonlinearity factor η=3.7 相似文献
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随着科学技术的进步、电力工业的迅速发展,生产系统中的电机数量和单机容量不断增加,相应的电机保护技术也需要有进一步的提高。文中针对电机的各种故障类型,借鉴国内外电机保护装置的经验,并结合现有的高压电机保护技术,提出了一套完整的电机保护方案。这套保护装置包括了低电压保护、过电流保护、差动保护和单相接地保护,可以同时对电机的多种问题实现保护,能有效保障高压电机的正常运行。 相似文献
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A split field-effect transistor (SFET) is proposed for measuring source and drain series resistances. This device is made by splitting a conventional thin-film transistor (TFT) from the source to the drain in such a way that the gate width of each half is a linear function of the distance from the source. The analysis shows that the intrinsic current-voltage characteristics of such a device should be symmetrical with respect to the polarity of the drain-to-source voltage. Hence, the observed asymmetry of the device characteristic yields direct information about the differences between source and drain series resistances, which are inversely proportional to the contact width. For an a-Si TFT it is shown that the source series resistance is proportional to the inverse square root of the drain current in a wide range of currents. The technique can be applied to a large variety of FETs. For a-Si TFTs, it provides an accurate tool for determining the effects of contact overlap, bias stress, and temperature dependences of series resistances 相似文献
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文章在分析了电动机运行状况的基础上,根据电动机常见的故障特征,如相间接地;定子绕组开路、过负荷,失压,堵转、过热等,提出了基于ISPLSI及196系列单片机为核心的实用电动机保护方案,具有零序保护、负序电流保护,正序电流保护,过载保护,堵转保护,过热保护,失压保护等功能,在算法上进行了数学模型的建立和推导,在硬件,软件上进行了优化设计,特别是采用了在系统可编程逻辑器件(ISPLSI1032E),使装置具有简洁,稳定,速度快,抗干扰性好,保护功能强等特点。 相似文献
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基于泊松方程和边界条件,推导了对称三材料双栅应变硅金属氧化物半导体场效应晶体管(MOSFET:metal oxide semiconductor field effect transistor)的表面势解析解.利用扩散-漂移理论,在亚阈值区电流密度方程的基础上,提出了亚阈值电流与亚阈值斜率二维解析模型.分析了沟道长度、功函数差、弛豫SiGe层的Ge组份、栅介质层的介电常数、应变硅沟道层厚度、栅介质高k层厚度和沟道掺杂浓度等参数对亚阈值性能的影响,并对亚阈值性能改进进行了分析研究.研究结果为优化器件参数提供了有意义的指导.模型解析结果与DESSIS仿真结果吻合较好. 相似文献