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在高电压技术中,高电位脉冲微小电流信号测量是基本技术之一。对脉冲微小电流信号进行测量,是对于使用人员的人身安全加以保护,满足设备抗干扰性能要求的必要手段。混合式光电电流互感器是电力系统重要组成设备,在这一电流互感器基础上发展而来的宽带模拟光电测量系统具有较高的稳定性,测量精确度较高,可以在极为复杂的电磁环境中对脉冲微小电流信号进行精确测量,在电力系统中具有较高的应用价值。 相似文献
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传统方法检测微弱信号具有一定的困难,利用混沌振子对微弱信号敏感以及对强噪声具有良好免疫力的特性,提出基于耦合Van der Pol-Duffing振子系统检测微弱信号的新方法。对比不同参数下耦合系统的动力学行为,通过分岔图和二分法确定临界阈值,保证阈值搜索速度和阈值精度。阐述基于相图的微弱信号检测原理,通过从混沌态到周期态的转变成功检测淹没在强噪声中的微弱信号,信噪比门限达到–30 d B。同时考察不同精度幅值下噪声对系统状态的影响,不同频率信号以及相移对检测的影响。仿真结果表明,该耦合系统在强噪声条件下对微弱信号敏感,用于检测微弱信号是可行的。 相似文献
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在高电压及大电流的测量中,测量器具往往无法对被测电压或电流进行直接测量,需要对电压或电流进行变换,这时便出现了互感器。互感器是为电力系统进行电能计量、测量、控制、保护等提供电流/电压信号的重要设备,其精度及可靠性与电力系统的安全、稳定和经济运行密切相关,是电力系统必不可少的设备。目前我国电力系统运行中的电流、电压互感器主要是采用电磁式电流、电压互感器和电容式电压互感器。 相似文献
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针对无源光学电流互感器的线性双折射问题,用琼斯矩阵分析了双折射对系统输出的影响.分析了输出光退化成圆偏振情况下光学电流互感器仍能传感电流的现象,以及输出光保持线偏振条件下系统输出电压仍受线性双折射影响的现象.分析了入射光偏转角、入射光湘移与初始线性双折射对光学电流互感器输出的联合影响.结果表明,当初始双折射存在的情况下,随着入射光相移的变化,系统输出相对偏差存在极小值,且极小值对应的入射光相移随着初始双折射值而单调递增.由此提出增加入射光相移来减小初始线性双折射对系统输出影响的方法.用计算机仿真了理论计算结果,实验验证了这种方法的可行性.对改进无源光学电流互感器的性能、开发实用光学电流互感器具有参考意义. 相似文献
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随着电力系统的不断发展,特别是电压等级的不断提高,传统电流互感器逐渐暴露出自身无法克服的缺点,如体积过大,绝缘结构越来越复杂,制造难度加大,磁滞饱和,动态准确范围小,输出为模拟信号,需要布设大量电缆等问题日益突出。光学电流互感器是一种基于新型原理的电流互感器,由于采用光学特性实现测量功能,一二次全部采用光缆连接,因此绝缘简单,体积小,克服了传统互感器的磁滞和饱和。本文论述了光学电流互感器的原理、结构、运行管理模式,并结合110kV东华山智能变电站运行中一起光电流互感器引起的事故分析了光电流互感器在运行中的注意事项。 相似文献
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A novel method of de-noise and harmonics detection is presented. Firstly, based on periodicity analysis and signals which have been detected, one minimum period signal with slight noise could be calculated. This signal is named as Standard unit-Period (SuP). Then a correction model is constructed based on SuP and 3-sigma rule, aiming to revise the rough harmonic signal. From the view of solutions, SNR could be risen about 15 dB in a high-SNR background. Furthermore, SuP could be applied to improve DFT in harmonic detection by adjusting the length of harmonic signal. It not only helps to avoid errors caused by spectral leakage effectively in particular situations, but also makes detection method run faster and more precise. At last, applications of SuP in several complex situations are simulated. It showed that SuP could deal with various coloured noise effectively, and this method could be used when the system fluctuates with changing parameters. 相似文献
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针对强噪声背景下微弱信号难以检测的难题,提出基于变尺度多稳随机共振的微弱信号检测方法。多稳随机共振系统比双稳随机共振系统具有更好的微弱信号检测能力,为强噪声背景下微弱信号的检测提供了新方法。首先对大频率信号进行尺度变换使之满足随机共振条件,将频率压缩后的信号通过多稳系统,调整参数使其发生随机共振得到信号的频谱特征,并与双稳随机共振方法得到的特征频率进行比较,仿真和实例结果均表明:相同条件下,多稳随机共振方法比双稳随机共振方法得到的频率准确,可以增强信号的幅值,有效地检测出被噪声淹没的微弱信号。 相似文献
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针对滚动轴承微弱故障信号难以检测的难题,提出一种基于新型非线性耦合双稳态随机共振模型的轴承微弱故障信号增强检测方法。噪声背景下,随机共振可以实现微弱信号的增强输出,提高微弱信号特征的检测。提出的非线性耦合双稳态系统是由两个单一双稳态系统经非线性方式耦合而成,通过分析耦合系数、阻尼系数随着噪声强度改变的信噪改善比响应特性曲线图研究了不同参数对随机共振现象的影响。结果表明,耦合双稳系统比单一双稳态系统具有更强随机共振现象的产生。最后采用模型对轴承故障微弱信号进行了增强检测应用,所提出的非线性耦合双稳态随机共振能够实现在复杂的噪声背景下对微弱故障信号的检测。 相似文献
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本文介绍了一种基于FPGA的电磁金属探伤系统,该系统用于研究电磁无损检测技术在金属板损伤探测上的应用。在该电磁金属探伤系统中,传感系统提供的测量感应信号为强噪声背景下的微弱信号。为了提高信号的检测精度,本文采用信号调理电路结合FIR数字滤波的方法,将基于FPGA的电磁成像金属探伤系统中微弱的测量感应信号从噪声中提取出来,仿真实验证明,该方案能为后续信号处理环节提供一个低噪声背景下的较强的感应信号。 相似文献
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Investigation of interferometric noise in fiber-optic bragg grating sensors by use of tunable laser sources 总被引:1,自引:0,他引:1
Jin W 《Applied optics》1998,37(13):2517-2525
Interferometric noise in fiber-optic grating sensors isinvestigated. Interference between a signal wave and reflectedwaves causes signal fluctuation in the output that limits thewavelength detection accuracy of the sensing system. Themeasurement error limited by interferometric noise is calculated forboth reflective-type and transmission-type sensors. 相似文献
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The nonlinear stochastic resonance system possesses the ability of taking advantage of background noise to enhance the weak signal. It provides a new approach to detect the weak signal embedded with heavy noise. This study proposes a new varying parameter stochastic resonance employing the fourth-order Runge–Kutta numerical method as well as the normalized transformation of a bistable stochastic resonance system. The model performs well in the detection of a time-varying signal with background noise for denoising and signal recovery. We take the fitness coefficient and cross-correlation coefficient as the criteria and analyze the influence of different parameters. The simulating results indicate its availability, validity and that it generates a better performance than the traditional stochastic resonance. The method develops the area of time-varying signal detection with stochastic resonance and presents new strategy for detection and denoising of a time-varying signal. It can be expected to be widely used in the areas of aperiodic signal processing, radar communication, etc. 相似文献
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Dual-trap technique for reduction of low-frequency noise in force measuring optical tweezers 总被引:1,自引:0,他引:1
High-resolution long-time force measurements by optical tweezers are often limited by low-frequency (1/f) noise. A dual-trap technique is presented that can reduce such noise in the force signal. It incorporates a second trap (a reference trap) that probes the noise in the system and it is based upon the assumption that the low-frequency parts of the noise from the two traps are correlated. A subtraction of the low-frequency signal from the reference trap from the signal from the force measuring trap will therefore yield a net signal that is significantly less influenced by noise. It is shown that this dual-trap technique can reduce the noise in the force signal up to 60% depending on detection bandwidth. 相似文献