共查询到19条相似文献,搜索用时 140 毫秒
1.
针对电力系统微机自动安全控制装置对频率信号精度的要求,全面分析了频率变化暂态过程时的误差情况,研究推导出了基于傅氏测频算法的理论频率修正系数,给出了实用的自适应调整策略。通过数字仿真验证了该自适应测频算法的有效性和实用性。 相似文献
2.
针对电力系统中频率变化而引起的数据采集及计算误差 ,分别提出了基于硬件测频和递推傅氏算法测频的自适应数据采集两套方案 ,并对递推傅氏测频算法进行了数值仿真 ,其结果表明基于该算法的自适应数据采集方案完全满足电力系统中安全自动装置的要求。两套方案各有特点 ,均可用来快速精确测量电力系统中的频率、电压、电流等信号 相似文献
3.
针对电力系统中频率变化而引起的数据采集及计算误差,分别提出了基于硬件测频和递推傅氏算法测频的自适应数据采集两套方案,并对递推傅氏测频算法进行了数值仿真,其结果表明基于该算法的自适应数据采集方案完全满足电力系统中安全自动装置的要求.两套方案各有特点,均可用来快速精确测量电力系统中的频率、电压、电流等信号. 相似文献
4.
为比较自适应递推傅氏算法和电力系统实时测频新算法的优劣,介绍了两种算法的原理,并从实验硬件装置误差、谐波及非周期分量的干扰和采样时间间隔等方面对两种测频方法进行了对比分析.通过实验验证了两种算法的准确性,并发现自适应递推傅氏算法的测量值精度略高于实时测频新算法的测量值精度.实际频率值越接近50Hz,测频精度越高. 相似文献
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基于自适应短时傅立叶变换的电频率跟踪测量算法 总被引:6,自引:0,他引:6
电频率快速、准确测量是电网及电气设备运行、控制、调节的基础.基于电气信号的异步采样数据,应用短时傅立叶变换(STFT)估计电气信号频率,选用矩形自卷积窗抑制谐波对测频的影响,并根据频率变化自适应调整时间窗宽度.算法实现简单、计算量小,测频范围大,在信号频率缓慢变化和快速变化时,均具有较好的测量精度和跟踪速度.仿真研究对测频算法在各种情况下的可行性和有效性进行了验证. 相似文献
6.
电力系统测频的自适应算法 总被引:10,自引:1,他引:10
本文提出了一种采用自适应技术调整采样间隔的递推富氏算法,计算机仿真表明,本文算法能较好地跟踪系统频率的变化,对谐波分量具有较强的抑制作用。通过自适应技术调整产间隔,提高了频率测量的精度,实现了宽范围的测频。满足电力系统频率测量要求。 相似文献
7.
针对传统软件测频方法存在的问题,提出了一种新的基于傅立叶算法的频率测量方法。首先仔细研究傅立叶修正系数测频法的误差情况,调整了修正系数的计算方法,提出傅立叶修正系数测频法的改进算法。然后根据信号频率偏移时傅立叶算法误差较大这一问题,提出根据信号近似频率进行插值,对插值后新序列进行傅立叶计算。为了提高含有谐波时的测频精度,对频率进行迭代计算,直至达到精度要求或迭代次数达到限值。最后对含谐波、不含谐波两种信号进行仿真计算,对比其频率计算误差。结果表明,该算法计算精度高,计算量小且实现了频率的高精度跟踪,可以满 相似文献
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快速、准确测量电频率是电网及电气设备运行、控制、调节的重要基础。电压的谐波和噪声会影响频率的测量,特别是分布式发电引入了各种电力电子设备,产生的谐波较大,谐波中不仅包含整次谐波,还包含有大量的非整次谐波。常规傅氏测频法抗非整次谐波和噪声能力弱,测频精度会受到一定影响。提出了一种基于Kaiser窗的改进傅氏测频算法,提高了谐波和噪声环境下的测频精度。仿真结果显示改进测频算法的测量误差小于0.005Hz,优于常规傅氏算法。 相似文献
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Spectral leakage caused by synchronous error in a nonsynchronous sampling system is an important cause that reduces the accuracy
of spectral analysis and harmonic measurement. This paper presents a software sampling frequency adaptive algorithm that can
obtain the actual signal frequency more accurately, and then adjusts sampling interval base on the frequency calculated by
software algorithm and modifies sampling frequency adaptively. It can reduce synchronous error and impact of spectral leakage;
thereby improving the accuracy of spectral analysis and harmonic measurement for power system signal where frequency changes
slowly. This algorithm has high precision just like the simulations show, and it can be a practical method in power system
harmonic analysis since it can be implemented easily.
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Translated from Journal of North China Electric Power University, 2005, 32(6): 5–8 (in Chinese) 相似文献
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Tarun Kumar Rawat H. Parthasarathy 《International Journal of Electrical Power & Energy Systems》2009,31(2-3):111-115
The mean squared error criterion is widely used in the literature. However, there are applications where the squared error is not the primary parameter affecting the performance of a system. In this paper, we introduce a cost function that is based on the phase error. The criterion is useful for applications where the performance depends primarily on the phase of the estimated (recovered) signal. A continuous-time adaptive filter is then developed using the proposed criterion in stochastic differential equation formalism. The proposed adaptive filter is used to estimate power system frequency where the formulated structure is very simple. The three-phase voltages are converted to a complex form for processing by the proposed algorithm. The performance of the new algorithm is studied through simulations at different situations of the power system. 相似文献
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孙莉 《电力系统保护与控制》2006,34(19):38-41
频率是电力系统中一个非常重要的特征量,同时频率也是继电保护、测控等继电保护装置进行相应动作的重要判据,因此频率测量是电力系统测量装置中十分重要的环节。电力系统最常用的软件测频方法为离散傅氏算法,采用分段三次Herm ite插值对离散傅氏测频算法进行改进。所提出的新改进方法具有精度高,计算量相对不大,实时性好的优点。通过数值仿真,分析了本改进方法的时间响应数据窗、绝对误差和谐波对本方法的影响。理论和仿真结果都证明本方法的实用性好。 相似文献
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为满足传动系统在牵引电机无速度传感器控制、速度传感器异常诊断与预测等领域对牵引电机转速精确估计的要求,提出了一种基于频率自适应锁相环的转速实时估计方法。首先针对传统锁相环(PLL)算法无法实现频率大范围跟踪问题,提出了一种前馈参考频率自适应调节的二阶广义积分锁相环(RFSOGI-PLL)算法,实现定子电流基波频率的大范围实时跟踪;再利用牵引电机转速与定子电流基波频率以及齿槽谐波关系模型,结合电机结构参数,实现了传动系统牵引电机转速大范围实时估计;最后在某型大功率交流传动系统上对所提算法的有效性进行了验证。仿真与试验结果表明,与传统PLL算法相比,所提的RFSOGI-PLL算法可有效提升算法对跟踪频率变化的适应性,满足牵引电机转速估计在快速性和估计误差等指标方面的要求。 相似文献
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Giulio Antonini Dirk Deschrijver Tom Dhaene 《International Journal of Numerical Modelling》2009,22(1):57-76
This paper presents an adaptive frequency sampling algorithm to generate a rational macromodel of a power delivery network. To this aim, the cavity model is assumed to represent the structure and accurate models of conductor and dielectric losses are incorporated. The adaptive sampling algorithm allows one to minimize the order of the macromodel and number of frequency samples used to extract the rational macromodel. The numerical results demonstrate the effectiveness of the proposed method. Copyright © 2008 John Wiley & Sons, Ltd. 相似文献
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RFID即射频识别,是1种通过无线射频方式在标签和阅读器之间进行非接触双向数据传输以达到目标识别和数据交换目的的技术.防碰撞算法是射频识别系统中一种提高系统识别效率的关键技术.通过对二进制搜索算法进行数学分析,提出了1种最优分组式的二进制搜索算法.算法首先估计出标签数量,然后利用数学归纳法和求导的方法算出最优的分组因子... 相似文献
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This paper presents an adaptive filter for fast estimation of frequency and harmonic components of a power system voltage or current signal corrupted by noise with low signal to noise ratio (SNR). Unlike the conventional linear combiner (Adaline) approach, the new algorithm is based on an objective function often used in independent component analysis for robust tracking under impulse noise conditions. However, the accuracy and speed of convergence of this algorithm depend on the choice of step size of the filter and its adaptation. Instead of choosing the step size η and the parameter β of the cost function by trial and error, an adaptive particle swarm optimization technique is used alternatively to obtain both η and β to reduce the error between the observed voltage or current samples and the estimated ones. Using the optimized values, the amplitude and phase of the fundamental and harmonic components are estimated. Further, the extracted fundamental component is used to estimate any frequency drift of the power system recursively using an optimized error function obtained from three consecutive voltage samples. To test the effectiveness of the algorithm, several time-varying power system signals are simulated with harmonics, interharmonics, and decaying dc components buried in noise with low signal-to-noise ratio (SNR) and are used to estimate the frequency and harmonic components. This approach will be useful in islanding detection of a distributed generating system. 相似文献
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