计及频率偏移的相量测量算法及谐波测量应用

发布时间：2018-06-27 06:05

本文选题：频率偏移 + 泰勒估计　；参考：《西南交通大学》2017年硕士论文

【摘要】：广域测量系统的出现使同步相量测量单元广泛应用于电力系统的数据采集、状态监测等应用中。现有的商用同步相量测量算法在静态条件下具有较好的测量效果,但系统受到扰动时,电压/电流信号的频率和幅值无法维持一常数,静态算法已无法提供有效的测量精度。尤其当信号的频率发生较大偏移的情况下,动态同步相量测量算法面临更严峻的测量条件。因此,本论文着重研究了考虑频率偏移的动态同步相量测量算法,并研究了算法谐波相量测量中的应用。针对测量精度较高的应用,将频率偏移因素考虑进基于时域模型的基波相量建模中。首先,考虑频率偏移量,建立更接近真实频率的基波相量模型并通过短时傅里叶变换得到预估相量值,通过时移操作,得到相邻数据窗下的相量预估值;其次,根据频率与相角的关系,计算出偏移基准频率的频率偏移量;然后,根据频率偏移量,从表中选择对应的离线矩阵;最后,通过相移运算得到报告时刻的相量值及其准确频率。通过MATLAB的理想信号、PDCAD/EMTDC的动态信号、实测信号等的验证,与其他动态相量测量算法比较,证明了基于时域模型的动态同步相量估计算法的正确性和有效性。针对响应速度较快的应用,将频率偏移因素考虑进基于频模型的基波相量建模中。首先,考虑频率偏移量,建立更接近真实频率的基波相量模型并通过短时傅里叶变换得到预估相量值,并得到频域下的多个相量预估值;其次,根据频率与相角的关系,计算出偏移基准频率的频率偏移量;然后,根据频率偏移量,从表中选择对应的离线矩阵;最后,通过相移运算得到报告时刻的相量值及其准确频率。通过MATLAB的理想信号、PDCAD/EMTDC的动态信号、实测信号等的验证,与其他动态相量测量算法比较,证明了基于频域模型的动态同步相量估计算法的正确性和有效性。考虑信号的动态特性,建立基于泰勒级数的谐波相量模型;考虑频率偏移对泰勒估计精度的影响,提出计及频率偏移的动态谐波相量测量算法。首先,建立基于泰勒级数的谐波相量模型;其次,通过动态相量测量来准确获取基波相量的频率信息;再根据基波频率偏移量计算得到各次谐波的频率偏移量;最后据此查表获得各次谐波的系数修正矩阵,并修正离散傅里叶变换的初始估计值来获得谐波相量的精确估计。通过理想信号及实测数据,与传统傅立叶算法、加窗插值算法对比,验证了计及频率偏移的动态谐波相量测量算法的有效性和实用性。论文所做的理论研究和仿真结果表明:将频率偏移因素考虑到基波和谐波相量的建模中是合理的,得到的结果更贴合信号的实际值,能为未来同步相量测量技术提供重要的理论依据。
[Abstract]:The appearance of wide area measurement system makes synchronous phasor measurement unit widely used in power system data acquisition, state monitoring and other applications. The existing commercial synchronized phasor measurement algorithms have good measurement effect under static condition, but when the system is disturbed, the frequency and amplitude of the voltage / current signal can not maintain a constant, and the static algorithm can not provide effective measurement accuracy. Especially when the frequency of signal deviates greatly, the dynamic synchronous phasor measurement algorithm is faced with more severe measurement conditions. Therefore, this paper focuses on the dynamic synchronized phasor measurement algorithm considering frequency offset, and the application of the algorithm in harmonic phasor measurement. For the application of high measurement precision, the frequency migration factor is considered in the fundamental phasor modeling based on time domain model. Firstly, considering the frequency offset, the fundamental phasor model which is closer to the real frequency is established, and the predicted phase value is obtained by short-time Fourier transform, and the pre-estimated phasor under the adjacent data window is obtained by time-shift operation. According to the relationship between the frequency and the phase angle, the frequency offset of the offset reference frequency is calculated. Then, according to the frequency offset, the corresponding off-line matrix is selected from the table. Finally, the phase value of the reporting time and its exact frequency are obtained by phase shift operation. Compared with other dynamic phasor measurement algorithms, the validity and validity of the dynamic synchronous phasor estimation algorithm based on time-domain model is proved by the verification of the dynamic signal of PDCAD / EMTDC and the measured signal in MATLAB. For the application of high response speed, the frequency migration factor is taken into account in the fundamental phasor modeling based on the frequency model. First of all, considering the frequency offset, the fundamental phasor model which is closer to the real frequency is established, and the predicted phasor value is obtained by short-time Fourier transform, and several phasor preestimates in frequency domain are obtained. Secondly, according to the relationship between frequency and phase angle, The frequency offset of the offset reference frequency is calculated. Then, according to the frequency offset, the corresponding off-line matrix is selected from the table. Finally, the phase value of the reporting time and its exact frequency are obtained by phase shift operation. Compared with other dynamic phasor measurement algorithms, the validity and validity of the dynamic synchronous phasor estimation algorithm based on the frequency domain model is proved by the verification of the dynamic signal of PDCAD / EMTDC and the measured signal of the ideal signal of MATLAB, and compared with other dynamic phasor measurement algorithms. Considering the dynamic characteristics of the signal, the harmonic phasor model based on Taylor series is established, and considering the influence of frequency offset on Taylor estimation accuracy, a dynamic harmonic phasor measurement algorithm considering frequency offset is proposed. Firstly, the harmonic phasor model based on Taylor series is established; secondly, the frequency information of fundamental phasor is accurately obtained by dynamic phasor measurement, and the frequency offset of each harmonic is calculated according to the fundamental frequency offset. Finally, the coefficient correction matrix of each order harmonic is obtained by looking up the table, and the initial estimation value of discrete Fourier transform is revised to obtain the accurate estimation of harmonic phasor. Compared with the traditional Fourier algorithm and the windowed interpolation algorithm, the validity and practicability of the dynamic harmonic phasor measurement algorithm with frequency offset are verified by the ideal signal and measured data. The theoretical research and simulation results show that it is reasonable to take the frequency offset factor into account in the fundamental and harmonic phasor modeling, and the results are more suitable for the actual value of the signal. It can provide important theoretical basis for the future synchronized phasor measurement technology.
【学位授予单位】：西南交通大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TM935

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