复杂电力动态负荷信号典型特征提取与建模

Typical feature extraction and modeling of complex power dynamic load signals

  • 摘要: 随着新型电力系统加快构建,可再生新能源和非线性大功率动态负荷大规模应用,引起了电能计量的严重超差. 为研究复杂电力动态负荷信号中导致电能计量误差的重要特征,亟需探索负荷信号局部与全局特征提取方法,以应对已有研究无法准确表征大功率动态负荷信号全局特征的难题. 因此,本文提出了基于波形域与游程域的典型特征提取与特征建模方法. 首先,现场采集电气化铁路和电弧炉两类大规模复杂电力动态负荷信号并构建离散数学模型,在波形域分析其典型特征并提取特征参数;其次,研究信号从波形域到游程域的映射方法,构建游程域特征参数,表征负荷电流快速随机动态波动的局部和全局特征;最后,根据复杂电力动态负荷信号游程域和波形域的典型特征构建约束条件,基于特征建模方法,构建具有特定参数的二元动态电流测试信号模型,并实验分析了测试信号能够反映动态负荷典型特征对电能计量误差的影响,具备有效性.

     

    Abstract: The scale of clean energy and electric energy substitution is expanding with the rapid development of China's new power system and the steady introduction of “dual carbon” strategic goals. Electric energy signals under the high proportion of renewable energy access and high-power dynamic load applications lead to nonlinear random dynamic changes, often causing serious deviations in electric energy measurements and affecting the fairness and rationality of electric energy trading. This study focuses on the energy economy, in the context of problems in implementing the aforementioned national strategies. Furthermore, this study identifies scientific problems, explores the important characteristics of dynamic loads that cause power metering deviations, and analyzes the local and global features of complex power dynamic load signals to address the challenges in accurately characterizing the global features of high-power dynamic load signals in existing research. Additionally, the method of constructing binary dynamic power testing signal models is explored. First, a discrete mathematical model is constructed for complex dynamic load signals of electrified railways and electric arc furnaces collected onsite. The important features of instantaneous voltage and current amplitudes are analyzed and extracted in the waveform domain, which reflects the approximate stability of voltage signals, the fast random dynamic fluctuation characteristics of current signals, the main characteristics of current amplitudes being an approximately Gaussian distribution, and decreasing autocorrelation coefficients. Second, based on run-length sequence mapping, a binary run-length sequence of complex dynamic load signals is constructed to analyze and extract important features, such as local and global run-length mode changes, modulation depth, and impact strength of current amplitudes on electrified railways and electric arc furnaces in the run-length domain. Compared with the proposed time-, frequency-, and time-frequency domain feature analysis methods proposed, the method suggested in this study has significant advantages in simultaneously extracting the local and global features of complex dynamic electrical-energy signals, characterizing important features such as large-scale fluctuations (large fluctuations), rapid changes over time (fast time-varying), and strong randomness. Finally, constraint conditions are constructed based on the typical characteristics of the run and waveform domains of complex power dynamic load signals. Using feature modeling methods, a binary m-sequence dynamic energy-testing signal model with specific parameters is constructed such that the testing signal reflects the typical features of the dynamic load signal and the most significant factors affecting energy measurement errors and covers the maximum range of feature parameter changes. This can also allow the simultaneous completion of the dynamic error testing of energy meters and the traceability of energy values. A dynamic error-testing system is built for electric-energy measurements, and the dynamic error of the electric-energy meter is tested under binary dynamic electric-energy-testing signal conditions. Experimental verification showed that the test signal reflected the typical characteristics of dynamic loads under the influence of electric-energy measurement errors. The research content of this paper provides a theoretical basis for the analysis of dynamic energy signal characteristics in complex scenarios, the construction of multifeature constraint models, and the dynamic error testing of energy meters.

     

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