电力系统工频量测伪振荡现象的判别方法

发布时间：2018-06-01 03:23

本文选题：电力系统振荡 + 谐波　；参考：《中国电机工程学报》2017年03期

【摘要】：由电力电子开关组成的换流器在换流及控制过程中会产生大量谐波和间谐波,在特定条件下会导致工频测量结果出现振荡现象。针对这一问题,该文给出了电力系统工频量测结果出现振荡时,判别该振荡是由于量测原因导致的伪振荡还是真实的电气振荡的方法。文中指出,电网频率偏离额定频率,且采样频率不满足采样定理时,电气信号中,频率高于奈奎斯特频率的高次谐波在采样信号中会映射为频率低于奈奎斯特频率的间谐波,这一间谐波的频率与其对应的高频谐波的真实频率关于奈奎斯特频率对称。在特定条件下,这一间谐波的频率会接近基波频率,从而导致基波幅值测量结果出现伪振荡。针对直流换流站,该文给出了交流采样频率与换流站特征谐波的配合原则。仿真算例和实际算例都验证了该文的分析结论。
[Abstract]:A large number of harmonics and interharmonics will be produced in the process of commutation and control of the converter composed of power electronic switches, which will lead to the oscillation of the measurement results of power frequency under certain conditions. In order to solve this problem, this paper presents a method to determine whether the oscillation is a pseudo-oscillation caused by measurement or a real electrical oscillation when the power system power frequency measurement results are oscillating. It is pointed out in this paper that when the power network frequency deviates from the rated frequency and the sampling frequency does not satisfy the sampling theorem, the high-order harmonics with a frequency higher than Nyquist frequency in the electrical signal will be mapped to the interharmonics with a frequency lower than the Nyquist frequency in the sampled signal. The frequency of this harmonic is symmetrical to that of the corresponding high frequency harmonic in relation to the Nyquist frequency. Under certain conditions, the frequency of the harmonics is close to the fundamental frequency, which leads to pseudo oscillation of the measurement results of the fundamental amplitude. For DC converter station, the coordination principle of AC sampling frequency and characteristic harmonic of converter station is given in this paper. Both the simulation example and the actual example verify the conclusion of the paper.
【作者单位】：国家电网华北电力调控分中心;国网冀北电力有限公司经济技术研究院;
【分类号】：TM712

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