摘要
随着非线性负荷和冲击性负荷的不断增加以及新能源的大规模并网,电网环境日趋复杂,各类电能质量问题日益凸显。其中,谐波问题尤为突出,准确估计谐波参数不仅是谐波治理的关键,也是电力企业和用户评价电能质量的重要依据。为此,该文提出一种基于自适应移频滤波的电力系统谐波分析方法。首先,对电网谐波信号进行初次移频滤波操作,以获得信号实际基波频率;然后,根据信号实测基波频率,对信号进行二次移频滤波处理,进而准确获取各次谐波的幅值和相角;最后,仿真实验表明,该文所提算法能够有效地克服非同步采样和噪声的影响,并且具有测量精度高、实时性好和适应性强等特点。此外,通过实际构建的硬件测试平台,进一步验证了所提算法的准确性和可靠性。
With the increasing proportion of various types of nonlinear and impactive loads in the power grid,especially the large-scale integration of new energy sources represented by photovoltaic and wind power,the harmonic issues in the current power system are becoming increasingly severe.Accurately estimating harmonic parameters is not only critical for harmonic control but also an essential basis for power companies and users to evaluate power quality.To achieve accurate and effective detection of harmonic parameters in modern power systems,this paper proposes a power system harmonic analysis method based on adaptive frequency-shift filtering,which estimates harmonic parameters by dynamically and adaptively adjusting frequency deviations.This method first performs a frequency-shift operation on the original power grid sampled signal based on the nominal frequencyωnom.Then,considering that it is difficult to completely filter out frequency components other than the target frequency component in a single filtering operation,this paper performs multiple iterations of filtering on the frequency-shift signal.Specifically,the frequency-shift signal is convolved with a p-order self-convolution mean filter(SCMF)to reduce the interference from other frequency components on the target frequency component.After the initial frequency-shift filtering of the power grid harmonic signal,the harmonic angular frequency deviationΔω,the actual fundamental frequency fr,and the new frequency-shift function corrected byΔωcan be obtained.Next,according to the desired harmonic order hs and the frequency-shift function after correction,a second frequency-shift filtering process is carried out,moving the desired harmonic spectral line to the zero frequency position.Finally,the amplitude and phase of the desired harmonic component can be accurately obtained by using the derived formulas.For a power grid sampled signal with length N and using fast convolution for the convolution operation in the algorithm,the time complexity of the proposed algorithm is O(Nlog2N).Compared with the windowed interpolation FFT algorithm(WIFFT),the time complexity of both algorithms is similar.However,the WIFFT algorithm requires prior determination of fitting coefficients through polynomial fitting.Therefore,the algorithm proposed in this paper is more convenient and straightforward in practical applications,thus offering distinct advantages.This paper conducted simulation experiments on the algorithm under conditions of weak amplitude harmonic signal,fundamental frequency deviation,noise impact,etc.,and also established an actual hardware testing platform.The amplitude relative error and the phase absolute error of the actual measurement results fully meet the requirements of Class A meters in GB/T 14549“Quality of electric energy supply-Harmonics in public supply network”.Simulation experiments and practical measurement results demonstrate that the proposed method can accurately and effectively detect power system harmonic parameters,showing significant advantages in robustness,adaptability,and real-time performance.Especially for detecting weak amplitude harmonic components,this method exhibits strong applicability.The proposed method can provide new solutions and ideas for the effective and fast analysis of harmonic parameters in complex power grid environments,as well as theoretical and engineering application issues related to electric energy science and accurate metering in the electric power system.
作者
李建闽
曹远远
姚文轩
梁成斌
于佳琪
Li Jianmin;Cao Yuanyuan;Yao Wenxuan;Liang Chengbin;Yu Jiaqi(College of Engineering and Design Hunan Normal University,Changsha 410081,China;College of Electrical and Information Engineering Hunan University,Changsha 410082,China;College of Electrical Engineering Guizhou University,Guiyang 550025,China;College of Electronic Information and Electrical Engineering Changsha University,Changsha 410022,China)
出处
《电工技术学报》
EI
CSCD
北大核心
2024年第13期4015-4024,共10页
Transactions of China Electrotechnical Society
基金
国家自然科学基金(51907062,52207076)
湖南省自然科学基金(2021JJ40354)
湖南省自科区域联合基金(2023JJ50025)资助项目。
关键词
电力系统分析
电能质量
电网谐波
移频滤波
Power system analysis
power quality
grid harmonics
frequency-shift filtering
