The Research Of Precision Time Performance Analysis Algorithm Of Intelligent Substation Sampling Loop

At present, the digital, networked, intelligent improvements of substation bring a lot of technological superiorities. However, these improvements inevitably have an impact on the sampling circuit of intelligent substation. So it is necessary to analyze the time delay and synchronization performance of the sampling circuit. Signal analysis method based on fast Fourier transform is used widely, but in the case of spectral leakage and fence effect of asynchronous sampling, the accuracy of signal parameter estimation is low. Therefore, the study of the window function with excellent performance and the improved FFT signal analysis method has important theoretical and practical significance.This paper proposes an improved interpolation FFT analysis algorithm based on cosine-combined self-convolution window, whose ability to inhibit spectral leakage increases rapidly with the number of convolution. Then the dissertation discusses the impact of the algorithm parameters setting on the algorithm performance through simulations, which lays the foundation for reasonable selection of algorithm parameters in practical application. Meanwhile, compared with the traditional two-line interpolation FFT method, the method proposed in this paper can effectively suppress frequency fluctuations, the impact of white noise, and improve the accuracy of the fundamental wave parameters estimation.Finally, the improved algorithm in this paper is used in the time performance analysis of the intelligent substation’s sampling circuit, and realized as the time performance analysis system by the module design of LabVIEW software. This analysis system can calculate the fundamental wave parameters of the sampling data of voltage and current, achieving time delay and synchronization performance analysis. Besides, it has a friendly interface and powerful data storage function and broad space for upgrade. Through field tests conducted in110kV Lanjiatuo intelligent substation, the testing and application results have verified the validity of the improved FFT algorithm in time delay performance and synchronization performance analysis.