Frequency conversion method for implementing multi-sampling rate signal using window function in electric network

Abstract

The invention relates to a method for realizing the frequency conversion of multi-sample rate signals by using window function, pertaining to the technical fields of digital transformer substations and wide area measurement of an electric grid. The method comprises the following steps: zero value interpolation of I time is operated on a sampled signal x (n) to obtain an interpolation sequence x1 (1) of I time; Kaiser window FIR low pass filtering, with window length of 10 and Beta value equaling to 7.865, is operated on the signal x1 (1) to obtain a signal y1 (1); Extraction of D time(s) is operated on the signal y1 (1) to obtain a converted signal y (m). The method can complete frequency normalization of different-sample rate signals by using the three-stage-connection of extraction, interpolation and Kaiser window FIR (Finite Impulse Response Filter) low pass filtering, thus totally avoiding the occurrence of aliasing and mirror images of the sampled frequencies.

Description

technical field [0001] The invention relates to the technical field of wide-area measurement of digital substations and power grids, in particular to a method for converting and unifying sampling frequencies of multi-sampling rate signals for real-time monitoring, protection and control. Background technique [0002] The digital substation based on the IEC61850 standard has entered the stage of practical application. The primary and secondary equipment in the substation have been digitized, and have a unified data model and communication platform for the whole station. On the basis of this platform, the interoperability between intelligent devices can be realized. . At the same time, with the application of the Global Positioning System (GPS) in the power system, the development of computer networks and communications, a real-time monitoring system based on synchrophasor measurement technology and aimed at monitoring, analyzing and controlling the dynamic process of the powe...

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Problems solved by technology

Zhou Bin and Zhang He wrote the interface technology of sampling value of substation intelligent equipment based on electronic transformer (Jiangsu Electrical Engineering, 2007, 26(2): 37-39), and proposed a Lagrange interpolation (linear interpolation) method, but when the Larger errors will be generated when the harmonic order in the band is higher; the extraction, interpolation method and sequence of digital signals written by Zheng Shilin (Communication Technology, 2001, (7): 106-108) From the perspective of signal fidelity, the average The interpolation method realizes the conversion of the sampling frequency, but the frequency of the interpolation method is 2 l multiplied

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