Method of measuring dynamic performance based on phasor and frequency
A technology of frequency measurement and dynamic performance, applied in the field of automatic measurement of power systems, can solve problems such as spectrum leakage, difficult to meet the accuracy requirements, and inability to suppress harmonics
Active Publication Date: 2017-01-11
CHINA SOUTHERN POWER GRID COMPANY +1
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Problems solved by technology
[0003] The traditional discrete Fourier transform algorithm (DFT Discrete Fourier Transform for short), when the frequency deviates from the rated frequency, due to spectrum leakage, the accuracy is difficult to meet the requirements
At present, there is a phasor measurement algorithm that corrects the DFT calculation results through two data windows. Compared with the traditional DFT algorithm, this algorithm greatly improves the calculation accuracy. However, due to the need for two data windows and the signal model The limitation of the response speed to dynamic processes such as sudden changes is limited, and it is difficult to meet the accuracy requirements when the amplitude changes at all times
Algorithms based on frequency-domain dynamic models have been used to correct DFT estimation results by using the responses of filters at different frequency points in the same data window, which improves the response speed to dynamic processes such as sudden changes, but cannot suppress harmonics, and no calculation is given. How to get frequency and rate of change of frequency
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[0027] The present invention will be described in detail below in conjunction with the accompanying drawings. The method for measuring the dynamic performance of the synchrophasor and frequency proposed by the present invention can be realized by using various hardware schemes, which will not be repeated here. The measuring algorithm flow process that the present invention proposes is as figure 1 As shown, the algorithm flow of the synchrophasor measurement unit (PMU) is as follows figure 2 shown. The measurement method includes the following steps:
[0028] (1) Initialize and determine the number of sampling points N per cycle. It should be noted that g in the DFT coefficient k The selection should make the matrix M -1 The condition number should be as small as possible to avoid pathological conditions, suppress noise interference, and at the same time suppress power system harmonic interference. In order to suppress common odd-order harmonic interference, 1, 2, 4... ar...
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The invention relates to a method of measuring dynamic performance based on phasor and frequency. The invention provides a method of solving phasor and frequency only through one data window. According to the method, a power signal model is expanded in Taylor series, and the phasor, frequency and frequency variation are calculated based on the fundamental and harmonic contents on one data window. Response is quick. Frequency and frequency variation can be calculated in one data window. The problem on how to implement phasor calculation under the condition of harmonic is solved. The method can be widely applied to power system phasor and frequency measurement.
Description
technical field [0001] The invention relates to the technical field of automatic measurement of power systems, in particular to a method for measuring dynamic performance of synchronized phasors and frequencies. Background technique [0002] In recent years, the wide-area measurement system based on the phasor measurement unit (PMU) has been widely used in the fields of power system dynamic process monitoring, online identification, security and stability analysis, and wide-area control. With the continuous deepening of wide-area measurement system application research, PMU devices have higher and higher requirements for synchronized phasor measurement, and the rapidity of its phasor algorithm will directly affect the reliability of related application functions. [0003] The traditional discrete Fourier transform algorithm (DFT Discrete Fourier Transform for short), when the frequency deviates from the rated frequency, the accuracy cannot meet the requirements due to spectr...
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Login to View More IPC IPC(8): G01R23/02G01R23/16
CPCG01R23/02G01R23/16
Inventor 黄河徐全刘映尚苏寅生姚海成陆超韩英铎吴京涛
Owner CHINA SOUTHERN POWER GRID COMPANY