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Power signal synchronized phasor measurement method based on frequency domain dynamic model

A synchrophasor measurement and power signal technology, applied in spectrum analysis/Fourier analysis, etc., can solve the problems of increasing DFT algorithm error, unavailability, and reducing the dynamic security monitoring capability of power grid, and achieve the effect of accurate synchronous measurement

Active Publication Date: 2015-04-08
SOUTHWEST JIAOTONG UNIV
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Problems solved by technology

[0005] Therefore, the spectral leakage and fence phenomenon caused by the application of DFT to phasor measurement may cause large errors in the DFT algorithm, and even obtain an unusable result
And when the power grid is in a dynamic process, the frequency and amplitude of the power signal change with time, and the incomplete representation of the dynamic characteristics of the signal by the algorithm may also increase the error generated by the DFT algorithm
DFT algorithm can perform synchronized phasor measurement under certain conditions and scope, but there are certain limitations, and the accuracy of phasor measurement directly affects the application effect of WAMS
Inaccurate synchrophasor measurement will eventually reduce the dynamic security monitoring capability of the power grid and affect the safe and stable operation of the power grid

Method used

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  • Power signal synchronized phasor measurement method based on frequency domain dynamic model
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  • Power signal synchronized phasor measurement method based on frequency domain dynamic model

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Embodiment

[0028] A kind of embodiment of the present invention is, the power signal synchrophasor measurement method based on frequency domain dynamic model, its steps are:

[0029] A. Data collection and pre-estimation processing

[0030] The voltage transformer or current transformer in the power grid measures the voltage or current signal of the power grid, and collects the voltage or current signal to obtain the discrete sequence x(n) of the power signal of the power grid, where n is the sampling time; the digital signal processor processes the discrete sequence of the power signal Perform windowed Fourier transform on x(n) to obtain 2L+1 phasor measurement pre-estimated values ​​X(ω) offset by 50Hz fundamental wave ω radians, where ω=l·Δω, l=0, ±1, ±2, ..., ±L, Δω is the radian difference of the pre-estimated values ​​of adjacent phasors;

[0031] B. Correction of phasor pre-estimated value

[0032] The digital signal processor performs synchronized phasor measurement on the obta...

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Abstract

The invention discloses a power signal synchronized phasor measurement method based on a frequency domain dynamic model. The power signal synchronized phasor measurement method comprises the following steps of collecting the voltage or current signals of a power grid measured by a voltage transformer or a current transformer to obtain a power signal discrete series x(n) of the power grid, then carrying out windowed Fourier transform on the power signal discrete series x(n) to obtain 2L+1 phasor measurement pre-estimated values X(omega) of a deviation 50Hz fundamental wave omega radian; then using the dynamic model based on a frequency domain to carry out synchronized phasor measurement to obtain the corrected values of phasor pre-estimated values, namely obtaining the phasor value of the power signals of the power grid at the current moment trep through phase shift calculation. The method can effectively reduce the measurement errors, the influence of time-varying characteristics of signal fundamental components on phasor measurement can be eliminated or weakened under the dynamic conditions of low frequency oscillation, frequency deviation and the like, the phasor measurement precision of the signals is greatly improved, and the dynamic performance is improved.

Description

technical field [0001] The invention relates to a method for measuring synchronized phasors in a power system. Background technique [0002] With the development of global power marketization and regional interconnection of power grids, the operating environment of power grids has become increasingly complex, and the problem of its safe and stable operation has become increasingly prominent. It is urgent to improve the dynamic security monitoring capabilities of power grids. In recent years, Wide Area Measurement System (Wide Area Measurement System, WAMS), as a new dynamic monitoring system of power grid, provides new technical means for effective dynamic security monitoring of power grid. The data collection and processing method in WAMS requires that the processing result of the collected data be phasor data with precise time scale. Therefore, the synchrophasor measurement technology that can synchronously collect the time, phase and amplitude of power signals is the bas...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01R23/16
Inventor 符玲韩文朕何正友麦瑞坤
Owner SOUTHWEST JIAOTONG UNIV
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