Synchronous phasor measurement method

A synchronized phasor and measurement technology, which is applied to the measurement of electrical variables, measurement devices, and the phase angle between voltage and current, can solve the problem of spectrum leakage and averaging effects, and the dynamic measurement accuracy cannot meet new standards , error and other issues

Inactive Publication Date: 2016-07-13
CHINA ELECTRIC POWER RES INST +3
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  • Application Information

AI Technical Summary

Problems solved by technology

In the dynamic process of the power system, the parameters of the phasor will change with time. Therefore, due to the defects of the DFT itself, two problems will be caused in the phasor measurement: first, the frequency deviation and the dynamic signal input will be cause spectral leakage; second, the static phasor model will lead to the averaging effect of the DFT, resulting in large errors under dynamic conditions
However, most commercial PMUs still use the DFT algorithm, and the DFT algorithm is based on the static phasor model, which cannot solve the problems of spectrum leakage and averaging effects under dynamic conditions, and the dynamic measurement accuracy cannot meet the requirements of the new standard

Method used

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Embodiment 1

[0168] The above-mentioned measurement method is simulated and tested, specifically, the measurement accuracy of the 8th-order Legendre polynomial fitting algorithm is simulated and compared, and the data window length in the simulation is taken as two power frequency cycles, namely 40ms; the sampling rate 5000Hz. The simulation results are shown in Table 1:

[0169] Table 1 Measurement accuracy of synchrophasors based on Legendre polynomial fitting

[0170]

[0171] The following takes the steady-state 50Hz as an example for specific description.

[0172] The input signal frequency is a sinusoidal signal with a frequency of 50Hz, the initial phase angle of the signal is 60°, the sampling frequency is 5000Hz, and the upload frequency is 500Hz. The data window length is two power frequency cycles, namely 40ms, and the simulation time is 1s. The simulation results are as follows: figure 1 , figure 2 , image 3 and Figure 4 shown.

[0173] Depend on figure 1 The maxim...

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Abstract

The invention provides a synchronous phasor measurement method, and the method comprises the steps: carrying out the fitting of a signal through employing a synchronous phasor dynamic model and a Legendre polynomial; calculating a fitting coefficient, and obtaining an instant synchronous phasor. The method provided by the invention reduces the matrix condition number, can carry out the accurate and quick measurement of the phasor, and improves the measurement precision of the phasor.

Description

technical field [0001] The invention relates to the technical field of synchronized phasor measurement, in particular to a method for measuring synchronized phasors. Background technique [0002] In addition to providing synchronized phasors, the phasor measurement unit (PhasorMeasurementUnit, PMU) is widely used as a phasor data source in dynamic security monitoring because of its high precision and high-speed upload frequency. The application of the phasor measurement unit has brought a revolutionary change to the measurement technology of the power system. [0003] Discrete Fourier transform (DFT) can extract rated frequency components from waveforms containing harmonic components and is simple to calculate. This algorithm is widely used in PMUs. In the dynamic process of the power system, the parameters of the phasor will change with time. Therefore, due to the defects of the DFT itself, two problems will be caused in the phasor measurement: first, the frequency deviati...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01R25/00
CPCG01R25/00
Inventor 李劲松毕天姝杨威刘灏王璐杨文平吴锟
Owner CHINA ELECTRIC POWER RES INST
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