Synchronized phasor measurement method for electrical power system based on cubic spline interpolation

Abstract

The invention relates to the technical field of synchronized phasor measurement for an electrical power system and particularly relates to a synchronized phasor measurement method based on cubic spline interpolation. To the error problem of the traditional DFT method (Discrete Fourier Transformation) under non-synchronous sampling conditions of frequency deviation, firstly, a data window length is calculated according to constant sampling frequency and fundamental system frequency; secondly, the non-fundamental frequency integer multiple sampling time value is obtained through the cubic spline interpolation; finally, the synchronized phasor during the non-fundamental frequency integer multiple sampling time is obtained by Simpson formulas in the DFT method and numerical integration formulas. The method is higher in synchronized phasor measurement precision and excellent in synchronized phasor measurement noise immunity under the non-synchronous sampling conditions such as normal fluctuation and great deviation of the electrical power system frequency.

Description

technical field [0001] The invention relates to the technical field of power system synchrophasor measurement, in particular to a power system synchrophasor measurement method based on cubic spline interpolation. Background technique [0002] Since the 21st century, several large-scale power outages have occurred continuously, which have caused extremely adverse effects on social production and life. At the same time, with the development of the global power market and regional power grid projects, the operating environment of the power grid has become increasingly Real-time monitoring of the power grid becomes particularly important under the dynamic conditions of the power system. At present, Wide Area Measurement System (WAMS), as a new generation of high-efficiency power system dynamic monitoring system, provides advanced technical support for power system dynamic security monitoring, and has become one of the emerging technical fields that various countries are eager to...

AI Technical Summary

Problems solved by technology

The zero-crossing detection method is easily affected by the harmonics at the zero-crossing point of the signal and its real-time performance is not good, and it is easily affected by the dynamic characteristics of the system, resulting in large measurement errors

The Prony method has no way to reflect the non-stationarity under the dynamic characteristics of the system, and the noise has a great influence on the fitting result. When the signal-to-noise ratio of the noise is less than 40dB, incorrect results will be obtained.

The instantaneous value method has high requirements on the input waveform, and the waveform of the signal is required to be a standard power frequency sine wave, so its applicability is not strong, and the amount of calculation is large

When the Kalman filter method is used to measure the phase angle of the synchronized phasor, it has a large error and cannot meet the requirements of the phase angle measurement.

The wavelet transform method cannot achieve ideal results in the synchrophasor measurement of narrowband signals with the rated frequency as the center frequency, and because the wavelet analysis has a large amount of calculation, it will affect the speed of synchrophasor measurement and increase the number of digital signal processors. (DSP) Burden

When the signal frequency is shifted by the DFT method, a large error will be generated due to frequency leakage and other reasons.

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