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A Time-Frequency Domain Locating Method of Power System Forced Oscillation Source Based on Wavelet Transform

A technology of wavelet transform and forced oscillation, applied in the field of power system transient analysis, can solve problems such as misjudgment of forced oscillation mode, unstable positioning accuracy of oscillation source, complicated calculation process, etc., and achieve simplified positioning process, strong engineering practicability, Effects of Improving Analytical Efficiency

Active Publication Date: 2022-05-27
NORTHEAST DIANLI UNIVERSITY
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] Although the above methods realize the localization of forced oscillation sources based on wide-area measurement information, they all need to separate the time-domain components of the forced oscillation mode from the wide-area measurement information, and then calculate The corresponding energy consumption flow, the calculation process is more complicated
In addition, due to the influence of fault types and noise, the traditional method is prone to misjudgment of the forced oscillation mode, and the positioning accuracy of the oscillation source is unstable.

Method used

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  • A Time-Frequency Domain Locating Method of Power System Forced Oscillation Source Based on Wavelet Transform
  • A Time-Frequency Domain Locating Method of Power System Forced Oscillation Source Based on Wavelet Transform
  • A Time-Frequency Domain Locating Method of Power System Forced Oscillation Source Based on Wavelet Transform

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Embodiment 1

[0056] A time-frequency domain location method for power system forced oscillation source based on wavelet transform, see figure 1 , the embodiment of the present invention will be further described in detail below, wherein 101-109 are detailed steps of the calculation method.

[0057] 101: The synchronization vector measurement unit PMU collects the terminal voltage (U) signal of the generator, the power (P, Q) signal sent by the generator and the frequency (f) signal of the generator bus, and uses it as the input data of the present invention ;

[0058] Above, U is the generator terminal voltage amplitude; P is the active power generated by the generator; Q is the reactive power generated by the generator; f is the frequency.

[0059] 102: Let k=1, calculate the logarithm of the voltage amplitude of the generator k, and calculate the deviation value of each input data;

[0060] 103: Perform WT processing on the deviation value of each input data to obtain the corresponding...

Embodiment 2

[0069] The scheme in Example 1 will be further introduced in combination with specific calculation formulas and examples, see the description below for details:

[0070] 201: According to the scope of the oscillation influence, determine the key units greatly affected by the oscillation, and obtain the active power P and reactive power Q of the generator from the wide-area measurement system (a technical term known to those skilled in the art, which will not be described here) , frequency f and voltage amplitude U as input, calculate the logarithm of generator voltage amplitude, and calculate the deviation value of each input data;

[0071] Wherein, the wide-area measurement system is a technical term known to those skilled in the art, which will not be described in detail in this embodiment of the present invention.

[0072] In addition, the specific selection of the key units affected by the oscillation in the power system is performed according to the needs in practical app...

Embodiment 3

[0118] In the following, in conjunction with specific examples, a wavelet transform-based power system forced oscillation source time-frequency domain positioning method proposed in the embodiment of the present invention. In this example, the WECC179 node system is used as an example for simulation analysis and verification. The topology diagram of the WECC179 node system is as follows figure 2 As shown, generator G74 is set as a reference generator, and a sinusoidal signal with an oscillation frequency of 0.46 Hz is continuously injected into the excitation system of generator G79 as a forced oscillation disturbance signal for a duration of 20 s. The electrical parameters of each generator during the disturbance period are as follows: image 3 shown.

[0119] First, with image 3 The electrical quantity information of each generator terminal shown is input, for image 3 The active power of each generator is transformed by wavelet, and a total of 29 wavelet coefficient mat...

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Abstract

The invention discloses a time-frequency domain positioning method for a forced oscillation source of a power system based on wavelet transform. The method includes: performing wavelet transform processing on the deviation value of each input data, calculating the relative energy of each scale coefficient in the wavelet coefficient matrix, Determine the key wavelet scale coefficient corresponding to the forced oscillation mode; extract the deviation value of each input data corresponding to the wavelet coefficient of the key wavelet scale coefficient, and combine DEF analysis to obtain the DEF curve of each generator based on wavelet transform; the DEF curve least squares Fitting, normalize the fitting coefficients, and calculate the quantitative index μ of generator oscillation source location 0 ; if μ 0 = 1, the generator k is the forced oscillation source of the system, and output the location result of the forced oscillation source. The invention not only inherits the characteristics of the traditional DEF analysis for online positioning of the forced oscillation source, but also avoids the problem of unstable accuracy of the DEF algorithm, does not need to reconstruct the time domain signal during analysis, and significantly improves the positioning efficiency of the forced oscillation source.

Description

technical field [0001] The invention relates to the field of power system transient analysis, in particular to a time-frequency domain positioning method for a power system forced oscillation source based on wavelet transform (WT). Background technique [0002] With the strengthening of the power grid structure and the large-scale deployment of various damping control devices, the weakly damped low-frequency oscillation of the traditional power system has been better suppressed, and the forced oscillation has become one of the main factors that threaten the safe and stable operation of the power system. [1-2] . Forced oscillations are usually induced by continuous periodic small disturbances. When the disturbance frequency is close to the natural oscillation frequency of the system, it will cause the entire network to oscillate. [3-4] . Since forced oscillation has the characteristics of strong randomness, fast start-up, and rapid attenuation after the disturbance disappea...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): G06F17/14G06F17/10G06Q10/06
CPCG06F17/148G06F17/10G06Q10/06393
Inventor 姜涛李雪李孟豪陈厚合张儒峰王长江李国庆李本新李曙光
Owner NORTHEAST DIANLI UNIVERSITY