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Method for precisely marking arriving time of initial wave of fault generated traveling waves for electricity transmission line

A technology of fault traveling waves and transmission lines, applied to fault locations, emergency protection circuit devices, electrical components, etc., can solve problems such as inaccurate sampling points and inability to accurately locate the wave head time

Active Publication Date: 2008-10-22
KUNMING UNIV OF SCI & TECH
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Problems solved by technology

In the engineering application of traveling wave head detection, cubic B-spline wavelet is considered to be a wavelet base with good signal singularity detection ability, and mathematical morphology also constructs unique flat structural elements with different origins and combines multi-resolution morphological gradients to achieve Good detection effect of signal singularity, but these methods are not accurate to the sampling point when reflecting the wave head position, and still cannot accurately locate the wave head time

Method used

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  • Method for precisely marking arriving time of initial wave of fault generated traveling waves for electricity transmission line
  • Method for precisely marking arriving time of initial wave of fault generated traveling waves for electricity transmission line
  • Method for precisely marking arriving time of initial wave of fault generated traveling waves for electricity transmission line

Examples

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Effect test

Embodiment 1

[0099] This example is the traveling wave current analysis of the phase C fault of Hongqiao Changhongzhan II of Qujing Power Supply Bureau of Yunnan Power Grid at 20:43:25 on May 29, 2008.

[0100] (1) When a fault occurs in the line, the fault traveling wave analysis device is activated to perform fast and high sampling rate (1MHz) wave recording;

[0101] (2) Truncating the traveling wave data file, see Figure 5 , select the 2ms data time window before and after the initial wave head;

[0102] (3) For truncated data press figure 1 The process shown in the figure performs EMD decomposition to obtain the first few IMF components. For the results of EMD decomposition, see Figure 5 (IMF1), (IMF2), (IMF3) curves;

[0103] (4) Select IMF 1 For the object of investigation,

[0104] According to formula (1)

[0105] Y ( t ) = 1 π ∫ - ...

Embodiment 2

[0114] This example is an HHT analysis of fault traveling wave simulation data, including traveling wave heads of different polarities.

[0115] (1) When a fault occurs in the line, the fault traveling wave analysis device is activated to perform fast and high sampling rate (1MHz) wave recording;

[0116] (2) Truncating the traveling wave data file, see figure 2 , select the 1.5ms data time window before and after the initial wave head;

[0117] (3) For truncated data press figure 1 The shown process performs EMD decomposition to obtain the first few IMF components;

[0118] (4) Select IMF1 as the object of investigation, perform Hilbert transformation on it according to formula (1), calculate its instantaneous frequency according to formulas (5) and (6), and calculate its first-order difference, see figure 2 (IMF1 component instantaneous frequency), (IMF1 component first-order difference) curves are shown;

[0119] (5) see image 3 , the minimum value point of the firs...

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Abstract

The invention relates to a method for precisely calibrating the arrival moment of initial wave head of traveling wave in transmission line faults by utilizing Hilbert-Huang transformation (HHT). The method comprises the following steps that: HHT transformation is carried out to faulty traveling wave data; EMD decomposition is carried out first, and IMF1 component intensively embodies the high frequency information of raw data and completely self-adapts to the time scale of the raw data; the IMF1 component is taken as an investigation object; an order difference curve of the IMF1 component is evaluated, and Hilbert transformation is carried out to the order difference curve so as to obtain an instantaneous frequency curve of the IMF1 component; the advantages of two curves are combined to seek an extreme point, and the extreme point is compared with the raw data to obtain the precise calibration for the arrival moment of the head of a traveling wave, and error is controlled to be less than one sampling point. In a strong-noise environment, IMF2 or IMF3 is selected, and the precise calibration for the arrival moment of the head of the traveling wave can be achieved as well according to the method. All the other mathematical methods cannot achieve the precision of the method of the invention. Principle analysis, simulation data and engineering data verification show that the method is precise to calibrate the arrival moment of the initial wave head of the traveling wave in transmission line faults.

Description

technical field [0001] The invention relates to the technical field of electric power system relay protection, in particular to a method for accurately marking the arrival time of the initial wave head of a fault traveling wave of a transmission line using Hilbert-Huang Transform (HHT). Background technique [0002] Compared with the traditional fault location technology based on power frequency, the distance measurement technology based on traveling wave [1-6] It has high ranging accuracy and is not easily affected by system operation mode, transition resistance, CT saturation, and line distributed capacitance, so it has become one of the hot research topics in the field of relay protection. Among them, the precise positioning of the arrival time of the traveling wave head is one of the key technologies to improve the ranging accuracy. wavelet analysis [4，7，8] , Mathematical Morphology [9-10] and the combination of wavelet-mathematical morphology [12] The application of...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H02H7/26G01R31/08
Inventor 束洪春程春和王永治董俊刘志坚刘可真孙士云唐岚邱革非
Owner KUNMING UNIV OF SCI & TECH
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