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A distribution network fault startup method based on s-transform spectrum characteristics at fault time

A distribution network fault and spectrum characteristic technology, applied in the fault location and other directions, can solve the problem of low reliability and achieve the effect of simple principle

Active Publication Date: 2017-08-25
CHUXIONG POWER SUPPLY BUREAU OF YUNNAN POWER GRID CO LTD +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] The technical problem to be solved by the present invention is to propose a distribution network fault start-up method based on the S-transform spectrum characteristics at fault time to solve the problem of low reliability in the existing distribution network fault start-up method

Method used

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  • A distribution network fault startup method based on s-transform spectrum characteristics at fault time
  • A distribution network fault startup method based on s-transform spectrum characteristics at fault time
  • A distribution network fault startup method based on s-transform spectrum characteristics at fault time

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Embodiment 1

[0046] Embodiment 1: A flow chart of a distribution network fault startup method based on S-transform spectrum characteristics at fault time is as follows figure 1 shown. At 1MHZ sampling rate, collect the zero-sequence voltage time-domain waveform within the 16ms time window, such as figure 2As shown, perform S-transform on it, and then calculate the modulus of each element of the obtained S-matrix to obtain the S-mode matrix, and extract the amplitude-frequency characteristics of the S-mode matrix at the moment when the sudden change occurs, as shown in image 3 shown. Finally, calculate the variance ξ=1.0178 of the amplitude-frequency characteristic at this moment.

[0047] Set the variance threshold of the zero-sequence voltage S-mode matrix amplitude-frequency characteristics Because ξ=1.0178>0.1, it is determined that a single-phase fault occurs in the distribution network, and the line selection device starts.

Embodiment 2

[0048] Embodiment 2: A flow chart of a distribution network fault startup method based on S-transform spectrum characteristics at fault time is as follows figure 1 shown. At 1MHZ sampling rate, collect the zero-sequence voltage time-domain waveform within the 16ms time window, such as Figure 4 As shown, perform S-transform on it, and then calculate the modulus of each element of the obtained S-matrix to obtain the S-mode matrix, and extract the amplitude-frequency characteristics of the S-mode matrix at the moment when the sudden change occurs, as shown in Figure 5 shown. Finally, calculate the variance ξ=0.0154 of the amplitude-frequency characteristic at this moment.

[0049] Set the variance threshold of the zero-sequence voltage S-mode matrix amplitude-frequency characteristics Since ξ=0.0154<0.1, it is judged that there is no fault in the distribution network, and the line selection device does not start.

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Abstract

The invention relates to a distribution network fault startup method based on the S-transform spectrum characteristic at the fault time, and belongs to the technical field of electric power system relay protection. The method is as follows: at a sampling rate of 1MHZ, collect the zero-sequence voltage time-domain waveform in a short time window, perform S transformation on it to obtain the zero-sequence voltage S matrix, and then calculate the modulus of each element of the S matrix to obtain the S-mode matrix, and extract The amplitude-frequency characteristics of the S-mode matrix at the moment when the sudden change occurs, and finally calculate the variance ξ of the amplitude-frequency characteristics at this moment. If the calculated variance ξ is greater than the set threshold, it is judged that a single-phase fault occurs in the distribution network, and the line selection device starts; otherwise, no fault occurs, and the line selection device does not start. Theoretical analysis and verification of measured data show that the invention has a good effect.

Description

technical field [0001] The invention relates to a distribution network fault startup method based on the S-transform spectrum characteristic at the fault time, and belongs to the technical field of electric power system relay protection. Background technique [0002] my country's distribution network widely adopts the low-current grounding method. When a single-phase ground fault occurs in this grounding method, the power supply can still ensure the symmetry of the line voltage and will not affect the continuous power supply to the load. However, after a single-phase ground fault occurs, the reliable start-up of single-phase ground fault has not been well solved for a long time due to reasons such as weak fault current and unstable arc. [0003] The method based on the zero-sequence voltage and current power frequency component has low sensitivity and is affected by the arc suppression coil; although the method based on the 5th harmonic of the zero-sequence signal is not aff...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): G01R31/08
Inventor 黄兴仓李绍荣马庆龙段军鹏李起荣朱净松张航陈继金张宇韬蒋陈根张曦源杨以波束洪春余多白冰
Owner CHUXIONG POWER SUPPLY BUREAU OF YUNNAN POWER GRID CO LTD