Positioning method of fault points in power distribution network mixed circuits

A technology of hybrid lines and positioning methods, applied in the field of electric power, can solve problems such as poor stability, and achieve the effects of eliminating influence, accurate and effective calculation results, and improving efficiency and accuracy.

Inactive Publication Date: 2015-12-09
STATE GRID OF CHINA TECH COLLEGE +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, the above methods all use the wave velocity of fixed overhead lines and cable lines or use signal processing to extract the wave velocity. However, research shows that the wave velocity in overhead lines is relatively stable. With differen

Method used

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  • Positioning method of fault points in power distribution network mixed circuits
  • Positioning method of fault points in power distribution network mixed circuits
  • Positioning method of fault points in power distribution network mixed circuits

Examples

Experimental program
Comparison scheme
Effect test

Example Embodiment

(1) Simulation Example 1:

A single-phase grounding fault occurred at 2.500km from No. 3 in section 3-4 of the overhead line. After the fault, the traveling wave distance measuring devices at the measuring terminals M and N were started and recorded the initial fault traveling wave arrival time as 0.0201079s and 0.0200046s respectively. The traveling wave distance measuring device recorded the initial fault traveling wave waveforms at the measuring terminals M and N And its corresponding wavelet transform system, as shown in Figure 2a)-Figure 2d).

After calculating △t=103.3us, corresponding table 2 can be obtained, the fault zone is located between section 3-4, the distance between the fault point and node 2 is 2.482km, and the error is 0.018km.

Example Embodiment

(2) Simulation embodiment two:

A single-phase grounding fault occurred in the 2-3 section of the cable line 1.500km away from the No. 2 node. If ε is 1.002 and △l is 10m, the actual physical length of the line between the fault point and the measurement terminal M should be 16.554km. The arrival time of the fault traveling wave detected at the measuring terminals M and N is 0.0200669s and 0.0200457s respectively. The initial fault traveling wave waveforms at the measuring terminals M and N recorded by the traveling wave distance measuring device and their corresponding wavelet transform systems are shown in the figure 3a)-Figure 3d) shown.

After calculation, △t=21.2us, corresponding to Table 2 can be obtained, the fault interval is located between the section 2-3.

Compared with the conventional ranging method, the conventional FLT mode can get the fault point to be 16.401km from the M end with an error of 0.099km. Accurately calculated the fault distance is 16.557km, which i...

Example Embodiment

(3) Simulation embodiment three:

A single-phase ground fault occurred at 0.040km from No. 1 in section 1-2 of the overhead line. The arrival time of the fault traveling wave detected at the measuring terminals M and N is 0.0200840s and 0.0201621s respectively. The initial fault traveling wave waveform at the measuring terminal M and N recorded by the traveling wave distance measuring device and the corresponding wavelet transform system are shown in the figure 4a)-Figure 4d) shown.

After calculating △t=-78.1us, corresponding table 2 can be obtained, the fault zone is located between section 1-2, the distance between the fault point and node 2 is 0.023km, the error is 0.017km. Compared with the uncorrected time node, the fault point is incorrectly judged to be between zone 0-1. In the conventional mode, the fault point is 2.978km away from the M end, with an error of 0.062km. It can be seen that the node time difference determined by the present invention improves the accurac...

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Abstract

The invention discloses a positioning method of fault points in power distribution network mixed circuits. The positioning method comprises steps of adopting the method of monitoring external faults and measuring propagation speed of fault traveling waves in a cable circuit in an on-line manner; supposing one end in any one circuit zone breaks down and calculating time difference that the initial fault traveling waves achieve two measuring ends of the mixed circuit; setting the time difference as the node time difference, establishing corresponding relations between ends in circuit zone and the node time difference and storing the corresponding relations into a data base; when the mixed circuit breaks down, measuring the actual measurement time difference that the initial fault travelling waves reach two measuring ends of the mixed circuit; comparing the actual measurement time difference with the node time difference in the data base and determining fault circuit zones; and calculating the position of the actual fault point according to the factor that the difference value between the actual measurement time difference and the corresponding node time difference of the end in the fault circuit zone multiplied by a half of the propagation speed value of the fault travelling waves in the fault circuit zone equals the distance between the fault point and the fault circuit zone.

Description

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Claims

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Application Information

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Owner STATE GRID OF CHINA TECH COLLEGE
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