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Fault location method of power distribution network cable-wire combined circuit based on tested simulation

A technology of mixed line and post-test simulation, applied in the direction of fault location, information technology support system, etc., can solve the problems of large difference in propagation speed, different line wave impedance, and difficult identification of fault traveling wave head, etc., to achieve a simple and robust principle good sex effect

Active Publication Date: 2013-09-04
KUNMING UNIV OF SCI & TECH
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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 overcome the problem that the same wave speed cannot be used to calculate the simulated fault distance due to the large difference in the propagation speed of the fault traveling wave between the overhead line and the cable line, and to overcome the problem that the wave impedance of the overhead line part and the cable part are different. Can not use the same line wave impedance to calculate the reverse voltage traveling wave to eliminate the problem of reflected traveling wave interference at the end of the healthy feeder, and overcome the difficulty of identifying the head of the fault traveling wave

Method used

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  • Fault location method of power distribution network cable-wire combined circuit based on tested simulation
  • Fault location method of power distribution network cable-wire combined circuit based on tested simulation
  • Fault location method of power distribution network cable-wire combined circuit based on tested simulation

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Experimental program
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Effect test

Embodiment 1

[0040] Embodiment 1: as figure 1 The cable hybrid model in the PSCAD simulation software model shown, in which the feeder L 1 It is a hybrid cable feeder, the length of the overhead line is 10km, the length of the cable is 5km, and the feeder is sound L 2 and L 3 Both are overhead lines with lengths of 5km and 15km respectively. The fault feeder is arranged on the right side of the busbar in the distribution network L 1 , the sound feeder is arranged on the left side of the busbar L 2 and L 3 , T is the main transformer, the voltage ratio is 110kV / 35kV, and the connection group is YN / d11; the arc suppression coil L is switched through the isolating switch K; the point M is the measurement terminal of the fault traveling wave at the busbar, and the busbar system is ground equivalent capacitance C E is 0.0001μF, the equivalent capacitance to ground of the step-down transformer on the load side is as follows figure 1 Shown in dashed box.

[0041] Suppose the fault ...

Embodiment 2

[0047] Embodiment 2: The model in Embodiment 1 is also used, assuming that the fault occurs in the cable part, the fault point is 11km away from the measurement end, 1km away from the cable node, the fault time is 0.084ms, and the transition resistance is 0.01Ω. Three B-spline wavelet transforms are performed on the fault current traveling wave detected at the busbar measurement terminal to obtain the maximum value of the traveling wave modulus. The result is as follows Figure 8 shown. Such as Figure 8 As shown in , the traveling wave ① is the initial traveling wave of the fault, the traveling wave ② is the reflected traveling wave of the cable node, and the traveling wave ③ is the reflected traveling wave at the end of the healthy feeder line, where, Δt 1 =0.015ms, Δt ２ =0.03ms. calculate first =0.015×300 / 2=2.25km, because l f0 The length of the short and healthy feeder is quite different, so it can be directly used Δt 1 Four simulated fault distances are calc...

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Abstract

The invention relates to a fault location method of a power distribution network cable-wire combined circuit based on tested simulation, and belongs to the technical field of electrical power system relay protection. When the cable-wire combined circuit breaks down, a time difference between a second wave head and a first wave head or a time difference between a third wave head and the first wave head of a fault traveling wave is obtained through the modulus maximum value so that simulated failure distance can be obtained, and the simulated failure distance is compared with the length of a short sound feeder line so that a time difference of tested simulation location can be determined. After the interference of the short sound feeder line is removed, the simulated failure distance between a cable part and an overhead part is calculated according to the corresponding time difference. A correlation analysis is carried out on wavelet coefficients corresponding to a zero sequence current traveling wave and an actual fault zero sequence current traveling wave feature band under all simulated failure distances, and the simulated failure distance of a maximum correlation coefficient obtained in an analysis result is regarded as an actual failure distance. The fault location method is simple in principle, capable of not being interfered by a reflected wave at the tail end of the sound feeder line and good in robustness.

Description

technical field [0001] The invention relates to a fault location method for distribution network cable-line hybrid lines based on post-measurement simulation, and belongs to the technical field of electric power system relay protection. Background technique [0002] With the rapid development of the power system and the gradual increase of urban electricity load, the existing overhead lines can no longer meet the needs of urban development. Therefore, the replacement of the original overhead line power supply by cable network power supply has become an inevitable trend in the development of urban power grids. With the continuous upgrading of the urban power grid, the urban cable network is gradually developing to a voltage level of 35kV and above. Because the investment cost of high-voltage cables is quite high, most of them use the route selection of overhead lines, and use the hybrid line power supply mode of high-voltage overhead lines and cables to replace the simple ca...

Claims

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Application Information

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IPC IPC(8): G01R31/08
CPCY04S10/52
Inventor 束洪春荣潇王明锦董俊
Owner KUNMING UNIV OF SCI & TECH
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