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Distributed fault location method for overhead line-cable hybrid circuit

A hybrid line and fault location technology, applied to fault locations, emergency protection circuit devices, electrical components, etc., can solve problems such as complex calculations, large errors, and overhead line faults, and achieve good application prospects

Active Publication Date: 2013-10-23
SHANGHAI JIAO TONG UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0019] 2. Overhead line failure
Simplify the mixed line into a single line for fault location, and then convert it back to the mixed line. This method needs repeated conversion, and the error is large
The connection point voltage calculation method developed from the traditional fault analysis method determines the fault section by calculating the voltage of the connection point, and then solves the fault point distance through iteration. This method is only suitable for hybrid lines with simple structures. For power cables , mixed lines with alternating overhead lines, the calculation of this method is too complicated, and the error will increase with the increase of lines
The traveling wave time difference method developed from the traveling wave method is relatively accurate and simple. The fault line is first determined by the time difference between the arrival of the fault traveling wave at both ends, and then the precise location is performed according to the single-ended or double-ended method. However, due to the complexity of the mixed line wave process, this It is difficult for the method to fully consider traveling wave refraction

Method used

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  • Distributed fault location method for overhead line-cable hybrid circuit
  • Distributed fault location method for overhead line-cable hybrid circuit
  • Distributed fault location method for overhead line-cable hybrid circuit

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0098] The fault occurred on hybrid circuit cable 1. The fault occurred 0.245s after the system was started. It was a single-phase ground fault, and the fault resistance was 50 ohms. By analyzing the fault traveling wave current detected by detection points 1-7, the current polarity can be obtained as shown in Table 1.

[0099] Table 1 Current polarity analysis of each detection point

[0100] check Point

1

2

3

4

5

6

7

polarity

+

+

-

-

-

-

-

[0101] It can be seen from Table 1 that the fault occurred between detection points 2 and 3, that is, cable 1.

[0102] The arrival time of the first fault traveling wave detected by detection point 2 is 0.245200s, and the arrival time of the first fault traveling wave detected by detection point 3 is 0.245064s, so the fault occurs in the lower half of cable 1. Set the cable wave velocity v b =1.5×10 8 m / s, the velocity of the overhead line wave is v a =...

Embodiment 2

[0104] The fault occurred on the overhead line 3 of the hybrid circuit. The fault occurred 0.240s after the system was started. It was a two-phase ground fault, and the fault resistance was 500 ohms. By analyzing the fault traveling wave current detected by detection points 1-7, the current polarity can be obtained as shown in Table 2.

[0105] Table 2 Current polarity analysis of each detection point

[0106] check Point

1

2

3

4

5

6

7

polarity

+

+

+

+

+

-

-

[0107] It can be seen from Table 2 that the fault occurred between detection points 5 and 6, that is, overhead line 3.

[0108] The arrival time of the first fault traveling wave detected by detection point 5 is 0.240030s, and the arrival time of the first fault traveling wave detected by detection point 6 is 0.240098s, so the fault occurred in the upper half of overhead line 3. Set the cable wave velocity v b =1.5×10 8 m / s, the velocity ...

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Abstract

The invention discloses a distributed fault location method for an overhead line-cable hybrid circuit. The method comprises the following steps: S1, arranging fault traveling wave detection devices at the joint of the hybrid circuit and a bus and the joints of different circuits in the hybrid circuit, judging a failed circuit according to the polarity of a first fault travelling wave head detected by each fault traveling wave detection device, wherein when fault current travelling wave heads detected by two adjacent fault travelling wave detecting devices are of opposite polarities, a circuit between the two adjacent fault travelling wave detection device is the failed circuit; and S2, judging the source of a second travelling wave head according to the arriving time of the fault travelling wave heads detected by the fault travelling wave detection devices at the two ends of the failed circuit, and selecting a proper fault location method for positioning. According to the distributed fault location method, online calculation of the travelling wave transmission speed of a power transmission line is realized, and the source of a second fault travelling wave of a detection point is judged according to the analysis of a travelling wave sequence; and the method has a good application prospect.

Description

technical field [0001] The invention relates to a method for distributed fault distance measurement of an overhead wire-cable hybrid line based on fault current traveling wave head information. Background technique [0002] In areas with high urban load density, land resources are quite precious. Due to the large area occupied by overhead transmission line corridors, the development of urban underground space and the laying of cables have become an important part of power grid construction. Urban cables make reasonable use of urban underground space, which alleviates the contradiction between urban development and land resource constraints, and improves land utilization. [0003] Although urban cables are more reliable than overhead lines, their laying costs are higher, and once a fault occurs, it is difficult to find the fault point, it is inconvenient to deal with it in time, and the maintenance cost is not low. Therefore, most cities have adopted the overhead line-cable ...

Claims

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Application Information

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IPC IPC(8): G01R31/08
CPCH02H7/265
Inventor 刘亚东申文严英杰岳天琛盛戈皞江秀臣
Owner SHANGHAI JIAO TONG UNIV
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