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Power distribution network single-phase earth fault development trend discrimination method based on zero-sequence volt-ampere curve area

A single-phase ground fault and volt-ampere curve technology, applied in the fault location, detecting faults according to conductor types, measuring electricity and other directions, can solve problems such as affecting the reliability of power supply, surge in trip rate, adverse personnel and equipment safety, etc., to achieve judgment. The results are reliable and the effect of simplifying the judgment process

Active Publication Date: 2020-03-13
KUNMING UNIV OF SCI & TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0002] The neutral point is grounded by the arc suppressing coil or the ungrounded distribution network can continue to operate for 1 to 2 hours after a single-phase ground fault, but it is not conducive to the safety of personnel and equipment, and the small resistance grounding method is often used for the operation of overhead distribution lines. There is a problem that the trip rate surge affects the reliability of power supply
In recent years, power grid enterprises intend to use changes in the neutral point grounding method to improve the rapid handling capacity of single-phase ground faults in the distribution network. Fault tripping is one of the main reasons for

Method used

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  • Power distribution network single-phase earth fault development trend discrimination method based on zero-sequence volt-ampere curve area
  • Power distribution network single-phase earth fault development trend discrimination method based on zero-sequence volt-ampere curve area
  • Power distribution network single-phase earth fault development trend discrimination method based on zero-sequence volt-ampere curve area

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0034] (1) Assuming that a permanent fault with constant transition resistance occurs on the line L2 at a distance of 7 kilometers from the bus, its zero-sequence voltage and zero-sequence current are as follows: figure 2 , image 3 shown.

[0035] (2) Intercept the zero-sequence volt-ampere curve from 20ms to 120ms after the fault, such as Figure 4 As shown, the area of ​​each curve and its one-time fitting are as follows Figure 5 shown.

[0036] (3) The area of ​​each surface is 37.8068, 37.8022, 37.8017, 37.8018, 37.8021, and the slope of the straight line fitting is -0.00068, which is greater than -0.01, so it is predicted to be a permanent failure;

Embodiment 2

[0038] (1) Assuming that a transient fault occurs on the line L4 at a distance of 10 kilometers from the bus, its zero-sequence voltage and zero-sequence current are as follows: Image 6 , Figure 7 shown.

[0039] (2) Intercept the zero-sequence volt-ampere curve from 20ms to 120ms after the fault, such as Figure 8 As shown, the area of ​​each curve and its one-time fitting are as follows Figure 9 shown.

[0040] (3) The area of ​​each surface is 34.3355, 29.7728, 21.7906, 12.1546, 5.0260, and the slope of the straight line fitting is -0.3812, which is less than -0.01, so it is predicted to be an instantaneous fault;

Embodiment 3

[0042] (1) Assuming that a permanent fault occurs on the line L5 at a distance of 3 kilometers from the busbar, the transition resistance becomes smaller, and its zero-sequence voltage and zero-sequence current are as follows: Figure 10 , Figure 11 shown.

[0043] (2) Intercept the zero-sequence volt-ampere curve from 20ms to 120ms after the fault, such as Figure 12 As shown, the area of ​​each curve and its one-time fitting are as follows Figure 13 shown.

[0044] (3) The area of ​​each surface is 18.5833, 29.0997, 44.4465, 65.7231, 93.0446, and the slope of the straight line fitting is 0.9277, which is greater than -0.01, so it is predicted to be a permanent failure;

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Abstract

The invention relates to a power distribution network single-phase earth fault development trend discrimination method based on zero-sequence volt-ampere curve area, and belongs to the technical fieldof power system relay protection. According to the invention, a single-phase earth fault is set along a feeder line of a power distribution network through electromagnetic transient simulation to take the feeder line as a fault feeder line, a zero-sequence voltage and a zero-sequence current of the fault feeder line are extracted to form a zero-sequence volt-ampere curve, the change of fault transition resistance is speculated according to the slope of a straight line obtained by fitting on the curve area, and then, the development trend of the single-phase earth fault is deduced. It can be seen from simulation verification and actual measurement data that the method is correct and effective.

Description

technical field [0001] The invention relates to a method for discriminating the development situation of a single-phase grounding fault in a distribution network based on the area of ​​a zero-sequence volt-ampere curve, and belongs to the technical field of electric power system relay protection. Background technique [0002] The neutral point is grounded by the arc suppressing coil or the ungrounded distribution network can continue to operate for 1 to 2 hours after a single-phase ground fault, but it is not conducive to the safety of personnel and equipment, and the small resistance grounding method is often used for the operation of overhead distribution lines. There is a problem with surges in trip rates affecting the reliability of the power supply. In recent years, power grid enterprises intend to use changes in the neutral point grounding method to improve the rapid handling capacity of single-phase ground faults in the distribution network. Fault tripping is one of ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01R31/08
CPCG01R31/086G01R31/088
Inventor 董俊李一凡束洪春于永波
Owner KUNMING UNIV OF SCI & TECH
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