Zero sequence current difference polarity comparison based power distribution network fault line selection method

A distribution network fault and zero-sequence current technology, which is applied to the fault location, detects faults according to the type of conductor, and measures electricity. It can solve problems such as potential safety hazards in the distribution network, and achieve low sampling frequency and simple and accurate line selection principles. high degree of effect

Active Publication Date: 2017-02-22
KUNMING UNIV OF SCI & TECH
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Problems solved by technology

However, such a long-term operation will bring huge hidden dangers to the distribution network, ...

Method used

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  • Zero sequence current difference polarity comparison based power distribution network fault line selection method
  • Zero sequence current difference polarity comparison based power distribution network fault line selection method
  • Zero sequence current difference polarity comparison based power distribution network fault line selection method

Examples

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Embodiment 1

[0021] Example 1: A method for fault line selection in a distribution network based on the comparison of the zero sequence current differential polarity. A simulation model is built according to the parameters of the distribution network. By setting different lines and phase single-phase ground faults in the simulation model, Obtain the line power frequency zero sequence current signal i generated by each simulated line under ground fault 0i (t); select the zero sequence current i within 10ms after the fault 0i (t); Then define the zero sequence current difference function F of the line i (t), find the zero sequence current i 0i (t) difference function F i (t), and then use the difference function F i (t) Construct P i (t), using P i (t) Compare the polarity of the zero sequence current of each line, when P i (t)=max{P 1 (t),P 2 (t)...,P n (t)}, then line i is a faulty line; when P i (t)≠max(P 1 (t),P 2 (t)...,P n (t)}, then i is a non-faulty line.

[0022] The specific steps are: ...

Embodiment 2

[0035] Embodiment 2: The other parts of this embodiment are the same as those of embodiment 1, such as figure 1 As shown, the 110kV / 35kV distribution network simulation model is as figure 1 As shown, it has 6 feeders, and the neutral point of the Z-shaped transformer is grounded through a series resistance of the arc suppression coil. Overhead feeder L 1 =18km, L 3 =30km, cable feeder L 2 = 7km. The G in the grid is an infinite power source; T is the main transformer, the transformation ratio is 110kV / 35kV, and the connection group is Y N / d11; T Z It is a zigzag transformer; L is the arc suppression coil; R is the damping resistance of the arc suppression coil. The feeder adopts three lines: overhead line, overhead line-cable hybrid line and cable line. The load uses a constant power load model.

[0036] (1) Feeder L 2 A single-phase ground fault occurred in phase B at a distance of 10 kilometers from the starting end, the ground resistance was 10Ω, the fault angle was 60°, a...

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Abstract

The invention relates to a zero sequence current difference polarity comparison based power distribution network fault line selection method, which belongs to the technical field of electric power system fault line selection. According to the parameters for the operation of a power distribution network, a simulation model is set up. By setting different lines to have grounding faults with the phases respectively in the simulation model, power line work frequency zero-sequence current signals are generated among the simulated lines. The zero-sequence current within 10ms is selected after the faults occur. Then, the zero-sequence current differential function is defined and calculated; after that, the differential function is used to construct fault discriminators; based on the fault discriminators, the polarity of the zero sequence current of each line is compared. When the value of the fault discriminator of a certain line is equal to the maximum value of all the line fault discriminators, the line is determined as a faulty line. When the value of the fault discriminator of the certain line is not equal to the maximum value of all the line fault discriminators, the line is determined as a non-faulty line.

Description

Technical field [0001] The invention relates to a distribution network fault line selection method based on zero sequence current differential polarity comparison, and belongs to the technical field of power system fault line selection. Background technique [0002] The distribution network is the most direct link with users in the power system. It has a wide range of coverage. Compared with the transmission network, the probability of failure is higher. And single-phase grounding is the main type of fault that occurs in the operation of the distribution network. When a single-phase grounding fault occurs in a distribution network where the neutral point is grounded by the arc suppression coil, the three-phase line voltage of the grid always maintains symmetry. Due to the compensation function of the arc suppression coil, the fault current generated is small. According to the power system Operating Regulations In this case, the system can continue to operate with a fault for 1-2 ...

Claims

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Application Information

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IPC IPC(8): G01R31/08
CPCG01R31/086G01R31/088
Inventor 王书领李文泽马聪
Owner KUNMING UNIV OF SCI & TECH
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