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Fault line selection method based on time domain waveform correlation analysis of three-phase current breaking variable

A technology of time-domain waveform and three-phase current, which is applied in the direction of the fault location, etc., can solve the problems of inconsistency in the transmission characteristics of three-phase current transformers and the reliability of fault line selection methods that affect zero-sequence currents, etc.

Inactive Publication Date: 2013-07-10
KUNMING UNIV OF SCI & TECH
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Problems solved by technology

[0004] Most of the line selection methods based on transient quantities use zero-sequence current as the analysis object, but for distribution networks that only install three-phase current transformers but not zero-sequence , the zero-sequence current synthesized by the three-phase current often has a large deviation from the real situation, which often affects the reliability of the fault line selection method based on the zero-sequence current

Method used

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  • Fault line selection method based on time domain waveform correlation analysis of three-phase current breaking variable
  • Fault line selection method based on time domain waveform correlation analysis of three-phase current breaking variable
  • Fault line selection method based on time domain waveform correlation analysis of three-phase current breaking variable

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Embodiment 1

[0071] Embodiment 1: as Figure 4 The single-phase ground fault simulation model of the 110kV / 35kV distribution network shown has 6 feeders, and the neutral point of the Z-shaped transformer is grounded through the arc-suppression coil series resistance. overhead feeder =15km, =18km, =30km, wire-cable hybrid feeder =17km, the overhead feeder is 12km, the cable is 5km, and the cable feeder =6km, =8km. Among them, the overhead feeder is JS1 rod type, LGJ-70 type conductor, the span is 80m, and the cable feeder is YJV23-35 / 95 type cable. G in the power grid is an infinite power source; T is the main transformer with a transformation ratio of 110 kV / 35kV, and the connection group is / d11; Is a zigzag transformer; L is the arc suppression coil; R is the damping resistance of the arc suppression coil. The feeder adopts three types of lines: overhead line, overhead line-cable hybrid line and cable line. The load uses a constant power load model. hypothetical feeder...

Embodiment 2

[0078] Embodiment 2: as Figure 4 The parameters of the single-phase-to-ground fault simulation model of the 110kV / 35kV distribution network shown in the example have been described in Embodiment 1, and will not be repeated here. Now assume the feeder A single-phase ground fault occurs in phase A 4 kilometers away from the beginning, the ground resistance is 60Ω, the fault angle is 30°, and the sampling frequency is 10kHz. The data of the 5 ms time window after the fault in the time domain waveform of the three-phase current mutation of each feeder collected by the three-phase current transformer is used to calculate the phase-to-phase correlation coefficient and the comprehensive correlation coefficient. The calculation results are shown in Table 2.

[0079] It can be seen from Table 2 that the correlation coefficient between the faulty phase and the healthy phase is small, and the correlation coefficient between the healthy phase and the healthy phase is large; the compre...

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Abstract

The invention provides a fault line selection method based on time domain waveform correlation analysis of a three-phase current breaking variable, and belongs to the technical field of electric system relay protection. The method includes the steps that as for a power distribution network with a feed-out line only provided with a three-phase current mutual inductor and not provided with a zero sequence current mutual inductor, when single-phase earth fault of the power distribution network occurs, a device is immediately started, and three-phase breaking currents of feeder lines on measurement positions are measured. A three-phase breaking current time domain waveform inside a time window 5 milliseconds after the fault occurs is extracted, correlation analysis of the three-phase breaking current time domain waveform is carried out to acquire an interphase correlation coefficient and a comprehensive correlation coefficient, the comprehensive correlation coefficient and the interphase correlation coefficient respectively serve as a line selection criterion characteristic quantity and a phase selection criterion characteristic quantity, and line selection and phase selection of the distribution network single-phase earth fault are achieved according to criterion principles. Theoretical analysis and a great quantity of emulation indicate that the fault line selection method is good in effect.

Description

technical field [0001] The invention relates to the technical field of electric power system relay protection, in particular to a fault line selection method based on time-domain waveform correlation analysis of three-phase current mutations. Background technique [0002] When a single-phase ground fault occurs in a distribution network whose neutral point is grounded by an arc-suppression coil, the fault transient current amplitude is much larger than the steady-state current and is not affected by the arc-suppression coil. Compared with the steady-state component, the transient component after the fault has great advantages, so the method of using the transient component to select the line has become the mainstream of the distribution network fault line selection method. Most of the line selection methods based on transient quantities make use of the differences between faulty lines and healthy lines in the characteristics of sudden changes in direction and amplitude, and ...

Claims

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Application Information

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IPC IPC(8): G01R31/08
Inventor 束洪春高利朱梦梦段锐敏
Owner KUNMING UNIV OF SCI & TECH
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