Method for positioning single-phase grounding fault sections of feeders of low-current grounding systems

A single-phase grounding fault, low-current grounding technology, applied in the fault location, measuring current/voltage, detecting faults by conductor type, etc. problems, to achieve the effect of easy promotion and use, easy operation and convenient realization

Inactive Publication Date: 2019-03-22
XIAN UNIV OF SCI & TECH
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  • Claims
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Problems solved by technology

Although the steady-state signal characteristics obtained by the method based on steady-state electrical quantities are stable, the steady-state method using zero-sequence current characteristics cannot accurately select the fault section due to its own inherent defects in the resonant grounding mode. Although the electrical quantity method has rich signal characteristics, the transient quantity decays quickly and is unstable, and the method fails when the voltage crosses zero

Method used

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  • Method for positioning single-phase grounding fault sections of feeders of low-current grounding systems
  • Method for positioning single-phase grounding fault sections of feeders of low-current grounding systems
  • Method for positioning single-phase grounding fault sections of feeders of low-current grounding systems

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Embodiment 1

[0072] Such as image 3 As shown, when the present invention is used, the small current grounding system is a 10kV resonant grounding system, and there are three outgoing lines on the bus, and the circuit 1 3 is the fault line, line l 1 The length is 12km, the line l 2 The length is 18km, the fault line l 3 The length of each section is 2km, and the line parameters are LGJ-240 type wires; the arc suppressing coil adopts the overcompensation method, and the compensation degree is 10%; In the phase-to-ground fault section, in this embodiment, 6 distribution automation terminals 2 are used to respectively collect the current i of each monitoring point of the feeder ka i kb and i kc ,k=1,2,...,6, 6 distribution automation terminals 2 simultaneously calculate the three-phase additional state current Δi of the feeder monitoring point ka , Δi kb and Δi kc , and then calculate the fault instantaneous positive sequence current at the feeder monitoring point real part of Get...

Embodiment 2

[0077] The difference between this embodiment and Embodiment 1 is that for a small current grounding system with an initial voltage phase angle of 90°, the grounding resistance is transformed to calculate the single-phase grounding fault section; in the simulation environment of MALAB, two adjacent monitoring points are The amplitude difference of the internal current is shown in Table 2.

[0078] Table 2

[0079]

[0080]

[0081] In the experiment, the main power distribution station 1 judges the single-phase ground fault section of the feeder through the difference of the magnitude of the fault instantaneous positive sequence current real part power frequency component of two adjacent monitoring points on the feeder, which is still the third monitoring point and the first The amplitude difference of the real part power frequency component of the fault instantaneous positive sequence current at the four monitoring points is the largest. Therefore, the feeder section be...

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Abstract

The invention discloses a method for positioning single-phase grounding fault sections of feeders of low-current grounding systems. The method includes steps of firstly, judging single-phase groundingfault occurrence and recording fault signals; secondly, computing three-phase additional state currents and additional state current variables of feeder monitoring points by power distribution automation terminals; thirdly, computing real parts of fault instantaneous positive sequence currents of the feeder monitoring points; fourthly, extracting amplitudes of the real part of the fault instantaneous positive sequence currents of the feeder monitoring points by the power distribution automation terminals and uploading the amplitudes to power distribution master stations; fifthly, positioningand judging the single-phase grounding fault sections and issuing isolation commands. The method has the advantages that the fault sections can be discriminated by the aid of difference values of theamplitudes of the real parts of the fault upstream and downstream instantaneous positive sequence currents, fault upstream features and fault downstream features are obvious in difference, and accordingly obvious positioning effects can be realized by the aid of the method; the method is high in adaptability, and a reliable basis can be provided to shortening the repair time.

Description

technical field [0001] The invention belongs to the technical field of locating single-phase ground fault sections of feeder lines, and in particular relates to a method for locating single-phase ground fault section of feeder lines of small current grounding systems. Background technique [0002] In recent years, as my country's smart grid has become a hot topic in the research field and power consumption has increased sharply year by year, the distribution network, as an indispensable hub between the transmission network and users, has higher requirements for power supply reliability. As an important part of fault isolation and recovery, location has become a research hotspot in smart distribution network. [0003] Since the resonant grounding system has the advantages of small fault current and the self-extinguishing of the arc, it can be widely used in the distribution network; although the resonant grounding system can continue to operate in the case of a single-phase gr...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01R31/08G01R19/25
CPCG01R19/2506G01R31/086G01R31/088
Inventor 赵建文史欣赵睿洁时伟段嘉鑫马楠兵张乃元黄永平高瑜
Owner XIAN UNIV OF SCI & TECH
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