T-shaped line fault ranging method based on longitudinal impedance

A technology for longitudinal impedance and line faults, applied in the direction of fault location, measuring resistance/reactance/impedance, measuring devices, etc., which can solve the problems of wrong judgment of fault branches, high investment cost of traveling wave method equipment, etc.

Inactive Publication Date: 2019-05-24
XI'AN POLYTECHNIC UNIVERSITY
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  • Application Information

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Problems solved by technology

[0005] The purpose of the present invention is to provide a T-type line fault distance measurement method based on longitudinal impedance, which can simplify the calculation and improve the distance measurement accuracy while effectively distinguishing the fault branch, and solve the problem of high equipment investment cost of the traveling wave method. There is a problem that the fault branch is judged incorrectly in

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  • T-shaped line fault ranging method based on longitudinal impedance
  • T-shaped line fault ranging method based on longitudinal impedance
  • T-shaped line fault ranging method based on longitudinal impedance

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Embodiment

[0235] Using PSCAD and MATLAB simulation to verify the effectiveness of the algorithm, the parameters are as follows: line length D 1 ,D 2 ,D 3 They are 200, 150, and 120km respectively, and the unit positive sequence and zero sequence resistance, inductance, and capacitance of the line are: R 1 = 0.02083Ω / km, L 1 =0.8948mH / km, C 1 =0.0129μF / km; R 0 = 0.1148Ω / km, L 0 =2.2886mH / km, C 0 = 0.00523 μF / km. The system parameters of the M side are: R M1 =1.0515Ω, L M1 =80.154mH, R M0 = 0.6Ω, L M0 =63.4mH. N-side system parameters are: R N1 =8.76Ω, L N1 =102.54mH, R N0 =2.53Ω, L N0 =78.823mH. P side system parameters are: R P1 =3.672Ω, L P1 =138.46mH, R P0 =5.7Ω, L P0 =90.8mH. System three-terminal potential E M ,E N ,E P They are 550∠0°kV, 500∠-35°kV, and 520∠-22°kV.

[0236] Table 1 Fault branch discrimination and location results when phase A is grounded through different transition resistances

[0237]

[0238] First, determine the branch where the fau...

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Abstract

The invention discloses a T-shaped line fault ranging method based on longitudinal impedance. The method includes the steps: firstly, setting a three-terminal circuit into three double-terminal lineson an equivalent single-phase R-L-phased circuit diagram of a T-shaped high-voltage power transmission line, and acquiring three criteria by the aid of the linear relationship between longitudinal impedance and fault distance to determine fault branches; secondly, adding original third current and determining the expression x10 of the fault distance for the first time; taking distributed capacitance in the T-shaped power transmission line into account, and correcting equivalent n-shaped lines on the left side and the right side of a fault point by the aid of preliminary measuring results x10 to obtain accurate fault distance expression x11 in the T-shaped power transmission line. The method is clear in principle and simpler in calculation process, can meet the requirements of different running environments and line structures, and can solve the problem of difficulty in ranging near a T-joint. Two-step fault positioning is high in ranging accuracy and wide in use range.

Description

technical field [0001] The invention belongs to the field of relay protection of AC transmission lines, and in particular relates to a T-shaped line fault distance measurement method based on longitudinal impedance. Background technique [0002] T-shaped lines are more and more popular in the construction of high-voltage power grids due to their advantages of speeding up project construction, improving operating efficiency, and saving land resources. At the same time, it also has the advantages of high utilization rate of power transmission and wide range of users. However, once an internal failure occurs, the impact of power outages is relatively large. [0003] At present, the fault location method of the T-type line is mainly divided into two steps: firstly, the fault branch is determined, and secondly, the fault location is determined by using the mature double-terminal fault location method. The methods used include the traveling wave method and the fault analysis meth...

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Application Information

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IPC IPC(8): G01R31/08G01R27/04
Inventor夏经德刘欢庆
OwnerXI'AN POLYTECHNIC UNIVERSITY