Fault location method for t-shaped line 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 high investment cost of traveling wave method equipment and incorrect identification of fault branches

Inactive Publication Date: 2021-02-05
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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  • Fault location method for t-shaped line based on longitudinal impedance
  • Fault location method for t-shaped line based on longitudinal impedance
  • Fault location method for t-shaped line based on longitudinal impedance

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[0234] 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.

[0235] Table 1 Discrimination and location results of fault branches when phase A is grounded through different transition resistances

[0236]

[0237] First, determine the branch where the...

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Abstract

In the T-type line fault location method based on longitudinal impedance disclosed by the present invention, firstly, on the equivalent single-phase R-L-shaped circuit diagram of the T-type high-voltage transmission line, the three-terminal circuit is set as three double-terminal lines, and the longitudinal The linear relationship between the impedance and the distance to the fault yields three criteria to determine the fault branch. Then, increase the original third current, and determine the expression x of the fault distance for the first time 10 ;Taking into account the distributed capacitance in the T-shaped transmission line, and using the preliminary test result x 10 , correct the equivalent ∏-shaped lines on the left and right sides of the fault point, and obtain the exact fault distance expression x in the T-shaped transmission line 11 . The principle of the method disclosed by the invention is clear, the calculation process is relatively simple, and it can adapt to different operating environments and line structure requirements, including the problem of difficult distance measurement near the T node, and the two-step fault location not only has high distance measurement accuracy but also has a wide range of applications .

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