In-cabinet cable head fault positioning method and system based on phase CT and zero sequence CT

A technology of fault location and cable head, which is applied in the direction of fault location, information technology support system, fault detection according to conductor type, etc., can solve problems such as inability to locate, achieve improved safety and reliability, high correct rate of line selection, and reduce Effects on personal injury

Pending Publication Date: 2022-05-27
TANGSHAN JIDONG CEMENT SANYOU CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0006] In order to solve the deficiencies in the prior art, the object of the present invention is to provide a cable head fault location method and system in the cabinet based on phase CT and zero-sequence CT, which is easy to operate and makes up for the inability to locate a single-phase ground fault at the cable head. Positioning defects, high positioning accuracy, can effectively improve the safety and reliability of the distribution network, and have high engineering value

Method used

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  • In-cabinet cable head fault positioning method and system based on phase CT and zero sequence CT
  • In-cabinet cable head fault positioning method and system based on phase CT and zero sequence CT
  • In-cabinet cable head fault positioning method and system based on phase CT and zero sequence CT

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Effect test

Embodiment 1

[0070] like figure 1 , a method for locating cable head faults in a cabinet based on phase CT and zero-sequence CT, including steps 1 to 4.

[0071] Step 1: Collect the neutral point zero-sequence voltage of the distribution network, the synthetic zero-sequence current of the three-phase CT, and the zero-sequence current of the zero-sequence CT.

[0072] Preferably, in step 1, the real-time sampling frequency of each electrical quantity in the distribution network is not lower than 12 kHz.

[0073] Preferably, in step 1, for any line, the currents of the three-phase CTs are added to obtain the combined zero-sequence current of the line.

[0074] Step 2, according to the real-time mutation and real-time amplitude of the neutral point zero-sequence voltage, determine whether a single-phase ground fault occurs in the system.

[0075] Preferably, in step 2, when at least one of the following two conditions is met, it is determined that there is a single-phase ground fault:

[0...

Embodiment 2

[0108] Embodiment 2 of the present invention establishes in ATP simulation software such as figure 2 The 10kV simulation model shown, the transition resistance is 80Ω, the synthetic zero-sequence current of phase CT and the zero-sequence current signal of zero-sequence CT are obtained when the fault occurs at different positions.

[0109] The parameters of each line and fault transition resistance are shown in Table 1 below:

[0110] Table 1 Line parameters

[0111]

[0112] When a fault occurs on the busbar, such as figure 1 For fault 1 shown, the combined zero-sequence current of the three-phase CTs on each line is as follows: image 3 shown. The combined zero-sequence current waveforms of lines 1 to 4 are similar, and the combined zero-sequence current value gradually decreases as the distance between the line and the bus fault point increases. Depend on image 3 It can be seen that the synthetic zero-sequence current signal of the three-phase CT shows that no faul...

Embodiment 3

[0133] Cable head fault location system in cabinet based on phase CT and zero-sequence CT, including: electrical quantity acquisition module and single-phase ground fault location device;

[0134] The electrical quantity acquisition module is used to collect the neutral point zero-sequence voltage of the distribution network, the three-phase current and zero-sequence current of each line in the distribution network in real time with a sampling frequency of not less than 12kHz; the electrical quantity acquisition module, the The neutral point zero-sequence voltage of the distribution network, the three-phase current and zero-sequence current of each line in the distribution network are all input to the single-phase grounding fault location device;

[0135] The fault location results output by the fault location module include: cable line fault, busbar fault, and cable head fault in the switch cabinet of the line.

[0136] The electrical quantity acquisition module includes: neu...

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Abstract

The invention discloses an in-cabinet cable head fault positioning method and system based on a phase CT and a zero-sequence CT. The method comprises the steps of collecting a neutral point zero-sequence voltage of a power distribution network, a synthesized zero-sequence current of the three-phase CT and a zero-sequence current signal of the zero-sequence CT; judging whether the system has a single-phase earth fault or not according to the real-time break variable and the real-time amplitude of the zero-sequence voltage of the neutral point; when a fault occurs, the zero-sequence voltage and the synthesized zero-sequence current signal are utilized to perform primary line selection, and if a certain line is selected, the synthesized zero-sequence current signal and the zero-sequence current signal are utilized to perform secondary line selection so as to judge whether the fault occurs on a cable head in a switch cabinet of the line or on the cable line. The method is simple and convenient to operate, overcomes the defect that the cable head in the switch cabinet cannot be positioned when the single-phase earth fault occurs, is high in positioning accuracy, can effectively improve the safety and reliability of a power distribution network, and has relatively high engineering value.

Description

technical field [0001] The invention belongs to the technical field of power system fault location, and in particular relates to a method and system for fault location of a cable head in a cabinet based on phase CT and zero-sequence CT. Background technique [0002] With the acceleration of urbanization in my country and the expansion of the economic scale of existing cities, traditional overhead lines not only need to occupy a lot of line corridor resources, affecting the beauty of the city, but also easily affected by external factors and cause failures; and power cables are generally laid in Underground, it can greatly save land resources and have high operational reliability. With the continuous development of the power industry, cables have become an important carrier for information transmission and energy distribution in modern networks, and are widely used in communications, traditional electromagnetic energy, etc. It can be seen that the normal operation of the cabl...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01R31/08G01R31/52
CPCG01R31/083G01R31/088G01R31/52Y04S10/52
Inventor 张立华王铁谷亚东赵猛杨国栋武晓峰王晨光贾祖光徐涛崔玉辉郭欠军马劲松王艳兵刘晓庆李玉军郑子墨齐海星刘文祥
Owner TANGSHAN JIDONG CEMENT SANYOU CO LTD
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