CN210863998U

CN210863998U - 0.4kV line ground fault finder

Info

Publication number: CN210863998U
Application number: CN201921277770.5U
Authority: CN
Inventors: 韩成超; 罗正锋; 谢万力; 罗新永; 刘哲; 陈华颂; 陈剑
Original assignee: Guangdong Power Grid Co Ltd; Zhanjiang Power Supply Bureau of Guangdong Power Grid Co Ltd
Current assignee: Guangdong Power Grid Co Ltd; Zhanjiang Power Supply Bureau of Guangdong Power Grid Co Ltd
Priority date: 2019-08-06
Filing date: 2019-08-06
Publication date: 2020-06-26
Anticipated expiration: 2029-08-06

Abstract

The utility model provides a 0.4kV circuit ground fault finder, including two ampere meters and four current clamp, the current input end of one of them ampere meter is parallelly connected to have four group's current input terminals, and the current input end of another ampere meter is connected with a set of current input terminal, and any current clamp all can be connected with arbitrary a set of current input terminal through the wire. Use the utility model discloses during the troubleshooting, jaw ABC three-phase wire and zero line are sampled respectively through four current clamp, wire of every current clamp jaw, avoid many wires of current clamp jaw simultaneously of traditional current clamp to cause the jaw card of current clamp not to advance, can't carry out the circuit measurement, also need not tear open overhead line conductor insulator binding wire and the trouble that causes, make things convenient for the staff to seek fast of trouble, alleviate operating personnel's labour and reduction user power off time, improve customer satisfaction.

Description

0.4kV line ground fault finder

Technical Field

The utility model belongs to the technical field of power tool, concretely relates to 0.4kV circuit ground fault finder.

Background

The 0.4kV system of Guangdong power grid company adopts a neutral point direct grounding system, has no residual current total protection, and is divided into two types of transformer areas of repeated grounding and non-repeated grounding, and when single-phase grounding faults occur in the transformer areas, the production and the domestic power consumption are seriously influenced and the safety is endangered. The concealment of the fault point is very strong, and other fault points are not easy to find visually except the fault caused by the forced damage.

When a 0.4kV line has a ground fault at present, a low-voltage line without repeated grounding adopts a clamp-type ammeter to measure residual current to judge a fault point, and during operation, four leads are clamped together by using one current clamp, as shown in figure 1; the searching of the fault point of the single-phase line grounding of the low-voltage line with the repeated grounding adopts two clamp type current meters to simultaneously measure the magnitude of the zero-sequence current and the zero-line current of the phase line for judging the fault point, when in operation, the current clamp of one clamp type current meter simultaneously clamps the ABC three-phase wire, and the current clamp of the other clamp type current meter clamps the zero line, as shown in figure 2. When a fault point is searched, the problems that an overhead line insulator binding wire needs to be detached, a jaw clamp does not enter a lead with a large wire diameter or four leads and the like exist, the phenomenon that power failure is possibly required to adopt single-phase power supply for searching is caused, the labor intensity is high, the working efficiency is low, and the problem that a user complains due to power failure is caused.

SUMMERY OF THE UTILITY MODEL

At least one to prior art is not enough, the utility model aims at providing a make things convenient for 0.4kV circuit ground fault finder of troubleshooting.

In order to achieve the above purpose, the utility model provides a technical scheme does: the utility model provides a 0.4kV circuit ground fault finder, includes two ampere meters and four current clamp, and the current input end of one of them ampere meter is parallelly connected with four groups current input terminal, and the current input end of another ampere meter is connected with a set of current input terminal, and any current clamp all can be connected with the current input terminal of any group through the wire.

Among the above-mentioned scheme, during the troubleshooting, sample through four current clamp difference forceps holder ABC three-phase conductor and zero line, wire of every current clamp forceps holder, avoid a current clamp of tradition many wires of forceps holder simultaneously to cause the jaw card of current clamp not to advance, can't carry out the circuit measurement, so that need not tear open the trouble that the wire insulator ligature and cause with overhead line, make things convenient for the staff to seek fast of trouble, alleviate operating personnel's labour and reduction user power off time, improve customer satisfaction.

Furthermore, the fault finding instrument further comprises a shell, the two ammeters are arranged in the shell, the fault finding instrument is convenient to hold integrally, the current indication screens of the ammeters are exposed out of the shell, the two ammeters can read conveniently, the five groups of current input terminals are arranged on the shell, and the five groups of current input terminals are conveniently connected with the current clamp.

Furthermore, the current clamp is a current transformer, and current data can be acquired conveniently and accurately.

The utility model discloses a 0.4kV circuit ground fault finder can both accurately find the ground fault point fast when having two kinds of ground system ground fault of repeated ground connection and no repeated ground connection, through a wire of every electric current clamp forceps holder, has and need not have a power failure, need not demolish overhead line's wire insulator binding, does not have the problem that wire pincers mouth card does not advance, advantages such as easy operation, quick, accurate.

Drawings

Fig. 1 is a schematic diagram of a conventional low-voltage line fault finding without repeated grounding.

Fig. 2 is a schematic diagram of a conventional low-voltage line fault finding with repeated grounding.

Fig. 3 is a schematic diagram of the fault finding instrument for finding faults of low-voltage lines without repeated grounding.

Fig. 4 is a schematic diagram of a frame when the fault finder of the embodiment of the present invention is used for fault finding of a low-voltage line without repeated grounding.

Fig. 5 is a schematic diagram of the fault finding instrument for finding faults of a low-voltage line with repeated grounding.

Fig. 6 is a schematic diagram of a frame when the fault finder of the embodiment of the present invention is used for fault finding of a low-voltage line with a repeated grounding.

Detailed Description

The present invention will be described in further detail with reference to the accompanying drawings.

Examples

As shown in fig. 3-6, the present embodiment provides a 0.4kV line ground fault finder, which includes a housing, an ammeter a1, an ammeter a2, a current clamp 1, a current clamp 2, a current clamp 3, and a current clamp 4. The ammeter A1 and the ammeter A2 are arranged in the shell, the current indicating screens of the ammeter A1 and the ammeter A2 are exposed out of the shell, the ammeter A1 and the ammeter A2 can share one current indicating screen or respectively have the current indicating screen, and the current indicating screens are located on the shell, so that the readings of the two ammeters can be conveniently read. The current input end of the ammeter a1 is connected in parallel with four sets of current input terminals S11, S12, S13 and S14, the current input end of the ammeter a2 is connected with a set of current input terminals S21, the current input terminals S11, S12, S13, S14 and S21 are all located on the housing, and any one of the current clamp 1, the current clamp 2, the current clamp 3 and the current clamp 4 can be connected with any one of the current input terminals S11, S12, S13, S14 and S21 through a wire.

The current clamp 1, the current clamp 2, the current clamp 3 and the current clamp 4 are all current transformers.

When the fault finder of the embodiment is used for searching for the ground fault of the 0.4kV line, the operation is as follows:

1. for the non-repeated grounding line, the residual current of the line is measured in the line to judge the fault point. During measurement, as shown in fig. 3 and 4, the current clamps 1, 2, 3 and 4 are respectively electrically connected with the current input terminals S11, S12, S13 and S14 of the ammeter a1, and the current clamps 1, 2, 3 and 4 are respectively clamped with A, B, C three-phase wires and a zero wire, and at this time, data read by the ammeter a1 is a line residual current. If the residual current (reading of an ammeter A1) of the measuring point is greater than 0, the fault point is located at the rear section (load side) of the measuring point, and if the residual current (reading of an ammeter A1) of the measuring point is equal to 0, the fault point is located at the front section (power side) of the measuring point, and the fault point can be quickly found through a bisection method.

2. For a circuit with repeated grounding, zero sequence current and zero line current of an ABC three-phase conductor are measured in the circuit to judge a fault point. During measurement, as shown in fig. 5 and 6, the current clamps 1, 2 and 3 are electrically connected with current input terminals S11, S12 and S13 of an ammeter a1 respectively, the current clamp 4 is electrically connected with a current input terminal S21 of the ammeter a2, and the current clamps 1, 2, 3 and 4 clamp A, B, C three-phase wires and a zero wire respectively.

The data read by the ammeter A1 is the zero sequence current of the ABC three-phase conductor, and the data read by the ammeter A2 is the zero line current. The data of the ammeter A1 and the ammeter A2 are displayed on a current indicating screen of the same fault finding instrument, so that the magnitude of the two currents can be visually compared, and a fault point can be judged. If the zero-sequence current (ammeter A1 reading) of the ABC three-phase conductor at the measuring point is larger than the zero-line current (ammeter A2 reading), the fault point is at the rear section (load side) of the measuring point, and if the zero-sequence current (ammeter A1 reading) of the ABC three-phase conductor at the measuring point is smaller than or equal to the zero-line current (ammeter A2 reading), the fault point is at the front section (power side) of the measuring point, and the fault point can be quickly found through a bisection method.

The 0.4kV line ground fault finder of this embodiment is applicable to fast finding the fault point when 0.4kV line ground fault. Four wires are sampled by four current clamp jaws respectively, and the current is analyzed, so that fault points can be quickly searched. When the device is operated, the insulator binding of the conductor does not need to be removed from the overhead line, the power failure does not exist, the problem that the conductor does not enter a jaw clamp does not exist, the data of the ammeter A1 and the ammeter A2 are read on the same fault finding instrument, the sizes of the two currents can be visually compared, the problem of misjudgment does not exist, the labor force of operators is greatly reduced, the power failure time of users is reduced, and the customer satisfaction is improved.

The above-described embodiments of the present invention do not limit the scope of the present invention, and any modifications, equivalent replacements, and improvements made within the spirit of the present invention should be included in the scope of the claims of the present invention.

Claims

1. The 0.4kV line ground fault finder is characterized by comprising two ammeters and four current clamps, wherein the current input end of one of the ammeters is connected with four groups of current input terminals in parallel, the current input end of the other ammeter is connected with one group of current input terminals, and any one current clamp can be connected with any one group of current input terminals through a lead.

2. The 0.4kV line ground fault finder of claim 1, wherein: the ammeter is characterized by further comprising a shell, the two ammeters are arranged in the shell, a current indicating screen of each ammeter is exposed out of the shell, and the five groups of current input terminals are arranged on the shell.

3. The 0.4kV line ground fault finder of claim 1, wherein: the current clamp is a current transformer.