CN210863998U - A 0.4kV Line Grounding Fault Finder - Google Patents

Abstract

The utility model provides a 0.4kV line grounding fault finding instrument, comprising two ammeters and four current clamps, wherein the current input end of one ammeter is connected in parallel with four groups of current input terminals, and the current input end of the other ammeter is connected with one group of current input terminals. Current input terminals, and any current clamp can be connected to any group of current input terminals through wires. When using the utility model for fault finding, sampling is carried out by clamping the ABC three-phase wire and the neutral wire respectively by four current clamps, and each current clamp clamps a wire to avoid the traditional one current clamp clamping multiple wires at the same time. As a result, the jaws of the current clamp cannot enter, and the circuit measurement cannot be performed, and there is no need for the trouble caused by removing the wire insulator and tying the overhead line, which is convenient for the staff to quickly find the fault, reduce the labor of the operator and reduce the power outage of the user. time and improve customer satisfaction.

Description

A 0.4kV Line Grounding Fault Finder

technical field

The utility model belongs to the technical field of electric tools, in particular to a 0.4kV line grounding fault finding instrument.

Background technique

The 0.4kV system of Guangdong Power Grid Corporation adopts the neutral point direct grounding system without total residual current protection. and jeopardize safety. The fault point is very concealed. Except for the fault caused by force damage, other fault points are not easy to be found intuitively.

At present, when the 0.4kV line has a ground fault, the low-voltage line without repeated grounding uses a clamp-type ammeter to measure the residual current to determine the fault point. During operation, a current clamp is used to clamp the four wires together, as shown in Figure 1; To find the ground fault point of the single-phase line of the low-voltage line with repeated grounding is to use two clamp-type ammeters to measure the phase line zero-sequence current and the zero-line current at the same time to determine the fault point. During operation, the current clamp of one of the clamp-type ammeters simultaneously Clamp the ABC three-phase wire, and the current clamp of the other clamp-type ammeter clamps the neutral wire, as shown in Figure 2. When looking for the fault point, there are problems such as the need to remove the overhead line insulator to tie the wire, the jaws cannot be inserted into the large wire diameter wire or four wires, etc., which may cause the phenomenon that single-phase power supply may need to be used to find the power outage, resulting in high labor intensity. , low work efficiency, power outages causing user complaints and other issues.

Utility model content

Aiming at at least one deficiency of the prior art, the purpose of the present invention is to provide a 0.4kV line grounding fault finding instrument which is convenient for fault finding.

In order to achieve the above purpose, the technical solution provided by the present utility model is: a 0.4kV line grounding fault finding instrument, comprising two ammeters and four current clamps, wherein the current input end of one ammeter is connected in parallel with four groups of current input terminals, A group of current input terminals is connected to the current input end of the other ammeter, and any current clamp can be connected to any group of current input terminals through wires.

In the above scheme, during fault finding, four current clamps are used to clamp the ABC three-phase wire and the neutral wire respectively for sampling, and each current clamp clamps one wire, avoiding the traditional one current clamp clamping multiple wires at the same time. As a result, the jaws of the current clamp cannot enter, and the circuit measurement cannot be performed, so that there is no need for the trouble caused by disconnecting the wire insulator and tying the overhead line, which is convenient for the staff to quickly find the fault, reduces the labor of the operator and reduces the power outage of the user. time and improve customer satisfaction.

Further, the above-mentioned fault finder also includes a housing, and the two ammeters are arranged in the housing, which is convenient for the fault finder to hold as a whole, and the current indicating screen of the ammeter is exposed outside the housing, which is convenient for the reading of the two ammeters and the five groups of currents. The input terminals are all arranged on the shell, which is convenient to connect with the current clamp.

Further, the above-mentioned current clamp is a current transformer, and the acquisition of current data is convenient and accurate.

The 0.4kV line grounding fault finder of the utility model can quickly and accurately find the grounding fault point for both grounding faults of the grounding system with repeated grounding and without repeated grounding. Power outages are required, no need to remove the wire insulators of the overhead lines to tie the wires, there is no problem that the wire jaws cannot get in, and the operation is simple, fast and accurate.

Description of drawings

FIG. 1 is a schematic diagram of the existing low-voltage line fault finding without repeated grounding.

FIG. 2 is a schematic diagram of the existing low-voltage line fault finding with repeated grounding.

FIG. 3 is a schematic diagram of using the fault finder according to the embodiment of the present invention to find faults in low-voltage lines without repeated grounding.

FIG. 4 is a schematic diagram of a framework when a fault finder according to an 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 using the fault finder according to the embodiment of the present invention to find faults of low-voltage lines with repeated grounding.

FIG. 6 is a schematic diagram of a framework when a fault finder according to an embodiment of the present invention is used for fault finding of a low-voltage line with repeated grounding.

Detailed ways

The present utility model will be described in further detail below in conjunction with the accompanying drawings.

Example

As shown in Figures 3-6, this embodiment provides a 0.4kV line grounding fault finder, including 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. Among them, the ammeter A1 and the ammeter A2 are both arranged in the casing, and the current indicating screens of the ammeter A1 and the ammeter A2 are exposed outside the casing. On the casing, it is convenient to read the readings of the two ammeters. The current input terminal of ammeter A1 is connected in parallel with four sets of current input terminals S11, S12, S13 and S14, and the current input terminal of ammeter A2 is connected to a set of current input terminals S21. The current input terminals S11, S12, S13, S14 and S21 are all located in the shell. On the body, and any one of the current clamp 1, the current clamp 2, the current clamp 3, and the current clamp 4 can be connected to any one of the current input terminals S11, S12, S13, S14, and S21 through wires.

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

When using the fault finder of this embodiment to find the ground fault of the 0.4kV line, the operation is as follows:

1. For the non-repetitive grounding line, the residual current of the line is measured in the line to determine the fault point. During measurement, as shown in Figures 3 and 4, the current clamps 1, 2, 3, and 4 are respectively electrically connected to the current input terminals S11, S12, S13, and S14 of the ammeter A1, and the current clamps 1, 2, 3, and 4. Clamp with A, B, C three-phase wires and neutral wire respectively. At this time, the data read out by ammeter A1 is the line residual current. If the residual current of the measuring point (the reading of the ammeter A1) is greater than 0, the fault point is at the back of the measuring point (load side). The bisection method can quickly find the fault point.

2. For lines with repeated grounding, the fault point is determined by measuring the zero sequence current and zero line current of the ABC three-phase conductors in the line. During measurement, as shown in Figures 5 and 6, the current clamps 1, 2, and 3 are respectively electrically connected to the current input terminals S11, S12, and S13 of the ammeter A1, and the current clamp 4 is electrically connected to the current input terminal S21 of the ammeter A2. And clamp the current clamps 1, 2, 3, and 4 to the three-phase wires and neutral wires of A, B, and C, respectively.

The data read by ammeter A1 is the zero-sequence current of the ABC three-phase wire, and the data read by ammeter A2 is the zero-line current. The data of ammeter A1 and ammeter A2 are displayed on the current indicator screen on the same fault finder, which can intuitively compare the magnitude of the two currents and determine the fault point. If the zero-sequence current (the reading of the ammeter A1) of the three-phase conductor at the measuring point ABC is greater than the zero-line current (the reading of the ammeter A2), the fault point is at the rear section (the load side) of the measuring point, such as the zero-sequence current ( If the reading of the ammeter A1) is less than or equal to the zero line current (the reading of the ammeter A2), the fault point is in the front section of the measurement point (power supply side), and the fault point can be quickly found by the bisection method.

The 0.4kV line ground fault finder of this embodiment is suitable for quickly finding the fault point when the 0.4kV line ground fault occurs. The four wires are sampled with four current clamps respectively, and analyzing the current can quickly find the fault point. There is no need to remove the wire, insulator, tie wire and power failure of the overhead line during operation. There is no problem that the jaw cannot enter the wire, and the data of the ammeter A1 and the ammeter A2 can be read on the same fault finder, and the two can be compared intuitively. The size of the current does not have the problem of misjudgment, which greatly reduces the labor force of the operators and reduces the user's power outage time, and improves the customer satisfaction.

The above-mentioned embodiments of the present invention do not constitute a limitation on the protection scope of the present invention. Any modifications, equivalent replacements and improvements made within the spirit and principles of the present invention shall be included in the present invention. within the scope of protection of the claims.

Claims (3)

1. A 0.4kV line ground fault finding instrument is characterized in that, comprising two ammeters and four current clamps, wherein the current input end of one ammeter is connected in parallel with four groups of current input terminals, and the current input end of another ammeter is connected with a A group of current input terminals, and any current clamp can be connected to any group of current input terminals through wires. 2. The 0.4kV line grounding fault finder according to claim 1, characterized in that: it further comprises a casing, two ammeters are arranged in the casing, and the current indicating screen of the ammeter is exposed outside the casing, and five groups of current input The terminals are all arranged on the housing. 3 . The 0.4kV line grounding fault finding instrument according to claim 1 , wherein the current clamp is a current transformer. 4 .

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