CN203166320U - Wall bushing tap grounding device - Google Patents

Abstract

The utility model relates to an end screen grounding device of a wall-piercing bushing, which comprises an end screen grounding screw, an insulating porcelain sleeve used to insulate the end screen grounding screw from a flange, and a grounding cover arranged on the end screen grounding screw , The nut that fixes the grounding cover on the grounding screw of the last screen, an insulating gasket is arranged between the grounding cover and the flange, and a grounding down-conductor is connected to the grounding screw of the last screen, and the grounding down-conducting line A separable insulation on-line monitoring ammeter is connected, and the end of the insulation on-line monitoring ammeter is reliably grounded. By leading the grounding wire of the last screen down, it is convenient for the test personnel to untie it for testing. At the same time, in the running state, it can detect the capacitance current of the bushing and monitor the main insulation of the bushing in real time, so as to realize the condition detection and condition maintenance.

Description

End screen grounding device of wall bushing

technical field

The utility model relates to a grounding device for the end screen of a wall-piercing bushing in a power supply system.

Background technique

At present, the 110kV incoming line of the 110kV substation and the grounding method of the end screen of the main transformer wall bushing are shown in Figure 1, which includes the end screen grounding screw 1, the insulating porcelain sleeve 2 used to insulate the end screen grounding screw 1 from the flange 10, The grounding cover 3 installed on the grounding screw 1 of the last screen, the nut 4 fixing the grounding cover 3 on the grounding screw 1 of the last screen, under the running state, the grounding cover 3 is fixedly connected with the flange 10, Reliable grounding. When a routine test is required, the maintenance personnel need to climb to the vicinity of the end screen of the bushing through an insulation ladder, and untie the nut 4 on the end screen, so that the ground cover 3 is disconnected from the flange 10, so that it is convenient to use the dielectric loss bridge to correct The wiring method is used to test the capacitance and dielectric loss tangent of the bushing. Since the entire casing is very high and there is no maintenance platform, it is very difficult for the staff to reach the end screen of the casing and untie the fixing nuts. The workload is very heavy, and the insulation ladder is large and heavy. It is difficult to carry, and when the insulation ladder is erected, there is a danger of tipping over, endangering the safety of personnel and surrounding electrical equipment.

Utility model content

The purpose of the utility model is to overcome the deficiencies of the prior art and provide a grounding device that is convenient for testing during routine testing and can detect the capacitance current of the bushing in real time in the running state.

In order to achieve the above purpose, the technical solution adopted by the utility model is: a grounding device for the end screen of the wall bushing, which includes the end screen grounding screw, the insulating porcelain sleeve used to insulate the end screen grounding screw from the flange, the installation The grounding cover on the grounding screw of the last screen, the nut that fixes the grounding cover on the grounding screw of the last screen, an insulating gasket is arranged between the grounding cover and the flange, and connected on the grounding screw of the last screen There is a grounding down-conductor, and the grounding down-conducting line is connected with a separable insulation on-line monitoring ammeter, and the end of the insulation on-line monitoring ammeter is reliably grounded.

The further transformation and optimization adopted to the above-mentioned technical scheme are:

The insulating gasket is made of punctureable material. The breakdown voltage of the insulating gasket used can reach 2000V, and when the grounding down-conductor is broken, it can protect the end screen of the bushing from being broken down.

The thickness of the insulating gasket is 2-4mm.

The insulation on-line monitoring ammeter is also connected in parallel with multiple groups of piezoresistors for protecting the ammeter from being broken down during high-frequency overvoltage.

The online monitoring current is connected in series with a first indicator light for detecting whether the grounding loop of the last screen is in normal operation.

A second indicator light for displaying whether the piezoresistor is broken down is also connected in series on the circuit composed of multiple groups of piezoresistors.

Due to the application of the above-mentioned technical scheme, the utility model has the following advantages compared with the prior art: the utility model leads down the grounding wire of the last screen, so that the test personnel can easily untie it for testing, and at the same time, it can carry out casing Capacitive current detection, real-time monitoring of the main insulation of the bushing, so as to realize the condition detection and condition maintenance.

Description of drawings

Accompanying drawing 1 is the schematic diagram of existing bushing end screen grounding device;

Accompanying drawing 2 is the schematic diagram of the grounding device of the casing end screen of the utility model;

Among them: 1. Grounding screw of the last screen; 2. Insulating porcelain sleeve; 3. Grounding cover; 4. Nut; 5. Insulating gasket; 6. Grounding down conductor; 7. On-line monitoring ammeter; 91, the first indicator light; 92, the second indicator light; 10, the flange.

Detailed ways

Below in conjunction with accompanying drawing, preferred embodiment of the present utility model is described in detail:

As shown in Figure 2, the end screen grounding device of the wall bushing includes the end screen grounding screw 1, the insulating porcelain sleeve 2 used to insulate the end screen grounding screw 1 from the metal flange 10, and is installed on the end screen grounding screw 1. The ground cover 3 on the screw 1, the nut 4 that fixes the ground cover 3 on the last screen ground screw 1, an insulating gasket 5 is arranged between the ground cover 3 and the flange 10, and the flange 10 is grounded. The grounding down-conductor 6 of the final screen is drawn from the top of the grounding screw 1 of the final screen. The grounding down-conductor 6 is connected with a detachable online monitoring ammeter 7. The end of the ammeter 7 is reliably grounded, so that the final screen is reliably grounded.

Specifically, the insulating spacer 5 has a thickness of 2-4mm. It is made of punctureable material with a breakdown voltage of up to 2000V. When the grounding downconductor 6 breaks, it can protect the end screen of the bushing from breakdown.

When there is a high-frequency overvoltage, in order to protect the online monitoring ammeter 7 from being broken down, multiple groups of varistors 8 are arranged in parallel with the online monitoring ammeter 7. In this embodiment, three groups of varistor circuits are arranged in parallel.

In order to be able to intuitively reflect whether the grounding loop of the last screen in the operating state is in normal operation, in this embodiment, a first indicator light 91 is connected in series with the on-line monitoring ammeter 7 . At the same time, in order to further understand the working state of the piezoresistor 8, a second indicator light 92 for displaying whether the piezoresistor is broken down is connected in series on the circuit composed of multiple groups of piezoresistors 8.

The structure of the last screen grounding device of the present invention has been described above, and its working principle is briefly described below:

During the normal operation of the high-voltage bushing, the grounding down conductor 6 is connected in series with the on-line detection ammeter 7 and then grounded. The bushing capacitive current can be detected in real time, so as to monitor the main insulation of the bushing. When there is an overvoltage, due to the setting of the insulating gasket and the varistor, effective protection can be realized.

During routine maintenance, it is only necessary to remove the connection between the grounding down-conductor and the on-line monitoring ammeter to test the bushing. There is no need to climb up to remove the grounding of the last screen, which greatly reduces the difficulty of the operation, improves the production efficiency, and ensures the safety of the operator. safety.

The above-mentioned embodiments are only to illustrate the technical conception and characteristics of the present utility model, and its purpose is to allow those familiar with this technology to understand the content of the present utility model and implement it accordingly, and cannot limit the protection scope of the present utility model. Equivalent changes or modifications made according to the spirit of the utility model shall fall within the protection scope of the utility model.

Claims (6)

1. earthing device is shielded at a wall bushing end, it comprises end screen grounding screw rod (1), be used for the end is shielded the insulated porcelain sleeve (2) of grounding screw rod (1) and flange (10) insulation, be installed in the ground connection lid (3) on the end screen grounding screw rod (1), ground connection lid (3) is fixed on the last nut (4) that shields on the grounding screw rod (1), it is characterized in that: between described ground connection lid (3) and flange (10), be provided with insulation spacer (5), be connected with down conductor (6) at end screen grounding screw rod (1), described down conductor (6) is connected with separable insulated on-line monitoring ammeter (7), the terminal reliable ground of described insulated on-line monitoring ammeter (7).

2. wall bushing according to claim 1 end screen earthing device, it is characterized in that: described insulation spacer (5) is made by the material that can puncture.

3. wall bushing according to claim 1 end screen earthing device, it is characterized in that: the thickness of described insulation spacer (5) is 2-4mm.

4. according to any wall bushing of claim 1 to 3 end screen earthing device, it is characterized in that: described insulated on-line monitoring ammeter (7) also is parallel with for the protection of described ammeter not breakdown many groups piezo-resistance (8) when the high frequency overvoltage.

5. wall bushing according to claim 4 end screen earthing device is characterized in that: whether normally described on-line monitoring electric current (7) goes up series connection one for detection of end screen grounded circuit first indicator light (91) of operation.

6. wall bushing according to claim 4 end screen earthing device is characterized in that: organizing also connects on the circuit that described piezo-resistance (8) forms more one is used for showing whether breakdown second indicator light (92) of piezo-resistance.

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