CN211351448U - Fence-free grounding device for neutral point of main transformer - Google Patents
Fence-free grounding device for neutral point of main transformer Download PDFInfo
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- CN211351448U CN211351448U CN201922480784.3U CN201922480784U CN211351448U CN 211351448 U CN211351448 U CN 211351448U CN 201922480784 U CN201922480784 U CN 201922480784U CN 211351448 U CN211351448 U CN 211351448U
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Abstract
The utility model relates to an electric power technology field, concretely relates to main transformer neutral point does not have rail earthing device, including ground connection stranded wire, full insulation copper pipe generating line, earth connection pillar, fixed utensil and ground connection little well, ground connection stranded wire first end is connected with main transformer neutral line leading-out terminal, earth connection pillar fixed mounting is near main transformer, and the ground connection little well is located near the earth connection pillar, and full insulation copper pipe generating line one end is connected with the ground connection little well, and the full insulation copper pipe generating line other end is connected with ground connection stranded wire, and full insulation copper pipe generating line hugs closely the electrical connection pillar and is fixed by the fixed utensil. The utility model discloses a substantive effect is: the transformer neutral point is grounded through the grounding stranded wire and the fully insulated copper pipe bus, and the insulating property of the fully insulated copper pipe bus enables the surrounding of the grounding small well not to be provided with a fence, so that the occupied area of the neutral point grounding can be greatly reduced.
Description
Technical Field
The invention relates to the technical field of electric power, in particular to a fence-free grounding device for a neutral point of a main transformer.
Background
The electrical connection between the neutral point of the three-phase ac power system and the ground is called a grid neutral point grounding system. The neutral point grounding mode relates to the safety reliability and the economy of a power grid; meanwhile, the selection of the insulation level of system equipment, the overvoltage level, the relay protection mode, communication interference and the like are directly influenced. A large-current grounding mode, namely a neutral point effective grounding mode, is generally adopted for 110kV and above power grids. The potential of a neutral point is fixed to the ground potential, and when a single-phase ground fault occurs, the voltage of a non-fault phase is increased and cannot exceed 1.4 times of the voltage of an operating phase; the transient overvoltage level is also low; the fault current is very large, the relay protection can act on tripping rapidly to remove the fault, and the time for bearing the overvoltage by the system equipment is short. The large-current grounding system can reduce the insulation requirement level of the whole system equipment, thereby greatly reducing the manufacturing cost. At present, a mode of adding a fence to a bare conductor is adopted for the conventional installation of the neutral point grounding of a main equipment transformer of a 220kV or 500 kV transformer substation, and the installation mode occupies a large area as shown in fig. 1 and 2. For indoor substations, small wells of sufficient size often cannot be made due to site constraints or the distance of the small wells from the transformer is limited. The demand for reducing the floor space of outdoor substations is also increasing in some areas. Therefore, a reliable and relatively economic installation mode for grounding the neutral point of the main transformer needs to be invented based on design technology.
For example, chinese patent CN103839657B, published 2016, 3, and 2 days, the present invention relates to a system for connecting a neutral point of a transformer and a double-shell ground, which includes a transformer, a ground flat iron and a current transformer, wherein the ground flat iron is vertically and fixedly mounted on a grounding device, the neutral point of the transformer is connected to the current transformer, the current transformer is connected to a copper wire nose B of the ground flat iron through a neutral point ground wire, the shell ground point of the transformer is connected to a copper wire nose a of the ground flat iron through a transformer shell ground wire, the distance between the copper wire nose a and the copper wire nose B is 60mm, the copper wire nose a and the copper wire nose B are connected through a wiring wire, and the wiring wire has a BVR35 specification. It ensures that effective grounding can be continuously maintained after the grounding end at one position is corroded and disconnected. But it can not solve the technical problem that the occupied area of the neutral point grounding of the transformer is large.
Disclosure of Invention
The technical problem to be solved by the invention is as follows: the technical problem that the occupied area of the neutral point grounding of the existing transformer is large is solved. The fence-free grounding device for the neutral point of the main transformer is small in occupied area and flexible in deployment.
In order to solve the technical problems, the technical scheme adopted by the invention is as follows: the utility model provides a main transformer neutral point does not have rail earthing device, includes ground connection stranded conductor, full insulation copper pipe generating line, earth connection pillar, fixing tool and ground connection little well, the first end of ground connection stranded conductor is connected with main transformer neutral line leading-out terminal, earth connection pillar fixed mounting is near main transformer, and the ground connection little well is located by the earth connection pillar, and full insulation copper pipe generating line one end is connected with the ground connection little well, and the full insulation copper pipe generating line other end is connected with ground connection stranded conductor, and full insulation copper pipe generating line hugs closely the power connection supporting column and is fixed by the fixing tool. Through grounding strand wires and all-insulated copper pipe bus with transformer neutral point ground connection, the insulating nature that all-insulated copper pipe bus itself has makes need not install the rail around the earthing small well, therefore can reduce neutral point grounded's area by a wide margin for transformer neutral point ground connection is easy.
As preferred, still include zinc oxide arrester, arrester pillar, earth connection supporting insulator and maintenance case, the arrester pillar is installed by main transformer, zinc oxide arrester and earth connection supporting insulator are installed side by side on the arrester pillar, earth connection supporting insulator supports the ground connection stranded conductor, the zinc oxide arrester is connected with the ground connection stranded conductor, the zinc oxide arrester passes through ground connection metalwork ground connection, the maintenance case is installed at the arrester pillar. The lightning arrester can assist in shunting instantaneous large current, guarantees that the insulating layer of ground connection stranded conductor and full insulation copper pipe generating line is not punctured, improves the security of ground connection stranded conductor and full insulation copper pipe generating line.
Preferably, the lightning arrester further comprises a lightning arrester counter, a first discharge tip is mounted at the top of the zinc oxide lightning arrester, the lightning arrester counter comprises a base, a conductive column, a counting circuit, a discharge number indicator driving coil and a second discharge tip, the base and the zinc oxide lightning arrester are mounted on the lightning arrester support column in parallel, the second discharge tip is fixedly mounted on the base through the conductive column, the second discharge tip is an expansion piece, the input end of the counting circuit is connected with the conductive column, and the output end of the counting circuit is connected with the discharge number indicator driving coil. The number of times of discharging of zinc oxide arrester is counted through the arrester counter, conveniently looks over the state of zinc oxide arrester to in time change.
Preferably, the grounding small well is provided with a surrounding wall higher than the ground, a cover plate is covered on the surrounding wall, the side surface of the surrounding wall is provided with an opening used for penetrating through a full-insulation copper pipe bus, and the end of the full-insulation copper pipe bus connected with the grounding small well is divided into two branches which are respectively connected with two trunks of the main grounding network. The two trunks connected with the main grounding grid can reduce the grounding resistance of the fully-insulated copper tube bus and increase the grounding reliability.
Preferably, the grounding device further comprises a wall bushing, when the indoor space of the main transformer is smaller than a set value, the grounding small well, the fully-insulated copper pipe bus and the grounding wire support are located outdoors or in a next room, a gap is formed in the corresponding position of the wall of the main transformer room, the grounding wire support insulator is fixed beside the gap, the wall bushing is fixed in the gap, and the grounding stranded wire is supported by the grounding wire support insulator and penetrates through the wall bushing to be connected with the fully-insulated copper pipe bus. For a transformer room with more limited indoor area, the scheme provides a feasible and reliable neutral point grounding scheme.
Preferably, the grounding small well located outdoors is provided with a surrounding wall higher than the ground, a cover plate is covered on the surrounding wall, an opening used for penetrating through a full-insulation copper pipe bus is formed in the cover plate, and the end, connected with the grounding small well, of the full-insulation copper pipe bus is divided into two branches which are respectively connected with two trunks of the main grounding network. The two trunks connected with the main grounding grid can reduce the grounding resistance of the fully-insulated copper tube bus and increase the grounding reliability.
Preferably, the cable insulation skeleton shell comprises a hose and a hard tube which are sequentially connected in an interphase mode, the cable insulation skeleton shell is provided with two sections, the first section of the cable insulation skeleton shell is sleeved between a main transformer and a zinc oxide arrester when a grounding stranded wire is located, the second section of the cable insulation skeleton shell is sleeved between the zinc oxide arrester and a full-insulation copper tube bus, the inner diameters of the hose and the hard tube are matched with the outer diameter of the grounding stranded wire, the outer diameter of the hard tube is larger than that of the hose, the cable insulation skeleton shell limits the maximum curvature tau of the grounding stranded wire, the length L of the first section of the cable insulation skeleton shell meets the set minimum value of the distance between a grounding small well and the main transformer, and the D _0 is larger than that of the hose. The cable insulation bone shell can ensure that the grounding small well has enough distance with the main transformer, and the non-compliant construction design is avoided.
Preferably, the hose is a rubber tube added with a flame retardant, and the hard tube comprises a rubber matrix, the flame retardant added in the rubber matrix and a metal tube embedded in the rubber matrix.
The substantial effects of the invention are as follows: the transformer neutral point is grounded through the grounding stranded wire and the fully insulated copper pipe bus, and the insulation property of the fully insulated copper pipe bus enables no fence to be installed around the grounding small well, so that the floor area of neutral point grounding can be greatly reduced, and the transformer neutral point is easy to ground; various schemes for grounding the neutral point of the main transformer are improved, so that the neutral point of the main transformer is more flexibly grounded; the safety of the neutral point grounding of the main transformer is improved.
Drawings
Fig. 1 is a prior art top view of a mid-rail neutral connection.
Fig. 2 is a prior art fenced neutral point grounding side view.
Fig. 3 is a schematic top view of a neutral point grounding structure of a main transformer according to an embodiment.
Fig. 4 is a schematic side view of a neutral point grounding side of the main transformer according to the embodiment.
Fig. 5 is a schematic front side view of a neutral point grounding structure of a main transformer according to an embodiment of the present invention.
Fig. 6 is a schematic side view of a neutral point wall-through grounding structure of a main transformer according to an embodiment of the present invention.
Wherein: 100. the high-voltage power supply comprises a wall body, 102, an overhaul box, 200, a main transformer, 201, a low-voltage lead wire, 202, a medium-voltage outgoing wire, 203, a high-voltage outgoing wire, 204, a conservator, 205, a wall bushing, 301, a fence, 302, a grounding wire support, 303, a grounding wire insulator, 304, a lightning arrester, 305, a grounding stranded wire, 306, a lightning arrester counter, 307, a first discharging tip, 308, a second discharging tip, 309, a lightning arrester support, 310, a fully-insulated copper pipe bus, 311, a fixing tool, 401, a grounding small well, 402, a cover plate, 403, a grounding wire, 500, a radiator, 501 and a radiating water pipe.
Detailed Description
The following provides a more detailed description of the present invention, with reference to the accompanying drawings.
The first embodiment is as follows:
in the prior art, a transformer substation has a transformer room and a heat dissipation room disposed beside the transformer room, and as shown in fig. 1 and 2, the transformer room is a place for installing a main transformer 200, and the heat dissipation room and the transformer room are separated by a wall 100. The heat dissipation chamber is provided with a heat sink 500, and the heat sink 500 is connected to the main transformer 200 through a heat dissipation pipe 501, for dissipating heat from the main transformer 200. The main transformer 200 is provided with an oil conservator 204, a low-voltage lead 201, a medium-voltage outgoing line 202 and a high-voltage outgoing line 203, wherein the medium-voltage outgoing line 202 and the high-voltage outgoing line 203 are respectively provided with a neutral point correspondingly, each neutral point is grounded through a grounding device, and one side of the main transformer 200 is provided with an oil chromatography observation window. In the prior art, a bare wire is grounded, the bare wire is grounded through a grounding wire insulator 303, a lightning arrester 304 and a grounding wire support 302, and the surrounding of the part of the bare wire close to the ground is isolated by a fence 301. The ground of the neutral point of the main transformer 200 occupies a large area and is not safe.
The embodiment provides a neutral point fence-free 301 grounding device of a main transformer 200, as shown in fig. 3, the embodiment includes a grounding stranded wire 305, a fully insulated copper tube bus 310, a grounding wire support column 302, a fixing tool 311, a grounding small well 401, a zinc oxide arrester 304, an arrester support column 309, a grounding wire 403 supporting insulator and a maintenance box 102, a first end of the grounding stranded wire 305 is connected with a neutral wire outlet end of the main transformer 200, the grounding wire support column 302 is fixedly installed near the main transformer 200, the grounding small well 401 is located beside the grounding wire support column 302, one end of the fully insulated copper tube bus 310 is connected with the grounding small well 401, the other end of the fully insulated copper tube bus 310 is connected with the grounding stranded wire 305, and the fully insulated copper tube bus 310 is tightly attached to the grounding wire support. As shown in fig. 4 and 5, the arrester post 309 is installed beside the main transformer 200, the zinc oxide arrester 304 and the ground wire 403 support insulator are installed side by side on the arrester post 309, the ground wire 403 supports the ground stranded wire 305, the zinc oxide arrester 304 is connected with the ground stranded wire 305, the zinc oxide arrester 304 is grounded through a ground metal part, the maintenance box 102 is installed on the arrester post 309, and the maintenance box 102 has maintenance-related equipment such as a patrol record book and the like. The lightning arrester 304 can assist in shunting instantaneous large current, so that the insulating layers of the grounding stranded wire 305 and the fully insulated copper tube bus 310 are not broken down, and the safety of the grounding stranded wire 305 and the fully insulated copper tube bus 310 is improved.
The first discharge tip 307 is installed on the top of the zinc oxide arrester 304, the arrester counter 306 comprises a base, a conductive column, a counting circuit, a discharge number indicator driving coil and a second discharge tip 308, the base and the zinc oxide arrester 304 are installed on an arrester support column 309 side by side, the second discharge tip 308 is fixedly installed on the base through the conductive column, the second discharge tip 308 is a telescopic piece, the input end of the counting circuit is connected with the conductive column, and the output end of the counting circuit is connected with the discharge number indicator driving coil. The number of times of discharge of the zinc oxide arrester 304 is counted by the arrester counter 306, so that the state of the zinc oxide arrester 304 is conveniently checked and timely replaced. The grounding small well 401 is provided with a surrounding wall higher than the ground, a cover plate 402 is covered on the surrounding wall, the side surface of the surrounding wall is provided with an opening used for penetrating through the all-insulated copper pipe bus 310, and the end of the all-insulated copper pipe bus 310 connected with the grounding small well 401 is divided into two branches which are respectively connected with two trunks of a main grounding network. The two trunks connected with the main grounding grid can reduce the grounding resistance of the fully insulated copper tube bus 310 and increase the grounding reliability.
When the space in the main transformer room is smaller than a set value, the small grounding well 401, the fully insulated copper tube bus 310 and the grounding wire strut 302 are all located outdoors or in a next room, as shown in fig. 6, a gap is formed in a corresponding position of the main transformer room wall 100, a grounding wire 403 supporting insulator is fixed beside the gap, a wall bushing 205 is fixed in the gap, and a grounding stranded wire 305 is supported by the grounding wire 403 supporting insulator and penetrates through the wall bushing 205 to be connected with the fully insulated copper tube bus 310. The grounding small well 401 located outdoors is provided with a surrounding wall higher than the ground, a cover plate 402 is covered on the surrounding wall, an opening used for penetrating through the all-insulated copper pipe bus 310 is formed in the cover plate 402, and the end, connected with the grounding small well 401, of the all-insulated copper pipe bus 310 is divided into two branches which are respectively connected with two trunks of a main grounding network.
The cable insulation bone shell is arranged outside the grounding stranded wire 305 and comprises a hose and a hard tube which are sequentially connected in an alternate mode, the cable insulation bone shell is provided with two sections, the first section of the cable insulation bone shell is sleeved between the grounding stranded wire 305 and the main transformer 200 and the zinc oxide arrester 304, the second section of the cable insulation bone shell is sleeved between the zinc oxide arrester 304 and the full-insulation copper tube bus 310, the inner diameters of the hose and the hard tube are matched with the outer diameter of the grounding stranded wire 305, the outer diameter of the hard tube is larger than that of the hose, the cable insulation bone shell limits the maximum curvature tau of the grounding stranded wire 305, the length L of the first section of the cable insulation bone shell meets sin (tau L) > tau D _0, and D _0 is a set minimum value of the distance between the grounding small well. The cable insulation bone shell can ensure that the small grounding well 401 has enough distance with the main transformer 200, and the non-compliant construction design is avoided. The hose is a rubber tube added with a flame retardant, and the hard tube comprises a rubber substrate, the flame retardant added in the rubber substrate and a metal tube embedded in the rubber substrate.
The embodiment has the following beneficial technical effects: the transformer neutral point is grounded through the grounding stranded wire 305 and the fully insulated copper pipe bus 310, and the insulation of the fully insulated copper pipe bus 310 enables the surrounding of the grounding small well 401 not to be provided with the fence 301, so that the occupied area of the neutral point grounding can be greatly reduced, and the transformer neutral point is easy to ground. For a transformer room with more limited indoor area, a feasible and reliable neutral point grounding scheme is provided.
The above-described embodiments are only preferred embodiments of the present invention, and are not intended to limit the present invention in any way, and other variations and modifications may be made without departing from the spirit of the invention as set forth in the claims.
Claims (8)
1. A fence-free grounding device for the neutral point of a main transformer is characterized in that,
including ground connection stranded conductor, all insulation copper pipe generating line, earth connection pillar, fixing tool and ground connection little well, the first end of ground connection stranded conductor is connected with main transformer neutral line leading-out terminal, earth connection pillar fixed mounting is near main transformer, and the ground connection little well is located by the earth connection pillar, and all insulation copper pipe generating line one end is connected with the ground connection little well, and the all insulation copper pipe generating line other end is connected with the ground connection stranded conductor, and all insulation copper pipe generating line is hugged closely the electrical connection pillar and is fixed by the fixing tool.
2. The main transformer neutral point fencing-free grounding device of claim 1,
still include zinc oxide arrester, arrester pillar, earth connection support insulator and maintenance case, the arrester pillar is installed by main transformer, zinc oxide arrester and earth connection support insulator are installed side by side on the arrester pillar, earth connection support insulator supports the ground connection stranded conductor, the zinc oxide arrester is connected with the ground connection stranded conductor, the zinc oxide arrester passes through ground connection metalwork ground connection, the maintenance case is installed at the arrester pillar.
3. The main transformer neutral point fencing-free grounding device of claim 2,
still include the arrester counter, first pointed end that discharges is installed at zinc oxide arrester top, the arrester counter includes the base, leads electrical pillar, counting circuit, the number of times of discharging pointer drive coil and second point of discharging, the base is installed on the arrester pillar with the zinc oxide arrester side by side, the second point of discharging is through leading electrical pillar fixed mounting on the base, and the second point of discharging is the extensible member, the counting circuit input with lead electrical pillar and be connected, the counting circuit output with discharge the number of times pointer drive coil and be connected.
4. A main transformer neutral fencing free grounding arrangement as claimed in claim 1, 2 or 3,
the grounding small well is provided with an enclosing wall higher than the ground, a cover plate is covered on the enclosing wall, the side surface of the enclosing wall is provided with an opening used for penetrating through a full-insulation copper pipe bus, and the ends of the full-insulation copper pipe bus connected with the grounding small well are divided into two branches which are respectively connected with two trunks of a main grounding network.
5. A main transformer neutral fencing free grounding arrangement as claimed in claim 1, 2 or 3,
the grounding small well, the all-insulated copper pipe bus and the grounding wire support are located outdoors or in a next room when the indoor space of the main transformer is smaller than a set value, a gap is formed in the corresponding position of the wall of the main transformer room, the grounding wire support insulator is fixed beside the gap, the wall bushing is fixed in the gap, and the grounding stranded wire is supported by the grounding wire support insulator and penetrates through the wall bushing to be connected with the all-insulated copper pipe bus.
6. The main transformer neutral point fencing-free grounding device of claim 5,
the grounding small well located outdoors is provided with a surrounding wall higher than the ground, a cover plate is covered on the surrounding wall, an opening used for penetrating through a full-insulation copper pipe bus is formed in the cover plate, and the end, connected with the grounding small well, of the full-insulation copper pipe bus is divided into two branches which are respectively connected with two trunks of a main grounding network.
7. The main transformer neutral point fencing-free grounding device of claim 2 or 3,
still include cable insulation bone shell, cable insulation bone shell is including hose and the hard tube of alternate connection in proper order, cable insulation bone shell has two sections, and first section cable insulation bone shell cover is located between main transformer and the zinc oxide arrester at ground connection stranded conductor, and the second section cup joints between zinc oxide arrester and full insulation copper pipe generating line, the internal diameter of hose and hard tube all matches with ground connection stranded conductor external diameter, the external diameter of hard tube is greater than the hose external diameter, and cable insulation bone shell restricts the maximum curvature tau of ground connection stranded conductor, the length L of first section cable insulation bone shell satisfies sin (tau L) > tau D _0, and D _0 is the settlement minimum of ground connection small well and main transformer distance.
8. The main transformer neutral point fencing-free grounding device of claim 7,
the hose is a rubber tube added with a flame retardant, and the hard tube comprises a rubber matrix, the flame retardant added in the rubber matrix and a metal tube embedded in the rubber matrix.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201922480784.3U CN211351448U (en) | 2019-12-31 | 2019-12-31 | Fence-free grounding device for neutral point of main transformer |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201922480784.3U CN211351448U (en) | 2019-12-31 | 2019-12-31 | Fence-free grounding device for neutral point of main transformer |
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| Publication Number | Publication Date |
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| CN211351448U true CN211351448U (en) | 2020-08-25 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201922480784.3U Active CN211351448U (en) | 2019-12-31 | 2019-12-31 | Fence-free grounding device for neutral point of main transformer |
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| CN (1) | CN211351448U (en) |
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