CN105186147A - Lumped grounding device, power station grounding system and construction method - Google Patents
Lumped grounding device, power station grounding system and construction method Download PDFInfo
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- CN105186147A CN105186147A CN201510639778.1A CN201510639778A CN105186147A CN 105186147 A CN105186147 A CN 105186147A CN 201510639778 A CN201510639778 A CN 201510639778A CN 105186147 A CN105186147 A CN 105186147A
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Abstract
The invention discloses a lumped grounding device, a power station grounding system and a construction method. The power station grounding system comprises a lightning-protection facility, a main ground network and the lumped grounding device, wherein the lightning-protection facility is located on a power station foundation; the main ground network is located below the bottom surface; the lumped grounding device is located below the main ground network; the lumped grounding device comprises at least one circular metal body; a conductor and at least one vertically arranged grounding lead-up line are led out from the circular metal body; the conductor is at least 15m; the other end of the conductor is connected with the main ground network; and the grounding lead-up line is connected with the lightning-protection facility. Compared with a conventional distributed concentrated grounding device, through the arrangement of the 'lumped grounding device', after a lightning rod line is struck by lightning, a lightning wave entering the ground network from the lightning rod line can reach the main ground network after running a relatively long flow distance; sufficient attenuation is generated in a long-distance flow process; and threats to electrical equipment due to 'reverse overvoltage' are greatly reduced, so that the operation reliability of equipment is improved.
Description
Technical field
This invention relates to the lightning protected ground protection technical field that can be applicable to half indoor substation building or open type substation architecture.
Background technology
GB GB50065-2011 " the grounding design specification of alternating-current electric device " is as follows to the requirement of the lightning protected ground connection of transformer station:
1. on power distribution equipment framework, the down conductor of lightning rod (framework containing hanging lightning conducter) should be connected with ground network, and should install centralized earthing device additional in junction.The tie point of downlead and ground network, to the length along earth electrode between transformer (power distribution equipment) earthing conductor (line) and ground network tie point, should not be less than 15m;
2. main power house installing direct lightning strike protective device or for protecting other equipment to install lightning rod on main power house time, should take strengthen shunting, equipment earth point away from lightning rod down conductor enter place, lightning rod down conductor away from electric device etc. prevent strike back measure.The down conductor of lightning rod should be connected with main earth mat, and should install centralized earthing device additional in junction;
3. direct lightning strike protective device is installed on the roof of main control room, electrical room and 35kV and following transformer station, and during for metal roof or roof there being a metal structure, then should by metallic member ground connection; When roof is reinforced concrete structure, then should be welded into net ground connection; When structure is non-conductive roof, then lighting proof strip should be adopted to protect, and the grid of this lighting proof strip should be 8m ~ 10m, and should establish down conductor every 10m ~ 20m.This down conductor should be connected with main earth mat, and should install centralized earthing device additional in junction;
4. when earthing device is made up of more horizontal grounding pole or vertical grounding electrode, the spacing of vertical grounding electrode should not be less than 2 times of its length, and vertical grounding electrode length conventional is at present 2.5m, therefore vertical grounding electrode spacing should not be less than 5m;
5. power plant should be connected with ground network with the earthing conductor (line) of transformer substation arrester, and should arrange centralized earthing device in junction, as shown in Figure 1:
Along with the development of transformer station's miniaturization; half indoor substation increases gradually, for above requirement, protects at present to power distribution equipment building many employings lighting proof strip; steel construction adopts steel strut to protect as direct lightning strike, and outdoor zone adopts framework lightning rod or independent lightning rod.Each direct lightning strike protective device installs centralized earthing device all separately, and need meet the requirement to length distance in code.Above-mentioned result is, this interior centralized earthing device that just causes standing is more, and it is independent separately, material usage is more, and the transformer station less to area, due to the restriction in place, being not less than 15 meters along the length of earth electrode between the tie point of downlead and ground network to transformer grounding net tie point should not meet.
Summary of the invention
The present invention is optimized mainly for problem under the drawing of roof lighting proof strip, framework lightning rod, for lightning wave enter ground, lump type earthing device is proposed, each downlead is replaced to install traditional centralized earthing device additional, traditional distributed ground connection pattern is made into the ground connection pattern of lump type, and solve some practical problems produced in lump type earthing device implementation process.
The technical solution adopted for the present invention to solve the technical problems is:
A kind of lump type earthing device, comprises at least one endless metal body, and the grounding lead of drawing at least one vertical setting on described endless metal body is reached the standard grade, and extends a bonding conductor on endless metal body.
Further, the inside of described endless metal body is provided with the second endless metal body carrying out with endless metal body being connected.
A kind of power station grounding system, comprise and be positioned at lightening protection installation on basis, power station and main earth mat, described main earth mat is positioned under bottom surface, it is characterized in that, also comprise a lump type earthing device be positioned under main earth mat, described lump type earthing device comprises at least one endless metal body, and the grounding lead of drawing a conductor and at least one vertical setting on described endless metal body is reached the standard grade, described conductor is at least 15 meters and the other end connects main earth mat, and described grounding lead is reached the standard grade and to be connected with described lightening protection installation.
Further, described lump type device and main earth mat are all horizontally disposed with.
Further, the spacing between described lump type device and main earth mat is 1.7 meters.
Further, the inside of described endless metal body is provided with the second endless metal body.
Further, described conductor is have and only have the conductor a bit connected between lump type earthing device and main earth mat.
A construction method for power station grounding system, is characterized in that, carries out following steps successively:
Step one, in capital construction, lump type earthing device, main grounding grid, conductor, Grounding Grids are laid and put in place and use conductor to be connected lump type earthing device and main grounding grid, grounding lead lower end of reaching the standard grade is connected with lump type earthing device, upper end extends and exposes on ground, builds and after basis is firm, carries out equipment and install and lightening protection installation installation;
Step 2, is wired on grounding lead reaches the standard grade by lightening protection installation, it is firm to ensure to connect.
The invention has the beneficial effects as follows: propose a kind of novel lump type earthing device entering ground for lightning wave, and lump type earthing device can efficiently play lightning current diffusion, and reduce traditional design difficulty and economy system materials.
1. more conventional distributing centralized earthing device, be somebody's turn to do the setting of " lump type earthing device ", after thunderbolt lightning rod, line, the lightning wave entering earth mat from lightning rod, line has longer flow distance just can reach main earth mat, the flow process of long distance can produce enough decay, greatly reduce " back overrating voltage " threat to electric equipment, improve equipment reliability of operation.
2. more conventional distributing centralized earthing device, lump type earthing device can simplified design scheme, a large amount of minimizing vertical grounding electrode quantity, and combination is built, structure base cutting depth, lump type earthing device is arranged in and builds, under structure base, be generally no more than 2.5m, reduce difficulty of construction, reduce earthing material and construct artificial expense, more energy-conserving and environment-protective to a certain extent.
Accompanying drawing explanation
Fig. 1 is traditional System in Substation.
Fig. 2 is the impact (dotted portion) of lightning impulse on main grounding grid.
Fig. 3 is easy rectilinear earthing device.
Fig. 4 is the vertical view of the System in Substation in the present invention.
Fig. 5 is the stereogram of the System in Substation in the present invention.
Fig. 6 is the schematic diagram of the System in Substation in the present invention.
Fig. 7 is the further full view that Fig. 5 is corresponding.
Fig. 8 is the earth potential rising distribution map that the present invention analyzes generation in MALZ module.
Fig. 9 is the touch voltage distribution map that the present invention analyzes generation in MALZ module.
Figure 10 is the step voltage voltage distribution graph that the present invention analyzes generation in MALZ module.
In figure: 1 lump type earthing device, 11 grounding leads are reached the standard grade, 12 endless metal bodies, 2 main earth mats, 3 conductors.
Embodiment
1. in traditional transformer station anti-direct thunder striking device drawing under process
For GB in requirement (scape technology of the passing away part) transformer station of this part: power distribution equipment (electric equipment) framework has lightning rod, lightning conducter, generally independently draw earthing device; Power distribution equipment roof establishes lighting proof strip, lightning rod, and roof is hardware, generally independently draws a set of earthing device; Power distribution equipment district arranges the position of lightning arrester, generally independently draws earthing device.In theory, each earthing device can be accessed by main grounding grid, consider to affect situation on ground network and surrounding devices under lightning impulse effect, visible Fig. 2, this structure Problems existing is: when lightning wave flows through lightening protection installation introducing earth mat, the instantaneous overvoltage of local can be caused, as can not diffusing in time, may cause damage (in power plant and electric substation to neighbouring electric equipment, if thunderbolt is on lightning rod, lightning current scatters in ground by framework down conductor, due to the existence of framework inductance and earth resistance, architecturally can produce very high above earth potential, high potential can produce very large potential difference to neighbouring electric equipment or charged wire.If between the two apart from little, lightning rod framework will be caused miscellaneous equipment or wire electrical discharge, cause counterattack flashover and cause the accident), therefore, centralized earthing device need be set up in above region.
In order to solve the problem, in Practical Project, normal employing has following several scheme:
1.1 arrange closeer centralized earthing device
As shown in fig. 1, in transformer station, each lighting proof strip in power distribution equipment building, lightning conducter downlead arrange centralized earthing device all separately, and centralized earthing device generally connects into ring-type or other shapes by 3-5 root vertical grounding electrode.And should ensure that the spacing of vertical grounding electrode should not be less than 2 times of its length.This arrangement strict implement GB relevant regulations, effectively can strengthen the diffusing effect to lightning current.
As seen from the figure, this arrangement adopts centralized earthing device quantity more, interval is closeer, pitch requirements is should be noted in design, and part downlead and ground network tie point are to close together between transformer grounding and ground network tie point, consider the decay of lightning wave, this distance should be not less than 15m, need do respective handling if desired at downlead and ground network junction.
Lay centralized earthing device at building edge, relate to and lay the impact that the degree of depth is subject to building foundation buried depth, easily increase difficulty of construction, increase construction investment.
1.2 arrange conventional vertical earth electrode substitutes
A large amount of engineering adopts Fig. 3 mode at present, in transformer station, each lighting proof strip in power distribution equipment building, lightning conducter downlead are all connected with main earth mat, connect intersection and a vertical grounding electrode is set, the program is simple and easy to realize, but centralized earthing device is not set in strict accordance with regulatory requirements, quite unfavorable to the diffusing of lightning current, once be struck by lightning, electric current passes back to electric equipment, very likely damages electric equipment.Therefore, should by this kind of design.
2. the proposition of lump type earthing device
For existing defect, consider all difficulties of process under the drawing of anti-direct thunder striking device in traditional transformer station, and the problem that the earthing device occurred disturbs each other, propose transformer station lump type earthing device scheme, the concrete plan of establishment is as Fig. 4: exploitation be that one has double-deck lightning protection net.
Based on above-mentioned description, concrete structure of the present invention is as follows:
In Fig. 2 to Figure 10, the downlead of direct striking thunder prevention protective devices all in power station is all connected to " lump type earthing device ", be connected by conductor 3 between this lump type earthing device 1 with main earth mat 2, wherein, lump type earthing device comprises endless metal body 12 and the second endless metal body, according to above ground structure, the layout of main transformer carries out rational deployment, in conjunction with building and main transformer foundation cutting depth, this earthing device is layed in foundation lower floor, incorporation engineering is actual, generally the degree of depth of this earthing device is about about 2.5m, vertical range H wherein between lump type earthing device and main earth mat is more than 1.5 meters, and the vertical range on main earth mat and ground is at about 0.8 meter, form three-dimensional layout pattern between the two, as Fig. 5, 7, grounding lead is reached the standard grade and 11 any one in power station can be needed that the lightning-arrest electric equipment framework connected has lightning rod as required, lightning conducter, lighting proof strip established by power distribution equipment roof, the lightning arrester in lightning rod and power distribution equipment district directly connects, and a Grounding Grids is set at a certain distance, strengthen the diffusing function of this earthing device.Only need this lump type earthing device, for substituting distributed earthing device.
In the present embodiment, as a kind of mode of the best, considering in the situations such as electrical distance, region, power station, the earth mat laying degree of depth, lump type earthing device 1 is designed to 1.7 meters with the vertical range of main earth mat 2, the length of connection and the conductor 3 between lump type earthing device and main earth mat is not less than 15 meters, the setting direction of conductor can be selected according to actual conditions and be connected with main earth mat away from lightening protection installation direction, meet the connectivity problem of lump type earthing device in small space and main earth mat, reduce difficulty of construction.
3. for the ground connection pattern of parameter above, to the performance evaluation of lump type earthing device
3.1 impacts on main earth mat
CDEGS software MALZ module is frequency domain Analysis of Grounding module.MALZ module is used for the earthing device of analysis and design power plant, transformer station and electric power line pole tower, and carries out the research of cathodic protection, but the Grounding mainly under computation and analysis high frequency condition.MALZ can adopt level, vertical demixing or any soil texture, can be described good performance of the present invention by this software, calculated by CDEGS software MALZ module according to the program, the distribution of earth potential, touch voltage, step voltage is as shown in Fig. 8 to Figure 10.
Wherein, Fig. 8 is earth potential rising figure, and in figure, the implication of a coordinate is as follows:
X-coordinate: distance y coordinate: the distance z coordinate of distance initial point: earth potential increasing degree value.
Wherein, Fig. 9 is touch voltage figure, and in figure, the implication of a coordinate is as follows:
X-coordinate: distance y coordinate: the distance z coordinate of distance initial point: the touch voltage amplitude under most harsh conditions.
Wherein Figure 10 is that in step voltage figure, figure, the implication of coordinate is as follows:
X-coordinate: distance y coordinate: the distance z coordinate of distance initial point: the step voltage amplitude under most harsh conditions.
Can draw to draw a conclusion by above-mentioned icon:
Grounding system classical insulation table
| Earth resistance (Ω) | Touch voltage (V) | Step voltage (V) | |
| Conventional scheme | 0.354 | 199.24 | 126.7 |
| Earthing device provided by the invention | 0.347 | 151.7 | 72.7 |
" lump type earthing device " in the present invention, is reduced to 151.7V by touch voltage from 199.24V, and each classical insulation of grounding system all has certain optimization.
The diffusing ability of 3.2 pairs of lightning currents
Relative to the distributing centralized earthing device of routine, be somebody's turn to do the setting of " lump type earthing device ", after thunderbolt lightening protection installation, the lightning wave entering earth mat from lightening protection installation needs first after lump type earthing device and wire, just can reach main earth mat, electric current has longer flow distance just can reach main earth mat in this course, the flow process of long distance can produce enough decay, greatly reduces the threat of back overrating voltage to electric equipment, improves equipment reliability of operation.
Construction method is as follows, first in the ground constructin phase, lump type earthing device, main grounding grid, wire, Grounding Grids are laid and put in place, after basis is firm, carry out equipment install and lightening protection installation installation, finally lightening protection installation is wired to grounding lead and reaches the standard grade.
Embodiment recited above is only be described the preferred embodiment of the present invention; not scope of the present invention is limited; under not departing from the present invention and designing the prerequisite of spirit; relevant technical staff in the field, to various distortion of the present invention and improvement, all should expand in protection range as determined in claims of the present invention.
Claims (8)
1. a lump type earthing device, comprise at least one endless metal body (12), and the grounding lead of drawing at least one vertical setting on described endless metal body is reached the standard grade (11), and on endless metal body, extend a conductor be obliquely installed.
2. a kind of lump type earthing device according to claim 1, is characterized in that, the inside of described endless metal body is provided with the second endless metal body carrying out with endless metal body being connected.
3. a power station grounding system, comprise and be positioned at lightening protection installation on basis, power station and main earth mat (2), described main earth mat is positioned at underground, it is characterized in that, also comprise a lump type earthing device (1) be positioned under main earth mat, described lump type earthing device comprises at least one endless metal body (12), and the grounding lead of drawing a conductor (3) and at least one vertical setting on described endless metal body reaches the standard grade (11), described conductor is at least 15 meters and the other end connects main earth mat (2), described grounding lead is reached the standard grade and to be connected with described lightening protection installation.
4. a kind of power station according to claim 3 grounding system, is characterized in that, described lump type device and main earth mat are all horizontally disposed with.
5. a kind of power station according to claim 4 grounding system, is characterized in that, the spacing between described lump type device (1) and main earth mat (2) is 1.7 meters.
6. a kind of power station according to claim 3 grounding system, is characterized in that, the inside of described endless metal body is provided with the second endless metal body.
7. a kind of power station according to claim 3 grounding system, is characterized in that, described conductor (3) is for having and only having the conductor a bit connected between lump type earthing device and main earth mat.
8. the construction method of a kind of power station according to claim 3 grounding system, is characterized in that, carry out following steps successively:
Step one, in capital construction, lump type earthing device, main grounding grid, conductor, Grounding Grids are laid and put in place and use conductor to be connected lump type earthing device and main grounding grid, grounding lead lower end of reaching the standard grade is connected with lump type earthing device, upper end extends and exposes on ground, builds and after basis is firm, carries out equipment and install and lightening protection installation installation;
Step 2, is wired on grounding lead reaches the standard grade by lightening protection installation, it is firm to ensure to connect.
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN106785508A (en) * | 2016-12-13 | 2017-05-31 | 深圳供电局有限公司 | A kind of overhead power transmission line pole tower combined type grounded screen |
| CN108020739A (en) * | 2017-11-29 | 2018-05-11 | 中国南方电网有限责任公司超高压输电公司广州局 | A kind of method for reducing deep well grounding electrode maximum current density |
| CN112563770A (en) * | 2020-12-03 | 2021-03-26 | 国网陕西省电力公司电力科学研究院 | Grounding device for independent lightning rod of transformer substation and optimization method |
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| CN205092323U (en) * | 2015-09-30 | 2016-03-16 | 国网山东省电力公司经济技术研究院 | Lump formula earthing device , power station ground system |
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| CN201038348Y (en) * | 2007-02-17 | 2008-03-19 | 周明 | Transmission line bracket maintenance-free earthing network |
| CN103259104A (en) * | 2013-06-07 | 2013-08-21 | 国家电网公司 | Well group grounding net |
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| CN106785508A (en) * | 2016-12-13 | 2017-05-31 | 深圳供电局有限公司 | A kind of overhead power transmission line pole tower combined type grounded screen |
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| CN108020739A (en) * | 2017-11-29 | 2018-05-11 | 中国南方电网有限责任公司超高压输电公司广州局 | A kind of method for reducing deep well grounding electrode maximum current density |
| CN112563770A (en) * | 2020-12-03 | 2021-03-26 | 国网陕西省电力公司电力科学研究院 | Grounding device for independent lightning rod of transformer substation and optimization method |
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