National standard GB50065-2011《The grounding design specification of alternating-current electric device》The lightning protected ground connection of transformer station is wanted
Ask as follows：
1. the down conductor of lightning rod (framework of the lightning conducter containing suspension) should be connected with grounded screen on power distribution equipment framework,
And centralized earthing device should be installed additional in junction.Downlead and the tie point of grounded screen are to transformer (power distribution equipment) earth conductor
Along the length of earthing pole, no less than 15m between (line) and grounded screen tie point；
, should 2. main building installs direct lightning strike protection device or installs lightning rod on main building for protection other equipment
Reinforcement shunting, the earth point of equipment is taken to enter place, lightning rod down conductor away from electricity away from lightning rod down conductor
Device of air etc. prevents the measure of counterattack.The down conductor of lightning rod should be connected with main earth mat, and should install concentration additional in junction
Earthing or grounding means；
3. direct lightning strike protection device is installed on the roof of main control room, electrical room and 35kV and following transformer station, and
During to have metal structure in metal roof or roof, then metal part should be grounded；When roof is reinforced concrete structure, then should
Welded networking ground connection；When structure is non-conductive roof, then 8m should be should be using lighting proof strip protection, the grid of the lighting proof strip
~10m, and down conductor should be set every 10m~20m.The down conductor should be connected with main earth mat, and should be added in junction
Fill centralized earthing device；
4. when earthing or grounding means is made up of more horizontal grounding pole or vertical grounding electrode, the spacing of vertical grounding electrode should not be small
In 2 times of its length, conventional vertical grounding electrode length is 2.5m at present, therefore vertical grounding electrode spacing is no less than 5m；
5. the earth conductor (line) of power plant and transformer substation arrester should be connected with grounded screen, and should set collection in junction
Middle earthing or grounding means, as shown in Figure 1：
The development minimized with transformer station, half indoor substation gradually increases, for requirements above, at present to Denso
Put using lighting proof strip protection more than building, steel construction is protected using steel strut as direct lightning strike, and outdoor zone is kept away using framework
Thunder pin or independent lightning rod.Each direct lightning strike protection device individually installs centralized earthing device, and need to meet in code to length
The requirement of distance.Above-mentioned as a result, this is resulted in, centralized earthing device in station is more and each independent, and material usage is more,
And to the less transformer station of area, due to the limitation in place, tie point to the transformer grounding net of downlead and grounded screen is connected
It should not be met not less than 15 meters along the length of earthing pole between point.
The content of the invention
Optimized present invention is generally directed to problem under roof lighting proof strip, the drawing of framework lightning rod, enter ground for lightning wave
, lump type earthing or grounding means is proposed, traditional centralized earthing device is installed additional instead of each downlead, by traditional distributed ground connection
Pattern makes the ground connection pattern of lump type, and some practical problems that solution is produced in lump type earthing or grounding means implementation process into.
The technical solution adopted for the present invention to solve the technical problems is：
A kind of lump type earthing or grounding means, including at least one endless metal body, and led on the endless metal body
A few vertically arranged grounding lead is reached the standard grade, and extends on endless metal body a connection conductor.
Further, the inside of the endless metal body is provided with the second endless metal being attached with endless metal body
A kind of power station earthed system, including lightening protection installation and main earth mat on the basis of power station, the main earth mat position
Under bottom surface, it is characterised in that also including a lump type earthing or grounding means being located under main earth mat, the lump type ground connection
Device include at least one endless metal body, and on the endless metal body draw a conductor and at least one vertically set
The grounding lead put is reached the standard grade, and the conductor is at least 15 meters and the other end connects main earth mat, and the grounding lead is reached the standard grade takes shelter from the thunder with described
Facility is connected.
Further, the lump type device is all horizontally disposed with main earth mat.
Further, the spacing between the lump type device and main earth mat is 1.7 meters.
Further, the inside of the endless metal body is provided with the second endless metal body.
Further, the conductor is to have and conductor only a little between connection lump type earthing or grounding means and main earth mat.
A kind of construction method of power station earthed system, it is characterised in that carry out following steps successively：
Step one, lump type earthing or grounding means, main grounding grid, conductor, Grounding Grids are put in place simultaneously in infrastructure
Lump type earthing or grounding means is connected with main grounding grid using conductor, grounding lead lower end of reaching the standard grade is connected with lump type earthing or grounding means, on
End extends and exposed on ground, pours and progress equipment is installed after basis is firm and lightening protection installation is installed；
Step 2, lightening protection installation is wired on grounding lead reaches the standard grade, it is ensured that connection is firm.
The beneficial effects of the invention are as follows：A kind of new lump type earthing or grounding means for entering ground for lightning wave is proposed, and
Lump type earthing or grounding means can efficiently play lightning current diffusion, and reduce traditional design difficulty and save device materials.
1. more conventional distributing centralized earthing device, is somebody's turn to do the setting of " lump type earthing or grounding means ", thunderbolt lightning rod, line
Afterwards, the lightning wave for entering earth mat from lightning rod, line has longer flow distance to can be only achieved main earth mat, the flow process of long range
Enough decay can be produced, the threat of " back overrating voltage " to electrical equipment is greatly reduced, equipment reliability of operation is improved.
2. more conventional distributing centralized earthing device, lump type earthing or grounding means can simplify design, a large amount of reduce is hung down
Directly number of poles, and combine build, structure base cutting depth, lump type earthing or grounding means is arranged in build, structure base
Under, 2.5m is usually no more than, difficulty of construction is reduced, earthing material and the artificial expense of construction are reduced to a certain extent, more
Energy-conserving and environment-protective.
1. processing under the drawing of anti-direct thunder striking device in traditional transformer station
In requirement (see background section) transformer station for national standard to the part：Power distribution equipment (electrical equipment) framework
On have lightning rod, a lightning conducter, it is general independent to draw earthing or grounding means；Power distribution equipment roof sets lighting proof strip, lightning rod, and roof is
Hardware, the general independent a set of earthing or grounding means of extraction；Power distribution equipment area sets the position of arrester, and general independent draw connects
Ground device.In theory, each earthing or grounding means can access main grounding grid, it is considered to grounded screen and surrounding devices under lightning impulse effect
Influence situation, it is seen that Fig. 2, the problem of this structure is present be：When lightning wave, which flows through lightening protection installation, introduces earth mat, it can cause
Local instantaneous overvoltage, such as can not diffusing in time, neighbouring electrical equipment may be caused damage (in power plant and electric substation
In, if be struck by lightning onto lightning rod, lightning current is scattered into ground by framework down conductor, due to framework inductance and ground connection electricity
The presence of resistance, can architecturally produce very high above earth potential, and high potential can be produced to neighbouring electrical equipment or powered wire
Give birth to very big potential difference.If may result in lightning rod framework to miscellaneous equipment or wire electrical discharge apart from small between the two, cause anti-
Hit flashover and cause the accident), therefore, area above need to set up centralized earthing device.
In order to solve the above problems, in Practical Project frequently with have following several schemes：
1.1 set closeer centralized earthing device
As shown in fig. 1, each lighting proof strip in power distribution equipment building, lightning conducter downlead are separately provided concentration ground connection in transformer station
Device, centralized earthing device typically by the connection of 3-5 roots vertical grounding electrode circlewise or other shapes.And should ensure that vertical grounding electrode
Spacing be no less than 2 times of its length.The arrangement strict implement national standard relevant regulations, can effectively strengthen to lightning current
Diffusing is acted on.
As seen from the figure, the arrangement is more using centralized earthing device quantity, and interval is closeer, and spacing is should be noted in design
It is required that, and part downlead and grounded screen tie point are to closer to the distance between transformer grounding and grounded screen tie point, it is considered to thunder
The decay of electric wave, the distance should be not less than 15m, need to do respective handling in downlead and grounded screen junction if necessary.
Centralized earthing device is laid at building edge, be related to laying depth is influenceed by building embedded depth of foundation, easily
Increase difficulty of construction, increase construction investment.
1.2 set conventional vertical grounding body to substitute
A large amount of engineerings use Fig. 3 modes at present, in transformer station each lighting proof strip in power distribution equipment building, lightning conducter downlead with
Main earth mat connection, connection intersection sets a vertical grounding electrode, and the program is simply easily realized, but will not in strict accordance with code
Setting centralized earthing device is sought, the diffusing to lightning current is quite unfavorable, once being struck by lightning, electric current passes back to electrical equipment, pole
It is possible to damage electrical equipment.Therefore, this kind of design should not be used.
2. the proposition of lump type earthing or grounding means
For existing defect, it is considered in traditional transformer station under the drawing of anti-direct thunder striking device processing all difficulties, and go out
The problem of being disturbed between existing earthing or grounding means, proposes transformer station's lump type earthing or grounding means scheme, the specific plan of establishment is as schemed
4：Exploitation is a kind of lightning protection net with double-decker.
Based on the description above, concrete structure of the invention is as follows：
In Fig. 2 into Figure 10, the downlead of all direct striking thunder prevention protection devices in power station is both connected to " lump type ground connection
Device ", is connected between the lump type earthing or grounding means 1 and main earth mat 2 by conductor 3, wherein, lump type earthing or grounding means includes annular
The endless metal body of metallic object 12 and second, carries out rational deployment, with reference to building according to the layout of above ground structure, main transformer
And main transformer foundation cutting depth, the earthing or grounding means is layed in foundation lower floor, incorporation engineering is actual, and generally this connects
The depth of ground device is about 2.5m or so, the wherein vertical range H between lump type earthing or grounding means and main earth mat 1.5 meters with
On, and main earth mat and ground vertical range at 0.8 meter or so, between the two formed three dimensions layout pattern, such as Fig. 5,
7, grounding lead is reached the standard grade and 11 can be needed have lightning-arrest on the electrical equipment framework of lightning-arrest connection with any one in power station as needed
The arrester that pin, lightning conducter, power distribution equipment roof set lighting proof strip, lightning rod and power distribution equipment area is directly connected to, and often
A piece Grounding Grids are set at a certain distance, strengthen the diffusing function of the earthing or grounding means.Only need to this lump type ground connection
Device, for substituting distributed earthing or grounding means.
In the present embodiment, as a kind of optimal mode, electrical distance, power station region, earth mat laying are being considered deeply
When degree, the vertical range of lump type earthing or grounding means 1 and main earth mat 2 is designed as 1.7 meters, connects and lump type earthing or grounding means
The length of conductor 3 between main earth mat is not less than 15 meters, and the setting direction of conductor can be selected away from lightning-arrest according to actual conditions
Facility direction is connected with main earth mat, meets the connectivity problem of the lump type earthing or grounding means and main earth mat in small space, and reduction is applied
3. by taking the ground connection pattern of parameter above as an example, to lump type earthing or grounding means performance evaluation
The influence of 3.1 pairs of main earth mats
CDEGS software MALZ modules are frequency domain Analysis of Grounding module.MALZ modules are used for analyzing and designing power plant, power transformation
The earthing or grounding means stood with electric power line pole tower, and the research of cathodic protection is carried out, but mainly under the conditions of calculating and analysis of high frequency
Grounding.MALZ can use level, vertical demixing or any soil texture, can be to the good of the present invention by the software
Performance illustrate, passing through CDEGS software MALZ modules according to the program calculates, ground potential, contact voltage, step voltage point
Cloth is as shown in Fig. 8 to Figure 10.
Wherein, Fig. 8 is that ground potential rise is schemed, and the implication of a coordinate is as follows in figure：
X-coordinate：Apart from y-coordinate：Apart from origin apart from z coordinate：Ground potential increasing degree value.
Wherein, Fig. 9 is contact voltage figure, and the implication of a coordinate is as follows in figure：
X-coordinate：Apart from y-coordinate：Apart from origin apart from z coordinate：Contact voltage amplitude under most harsh conditions.
Wherein Figure 10 is that the implication of a coordinate in step voltage figure, figure is as follows：
X-coordinate：Apart from y-coordinate：Apart from origin apart from z coordinate：Step voltage amplitude under most harsh conditions.
It can draw to draw a conclusion by above-mentioned icon：
Earthed system classical insulation table
||Grounding resistance (Ω)
||Contact voltage (V)
||Step voltage (V)
|The earthing or grounding means that the present invention is provided
" lump type earthing or grounding means " in the present invention, is reduced to 151.7V, earthed system is each by contact voltage from 199.24V
Classical insulation has certain optimization.
The diffusing ability of 3.2 pairs of lightning currents
Relative to conventional distributing centralized earthing device, the setting of " lump type earthing or grounding means " is somebody's turn to do, be struck by lightning lightening protection installation
Afterwards, the lightning wave for entering earth mat from lightening protection installation, which needs to first pass through, can be only achieved main earth mat after lump type earthing or grounding means and wire,
Electric current has longer flow distance to can be only achieved main earth mat in this course, and the flow process of long range can produce enough decline
Subtract, greatly reduce threat of the back overrating voltage to electrical equipment, improve equipment reliability of operation.
Construction method is as follows, first the ground constructin phase by lump type earthing or grounding means, main grounding grid, wire, vertically connect
Ground body is put in place, and equipment is carried out after basis is firm and is installed and lightening protection installation installation, finally connects lightening protection installation by wire
Grounding lead is connected to reach the standard grade.
The above-described embodiments are merely illustrative of preferred embodiments of the present invention, not to the model of the present invention
Enclose and be defined, on the premise of design spirit of the present invention is not departed from, various changes of the relevant technical staff in the field to the present invention
Shape and improvement, all should expand as determined by claims of the present invention in protection domain.