CN111244629A - Lightning protection grounding method of shared iron tower - Google Patents
Lightning protection grounding method of shared iron tower Download PDFInfo
- Publication number
- CN111244629A CN111244629A CN202010018428.4A CN202010018428A CN111244629A CN 111244629 A CN111244629 A CN 111244629A CN 202010018428 A CN202010018428 A CN 202010018428A CN 111244629 A CN111244629 A CN 111244629A
- Authority
- CN
- China
- Prior art keywords
- grounding
- iron tower
- ground
- grid
- machine room
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
Images
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01Q—ANTENNAS, i.e. RADIO AERIALS
- H01Q1/00—Details of, or arrangements associated with, antennas
- H01Q1/50—Structural association of antennas with earthing switches, lead-in devices or lightning protectors
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01Q—ANTENNAS, i.e. RADIO AERIALS
- H01Q1/00—Details of, or arrangements associated with, antennas
- H01Q1/48—Earthing means; Earth screens; Counterpoises
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01R—ELECTRICALLY-CONDUCTIVE CONNECTIONS; STRUCTURAL ASSOCIATIONS OF A PLURALITY OF MUTUALLY-INSULATED ELECTRICAL CONNECTING ELEMENTS; COUPLING DEVICES; CURRENT COLLECTORS
- H01R4/00—Electrically-conductive connections between two or more conductive members in direct contact, i.e. touching one another; Means for effecting or maintaining such contact; Electrically-conductive connections having two or more spaced connecting locations for conductors and using contact members penetrating insulation
- H01R4/58—Electrically-conductive connections between two or more conductive members in direct contact, i.e. touching one another; Means for effecting or maintaining such contact; Electrically-conductive connections having two or more spaced connecting locations for conductors and using contact members penetrating insulation characterised by the form or material of the contacting members
- H01R4/66—Connections with the terrestrial mass, e.g. earth plate, earth pin
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01T—SPARK GAPS; OVERVOLTAGE ARRESTERS USING SPARK GAPS; SPARKING PLUGS; CORONA DEVICES; GENERATING IONS TO BE INTRODUCED INTO NON-ENCLOSED GASES
- H01T19/00—Devices providing for corona discharge
- H01T19/04—Devices providing for corona discharge having pointed electrodes
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02G—INSTALLATION OF ELECTRIC CABLES OR LINES, OR OF COMBINED OPTICAL AND ELECTRIC CABLES OR LINES
- H02G13/00—Installations of lightning conductors; Fastening thereof to supporting structure
- H02G13/40—Connection to earth
Abstract
The invention relates to a lightning protection grounding method of a shared iron tower, which respectively provides a lightning protection method according to the carrying positions of 5G communication antennas, wherein when an antenna is positioned at the top of the tower (not within the protection range of a lightning rod), a lightning protection grounding down lead is arranged on an antenna fixing rod; when the antenna is positioned at other positions (within the protection range of the lightning rod), the tower body is used as a grounding conductor; the method optimizes a calculation formula of the grounding resistance, considers the influence of a horizontal grounding body, a vertical grounding body and a radial grounding body, and provides a ground grid transformation scheme based on the existing grounding system of the power iron tower, namely, an annular grounding device is added on the basis of the original ground grid, the annular grounding device and the original ground grid are on the same horizontal plane and are welded and communicated once every 3-5m, the annular grounding device comprises the horizontal grounding body, the vertical grounding body and the radial grounding body, and finally the grounding resistance of the shared iron tower meets the requirements of the power system and the communication system.
Description
Technical Field
The invention relates to a lightning protection grounding method of a shared iron tower, in particular to a lightning protection grounding system of a communication base station of the shared iron tower. Belongs to the technical field of power equipment.
Background
At present, China is in an era of beginning 4G and 5G, compared with connection between 4G people and people, the 5G application scene is expanded to connection between people and objects, and the connection between objects and objects has a huge market prospect. With the development of the society towards intellectualization, the internet + internet of things technology is rapidly advanced, and the technology needs a huge and full-coverage wireless communication network support. Compared with the 4G signal, the 5G signal is comprehensively improved in multiple aspects of speed, time delay and the like. However, the signal attenuation speed of the base station is high due to the high frequency and short wavelength of the signal. With the overall coverage of 5G signals, a large number of iron towers for mounting the antenna are necessary. Due to the defects of high cost, long period and the like of the newly built iron tower, a large number of newly built iron towers are obviously unrealistic, so that a large number of electric power iron towers are required to carry the antennas, and the shared iron tower becomes necessary.
However, the existing shared iron tower has a series of problems such as electromagnetic interference, lightning grounding, wiring and electricity taking. The lightning grounding problem is one of the problems to be solved. At present, few researches are carried out on the problem of lightning grounding of the shared iron tower.
The damage of lightning to the shared iron tower is mainly of the following types:
(1) direct lightning strike: the attack of the direct lightning is very destructive, and when the direct lightning strikes buildings and related equipment, strong electric energy and heat energy are generated and mechanical damage is often accompanied. Causing serious property damage and even endangering the personal safety of related workers.
(2) Induction thunder: the induction thunder is a phenomenon that when thundercloud, an electric field and a magnetic field approach a building, direct contact does not occur and energy is induced. This phenomenon can cause severe damage to the associated equipment, such as the line pipes on the ground, which in turn generate voltage. The inductive thunder has higher harm degree to relevant equipment in the mobile base station, and the occurrence probability is also higher.
(3) Lightning wave intrusion and lightning strike electromagnetic pulses: the lightning stroke electric wave means that the electric wave enters a base station along a line under the action of lightning and further damages equipment. The lightning stroke electromagnetic pulse is an interference effect caused when lightning directly hits a building or lightning protection equipment and the like, and can also cause serious damage to equipment in a base station.
Therefore, the lightning protection grounding protection of the shared iron tower is very important, and the lightning protection grounding system of the original electric power iron tower cannot meet the requirements of a 5G communication base station. In the aspect of lightning protection, the communication antenna can be carried on different parts such as the tower top, the tower head and body section, the tower body and the like, and the original lightning protection system can not protect the antennas at all positions. In the aspect of grounding, the grounding resistance of the original grounding grid is required to be less than 30 ohms, the grounding resistance of a communication system is required to be less than 10 ohms, and obviously, the existing lightning protection grounding level can not meet the requirements of a communication base station.
If the communication antenna is additionally arranged on an overhead transmission line tower of an electric power system, the original grounding grid needs to be improved, so that the grounding resistance needs to meet the design specification and standard requirements. The lightning protection system is also required to be designed, so that the communication antenna is carried in the protection range of the lightning protection system at any position of the electric power iron tower, especially at the position of the tower top. The lightning protection grounding system meets the requirements, can prevent the accident, and provides guarantee for the safe operation of the shared iron tower in thunderstorm days.
Disclosure of Invention
The invention aims to overcome the defects and provides a lightning protection grounding method for shared iron towers.
The purpose of the invention is realized as follows:
a lightning protection grounding method of a shared iron tower is characterized in that: when the antenna is positioned on the top of the tower, the antenna is not within the protection range of the lightning rod, the lightning-arrest grounded downlead is arranged on the antenna fixing rod, the downlead is arranged inside the body of the electric power iron tower, and the downlead is communicated with the grounding grid in a welding mode; when the antenna is positioned at other positions, the tower body is used as a grounding conductor within the protection range of the antenna lightning rod.
Further, the distance between the lead contact point of the down lead on the grounding grid and other grounding lead contact points on the grounding grid is not less than 5 m.
Furthermore, 16 phi 8mm holes are uniformly drilled on the upper part, the middle part and the lower part of the down lead for the grounding of the antenna feeder line.
Further, SPDs are configured at the low-voltage side of a machine room transformer, an alternating current distribution panel, an electric equipment power distribution cabinet and fine electric equipment ports; when the communication base station is introduced in a power supply line overhead manner, the maximum through-current capacity of the first-level SPD of the machine room power supply system is improved by one level upwards, and the feeder line is directly connected with an outdoor grounding network and is used for grounding the last point of the feeder line.
Furthermore, the grounding grid comprises an original grounding grid and an annular grounding device, the annular grounding device comprises a horizontal grounding body, a vertical grounding body and a radial grounding body, and the annular grounding device and the original grounding grid are on the same horizontal plane and are mutually welded and communicated once every 3-5 m;
the grounding grid also comprises a machine room grounding grid, an iron tower grounding grid and a transformer grounding grid; the machine room and the transformer can be arranged at the bottom of the tower;
the machine room grounding grid comprises a machine room building foundation and a peripheral annular grounding body; the annular grounding body is laid along the outside of a water scattering point of the machine room building and is welded and communicated with more than two main reinforcing steel bars in a transverse and vertical beam of a foundation of the machine room building and main reinforcing steel bars of each ground pile;
the iron tower ground net at least extends to the range of 1.5m far away from the four feet of the tower foundation, the size of the grid is less than 3m multiplied by 3m, and more than two main steel bars in the tower foundation ground pile are used as a vertical grounding body of the iron tower ground net to be welded with the iron tower ground net.
Furthermore, when the iron tower is positioned on the roof of the machine room, the four feet of the iron tower are welded and communicated with the lightning protection belt on the roof at least two nearby positions.
Furthermore, when the machine room is positioned near the iron tower, the iron tower grounding grid and the machine room grounding grid are welded and communicated with each other every 3-5m, and the number of connecting points is not less than two.
Further, when the power transformer is arranged in the machine room, the transformer ground net is a combined ground net consisting of a machine room ground net and an iron tower ground net; the power transformer is arranged outside the machine room, and a grounding grid of the transformer and a grounding grid of the machine room or a grounding grid of an iron tower of the grounding grid of the transformer are mutually welded and communicated once every 3-5m to form a grounding grid with a closed periphery.
A method for calculating the grounding resistance of a lightning grounding grid of a shared iron tower is characterized by comprising the following steps: the calculation formula of the grounding resistance is as follows:
in the formula, R1A ground resistance (Ω) for a horizontal ground screen; r2A ground resistance (Ω) which is a vertical ground electrode; rmIs the mutual grounding resistance (omega), R between the horizontal grounding grid and the vertical grounding electrodegIs a ground resistor;
where ρ is the soil resistivity (Ω · m); l isCThe total length (m) of the horizontal grounding electrode; h is the buried depth (m) of the earth screen; d is the diameter (m) of the horizontal earth conductor; s is the area covered by the conductor (m)2)；
Where ρ is the resistivity of soil (Ω · m) and S is the coverage area of the conductor (m)2) N is the number of vertical grounding electrodes; l isRA length (m) for each vertical ground electrode; h is the buried depth (m) of the earth screen; b is the diameter (m) of the vertical ground conductor;
in the formula, n is the number of the vertical grounding electrodes; l isRFor each ground electrode length (m); h is the buried depth (m) of the earth screen; b is the diameter (m) of the conductor;
the grounding resistance calculation steps are as follows:
s1: determining basic parameters of soil resistivity rho, the diameter d of a horizontal grounding electrode conductor, the diameter b of a vertical grounding conductor and the coverage area S of the conductor;
s2 determining buried depth h of the earth screen, number n of vertical grounding bodies and total length L of horizontal grounding electrodeCAnd the length L of each vertical grounding electrodeRTaking the value of (A);
s3 calculating the grounding resistance R according to the formulagAnd R isgAnd comparing with a grounding standard resistance value.
Compared with the prior art, the invention has the beneficial effects that:
the invention relates to a lightning protection grounding method of a shared iron tower, which provides a lightning protection method according to the carrying position of a 5G communication antenna; and a ground resistance calculation formula is optimized, the influence of a horizontal grounding body, a vertical grounding body and a radial grounding body is considered, and a ground grid transformation scheme is provided based on the existing grounding system of the power iron tower, so that the ground resistance meets the requirements of a power system and a communication system at the same time.
Drawings
Fig. 1 is a design diagram of a tower grounding grid of the lightning protection grounding method for shared towers of the present invention.
In the figure:
Detailed Description
The following description of the embodiments of the present invention will be made with reference to the accompanying drawings. The following examples are only for illustrating the technical solutions of the present invention more clearly, and the protection scope of the present invention is not limited thereby.
The 5G communication comprises a 3.5GHz frequency band and a millimeter wave frequency band with higher frequency, and the transmission characteristics of the frequency bands determine that a large number of iron towers are required for carrying the communication antenna in the 5G communication. The shared iron tower is characterized in that a communication antenna is additionally arranged on an overhead transmission line tower of an electric power system as the name suggests, but the grounding system of the existing electric power iron tower cannot meet the grounding requirement of a base station. The invention provides a lightning protection grounding method for a shared iron tower, which provides a lightning protection method according to the carrying position of a 5G communication antenna; when the antenna is positioned at the top of the tower (not within the protection range of the lightning rod), the antenna fixing rod is provided with a lightning-proof grounded down lead; when the antenna is positioned at other positions (within the protection range of the lightning rod), the tower body is used as a grounding conductor; the invention optimizes the calculation formula of the grounding resistance, simultaneously considers the influence of the horizontal grounding body, the vertical grounding body and the radial grounding body, and provides a ground grid transformation scheme based on the existing grounding system of the power iron tower, so that the grounding resistance simultaneously meets the requirements of the power system and the communication system.
Referring to fig. 1, the present invention relates to a lightning protection grounding method for shared iron towers, and the following problems need to be solved in the application process:
1. lightning protection of shared iron tower
The shared iron tower must be provided with lightning protection measures, and the protection range comprises a base station machine room and an antenna feeder system. An outdoor grounding bar is arranged at the position where the feeder line enters the machine room and is used for grounding the last point of the feeder line. According to the conditions of investigation and collection of materials and the relevant requirements of the national design standard GB50689-2011 design Standard for lightning protection and grounding engineering of the communication bureau (station), the communication base station antenna, the feeder line, the cabling rack and other facilities are all within the protection range of the lightning rod, and the lightning rod (rod) protects the antenna at an angle smaller than 45 degrees, so that the communication antennas at the positions of the tower head body section, the tower body and the like are within the protection range of the lightning rod. The lightning rod should be specially provided with a lightning down conductor, and if the electrical connection of the metal component of the iron tower is confirmed to be reliable, the special down conductor is not required to be arranged, and the tower body is used as a grounding conductor.
The communication antenna on the top of the tower is not in the protection range of the lightning conductor (pin), the antenna fixing rod needs to be specially provided with a lightning-protection grounding down lead, the down lead is arranged in the tower body of the power iron tower and close to one side of the pin nail and close to one side of the feeder clamp, so that the installation of the grounding of the feeder is convenient, the down lead is welded and communicated with a grounding net by using galvanized flat steel of 40mm multiplied by 4mm, and the distance between the lead contact of the down lead on the grounding net and other grounding lead contacts on the grounding net is not smaller than 5 m. 16 phi 8mm holes (the strength of the galvanized flat steel should be considered) should be uniformly punched on the upper part, the middle part and the lower part of the down lead for grounding of the antenna feeder.
In order to prevent larger lightning electromagnetic pulses generated by lightning from damaging base stations and antenna equipment, various types of SPDs (SPD surge protectors, also called lightning protectors, electronic devices for providing safety protection for various electronic equipment, instruments and meters and communication lines can be conducted and shunted within a very short time so as to avoid damages of surges to equipment in a loop) are configured at the low-voltage side of a machine room transformer, an alternating current distribution panel, an electric equipment power distribution cabinet, a fine electric equipment port and the like according to the relevant requirements of GB50689-2011 communication bureau (station) lightning protection and grounding engineering). When the communication base station is introduced by adopting power supply line overhead, the maximum through-current capacity of the first-stage SPD of the power supply system of the machine room is increased by one grade upwards, and the SPD can bear the maximum through-current capacity of 120kA and can be additionally provided with an intelligent reclosing overcurrent protector with a self-recovery function. When the feeder line is laid on the power iron tower, no additional protection facility is needed, and the feeder line is directly connected with an outdoor grounding grid and is used for grounding the last point of the feeder line.
2. Design of grounding ground net and resistance reduction
The grounding ground net consists of a machine room ground net, an iron tower ground net and a transformer ground net. The machine room grounding grid comprises a machine room building foundation (comprising a ground pile) and a peripheral annular grounding body. The annular grounding body is laid along the outside of the water scattering points of the machine room building and is welded and communicated with more than two main reinforcing steel bars in the transverse and vertical beam of the machine room building foundation and the main reinforcing steel bars of each ground pile. When the machine room is provided with the anti-static floor, a closed annular grounding wire made of copper wires is laid under the floor and around the machine room, and the closed annular grounding wire is used as a grounding lead row of the metal support of the floor, and the sectional area of the grounding lead row is not less than 50mm2At least two copper grounding wires with the cross section area of 50-75mm2 are led out from the grounding collection wire and are communicated with the south side, the north side or the east side and the west side of the lead row. Various grounding wires in the machine room should be respectively led in from a grounding collecting wire or a grounding network. The machine room connects the working ground, the protective ground and the lightning protection ground to form a combined grounding network according to the principle of voltage sharing and equipotential.
The tower foundation ground net at least extends to the range of 1.5m far away from the four feet of the tower foundation, the grid size is less than 3m multiplied by 3m, and simultaneously, more than 2 main steel bars in the tower foundation ground pile are used as a vertical grounding body of the tower foundation ground net to be welded with the ground net. When the machine room is positioned near the iron tower, the iron tower grounding grid and the machine room grounding grid are welded and communicated with each other once every 3-5m, and the connection point is not less than two points. When the communication iron tower is positioned on the roof of the machine room, no less than two positions of four feet of the iron tower and the lightning protection belt on the roof are welded and communicated, and meanwhile, radiation type grounding bodies are preferably arranged at four corners of a ground grid of the iron tower so as to facilitate lightning current dissipation.
When the power transformer is arranged in the machine room, the ground net of the power transformer can share a combined ground net consisting of the machine room and the iron tower ground net; when the power transformer is arranged outside the machine room, the transformer grounding net and the machine room grounding net or the iron tower are mutually welded and communicated once (at least two parts are communicated) every 3-5m so as to mutually form a grounding net with a closed periphery.
Because the grounding resistance of the original grounding grid can not meet the requirements of a communication system, the original grounding grid needs to be modified. There are many ways to reduce the resistance:
firstly, the grounding body can be deeply buried in the soil; secondly, a plurality of branch wires are used for externally leading the grounding device, and the required length is below the effective length; thirdly, using the resistance reducing agent, wherein the polymer resistance reducing solvent contained in the resistance reducing and corrosion resisting solvent filling layer permeates into the surrounding stratum to form a tree root effect, so that the grounding area can be effectively increased, and further the grounding resistance can be effectively reduced; and fourthly, replacing the soil, namely replacing the soil with higher resistivity in the ground net by using pond sludge, black soil and other substances with lower resistivity, thereby achieving the purpose of reducing the ground resistance.
The invention provides an improved ground grid scheme for reducing resistance of a ground grid, namely, an annular grounding device 2 is expanded on the basis of an original ground grid 1. The annular grounding device 2 consists of a horizontal grounding body 2.1, a vertical grounding body 2.2 and a radial grounding body 2.3, and the annular grounding device 2 and the original grounding grid 1 are on the same horizontal plane and are mutually welded and communicated once every 3-5 m. The original grounding grid 1 and the annular grounding device 2 form a new grounding grid to meet the grounding requirement of the shared iron tower.
3. Calculation of resistance of ground resistor
The relation between the grounding resistance value and the ground screen coverage area can be calculated by a corresponding formula.
Ground resistance R of horizontal ground net1Is vertically groundedThe pole grounding resistance is R2Mutual grounding resistance R between horizontal grounding grid and vertical grounding electrodem. Total ground resistance RGComprises the following steps:
in the formula, R1A ground resistance (Ω) for a horizontal ground screen; r2A ground resistance (Ω) which is a vertical ground electrode; rm is the mutual grounding resistance (omega) between the horizontal grounding grid and the vertical grounding electrode;
ground resistance of horizontal ground net:
where ρ is the soil resistivity (Ω · m); l isCThe total length (m) of the horizontal grounding electrode; h is the buried depth (m) of the earth screen; d is the diameter (m) of the horizontal earth conductor; s is the area covered by the conductor (m)2)
Ground resistance of vertical ground electrode:
where ρ is the resistivity of soil (Ω · m) and S is the coverage area of the conductor (m)2) N is the number of vertical grounding electrodes; l isRA length (m) for each vertical ground electrode; h is the buried depth (m) of the earth screen; b is the diameter (m) of the vertical ground conductor.
The mutual grounding resistance between the horizontal grounding grid and the vertical grounding electrode is as follows:
in the formula, n is the number of the vertical grounding electrodes; l isRFor each ground electrode length (m); h is the buried depth (m) of the earth screen; b is the diameter (m) of the conductor.
The specific grounding resistance calculation steps are as follows:
1) determining basic parameters of soil resistivity rho, the diameter d of a horizontal grounding electrode conductor, the diameter b of a vertical grounding conductor and the coverage area S of the conductor;
2) determining the buried depth h of the earth screen, the number n of vertical grounding bodies and the total length L of the horizontal grounding electrodeCAnd the length L of each vertical grounding electrodeRTaking the value of (A);
3) calculating the grounding resistance R according to the formulas (1) to (4)G。
The formula can calculate a composite grounding system consisting of the horizontal grounding body, the vertical grounding body and the radial grounding body, considers the influence of mutual grounding resistance between the horizontal grounding grid and the vertical grounding body, and reduces calculation errors.
The first embodiment is as follows:
1. lightning protection of the shared iron tower:
the outdoor lightning conductor (rod) has less than 45 degrees of protection to the antenna, so that facilities such as communication base stations, feeders, wiring racks and the like at the positions of the tower head section, the tower body and the like are all within the protection range of the lightning conductor. The lightning rod should be specially provided with a lightning down conductor, and if the electrical connection of the metal component of the iron tower is confirmed to be reliable, the special down conductor is not required to be arranged, and the tower body is used as a grounding conductor. The communication base station on the top of the tower is not in the protection range of the lightning conductor (pin), then the base station fixing rod needs to be specially provided with a lightning-protection grounding down lead, the down lead is arranged in the tower body of the power iron tower and close to one side of the pin nail and close to one side of the feeder clamp, so that the installation of the feeder grounding is convenient, the down lead is welded and communicated with the grounding grid by using galvanized flat steel of 40mm multiplied by 4mm, and the distance between the lead contact of the down lead on the grounding grid and other grounding lead contacts on the grounding grid is not less than 5 m. 16 phi 8mm holes (the strength of the galvanized flat steel should be considered) should be uniformly punched on the upper part, the middle part and the lower part of the down lead for grounding of the antenna feeder.
In a machine room, various types of SPDs (SPD surge protectors, also called lightning protectors) should be arranged at the low-voltage side of a transformer, an alternating current distribution panel, a power distribution cabinet of electric equipment, a port of fine electric equipment, and the like to prevent larger lightning electromagnetic pulses generated by lightning from damaging a base station and antenna equipment. When the communication base station is introduced by adopting power supply line overhead, the maximum through-current capacity of the first-stage SPD of the power supply system of the machine room is increased by one grade upwards, and the SPD can bear the maximum through-current capacity of 120kA and can be additionally provided with an intelligent reclosing overcurrent protector with a self-recovery function. When the feeder line is laid on the power iron tower, no additional protection facility is needed, and the feeder line is directly connected with an outdoor grounding grid and is used for grounding the last point of the feeder line.
2. Design of grounding ground net
The grounding ground net consists of a machine room ground net, an iron tower ground net and a transformer ground net. The machine room grounding grid comprises a machine room building foundation (comprising a ground pile) and a peripheral annular grounding body. The annular grounding body is laid along the outside of the water scattering points of the machine room building and is welded and communicated with more than two main reinforcing steel bars in the transverse and vertical beam of the machine room building foundation and the main reinforcing steel bars of each ground pile. When the machine room is provided with the anti-static floor, a closed annular grounding wire made of copper wires is laid under the floor and around the machine room, and the closed annular grounding wire is used as a grounding lead row of the metal support of the floor, and the sectional area of the grounding lead row is not less than 50mm2At least two grounding collection lines with cross-sectional areas of 50-75mm2The copper grounding wire is communicated with the south side and the north side or the east side and the west side of the lead row. Various grounding wires in the machine room should be respectively led in from a grounding collecting wire or a grounding network. The machine room connects the working ground, the protective ground and the lightning protection ground to form a combined grounding network according to the principle of voltage sharing and equipotential.
The iron tower ground net at least extends to the range of 1.5m far away from the four feet of the tower foundation, the size of the grid is less than 3m multiplied by 3m, and simultaneously, more than 2 main steel bars in the tower foundation ground pile are used as a vertical grounding body of the iron tower ground net to be welded with the ground net. When the machine room is positioned near the iron tower, the iron tower grounding grid and the machine room grounding grid are welded and communicated with each other once every 3-5m, and the connection point is not less than two points. When the communication iron tower is positioned on the roof of the machine room, no less than two positions of four feet of the iron tower and the lightning protection belt on the roof are welded and communicated, and meanwhile, radiation type grounding bodies are preferably arranged at four corners of a ground grid of the iron tower so as to facilitate lightning current dissipation.
When the power transformer is arranged in the machine room, the ground net of the power transformer can share a combined ground net consisting of the machine room and the iron tower ground net; when the power transformer is arranged outside the machine room, the transformer grounding net and the machine room grounding net or the iron tower are mutually welded and communicated once (at least two parts are communicated) every 3-5m so as to mutually form a grounding net with a closed periphery.
The grounding body is made of hot galvanized steel, and the specification requirements are as follows: the phi of the steel pipe is 50mm, and the wall thickness is not less than 3.5 mm; the angle steel should not be less than 50mm multiplied by 50mm, and the flat steel should not be less than 40mm multiplied by 4 mm. The length of the vertical grounding bodies is preferably 1.5-2.5m, and the distance between the vertical grounding bodies is 1.5-2 times of the length of the vertical grounding bodies. If the soil is in a place with uneven resistivity, the resistivity of the soil at the lower layer is low, and the soil can be properly lengthened. In the areas with stronger saline-alkali corrosion or higher earth resistivity and difficult to meet the requirement of the grounding resistance, the grounding body is preferably a non-metal grounding body with corrosion resistance and good moisture retention. All welding points between the grounding bodies except those poured in concrete should be subjected to anti-corrosion treatment. The welding length of the grounding device is 2 times of the width of flat steel, and the diameter of the grounding device is 10 times of that of round steel. The upper end of the grounding body is not less than 0.7m away from the ground, and in cold regions, the grounding body is buried below a frozen soil layer.
The grounding wire is suitable for short and straight, and the carrying area is 35-95mm2The material is a multi-strand copper wire. The length of the grounding lead-in wire is not more than 30m, the grounding lead-in wire is made of galvanized flat steel, and the sectional area is not less than 40mm multiplied by 4mm or not less than 95mm2A plurality of strands of copper wire. The grounding lead-in wire should be treated with corrosion-proof and insulation, and should not be laid in the heating trench, and should avoid the sewage pipeline and the ditch when being buried, and should be exposed on the part above the ground, and should have measures for preventing mechanical damage. The grounding lead-in wires are led out nearby from the central part of the ground screen and are communicated with grounding collection wires in the machine room, and the number of the grounding lead-in wires is not less than two for a newly built station. The ground collection line is generally designed into a ring or row shape, the material is copper material, and the sectional area should not be less than 120mm2Galvanized flat steel with the same resistance value can also be adopted. The ground collection lines in the machine room can be installed in the ground grooves, on the wall surface or on the cabling rack, and the ground collection lines should be insulated from the construction steel bars.
3. Examples of land grid modifications
The resistivity of soil in a certain place is 300 omega.m, the original ground grid is a composite ground grid consisting of a horizontal ground grid and vertical grounding bodies, the horizontal ground grid is an annular grounding body with the side length of 5m, and the vertical grounding bodies with the length of 2m are welded at four corners of the annular grounding body. The diameter of the grounding body is 50mm, the embedding depth is about 0.8m, and the grounding resistance of the original ground grid is 21.52 omega. The method comprises the steps of carrying out outward expansion treatment on the basis of an original grounding grid, additionally arranging an annular grounding body with the side length of 10m on the periphery of the original horizontal grounding grid, connecting the annular grounding body with the original grounding grid in a welding mode, additionally arranging a radial grounding body with the length of 5m on the annular grounding body, and welding vertical grounding bodies with the length of 2m at four corners of the annular grounding body and the tail end of the radial grounding body. The ground resistance of the reconstructed earth screen is calculated.
Ground resistance of horizontal ground net:
ground resistance of vertical ground electrode:
the mutual grounding resistance between the horizontal grounding grid and the vertical grounding electrode is as follows:
the total ground resistance is:
the ground resistance of the improved grounding grid is 9.3 omega and less than 10 omega, and the lightning protection grounding standard of the communication system is met.
According to the lightning protection grounding method for the shared iron tower, the standard of the power system and the standard of the communication system are met by modifying the original lightning protection system and the grounding system of the shared iron tower, so that an AAU (active antenna unit carried on the iron tower) can be erected on the power iron tower, and the stable work of the power system and the communication system is ensured. The technical effects are mainly embodied in the following aspects:
1. the lightning protection grounding method for the shared iron tower considers the carrying conditions of various communication antennas, provides communication antenna lightning protection schemes of different carrying positions and solves the problem of lightning protection of the shared iron tower.
2. The lightning protection grounding method for the shared iron tower adopts the strategy that the transformer and the machine room are placed at the bottom of the tower, so that the transformer and the machine room share the same grounding grid, the lightning protection grounding requirements of the transformer, the machine room and the tower are met, the land utilization area is saved, and the economic cost is reduced.
3. The invention provides a lightning protection grounding method of a shared iron tower, and provides a new grounding resistance calculation formula which can calculate a composite grounding system consisting of a horizontal grounding body, a vertical grounding body and a radial grounding body, and takes the influence of mutual grounding resistance between a horizontal grounding net and the vertical grounding body into consideration, so that calculation errors are reduced. The resistance value of the grounding resistor can be calculated according to local field conditions and used as a reference for actual construction. Therefore, a reasonable construction scheme is made, unnecessary workload and economic waste are avoided, the lightning protection grounding requirement of the base station can be met, and the utilization of the land range as small as possible can be guaranteed.
4. The invention discloses a lightning protection grounding method of a shared iron tower, and provides an earth network transformation scheme, which can perform external expansion and resistance reduction on the original earth network so as to meet the requirements of a communication system and provide favorable conditions for implementation of the shared iron tower.
5. The lightning protection grounding method for the shared iron tower, disclosed by the invention, has the advantages that the open sharing of the power tower and the communication tower is realized, the huge 'interest' is formed for promoting the coordinated development of power and communication infrastructure, particularly for the upcoming 5G network deployment, and the multiple purposes are realized.
In the above embodiments, the present invention is described only by way of example, but those skilled in the art, after reading the present patent application, may make various modifications to the present invention without departing from the spirit and scope of the present invention.
Claims (9)
1. A lightning protection grounding method of a shared iron tower is characterized in that: when the antenna is positioned on the top of the tower, the antenna is not within the protection range of the lightning rod, the lightning-arrest grounded downlead is arranged on the antenna fixing rod, the downlead is arranged inside the body of the electric power iron tower, and the downlead is communicated with the grounding grid in a welding mode; when the antenna is positioned at other positions, the tower body is used as a grounding conductor within the protection range of the antenna lightning rod.
2. The lightning protection grounding method for the shared iron tower according to claim 1, wherein: the distance between the lead contact point of the down lead on the grounding grid and other grounding lead contact points on the grounding grid is not less than 5 m.
3. The lightning protection grounding method for the shared iron tower according to claim 1, wherein; the down lead is evenly perforated with 16 phi 8mm holes at the upper part, the middle part and the lower part for the grounding of the antenna feeder line.
4. The lightning protection grounding method for the shared iron tower according to claim 1, wherein: SPDs are configured at the low-voltage side of a machine room transformer, an alternating current distribution panel, an electric equipment power distribution cabinet and fine electric equipment ports; when the communication base station is introduced in a power supply line overhead manner, the maximum through-current capacity of the first-level SPD of the machine room power supply system is improved by one level upwards, and the feeder line is directly connected with an outdoor grounding network and is used for grounding the last point of the feeder line.
5. The lightning protection grounding method for the shared iron tower according to claim 1, wherein: the grounding grid comprises an original grounding grid and an annular grounding device, the annular grounding device comprises a horizontal grounding body, a vertical grounding body and a radial grounding body, and the annular grounding device and the original grounding grid are on the same horizontal plane and are mutually welded and communicated once every 3-5 m;
the grounding grid also comprises a machine room grounding grid, an iron tower grounding grid and a transformer grounding grid; the machine room and the transformer can be arranged at the bottom of the tower;
the machine room grounding grid comprises a machine room building foundation and a peripheral annular grounding body; the annular grounding body is laid along the outside of a water scattering point of the machine room building and is welded and communicated with more than two main reinforcing steel bars in a transverse and vertical beam of a foundation of the machine room building and main reinforcing steel bars of each ground pile;
the iron tower ground net at least extends to the range of 1.5m far away from the four feet of the tower foundation, the size of the grid is less than 3m multiplied by 3m, and more than two main steel bars in the tower foundation ground pile are used as a vertical grounding body of the iron tower ground net to be welded with the iron tower ground net.
6. The lightning protection grounding method for the shared iron tower according to claim 5, wherein: when the iron tower is positioned on the roof of the machine room, no less than two positions of four feet of the iron tower and the lightning protection belt on the roof are welded and communicated nearby.
7. The lightning protection grounding method for the shared iron tower according to claim 5, wherein: when the machine room is positioned near the iron tower, the iron tower grounding net and the machine room grounding net are welded and communicated with each other once every 3-5m, and the connection point is not less than two points.
8. The lightning protection grounding method for the shared iron tower according to claim 5, wherein: when the power transformer is arranged in the machine room, the transformer ground net is a combined ground net consisting of a machine room ground net and an iron tower ground net; the power transformer is arranged outside the machine room, and a grounding grid of the transformer and a grounding grid of the machine room or a grounding grid of an iron tower of the grounding grid of the transformer are mutually welded and communicated once every 3-5m to form a grounding grid with a closed periphery.
9. A method for calculating the grounding resistance of a lightning protection grounding ground network of a shared iron tower is characterized by comprising the following steps: the calculation formula of the grounding resistance is as follows:
in the formula, R1A ground resistance (Ω) for a horizontal ground screen; r2A ground resistance (Ω) which is a vertical ground electrode; rmIs the mutual grounding resistance (omega), R between the horizontal grounding grid and the vertical grounding electrodegIs a ground resistor;
where ρ is the soil resistivity (Ω · m); l isCThe total length (m) of the horizontal grounding electrode; h is the buried depth (m) of the earth screen; d is the diameter (m) of the horizontal earth conductor; s is the area covered by the conductor (m)2)；
Where ρ is the resistivity of soil (Ω · m) and S is the coverage area of the conductor (m)2) N is the number of vertical grounding electrodes; l isRA length (m) for each vertical ground electrode; h is the buried depth (m) of the earth screen; b is the diameter (m) of the vertical ground conductor;
in the formula, n is the number of the vertical grounding electrodes; l isRFor each ground electrode length (m); h is the buried depth (m) of the earth screen; b is the diameter (m) of the conductor;
the grounding resistance calculation steps are as follows:
s1: determining basic parameters of soil resistivity rho, the diameter d of a horizontal grounding electrode conductor, the diameter b of a vertical grounding conductor and the coverage area S of the conductor;
s2 determining buried depth h of the earth screen, number n of vertical grounding bodies and total length L of horizontal grounding electrodeCAnd the length L of each vertical grounding electrodeRTaking the value of (A);
s3 calculating the grounding resistance R according to the formulagAnd R isgAnd comparing with a grounding standard resistance value.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202010018428.4A CN111244629B (en) | 2020-01-08 | 2020-01-08 | Lightning protection grounding method of shared iron tower |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202010018428.4A CN111244629B (en) | 2020-01-08 | 2020-01-08 | Lightning protection grounding method of shared iron tower |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN111244629A true CN111244629A (en) | 2020-06-05 |
| CN111244629B CN111244629B (en) | 2021-08-17 |
Family
ID=70880416
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202010018428.4A Active CN111244629B (en) | 2020-01-08 | 2020-01-08 | Lightning protection grounding method of shared iron tower |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN111244629B (en) |
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111834920A (en) * | 2020-06-17 | 2020-10-27 | 山东电力工程咨询院有限公司 | Lightning rod and wireless base station iron tower combined construction structure and grounding method thereof |
| CN111864420A (en) * | 2020-07-20 | 2020-10-30 | 广东电网有限责任公司 | Three-dimensional ground net |
| CN112086861A (en) * | 2020-07-31 | 2020-12-15 | 中国电建集团河北省电力勘测设计研究院有限公司 | Transformer substation lightning rod capable of serving as 5G base station antenna tower |
| CN112563769A (en) * | 2020-12-03 | 2021-03-26 | 上海宝冶集团有限公司 | Lightning protection grounding method for wind generating set in high resistivity area |
| 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 |
| CN112652896A (en) * | 2020-12-28 | 2021-04-13 | 国网河南省电力公司经济技术研究院 | Electric power and communication sharing iron tower complete set current-limiting grounding device |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108667079A (en) * | 2018-05-18 | 2018-10-16 | 云南电网有限责任公司电力科学研究院 | A kind of shared steel tower of power communication and its dispatching method of participation dispatching of power netwoks |
| CN108711684A (en) * | 2018-05-18 | 2018-10-26 | 云南电网有限责任公司电力科学研究院 | A kind of electric force pole tower shared system |
| CN108761175A (en) * | 2018-05-18 | 2018-11-06 | 云南电网有限责任公司电力科学研究院 | A kind of ground potential rises detecting system and transmission line lightning stroke situation determines method |
-
2020
- 2020-01-08 CN CN202010018428.4A patent/CN111244629B/en active Active
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108667079A (en) * | 2018-05-18 | 2018-10-16 | 云南电网有限责任公司电力科学研究院 | A kind of shared steel tower of power communication and its dispatching method of participation dispatching of power netwoks |
| CN108711684A (en) * | 2018-05-18 | 2018-10-26 | 云南电网有限责任公司电力科学研究院 | A kind of electric force pole tower shared system |
| CN108761175A (en) * | 2018-05-18 | 2018-11-06 | 云南电网有限责任公司电力科学研究院 | A kind of ground potential rises detecting system and transmission line lightning stroke situation determines method |
Non-Patent Citations (1)
| Title |
|---|
| 鲁修学，胡淑兵，胡能萍: "电力铁塔与通信行业共享的技术研究", 《2019年江西省电机工程学会年会论文集》 * |
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111834920A (en) * | 2020-06-17 | 2020-10-27 | 山东电力工程咨询院有限公司 | Lightning rod and wireless base station iron tower combined construction structure and grounding method thereof |
| CN111864420A (en) * | 2020-07-20 | 2020-10-30 | 广东电网有限责任公司 | Three-dimensional ground net |
| CN112086861A (en) * | 2020-07-31 | 2020-12-15 | 中国电建集团河北省电力勘测设计研究院有限公司 | Transformer substation lightning rod capable of serving as 5G base station antenna tower |
| CN112563769A (en) * | 2020-12-03 | 2021-03-26 | 上海宝冶集团有限公司 | Lightning protection grounding method for wind generating set in high resistivity area |
| 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 |
| CN112652896A (en) * | 2020-12-28 | 2021-04-13 | 国网河南省电力公司经济技术研究院 | Electric power and communication sharing iron tower complete set current-limiting grounding device |
| CN112652896B (en) * | 2020-12-28 | 2022-07-05 | 国网河南省电力公司经济技术研究院 | Electric power and communication sharing iron tower complete set current-limiting grounding device |
Also Published As
| Publication number | Publication date |
|---|---|
| CN111244629B (en) | 2021-08-17 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN111244629B (en) | Lightning protection grounding method of shared iron tower | |
| CN201975524U (en) | Arrangement structure for lightning protection grounding device of power tower | |
| CN103457044B (en) | The earthing device of 10kV distribution network overhead line tower pole and laying method thereof | |
| CN111541121A (en) | Method for reducing impact grounding impedance of power transmission line tower | |
| CN211182560U (en) | Novel tower lightning grounding device | |
| CN204156112U (en) | A kind of grounding system | |
| Basholli et al. | Protection of buildings on a university campus from lightning strikes | |
| CN203475926U (en) | Expanded type tower insulator crossarm assembly | |
| CN205092323U (en) | Lump formula earthing device , power station ground system | |
| CN105375126B (en) | The lightning protection earthing system of communication base station | |
| CN105186147B (en) | A kind of lump type earthing or grounding means, power station earthed system and construction method | |
| CN205790429U (en) | Lightning protection grounding component | |
| CN212908136U (en) | Combined grounding system of sewage treatment plant | |
| CN104184015A (en) | Installation construction process for grounding device | |
| CN105426558A (en) | Method for determining electrical connection mode between substation grounding grid and base station grounding grid | |
| CN209691432U (en) | A kind of resistance to dilatory cable | |
| CN215497123U (en) | Grounding structure of high-energy electron accelerator | |
| CN203910988U (en) | Cage type structure anticorrosion resistance reducing grounding pole suitable for small grounding net | |
| CN2796160Y (en) | Overvoltage protective earthing device for insulation conductor deep leading into earth | |
| CN106711905A (en) | Power transmission line anti-windage yaw pole based on flexible composite material and construction method thereof | |
| CN204333704U (en) | A kind of composite lightning-protection device of spherical thunder | |
| Naranjo-Villamil et al. | On the calculation of electrical surges in underground cables due to a direct lightning strike | |
| CN1855634A (en) | Overvoltage protecting ground device with insulative wire leading underground deeply | |
| CN208209029U (en) | Photovoltaic plant earthed system | |
| CN208753548U (en) | A kind of novel shaft tower grounding-for-lightning device |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |