GB 7946-1987 Installation and safe use of electrified barbed wire and electric fences
Some standard content:
National Standard of the People's Republic of China
Installation and safe operation of electricallyenergized entanglements and electric fencesUDC 728. 9: 621
3: 614.8 | use.
1 Terminology
The following terms apply to this standard.
1.1 Electrically energized barbed wire mesh (power grid)
Electrically energized entangiement is used to prevent the human body from crossing electrified obstacles. It consists of industrial frequency power supply, power leads, barbed wire, grounding devices and signaling devices. 1.2 Electric fence
elertric fence
A live obstacle used to prevent sexual livestock or wild animals from crossing. It consists of pulse power supply, power lead, barbed wire, grounding device and signaling device.
1.3 Barbed wire
entanglement
An integral part of the power grid or electric fence, consisting of iron wire (or barbed wire), pin insulators and pillars. 1.4 Protection net
barrier
A non-charged obstacle installed on one or both sides of the power grid to prevent the human body from approaching the power grid. 2 Design and installation requirements
2.1 To install the power grid or electric fence, you need to apply to the public security department, and construction can only be done after approval. 2.2 The power supply equipment should be dedicated (except for the low-voltage power grid). The high-voltage power grid uses a power frequency (50Hz) single-phase double-winding transformer as the power supply equipment, and the output voltage is not higher than 1.5kV. The electric fence uses pulse power supply equipment. If it receives power from the power grid, it should be equipped with a double-winding transformer. The output peak voltage should not be higher than 5kV and meet the following technical indicators: pulse width: less than or equal to 0.15;
a.|| tt||h.
c.
Pulse interval: not less than 0.75$;
Each pulse output power: less than 2.5mC; instantaneous output current value: less than 0.3ms or more 300mA; the average effective value of freewheeling during the pulse stop period: less than 0.7mA. The voltage to ground must be 250V or below.
** means the voltage to ground is above 250V.
Approved by the National Bureau of Standards on June 10, 1987
Implemented on 1988-03-01
1
GB7946—87
With 1: technical indicators See Appendix A (reference part) for test conditions. 2.3 The power leads can be overhead wires or power cables. 2.4 Barbed wire mesh is generally composed of #12 ($2.8) galvanized iron wire or #14 (±2.2) multi-strand barbed wire and pin insulators. 2.5 The height of the high-voltage power grid installed on the fence shall not be less than 4.0m (from the ground); the height of the fence of the low-voltage power grid shall not be less than 2.5m. The distance between the iron wires and the distance between the bottom iron wire and the grounded part of the top of the fence are both 200mm. 2.6 For power grids installed on flat ground, protective nets should be installed on one or both sides. The height should not be less than 1.2m, and the spacing between wires and the distance from the bottom wire to the ground should be 200mm. The clear distance between the protective net and the power grid shall not be less than 950mm. The protective net should be grounded, and the repeated grounding interval should be 50m. 2.7 The distance between power grid pillars should not be greater than 4m, the distance between electric fence pillars should not be greater than 6m, and a "Beware of Electric Shock" warning sign should be hung on every five pillars. Its graphics and size are in accordance with the provisions of GB2894-82 "Safety Signs" (the observation distance is 10m). The power grid should also hang red signal lights, one on every five pillars, and stagger the positions of warning signs. 2.8 For adjacent electric fences, the distance between adjacent wire fences and adjacent power supply leads shall not be less than 2m. If you need to seal the gap between adjacent electric fences, use insulating material. 2.9 The horizontal distance between the wire mesh of the power grid and electric fence and its power leads and the edge of the public road should be greater than 5m. 2. Overhead power lines of 101kV and below must not cross with the overhead power leads of electric fences, and the horizontal distance must be at least 2m. The height of electric fence wire shall not exceed 2m within 2m on both sides (from the outside conductor) of overhead power lines of 1kV and below. Overhead power lines above 1kV shall not cross with the overhead power leads of electric fences. When the height of the lead pole does not exceed 6m, the horizontal distance between the overhead power line and the lead wire should be 10m; when the height of the lead pole exceeds 6m, the horizontal distance should be greater than 10m. Within 10m on both sides of an overhead power line above 1kV (counting from the outer conductor), the height of the electric fence wire mesh shall not exceed 1.5m.
2.11 The minimum distance between the overhead power line and the power grid is shown in Table 1. Table 1 Minimum distance between overhead power lines and power grid
Overhead power lines
Voltage level.kv
10 and below
35~110
220||tt| |330
500
horizontal distance, m
2.5
5
t.
9
9|| tt||Minimum distance from the power grid
Vertical distance, m
2
3
5
5
2.12 Outside the communication line The horizontal distance between the conductors and the wire mesh of the power grid and electric fence and their power leads shall not be less than 2m. 2.13 Metal railings, water pipes and electric poles of power or communication lines shall not be used as pillars for the wire mesh of power grids and electric fences and their power leads.
2.14 When the electric fence receives power from the power grid, the switch should be able to automatically trip and cut off each pole, and the opening and closing positions should be obvious. It should be fixedly connected to the power line outdoors, and plug-in connectors are allowed to be connected indoors. 2.15 The power supply equipment of electric fences shall not be installed in flammable buildings such as grain yards and stockyards. 2.16 Lightning protection devices (lightning arresters or discharge gaps, etc.) should be installed on the high and low voltage sides of the power grid and electric fence. The ground wire of the lightning protection device should be connected to the metal shell of the power transformer and grounded together. CB 7946 -87
2.17 Plants should be prevented from growing upward along electric grids and electric fences. The minimum distance between wires and plants is 200mm. 2.18 In order to prevent the human body from contacting high-voltage power equipment, fences, mesh barriers or plate barriers can be installed around them, and warning signs about electric shock hazards can be hung.
The height of the fence shall not be less than 1.2m. The distance between the lowest railing and the ground shall not be greater than 200mm. The height of the mesh barrier is 1.7m, and the mesh opening is no larger than 40mm×40mm. 2.19 The clear distance from the live bare conductor of 1kV and above outside the star to the grounded part is 200mm, to the fence is 950mm, and to the mesh barrier is 300mm. The distance from the live part of the outlet wall bushing to the road surface of the external passage is 4m (see Figure 1) . (a) | | tt | (B) | The distance to the plate-shaped shield is 105mm, and the distance from the bare conductor without shield to the ground is 2375mm (see Figure 2). (a)wwW.bzxz.Net
(a) live part to grounded part;
(b) live part to fence;
(c) live part to mesh barrier and plate barrier . (b)
Figure 2 Schematic diagram of the safety distance of live equipment in the house Figure j: A-...the charged bare conductor is 105mm from the plate barrier and 175mm from the mesh barrier. 2.21 In areas with polluted air, measures such as dust prevention, anti-corrosion and insulation strength improvement should be taken for outdoor electrical equipment. 2.22 When the ambient temperature is lower than the freezing point of the insulating oil, a heating device should be installed at the bottom of the outdoor oil-filled appliance. In areas with serious snow and ice coverage, measures should be taken as much as possible to prevent accidents caused by ice and snow. 2.23 In areas where typhoons frequently strike or where wind speeds exceed 35m/year, equipment and foundations should be strengthened to be fixed. (c)
GB 7946
87
2.24 In areas where the earthquake intensity exceeds 8 degrees, anti-seismic measures should be taken, such as adding fixed fulcrums, strengthening foundations, etc. 2.25 In areas where the altitude exceeds 1000m, electrical equipment suitable for that altitude should be selected. 2.26 The grounding of electric fences should be separated from the grounding of power lines and should be at least 10m apart. 2.27 The grounding body of the power grid and electric fence should be buried at least 500mm deep and buried in humid places. The grounding resistance should not be greater than 10α. 2.28 The grounding body can be vertically laid angle steel, round steel, steel pipe or horizontally laid round steel, flat steel, etc. The specifications of the grounding body and grounding wire should not be less than the values ??listed in Table 2. Table 2 Minimum specifications of grounding bodies and grounding wires
Weight
Round steel diameter.mm
Flat
Steel
Angle steel thickness, mm||tt ||Steel pipe wall thickness, mm
Section, mm
Thickness, mm
Galvanized steel strand section, mm
Ground
6|| tt||上
48
4
25
2.29 For electric fences powered by batteries, the battery room should meet the following requirements: a.||tt| |The battery room should be fire-proof, acid (alkali)-proof, and explosion-proof. The battery room should be well ventilated, and the minimum temperature should not be lower than αC. b.
c.
The battery room should be drainable.
Ground
48
Today
3.5
In order to reduce the temperature difference of electrolyte in each battery, the battery room should be protected from direct sunlight and dust Waiting for intrusion into the room. d.
e.
The distance between the battery and the wall is 150mm. The distance between adjacent bare busbars and between bare busbars and grounded parts is 50mm, and the distance between busbar support points is 2m.
The battery should be installed on an acid (alkali) resistant stand. A glass insulating pad should be placed between each battery and the stand. A glass insulating pad should also be placed between the battery base and the glass f.
Acid (alkali) resistant paper pad. A glass insulating pad should also be placed between the battery stand and the ground. 3 Operation requirements
3.1 The operation and maintenance of the power grid and electric fence must be performed by qualified electricians. 3.2 The operating parts of the power supply equipment should be made of insulating materials. Insulating mats should be laid around indoor power equipment. 3.3 When high-voltage equipment is energized, electricians are not allowed to cross fences or barriers to perform repair work. 3.4 When the high-voltage equipment is grounded and there is no power outage, the human body is not allowed to enter the room centered on the fault point. Within a radius of 4m; human beings are not allowed to enter outdoors within a radius of 8m centered on the fault point. If you need to enter the above range, you must wear insulating boots, and when touching the shell of the equipment, you should wear insulating gloves. 3.5 When the power supply is interrupted, you must not touch high-voltage equipment or enter the fence (shield) before opening the relevant knife gates and taking safety measures to prevent sudden calls.
3.6 Insulating gloves should be worn when closing high-voltage knife switches, and goggles and insulating gloves should be worn when closing high-voltage fuses. 3.7 The power grid and electric fence equipment should be regularly inspected and maintained. After the transformer and pulse power supply are overhauled, an AC power frequency (50Hz) withstand voltage test should be performed. The withstand voltage standard for the high-voltage output side is 10kV for 1 minute, and the withstand voltage standard for the low-voltage input side is 2kV for 1 minute. 3.8 The operation of the equipment should be checked regularly, and the battery voltage, electrolyte ratio and liquid level height of the battery should be measured every week. 4
A.1 Peak voltage test
GB 7946 --87
Appendix A
Electric fence pulse power supply test conditions
(reference part)| |tt||A.1.1 The test load is a parallel resistor-capacitor circuit composed of a 1M2 non-inductive resistor and an adjustable capacitor of 0~0.2μF. A.1.2 Put the test load across the output terminals and adjust the capacitor to maximize the voltage. The maximum peak voltage seen on the oscilloscope should not be higher than 5kV.
A.2 Output current test
A.2.1 The test load is a parallel resistor-capacitor circuit composed of a non-inductive resistor of 5002 and an adjustable capacitor of 0~0.2μF. A.2.2 Put the test load across the output terminals, adjust the capacitor to maximize the output current, and the instantaneous value of the output current should be less than 300mA when it exceeds 0.3ms.
A.3 Pulse width and pulse interval test
A.3.1 The test load is the same as A.2.1, and the wiring and adjustment are the same as A.2.2. A.3.2 Measure the width from the start of the pulse to when the instantaneous value drops to 5mA, which should be less than or equal to 0.1s, and the pulse interval should not be less than 0.75s. A.4 Inter-pulse freewheeling test
A.4.1 The test load is the same as A.2.1, and the wiring and adjustment are the same as A.2.2. A.4.2 Measure the average effective value of the freewheeling between two adjacent pulses. It should be less than 0.7mA. A.5 Pulse output power test
A.5.1 The test load is the same as A.2.1, and the wiring and adjustment are the same as A.2.2. A.5.2 Use an oscilloscope to measure the area of ??each pulse. If a pulse contains one or several cycles, the area above and below the horizontal axis should be included. Each pulse output power should be less than 2.5mC.
Note: The above tests all use oscilloscopes.
Additional notes:
This standard is proposed and centralized by the Electric Power Branch of the National Electrical Safety Standardization Technical Committee. This standard was drafted by the Standardization Research Office of the Institute of Science and Technology Information of the Ministry of Water Resources and Electric Power. The main drafter of this standard is Dai Yaoji.
The instantaneous value of the output current should be less than 300mA when it exceeds 3ms.
A.3 Pulse width and pulse interval test
A.3.1 The test load is the same as A.2.1, and the wiring and adjustment are the same as A.2.2. A.3.2 Measure the width from the start of the pulse to when the instantaneous value drops to 5mA, which should be less than or equal to 0.1s, and the pulse interval should not be less than 0.75s. A.4 Inter-pulse freewheeling test
A.4.1 The test load is the same as A.2.1, and the wiring and adjustment are the same as A.2.2. A.4.2 Measure the average effective value of the freewheeling between two adjacent pulses. It should be less than 0.7mA. A.5 Pulse output power test
A.5.1 The test load is the same as A.2.1, and the wiring and adjustment are the same as A.2.2. A.5.2 Use an oscilloscope to measure the area of ??each pulse. If a pulse contains one or several cycles, the area above and below the horizontal axis should be included. Each pulse output power should be less than 2.5mC.
Note: The above tests all use oscilloscopes.
Additional notes:
This standard is proposed and centralized by the Electric Power Branch of the National Electrical Safety Standardization Technical Committee. This standard was drafted by the Standardization Research Office of the Institute of Science and Technology Information of the Ministry of Water Resources and Electric Power. The main drafter of this standard is Dai Yaoji.
The instantaneous value of the output current should be less than 300mA when it exceeds 3ms.
A.3 Pulse width and pulse interval test
A.3.1 The test load is the same as A.2.1, and the wiring and adjustment are the same as A.2.2. A.3.2 Measure the width from the start of the pulse to when the instantaneous value drops to 5mA, which should be less than or equal to 0.1s, and the pulse interval should not be less than 0.75s. A.4 Inter-pulse freewheeling test
A.4.1 The test load is the same as A.2.1, and the wiring and adjustment are the same as A.2.2. A.4.2 Measure the average effective value of the freewheeling between two adjacent pulses. It should be less than 0.7mA. A.5 Pulse output power test
A.5.1 The test load is the same as A.2.1, and the wiring and adjustment are the same as A.2.2. A.5.2 Use an oscilloscope to measure the area of ??each pulse. If a pulse contains one or several cycles, the area above and below the horizontal axis should be included. Each pulse output power should be less than 2.5mC.
Note: The above tests all use oscilloscopes.
Additional notes:
This standard is proposed and centralized by the Electric Power Branch of the National Electrical Safety Standardization Technical Committee. This standard was drafted by the Standardization Research Office of the Institute of Science and Technology Information of the Ministry of Water Resources and Electric Power. The main drafter of this standard is Dai Yaoji.
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