Lightning protection engineering design, budget, testing, auditing internship report

During my sophomore summer vacation, I came to the Henan Provincial Lightning Protection Center for internship. On July 18th, 2005, I came here on the first day. During the internship, I tried to put my theoretical knowledge in school into practice. Transformation, try to combine theory with practice, be able to abide by work discipline during the internship, not late, leave early, and earnestly complete the work assigned by the leaders and engineers of various departments and other professional and technical personnel, and they have won unanimous praise, but also found Many shortcomings of myself.

Thank you for providing me with such a good internship opportunity. In just one month, it was soon over. In this internship, I mainly worked in the engineering department, so I had the opportunity to participate in the design and construction of lightning protection projects such as new construction, renovation and expansion, and lightning disaster assessment. At the same time, the testing department and the auditing department also participated in the field inspection and acceptance of lightning protection projects and the review and evaluation of lightning protection engineering drawings. The combination of theory and practice has enabled me to have a clearer understanding of lightning protection engineering design, lightning protection engineering budget, lightning protection engineering inspection and acceptance, lightning protection engineering review and severe forms of lightning disasters.

Lightning protection engineering design

Combining with the knowledge I have learned, during the school hours, we mainly designed simple lightning protection for the second and third types of buildings and the inductive lightning protection of the low-voltage home line. During the internship, I had the opportunity to get in touch with the computer room. Lightning protection design, lightning protection design of the reconstruction and expansion project, lightning protection design of mobile communication station, gas station and other projects, so I have a clearer design idea for lightning protection engineering design:

First determine the characteristics of the protected object, determine the type of protected object, such as buildings, flammable and explosive places, information systems.

1. Building lightning protection

Firstly, lightning protection classification is carried out. According to the lightning protection category, according to the building lightning protection code GB50057-94, it should be clear that various preventive measures are designed one by one, and the main lightning protection projects are; a. direct lightning protection; b. Protection; c. lightning wave intrusion measures; d. other lightning protection measures.

2. Flammable and explosive

According to the nature of inflammable and explosive places, the corresponding design specifications should be found, and the lightning protection measures should be carried out in combination with the lightning protection measures of the first or second type of buildings in GB50057-94.

3. Information System

First, the entire system is divided into two parts: external lightning protection and internal lightning protection.

External lightning protection: There are mainly lightning receptors, down conductors and grounding devices.

Internal lightning protection: The main measures are power supply arrester, signal lightning protection prohibition, equipotential bonding, and integrated wiring.

Lightning system protection and signal system and computer network system lightning protection is the most important part of induction lightning protection, and it is also the most prone to accidents.

A. Protection of weak current system

The line is buried in the household and is equipped with a surge protector for classification protection. The surge protectors of the power line should be installed at the front end of the power line of the protected equipment. The terminals of the surge protector should be separately distributed. The line of the same name of the line inside the box is connected. Connect the grounding end of the surge protector to the grounding terminal block of the protective grounding wire of the power distribution box. The grounding terminal block of the power distribution box should be connected to the equipotential grounding terminal block of the lightning protection zone. The line connecting the surge protectors at all levels should be straight and the length should not exceed 0.5m. The power line surge protector with terminal block should be crimped; the surge protector with terminal block should be connected with the wire nose and the terminal.

B. Signal system and computer network system lightning protection

Install a surge protector for protection. The signal line surge protector SPD should be connected to the signal connection of the protected equipment. The SPD output of the surge protector is connected to the connection port of the protected device. The surge protector SPD can also be mounted in a cabinet and attached to the equipment rack or to nearby supports. The signal line surge protector SPD grounding end should adopt copper core wire with a cross-sectional area of ​​not less than 1.5mm2 and parts in the equipment room.

The potential ground terminal block is wired. The ground wire should be straight. The surge protector SPD should be securely mounted and properly positioned and routed.

Lightning protection project budget

The lightning protection project budget is the latest knowledge point that I have contacted during the internship process. In the actual project, I have come into contact with some lightning protection budget plans for the reconstruction project, which are summarized as follows:

The cost of construction and installation of lightning protection equipment consists of four parts: engineering direct fee, indirect fee, project profit and tax.

Lightning protection inspection and acceptance

The inspection includes observation, understanding, and measurement. Through the actual lightning protection engineering inspection and acceptance, I have a deeper understanding of the lightning protection project. In the inspection process, I also encountered many problems that were not mentioned in the specification. After the expert's explanation, I gained a lot of new knowledge.

The first is measurement inspection

Understand the environment, location, use properties, height, shape of the lightning protection device, the possibility of lightning strikes and its consequences. And draw a schematic diagram of the plane.

Check out the design drawings to understand the construction of the concealed project.

Detection method: The grounding resistance value is measured by the grounding resistance tester, the material specification is measured with a vernier caliper, the height is measured with a theodolite or a tape measure, the length is measured with a tape measure, and other appearances are detected.

1. Direct lightning protection

1. Detection of the lightning receptor

a. Independent lightning rod; measuring height, material specifications, corrosion protection, electrical connection

b. Lightning rod; lightning rod is mainly used to protect the equipment of the protruding roof. According to the ball radius method, the height and protection range of the lightning rod itself are calculated. The material specification has specific provisions.

c. Lightning protection line: measuring height, material specification, grid size, anti-corrosion, fixed condition, electrical connection. The lightning protection belt should be laid along the corners, ridges, eaves, horns, parapets and other places susceptible to lightning strikes. The lightning protection belts can be in the form of clear or dark coatings. Specific construction specifications are specified.

2. Detection of down-line: measure material specifications, anti-corrosion, wiring, fixing, laying method, and spacing. The down-conductor line should be evenly or symmetrically arranged around the building. It is easy to set the corner. The spacing of the down-conductor line is calculated according to the average circumference of the building. The distance between the lower and lower lines of the first, second and third types of buildings is not more than 12 meters and 18 meters respectively. 25 meters. It is easy to use the main ribs in the reinforced concrete structure column as the down-conducting line, and the hot-dip galvanized steel should be used for the lower line of the lining, and the round steel is preferred. The construction specifications are clearly defined. In the actual test, I also touched many new processes such as: pressure welding butt welding and bolting.

3. Detection of the grounding device: Refer to the design drawings, understand the grounding device to the construction worker and Party A, and make a record.

2. Side lightning protection

When the height of the building exceeds the radius of the ball, anti-side measures should be taken.

1. From no more than 6 meters from the radius of the ball, a pressure equalizing ring is placed around the building and connected to the down conductor.

2. Metallic objects such as metal doors and windows, railings, glass curtain wall metal frames, advertising frames, etc. on the outer radius of the ball should be connected to the equalizing ring.

Grounding resistance measurement

1. Inspection of the instrument before and after the test.

2. Measure soil resistance values ​​to prepare for calculations.

3. Measure the grounding resistance

4. Re-measure the reading and make a record

Induction lightning protection

1. The metal objects such as equipment, pipes, structures, cable metal skins, steel roof trusses, steel windows and other large metal objects and protruding pipes, air ducts and other metal objects in the building should be connected to the grounding device for lightning protection. . Metal roofing and prefabricated components are grounded once every 18-24 meters using the down conductor.

2. For long metal objects such as pipes, structures and cable metal sheaths laid in parallel, when the clearance is less than 100MM, they should be bridged once every 30M with metal wires. The cross-pitch is less than 100MM and the intersection should also be bridged. When the excessive resistance of the elbow, valve, flange, etc. of the metal object is greater than 0.03 Ω, the wire is connected by a wire, and the flange is not less than 5 bolts. In non-corrosive environments, it may not be bridged.

3. The lightning protection grounding device should be shared with the electrical equipment grounding device, and its power frequency grounding resistance should not exceed 10Ω. There should be no less than two connections between the grounding mains in the house and the lightning protection inductive grounding device.

Lightning wave intrusion

1. The low-voltage line should be directly buried by cable. The metal sheath and steel pipe of the cable should be connected to the lightning-proof induction grounding device at the entrance end. When it is difficult to use the cable in the whole line, the reinforced concrete rod and the iron cross-arm overhead line may be used, and a metal armored cable or sheathed cable shall be used to directly penetrate the steel pipe, and the buried length shall conform to the following expression. Requirements, but should not be less than 15m, lightning arresters should be installed at the cable and overhead line connection. Arrester, cable metal sheath, steel pipe and insulator iron feet, fittings, etc. should be grounded together, and the impact grounding resistance should not exceed 10Ω.

2. Overhead metal pipe construction shall be connected to the grounding device of lightning protection induction when entering and leaving the building. The pipeline within 100m of the building should be grounded once every 25m. The grounding resistance of the impact should not exceed 20Ω. It is better to use the metal bracket or reinforced concrete bracket for welding and tying the steel mesh as the down conductor. The reinforced concrete foundation should be used as the reinforced concrete foundation. G. Metal pipes in buried or trenches should also be connected to lightning protection induction grounding devices when entering and leaving the building.

5. Check the high potential generated by the lightning current flowing through the down conductor and the grounding device to check the counterattack of nearby metal objects or electrical lines.

six. For open-pit steel gas tanks with explosion hazard, when the wall thickness is not less than 4MM, the flasher may not be installed, but it should be grounded and the grounding point should not be less than two places. The distance between the two grounding points should not be greater than 30M.

7. An overvoltage protector should be installed at the main distribution box introduced by the power supply. And check if the electrical is grounded.

8. Data processing: All test readings and calculation results should be kept one decimal place.

Lightning protection engineering audit

Under the guidance of architectural theory, during the internship, I was exposed to the entire process of lightning protection engineering review.

I. Review the preliminary work of the drawings

Engineering construction drawing design drawings submitted

The complete set of drawings is divided into three categories: 1. Architectural design Figure 2. Structure drawing 3. Equipment drawing

Equipment drawings include: electric application, water application, etc.

The lightning protection project mainly reviews the “Lightning Protection Ground Plan” and the “Roof Lightning Plan”.

Write the registration form for the design review unit of the new building lightning protection device

Please submit to the examination unit, fill out the "Lightning Protection Device Design Audit Registration Form", and affix the official seal of the submitting unit.

2. Review the drawings and submit audit opinions that meet the requirements of the specifications.

Architectural design

Look at the general description and the general plan to find out the specific location. If it is a building complex, consider the distance between the buildings.

Structural drawing

Look at the description of the structure and find out whether the structural form is brick-concrete or frame-structured.

Electrical construction design

First look at the general electrical instructions, and make corresponding records in order to put forward an audit opinion.

Conduct an item-by-item review in accordance with the auditing points specified by the Ministry of Construction.

The review steps are:

Lightning belt

2. Does the basic down line correspond to the sky down line?

3. Elevator, cable tray, strong and weak electric well

The above steps must be specifically designed and constructed in accordance with the specifications to meet the audit criteria.

Severe forms of thunderstorms and publicity of science knowledge

According to the analysis of lightning disaster materials reported by local lightning protection centers, lightning disasters in Henan Province have a wide range of occurrences, serious hazards, frequent large-scale lightning disasters, frequent rural lightning disasters, winter lightning in some areas, and many lightning strikes. Lightning strike objects are mostly features such as microelectronic devices. Compared with the past, the number of thunderstorms and economic losses have increased significantly in recent years, and the number of deaths from lightning strikes has decreased and the number of injured people has increased. In XX, a total of 6 deaths and 36 injuries were caused by lightning disasters in our province. Compared with 15 deaths and 13 injuries in XX years, the number of deaths decreased and the number of injuries increased significantly. The direct economic loss was 4.721 million yuan. The annual economic loss of 1.422 million yuan has increased significantly. In the XX year, the lightning disasters with more serious hazards were: At about 7:00 pm on June 1, XX, squally showers hit Zhengzhou, and many places were hit by direct lightning strikes, and large-scale blackouts occurred. Key cultural relics protection unit - the top corner of the main exhibition hall of Henan Museum was hit by lightning. There was an obvious gap in this place. Three pieces of cement with a weight of about 10 kg went straight to the exhibition hall, and several hundred square meters of glass were automatically controlled. Serious damage to the monitoring equipment, etc., direct property losses of more than 1 million yuan, fortunately the museum's collection of cultural relics were not damaged. At about 15:50 on May 27, XX, the school building of the First Middle School of Zhonghe Town, Jia County was attacked by lightning. 28 students in the four classrooms on the second floor were injured by lightning. Among them, three or four students were seriously injured. In addition, the two-story teaching building was broken up and down, causing multiple lights, electric gates, fan governors, window glass to be crushed, three concrete arch beams, two concrete floors, and a concrete window sill. pit. Recently, the grievances in our province are very serious. Every time the strong convective weather is accompanied by thunderstorms and winds, it has caused a large area of ​​lightning disasters throughout the province. According to incomplete statistics, as of the date of this year, more than 30 lightning strikes have occurred in the province, resulting in 11 people being killed by lightning and more than 10 injured. The strong convective thunderstorms that occurred only in the early hours of June 21 caused more than 20 lightning strikes in the province, 6 people were killed by lightning, 5 were injured, and the economic losses were huge.

In order to implement the spirit of the provincial bureau archives and ensure that the meteorological services in the flood season are “people-oriented, meticulous and ubiquitous”, and minimize the harm caused by lightning disasters, the provincial lightning protection center actively cooperates with the news media on July 5, XX. In the mainstream media Dahe newspaper, a special edition was launched to carry out special lightning protection publicity, publicizing lightning hazards, how to prevent lightning strikes, countermeasures after lightning strikes, lightning protection hazards, the current situation of lightning protection and disaster reduction management in our province, and the work done by the provincial lightning protection center. . Taking this opportunity, the Provincial Lightning Protection Center and the Dahe Newspaper established an interactive mechanism for lightning disaster information, coordinated response, and mutual support, so as to respond quickly and investigate the disaster situation in time. At the same time, it also cooperated with the provincial Turing Company to announce the 24-hour free direct report telephone of the lightning disaster in the media to ensure timely and effective understanding of the lightning disaster. Really put the protection of lightning disasters into practice, which made me feel the sense of responsibility and mission as a lightning protection work. Lightning and disaster reduction, living and working in peace and contentment are my ideals. It is my goal to achieve success and serve the society.

The popularity of lightning protection knowledge is very important. The Chinese government has made great achievements in many years of popular science education activities to promote the construction of meteorological undertakings. The protection concept of lightning disasters has also been greatly improved. However, there are still some shortcomings in the depth and breadth of popular science knowledge. People's concept of lightning hazard is still weak. A case of mine disaster is placed in front of us. The people's personal safety and the state's property have suffered serious losses. The painful experience of the Huangdao oil depot explosion has awakened us. The country began. Vigorously promote lightning protection, a special organization has been set up throughout the country for monitoring and protection. The introduction of a department's laws and regulations has promoted the healthy and rapid development of our national defense mine.

Internship report, hope that the leadership can give a comprehensive assessment, I can also know my own shortcomings, and correct immediately.