Analysis of Lightning Protection and Explosion Protection of Security System in Energy Industry

Before discussing the construction issues of security monitoring projects in each type of energy project, we must first understand the common characteristics of the energy projects themselves. After understanding and mastering these characteristics, we can know the problems that the security monitoring system in the energy industry may face, and know the problems. Where can we have a sound construction solution to overcome.

The common characteristics of energy projects are generally directly related to the geographical environment. First of all, let's see:

1. Energy projects are usually located in remote locations or in places with few human exposures, such as areas far away from towns such as the seaside, rivers, mountains, or deserts. This means that the environment used by the security monitoring system is not a normal environment, and the environment is extremely harsh or good. It is possible that this is a commonality in the construction of the energy industry. It is also the first issue that cannot be ignored in any energy project project.

2. Energy projects often face special construction requirements that are different from general security monitoring projects, such as excavation/buried pipelines or pipelines, overhead lines, poles, or welded pipelines, which also means higher costs.

3. Energy projects usually have environmental pollution and interference with signals. For example, chemical substances in petrochemical plants may corrode the monitoring system, and if the power plant itself is an electromagnetic field, there is some interference with the signal of the monitoring system. This indicates that the energy project Its own characteristics usually bring some unexpected obstacles to security monitoring, which means that monitoring systems that do energy projects must strengthen their awareness of system protection.

4. The coverage of energy projects is large, and it is usually large to the entire mountainous area and coastal area. The signal transmission mode and distance of the monitoring system have their own characteristics.

The above four problems indicate that although energy projects such as hydropower, wind power, thermal power, and petrochemical exist in different forms, many construction details are the same. This article discusses solutions to the problem of lightning protection and explosion protection that the energy industry will face.

How to do a good job of lightning protection

Whether in hydroelectric power plants, thermal power plants or wind power plants, or even petrochemical or nuclear power plants, the monitoring system will set up cameras at certain commanding heights or in open areas in order to meet the demand for monitoring coverage. As soon as a lightning strike strikes, there is an unavoidable risk.

In the security monitoring system of the energy industry, there are generally two lightning protection methods. One is grounding and the other is lightning protection. Grounding is an important measure to protect the safety of people, equipment, and power supply. It is an indispensable security measure. The lightning protection is based on the environment and requirements of the installation of the video surveillance system. Although not absolutely necessary, the importance of grounding and lightning protection is a mechanism for mutual cooperation. Therefore, importance in the security monitoring system of the energy industry cannot be ignored.

Monitoring front-end grounding and lightning protection measures

1. Outdoor cameras should be equipped with lightning rods, and separate grounding lines should be used to isolate the power and image signals of the monitoring equipment so as to avoid interference with currents and damage to the lines. Lightning rods should be erected higher than the camera. It is within the range of the virtual three-dimensional vertebral body that is 45-60 degrees down from the tip of the lightning rod. It is the safety scope of the camera. When the lightning rod is installed, it should be insulated from the steel of the fixed camera.

2. The grounding of the front-end equipment of the camera should be concentrated on a grounding bus at the terminal part, so that the grounding of the entire monitoring front-end equipment can reach the requirement of no ground potential difference, otherwise it may cause a potential difference to the ground loop and cause the equipment to be burned.

3. The indoor front-end camera should be connected to the grounding terminal of the shared terminal by a grounding wire, and a non-fuse breaker and a leakage breaker must be installed on the power supply of the front-end device. At the same time, the 3000kV can be installed under the permit. Avoid inductive or conductive lightning damaging equipment.

4. After the outdoor camera is grounded, the test grounding resistance is less than 10Ω, and the grounding rod should be installed according to the standard three-point impedance test.

Grounding and lightning protection of transmission parts

1. Due to the long transmission distance of some monitoring signals in the energy industry and low voltage resistance, it is easily damaged by inductive and conductive lightning currents. In order to conduct the lightning current from the signal transmission line to the ground, the cable should be installed with surges. The protector must consider the signal transmission rate and voltage balance and grounding when designing the image signal transmission cable, so as to avoid inductive intrusion.

2, outdoor transmission and cable should have a good grounding, grounding resistance must be less than 10Ω.

3, overhead self-sustaining signal or power cable should be self-sustaining steel cable in the fixed section with a ground wire access to the earth.

4. The control signal transmission line adopts the cable with isolation shielding function.

5, the transmission part of the cable in the line erection as far as possible buried. When the environmental conditions are not permitted, the shortest distance can be used to avoid intrusion of induced lightning due to the reduced pressure resistance.

Monitoring terminal grounding and lightning protection

1. In the security monitoring system, the lightning protection measures at the monitoring end should be prudent, taking into account various possible types of lightning strike intrusion, ground loop potential difference phenomenon and power supply surge and other protection measures.

2. There should be lightning protection systems, grounding nets and grounding terminals in the building where the monitoring terminal is located.

3. All kinds of metal pipelines of the monitoring terminal should be grounded and connected to the grounding device. When the cable enters the terminal room, the cable outer metal sheath and self-sustaining cable cable should be connected to the grounding terminal.

4. The indoor terminal transmission and cables should have better grounding. The grounding resistance must be less than 10Ω, but the lower the impedance value to ground, the better.

The above is the basic effective method of grounding and lightning protection in the energy industry monitoring system. Although it will not be as stringent as national regulations or standards, careful handling of the details of grounding and lightning protection should be regarded as an effective lightning protection method.

Security system explosion protection in the energy industry

To do a good job in the explosion-proof construction of the petrochemical energy industry monitoring system, we must first understand its explosion-proof requirements, project regulations, and grade content. In China's petroleum and petrochemical refining plants, we can often see different explosion-proof instrumentation and piping, but with monitoring. For the system, whether or not to completely follow all explosion-proof specifications and regulations is based on system equipment and environmental factors. However, if it is from the perspective of engineering safety and construction regulations, construction personnel must understand all the norms in order to prevent accidents. There are many regulations and regulations relating to electrical explosion protection. Due to space limitations, we only specify the electrical explosion protection regulations related to security monitoring in Table 1.

Construction requirements of explosion protection for security monitoring in petrochemical industry

1. Whether the explosion-proof monitoring equipment is selected and classified according to the regional classification, whether it is suitable for the protection of the ambient gas classification; whether the temperature level of the explosion-proof monitoring and power control equipment is suitable for the spontaneous combustion of the surrounding flammable gas; qualified explosion-proof electrical explosion-proof equipment should be marked: Manufacturer name , certification unit, certification number, explosion-proof structure applicable gas group, temperature rating.

2. Whether the line marking data of the explosion-proof camera equipment is complete, whether the camera housing shield and the function are damaged, and whether the monitoring equipment protection cover and the sealing gasket can be completely sealed.

3, screw, cable interface equipment (direct or indirect) and spacing components of the model is correct, the pipeline screws or joints can not be loose, the junction is clean and no damage, monitoring cable joints must be explosion-proof joints and explosion-proof certification mark.

4, pressure explosion-proof equipment interface if any gasket should confirm whether it is purely waterproof.

5. Field signal transmission Explosion-proof box The gasket of the electrical equipment shell is normal. Is the screw locked to the position?

6, explosion-proof monitoring equipment, gaskets should be silicone type is not easy to aging, difficult to change the material.

7. Explosion-proof fillers should be used on explosion-proof joints of explosion-proof boxes and cameras to prevent electrical sparks inside the equipment.

8. Is the monitoring equipment and explosion-proof box installed according to requirements and properly grounded?

9, pressure explosion-proof box with a security lock, or must use special tools to open?

Energy and petrochemical monitoring explosion-proof construction skills

After understanding the construction of electrical explosion protection regulations, we discussed the focus of this article - explosion-proof construction techniques. The safety monitoring system does not have any special skills in explosion-proof construction. The installation of image equipment and main equipment, transmission and storage monitoring equipment is the same for explosion-proof and non-explosion-proof monitoring construction contents and projects. The only thing that must be taken care of is explosion protection. Protective cover and fittings and piping or equipment installed on the explosion-proof provisions. In addition, in chemical petrochemical plants, due to environmental protection factors, most of them are located in remote rural areas or coastal areas. Therefore, in addition to the fact that their chemical reactions are likely to generate some corrosive gases or liquids, the destructive nature of sulfur gas in the environment must also be noted. . Next, we will monitor explosion-proof construction techniques one by one.

1. Is the cable type used in the monitoring system suitable? Because the construction pipeline should not be replaced once it is completed.

2. The signal of explosion-proof pipeline and cable should be appropriate, RSG tube must be adopted, and EMT tube should not be used. This is the mistake of most manufacturers and deliberately obscuring the cost; the material should be made of galvanized thick steel pipe; explosion-proof pipelines are Into the explosion-proof box or equipment box terminal cable should be connected to the terminal table, copper wire can not be docked, so as to avoid sparks.

3. If metal hoses or explosion-proof hoses are used, use armored material configurations where possible.

4. The use of the explosion-proof cable for the cable must take into account its withstand voltage value, so as to avoid the thermal effects caused by insufficient pressure or short-circuit detonation.

5. There must be no connection in the pipeline. If there is, the processing of the line relay and the explosion-proof junction box cannot directly connect the cable in the pipeline.

6, the appearance of the cable can not be obviously damaged, the skin should be used without damage.

7. The construction of explosion-proof pipeline system should place the cable completely in the pipeline. When it crosses different explosion-proof areas, it should be buried sealed or groove sealed. The pipeline tightness of explosion-proof enclosures, conduits and metal hoses must be considered. At the entry end, pipelines should be connected with explosion-proof joints and filled with explosion-proof powder or explosion-proof paste to block line joints between pipelines and equipment. Explosion-proof pipeline joints should not be tightly loose. Pipes should be sealed with explosion-proof proof boxes filled with explosion-proof powder to block electrical sparks at about 30-45cm from the entrance and exit of the equipment body. The explosion-proof connection on the pipeline and the position of the drain hole on the blocking box should be at the lowest point of the pipeline. Explosion-proof cables or pipelines connected equipment outlets should use explosion-proof explosion-proof joints or safety joints.

8, explosion-proof equipment for all explosion-proof pipelines and monitoring systems end box and blocking box must do grounding treatment, while paying attention to the grounding of the diameter and grounding terminals are all in line with the provisions and corrosion resistance.

9. The grounding of explosion-proof equipment must comply with the general grounding requirements, and the electrical resistance must comply with the regulations of the electrical industry.

10, explosion-proof monitoring equipment requirements in strict accordance with the equipotential grounding, so only take a little grounding is appropriate.

11. Explosion-proof monitoring terminals should use electronic surge protection and open circuit protection equipment to ensure equipment safety.

12. Equipment grounding and line safety shall be kept in the explosion-proof box or distribution box or separated by metal partitions. The distance between the pressure-proof explosion-proof box and surrounding process objects shall be kept at a certain distance. If IIA stipulates that the explosion-proof equipment should maintain at least 10mm, and the higher IIB regulations, the explosion-proof equipment shall maintain at least 30mm or more, and to IIC, the explosion-proof equipment shall at least be maintained with other equipment. 40mm or more distance.

13. Explosion-proof electrical pipe construction piping, electrical equipment, metal shells and cable shields shall be grounded, and metal pipe indirect renewal (Bonding) shall be done with the pipe grounding line connecting the two-stage pipe. High-voltage and low-voltage lines should be configured in different cable ducts or trunkings on the principle of pipeline configuration; otherwise, isolation panels must be better separated.

14. Explosion-proof piping and pipe joints must be connected with at least 5 pitches.

15, explosion-proof monitoring pipeline cable allowable bending radius must be at least greater than 8 times the cable radius.

16, explosion-proof surveillance cameras should do a good job of the protection cover and camera lens and other pre-set operations, can not be in the hot work area for camera assembly operations.

19, all explosion-proof equipment fixed metal screws must use stainless steel # SuS316 material to avoid rust stuck.

20, pipeline cutting must also be cut outside the explosion-proof zone, the pre-set job can not enter and stop the fire area for pipe cutting.

21, the construction personnel in the explosion-proof area is best to wear pure cotton overalls and cotton belts, to avoid the risk of static burning and explosion caused by general clothing friction.

22, cameras and other equipment in the explosion-proof area to install a fixed part, can use the metal galvanized clamp to use the fixture, as far as possible in the chemical installation of monitoring and monitoring system without welding or drilling wall bolts.

23. It is better to use the PTZ camera as an integral type because too many line contacts increase the risk of explosion.

24, infrared projection lamp is not suitable for use in explosion-proof area monitoring, can only be used for non-explosion-proof area, do not make such mistakes.

Conclusion

The above is the report compiled by the author on the basis of past experience in the supervision of various hydraulic/firepower/nuclear/petrochemical monitoring projects at home and abroad. The monitoring system is important in the selection of equipment, but it is more aware of the requirements of construction and lightning protection and explosion protection. It is important that most of the mistaken and failed energy project monitoring cases are based on construction practices that do not provide lightning protection and explosion protection as required. Hope that through this article, can attract the attention of the majority of peers, so that the construction of energy monitoring projects more professional.

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