Research and Development|||Electrical Equipment Electrostatic Protection and Anti-corrosion Research Tian Guanghan (Kaijiaying Mining Group Branch Plumbing Branch, Tangshan 063301, Hebei, China) Shao Shao, the last brief introduction of electrical equipment corrosion protection measures.
Electrostatics can sometimes have an adverse effect on industrial production, especially electrostatic spark discharges, which can sometimes cause fires. Electrostatic sparks may cause explosions and fires in the production environment of coal mines; electrostatic discharges may directly cause electric shocks and cause death and injury; static electricity generation and accumulation may hinder normal production and work.
In modern industrial production, the generation of static electricity may be caused by a certain reason, but it may be the result of a combination of multiple causes. Because the charge on the surface of the material causes an electrostatic charge, this charge imbalance creates a measurable electric field that can affect other objects at a distance. At this time, we say that the object has static electricity. Electrostatic discharge refers to the transfer of electrostatic charge between two objects at different potentials. To control electrostatic discharge, you must first understand the process of electrostatic discharge. The most common cause of electrostatic charging is the contact and separation of the two materials. Any two solid materials, when they are in close contact, will have an electron transfer phenomenon on the contact surface. This is due to the different work functions of various substances. The so-called work function is the work needed to get electrons off the surface of the original material. When two substances are in contact, the one with the smaller work function loses electrons, and the other work with higher work function gains electrons. As a result of the electron transfer, a double electric layer is formed on the contact surface to achieve a certain electromotive force balance. For example, when one person walks on the floor of the room, static electricity is generated due to the soles being constantly separated from the ground. When the electronic device slides into or out of the packaging bag and the packaging box, its outer shell or metal lead is separated from the container by repeated contact to generate static charges. Maybe the amount of static charge in the above example is different, but it does produce static charges.
In modern industrial production, static electricity can cause harm. Fires and explosions are caused by static sparks; the production of static electricity can also hinder production; static electricity can also directly give people electric shocks and so on. Of these hazards, fires and explosions caused by static electricity are the most serious hazards. Although the electrostatic charge is not large, spark discharge is easily generated due to its high voltage. If there are all flammable materials in the field and the explosive mixture formed by flammable materials, including explosive gas and liquid vapor, and explosive dust, etc., static sparks may cause fire and explosion. Therefore, in modern industrial production, the harm of static electricity must be eliminated.
In modern industrial production, there are two main ways to eliminate static electricity hazards. One is to create conditions to accelerate the discharge or neutralization of static electricity generated in the production process and limit the accumulation of static electricity so that it does not exceed the safety limit. The second is to control the production process and limit the generation of static electricity.
The first method includes two kinds of measures, namely the deflation method and the neutralization method. The grounding of the power supply system, the wetness of the production environment, the addition of antistatic agents, and the application of conductive coatings are all examples of the bleed method. The use of various forms of neutralizers to remove static electricity is a method of neutralization. Neutralization also includes measures taken in the direction of material selection, process design, and equipment structure.
1) Preventing the formation of dangerous mixtures: One of the conditions for causing fire or explosion by static electricity is the presence of explosive mixtures. Control measures include: replacing flammable media with non-flammable media to reduce the concentration of explosive mixtures; to prevent the formation of explosive mixtures, the concentration of the explosive mixture may be lower than the lower explosion limit, and ventilation devices may be used in explosive and fire hazardous locations to expel the explosive mixture in time. Prevent static electricity sparks caused by fire or explosion. 2) Process Control: Process control refers to the process to take appropriate measures to limit and avoid the generation and accumulation of static electricity. The most commonly used methods include: controlling the flow rate of liquid; attenuation of strong electrostatic charge; Static electricity. 3) Anti-static grounding: Anti-static grounding is the simplest, most common, and most effective way to eliminate static electricity on conductors. It is mainly used to prevent the storage of static electricity on the conductors, and also limits the potential rise of the charged objects or the resulting electrostatic discharge, and the danger of preventing electrostatic induction.
Anti-static grounding methods vary with the electrical conductivity of the object. All metal conductors that may generate static electricity and electricity, as well as metal conductors that may be subjected to electrostatic induction, should be grounded directly. For different objects, the grounding method is different.
In addition, some factories should also use the production environment to add humidity, add chemical antistatic agent during the production process and use a special static eliminator device to reduce the harm of static electricity. In places where special requirements are required, corresponding measures must also be taken to eliminate the harm caused by the static electrification of the human body.
The air in coal mine working environment often contains a lot of special gas and dust. Some of these substances are corrosive, corrode electrical equipment, and damage the insulation of equipment. Due to the continuity of production, even if individual electrical components are damaged due to corrosion, it may cause the entire section or the entire plant to stop production, and its full wave and the whole plant. Therefore, the factory must strengthen the inspection and maintenance of electrical equipment and take certain measures to solve the problem of corrosion of electrical equipment.
1) There are many aluminum busbars, switches, transformers, and meter connectors in the substation, and the contact resistance at the joints will increase due to corrosion of the joints, causing heating of the joints and eventually causing damage.
For this purpose, all electrical connections should be painted with neutral petrolatum for sealing. The wire connectors were wrapped with polyethylene and black tape insulation tape, and the angle brackets and the steel panel screens on the screen were all painted with varnish. The copper-aluminum connection in electrical equipment is relatively common. This joint is extremely susceptible to gas corrosion and poor contact. The new product power grease can be applied to the contact of different materials of copper and aluminum. It can prevent corrosion, and it is conducive to electrical conductivity. it is good. 2) The 10 kV wall bushing porcelain part of the substation is often flashover due to the pollution of acid mist and dust; the copper end of the bushing through the screw end and the wire connection point, due to corrosion, the contact resistance is increased, burned. Disconnect wire. Therefore, the feedthrough screw can be removed and replaced by a hard plastic tube with a wall thickness of 34mm. Leave 40mm at both ends of the wall bushing to reinforce the insulation. Then insert the lead-in wire through the plastic tube. Not cut off. This will eliminate the above phenomenon.
1) When the factory overhead wire is made of bare aluminum wire, a powdery substance gradually forms on the surface of the wire and peels off, causing the conductivity and mechanical strength of the wire to continuously decrease. Therefore, in the corrosive gas and acid mist environment of the company, polyethylene-insulated wires should be used, and the joints should be wrapped with polyethylene and black tape to avoid entering corrosive gas. 2) The insulator of the line is preferably a high-voltage grade insulator, and the insulator is cleaned annually and coated with a special silicone oil so that the dust does not accumulate and the insulation level is improved. The line of the line is best used galvanized angle steel. 3) In addition to the explosion-proof workshops and buried underground pipelines, the power lines of each workshop can be hard PVC wiring. A single conductor should be used inside the conduit for zero-crossing or grounding protection of electrical equipment.
The contactor can be immersed in the insulating oil for the purpose of preventing corrosion. However, after the thermal relay is immersed in the oil, its operating value should be readjusted through experiments.
Most of the large motors used in air compressors, freezers, and centrifuges in enterprises are wire-wound, open-type motors. After these motors are shut down, the water containing acid and alkali salts in the air condenses easily in the motor windings, often causing the insulation resistance to drop. To a very low, even as a result, the impact of driving again. Therefore, after the motor is stopped, the bulb should be baked at the air inlet and outlet of the motor to prevent the insulation resistance from decreasing.
To completely solve the corrosion problem, use anti-corrosion devices. Classification of corrosion-resistant electrical equipment causes corrosion of electrical equipment In addition to corrosive substances, there are other environmental factors such as high temperature, humidity, and radiation.
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