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Electrical Equipments (19599)


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Electrical Equipment is a general term for generators, transformers, power lines, circuit breakers and other Equipment in the power system.

Electric power plays an important role in our life and production. It brings us great convenience and becomes an important energy source in our production and life. Electrical equipment is the most critical element in a power plant that allows the normal operation and transmission of electricity.

If there is a problem with the working ticket, the employee can make a request to change it face to face. If the accident is not corrected, the person responsible for the final instruction will be responsible.
(5) in emergency, special circumstances (such as harm to personal safety or heavy losses) too late to handle the work ticket, can be the business manager oral command or telephone command to reverse the switch operation, the operator must make records for future reference.
Three, electrical equipment maintenance operation rules:
(a) after the power failure of the electrical equipment for maintenance, the electroscope must be inspected. The electroscope should conform to the voltage level. The high voltage part must wear insulating gloves.
(2) a warning sign of "no closing, someone is working" shall be hung on the switch handle of the power cut line, and a sign of "high voltage power, no entry" shall be hung outside the safety fence of the non-power cut part.
(3) For key equipment with safety device after power failure of more than 4 hours, the safety should be pulled out.
(four) after the maintenance work, remove the grounding wire, personnel to evacuate the site, hand in the working ticket, remove the warning card after the resumption of power transmission.
(5) It is strictly prohibited to carry out on-line maintenance of various electrical equipment.
IV. Operation rules for overhead lines in mining areas:
(1) Before overhauling the overhead lines and poles in the mining area, they must be comprehensively inspected by the monitor or the person in charge to ensure that they have no defects and do not endanger personal safety and operational safety before they can be operated.
(2) overhead line up the work, must be in accordance with regulations of the high homework, to bar apparatus, there should carefully check, whether in good condition and reliable, and deliver goods with a small rope, rod should be set up under the guardian, it is forbidden to non-working personnel enter the assignments section, care workers must wear safety helmet, and keep a certain distance, to avoid the operator drop down items, tools, cause deaths and injuries.
(3) In the case of operation on the same high and low voltage line, if one line is live, the workshop shall take safety measures and report to the director in charge for approval before the operation.
(4) During the rush repair of two or more low-voltage lines with the same rod, when the power failure affects the production of important posts, the rush repair shall be carried out only when the professional mine manager is on the spot to carry out the monitoring.
(5) line inspection every quarter at least once a year, pole inspection once a year (including wiping porcelain bottles, inspection units should have a record, for future reference) the radian of the wire and line parallelism should meet the requirements.
(6) In the case of gale above grade 5, it is strictly prohibited to work on overhead lines.
Article 1 In order to strengthen the maintenance of electrical equipment, ensure its safe operation and reasonable use, this regulation is formulated.
Article 2 for the start and stop of electrical equipment, the operation shall strictly implement the stop and send card system sense and the shift handover system.
Article 3 Perambulatory inspection of electrical equipment in operation must be conducted in strict compliance with the Electrical Installation Regulations.
Article 4 The personnel on duty should use, see, touch, hear and smell the electrical equipment according to their own circumstances, so as to find out the problems in time and deal with the hidden dangers.
Article 5 The electrical equipment shall not be forced to operate under the condition of overload, overtemperature, overspeed or unprotected.
Article 6 The personnel on duty shall make full use of the parking time to clean, dust, inspect, maintain and make special inspection of the electrical equipment.
Security measures
The editor
Electrical safety
(1) Study and take various effective safety technical measures.
(2) Research and promote advanced electrical safety technology to improve the level of electrical safety.
(3) Formulate and implement safety technical standards and regulations.
(4) Establish and implement various safety management systems.
(5) To carry out the education of electrical safety thoughts and electrical safety knowledge.
(6) Analysis of accident cases to find out the causes and rules of the accident [1].
Basic elements
(1) Electrical insulation. Maintaining good insulation of distribution lines and electrical equipment is the most basic element to ensure personal safety and normal operation of electrical equipment. Whether the performance of electrical insulation is good or not can be measured by measuring its insulation resistance, compressive strength, leakage current and dielectric loss and other parameters.
(2) Safety distance. Electrical safety distance refers to the safe and reliable distance at which the human body or object is close to the charged body without danger. Such as between the charged body and the ground, between the charged body and the charged body, between the charged body and the human body, between the charged body and other facilities and equipment, should maintain a certain distance. Usually, when working near the distribution line and transformer and distribution device, the line safety distance, transformer and distribution device safety distance, maintenance safety distance and operation safety distance should be considered.
(3) safe flow carrying. The safe current carrying capacity of a conductor is the current that is allowed to pass continuously through the interior of the conductor. If the continuous current passing through the conductor exceeds the safe carrying capacity, the conductor's heating will exceed the allowable value, leading to insulation damage, and even cause electricity leakage and fire. Therefore, it is very important to determine the conductor cross section and select the equipment according to the safe current carrying capacity of the conductor.
(4) Signs. The obvious, accurate and uniform sign is an important factor to ensure the safety of electricity use. Signs generally have color signs, signs and type signs. Colour marks indicate conductors of different properties and uses. Signing boards are generally used as signs of dangerous places; The type mark is used to indicate the special structure of the equipment.
Basic safety technical requirements for electrical equipment
Statistics on electrical accidents indicate that a large proportion of accidents are caused by structural defects of electrical equipment, poor installation quality and failure to meet safety requirements. Therefore, in order to ensure the safety of people and equipment, there are the following requirements for electrical equipment in terms of safety technology:
(1) reliable protective measures should be taken for the live equipment exposed on the ground and easily touched by human beings.
(2) A certain safe distance should be kept between the live part of the equipment and the ground and other live parts.
(3) easy to produce overvoltage of the power system, there should be lightning rod, lightning line, lightning arrester, protection gap and other over-voltage protection device.
(4) Low voltage power system should have grounding and zero protection device.
(5) Different types of protective measures should be taken for various high-voltage electrical equipment, such as installing high-voltage fuses and circuit breakers; The low voltage electrical equipment should be protected by the corresponding low electrical protection measures.
(6) Safety signs should be set up at the installation site of electrical equipment.
(7) According to the characteristics and requirements of some electrical equipment, special safety measures should be taken.
Classification of electrical accidents and the classification of basic causes
Electrical accidents can be divided into personal accidents, equipment accidents, electrical fire accidents and explosion accidents according to the forms of disasters. According to the circuit condition when the accident occurs, it can be divided into short circuit accident, disconnection accident, grounding accident, leakage accident and so on; According to the seriousness of accidents, they can be classified into major accidents, major accidents, general accidents, etc. According to the degree of injury, it can be classified into death, serious injury, and minor injury.
According to the basic cause of the accident, electrical accidents can be divided into the following categories:
(1) electric shock accident. Personal injury caused by current flowing through the body when the body touches a charged body (or is too close to a high-voltage charged body). Electric shock accidents are caused by the application of electric energy to the human body. Electric shock can be divided into single - phase electric shock, two - phase electric shock and three step voltage electric shock.
(2) Lightning and static electricity accidents. Temporary imbalance of positive and negative charges within a local scope, under certain conditions will release the energy of the charge, causing injury to the human body or other accidents. Lightning strikes often destroy buildings, injure people and animals, and may cause fires. The biggest threat of electrostatic discharge is to cause fire or explosion accidents, may also cause harm to human body.
(3) RF injury. The energy of electromagnetic field causes harm to human body, namely electromagnetic field harm. Under the action of high frequency electromagnetic field, the human body absorbs radiation energy, and various organs will be harmed to varying degrees, thus causing various diseases. In addition to the high frequency electromagnetic field, the high intensity power frequency electromagnetic field of UHV will also cause certain harm to human body.
(4) circuit failure. An accident caused by the loss of control during the transmission, distribution and conversion of electrical energy. Line and equipment failures not only threaten personal safety, but also can seriously damage electrical equipment.
The above four kinds of electrical accidents, electric shock accident is the most common. But no matter what kind of accident, it is caused by the improper release or transfer of energy of various types of current, charge and electromagnetic field [2].
Security responsibilities
In terms of electrical safety, electrician operators should memorize and consciously perform the following duties:
(1) not allowed to operate without a license; If non-electricians are found to be engaged in electrical operation, they should be stopped in time and reported to the leader.
(2) Strictly abide by the relevant safety laws, regulations and systems, and shall not operate in violation of regulations.
(3) Responsible for the safety of electrical equipment and wiring in the jurisdiction.
(4) conscientiously carry out inspection, inspection and elimination of hidden dangers, and timely and accurately fill in the work records and prescribed forms.
(5) When erecting temporary lines and carrying out other dangerous operations, the approval procedures should be complete, otherwise the construction should be refused.
(6) Actively publicize electrical safety knowledge, and have the right to stop illegal operations and refuse to command illegal operations.

Protect the earth
The editor
Grounding refers to the electrical connection between a certain part of the electrical equipment and the soil. In order to ensure the normal work of the electrical equipment and the safety of the protective role must be grounded. For electrical equipment to be successfully grounded, it is necessary to use a grounding device. Grounding device mainly includes two kinds of grounding wire and grounding body. The grounding body is a metal body used to contact the soil directly. The grounding wire is the wire used to connect the grounding body to the electrical equipment.
Grounding classification
(1) Working grounding.
To take a point of electrical power to ground due to the operation of electrical equipment and electricity.
For example, the neutral point of power is grounded.
(2) Repeated grounding.
In the low-voltage distribution TN-C, in order to avoid the neutral line failure can not play the role of grounding protection, thus causing equipment damage or electric shock
The danger of neutral wire taking repeatable grounding. Point used for repeated grounding: a suitable point in an overhead line or the end of a line; Overhead lines or cables in the workshop or building of the incoming line; Four-core cable neutral wire.
(3) anti-static grounding.
Because the existence of static electricity will bring some harm to equipment or people, in order to eliminate static electricity and take grounding. For example, vehicles or metal pipes used to carry gas or liquids must be grounded.
(4) lightning protection grounding.
Lightning will produce overvoltage, in order to avoid equipment or personal injury, and take the overvoltage protection equipment ground. For example, the lightning arrester, lightning protection needle grounding processing.
(5) protection of grounding.
In order to prevent damage to the insulation of electrical equipment, limit the voltage of metal casing to earth of electrical equipment within the safety value to avoid production
Injury to human body by electric shock and grounding of electrical equipment that leaks out as conductors. Such as lighting appliances, transformers, mobile or hand-held electrical equipment and other electrical appliances housing and metal base; The frame of the panel for control, protection and distribution; Some transmission equipment of electrical equipment; Bracket or base for all kinds of electrical equipment in the substation; Metal casings for household appliances; The steel or metal frame of the reinforced concrete structure of the indoor and outdoor distribution device and the metal door or metal shield close to the live part; AC and DC power cable terminal box and junction box of metal shell, cable frame, thread steel pipe; The steel bars or metal poles and towers of the reinforced concrete structure of overhead lines, the supports or shells of the equipment on the poles and towers, the overhead ground wires of the poles and towers, etc. [3].
The technical standards
For electrical equipment with different voltages and uses, it is usually only required when there is no special requirement
Grounding resistance
Grounding resistance
A total grounding body, adhere to the principle of equal potential connection, the building of the metal pipe, component connected to the total grounding body;
1) In order to ensure equipment and personal safety, all electrical equipment must be protected by grounding according to national standards. And the protective grounding wire is only used for the specified protective grounding or working grounding, can not be used for other;
2) there are special requirements in grounding, such as medium voltage system and weak current, through small resistance or neutral grounding, must be implemented in accordance with the corresponding special provisions;
3) The artificial general grounding body must not be in the building. During grounding, the grounding resistance of the total grounding body must be set according to the requirements of the minimum grounding resistance [3].
Unit classification
(1) equipment grounding in flammable and explosive sites
All mechanical devices, metal pipes, electrical equipment including metal structures of buildings must be grounded in the flammable and explosive sites, and crossing lines are buried at the joints of each pipe. In case of dangerous accidents when measuring the grounding resistance of the equipment, the equipment that does not have the risk of explosion should be selected
Or take appropriate measures to pull the end knob of the measurement to a place where there is no danger for measurement; There should be at least 2 points connecting the grounding body and the grounding trunk, and the grounding body should be connected at both ends of the building respectively; In the ground line of the neutral point less than 1kV, the line must use current protection. Assuming that the line needs to pass through the fuse, the safety factor of the protection device used in the line must be above 4. Assuming that the circuit breaker is passed, the safety factor of the operation must be above 2 [3].
(2) about substation equipment grounding
The grounding body is best set outside the wall of the substation, more than 3m away from the wall, and the depth of the grounding network must be higher than the thickness of the permafrost, not less than 0.6m thin; The grounding body of the grounding equipment shall be horizontally laid. The grounding body shall be round steel with a length of 2.5m and a diameter of more than 12mm or steel pipe or Angle steel with a thickness of more than 4mm, and shall be connected with flat steel with a section of more than 25mm×4mm to form a closed connection
The main transformer
The main transformer
Annular, the edge Angle must be curved; The main transformer of the substation shall be grounded for protection and working, and both of them shall be connected to the artificial grounding grid. The lightning rod must be independently grounded.
(3) about DC line equipment grounding
Usually metals are chemically corroded by direct current, causing their contact resistance to become larger and larger. So if you want to install the grounding device on the DC line, and let it run well, you must take these measures.
1) the thickness of the artificial grounding body on the DC should be more than 5mm, and the erosion should be checked regularly;
2) For the grounding device on the DC line, neither the repeated grounding wire and the grounding body or the natural grounding body can be used as the PE line, nor can the natural grounding body be connected directly [4].
Grounding device
(1) Items to be inspected
Check whether the connection points of the grounding device are damaged, corroded, broken and whether the contact is good; Before the rainy season,
Grounding device
Grounding device
In other words, when the resistivity of the soil is the maximum, the ground resistance of the ground equipment is measured, and the measurement results are analyzed and compared. Check whether the ground body within 500mm of the ground where the soil is strong acid, alkali and salt is seriously corroded; Check whether the electrical equipment is connected to the grounding wire is normal, the grounding wire is connected to the ground grid is normal, and the grounding wire is connected to the grounding trunk is normal; For the overhauled electrical equipment, it is necessary to further check whether the grounding wire connection is firm [4].
(2) The period of inspection
The grounding equipment of the distribution (transformer) power station is usually checked once a year; The grounding equipment used for lightning protection must be checked once a year before the thunderstorm season; Depending on the specific situation of the building or workshop, check the general operation of the grounding wire 1 ~ 2 times a year; For the grounding device installed in corrosive soil, observe the specific operation situation and check the grounding body under the ground every 3 ~ 5 years as a cycle; Measuring the grounding resistance of the grounding equipment every 1 ~ 3 years; For mobile and hand-held electrical equipment, a grounding wire should be checked before each use [3].
Fire prevention measures
The editor
Electrical fires are usually caused by overheating caused by aging insulation of electrical equipment, loosening of joints, overload or short circuit. Especially in flammable and explosive places, the hidden dangers of the above electrical lines are greater. In order to prevent the occurrence of electrical fire accidents, fire prevention measures must be taken.
(1) often check the operation of electrical equipment, check whether the joint is loose, there is no electric spark, electrical equipment
Electrical fire
Electrical fire
Whether the performance of the overload and short circuit protection device is reliable and whether the insulation of the equipment is good.
(2) Reasonable selection of electrical equipment. When installing and using electrical equipment in places with flammable and explosive articles, explosion-proof electrical appliances should be selected. Insulated conductors must be sealed and laid in steel pipes. Electrical equipment should be selected and installed according to the grade of explosion hazard site.
(3) maintain a safe installation position. Keeping the necessary safe distance is one of the important measures of electrical fire prevention. In order to prevent fire caused by electrical sparks and dangerous high temperature, flammable and explosive items should not be piled up around electrical equipment that can produce sparks and dangerous high temperature.
(4) Keep electrical equipment in normal operation. Sparks and dangerous high temperature caused by electrical equipment in operation are important causes of electrical fire. In order to control excessive work spark and dangerous high temperature and ensure the normal operation of electrical equipment, it should be operated, used and maintained by qualified personnel who have been trained and assessed.
(5) the ventilation. Electrical equipment operating in inflammable and explosive dangerous places should be well ventilated to reduce the concentration of explosive mixtures. The ventilation system shall meet the relevant requirements.
(6) grounding. The grounding requirements in flammable and explosive dangerous places are higher than those in general places. No matter its voltage level, the normal uncharged device should be grounded reliably according to the relevant provisions.
Fire rules
(1) In case of fire of electrical equipment, the electric appliances and lines on fire may be electrified. In order to prevent the spread of fire and the occurrence of electric shock accident during fire fighting, the power supply should be cut off immediately in case of electrical fire.
(2) When the production cannot be stopped or the power is not allowed due to other needs and the fire must be extinguished with electricity, non-conductive fire extinguishing agents must be selected, such as carbon dioxide fire extinguisher, 1211 fire extinguisher, difluorodibromomethane fire extinguisher, etc., to extinguish the fire. Fire fighting personnel must wear insulating shoes and gloves when fighting a fire.
(3) The shortest distance when extinguishing the fire. When extinguishing with non-conductive extinguishing agent, the minimum distance between nozzle and charged body with 10kV voltage should not be less than 0.4m; 35kV voltage, the minimum distance between nozzle and charged body should not be less than 0.6m. If water extinguishing, the voltage is 110kV and above, the nozzle and the charged body must be maintained between more than 3m; For 220kV and above, not less than 5m.

It can not only keep the power plant in safe operation, but also improve the user's satisfaction to the power plant. For the electrical equipment of the power plant, if there is a fault, it can not provide electricity for the user, and the user's production and life will be paralyzed. If we do a good job in troubleshooting, we can find out the hidden dangers in the electrical equipment in time, and eliminate the hidden dangers, so as to provide uninterrupted power supply for users, meet the needs of users, and social production will not stop. Therefore, it is of great significance to do a good job in troubleshooting electrical equipment [5].
Equipment failure
After the operation of electrical equipment for a period of time, it will inevitably be subjected to wear or interference, if not
Insulating layer
Insulating layer
When excluded, it will threaten the safe operation of electrical equipment. But in order to solve electrical faults, it is necessary to understand what are the common faults of electrical equipment:
(1) Short circuit.
The main reason for short circuit of electrical equipment is that the insulation layer no longer has the insulation ability, and the cause of this situation is that the insulation layer is damp or wear, some are the line use time is too long there is the aging of the insulation layer, coupled with electrical equipment in disrepair will also have short circuit.
(2) Too high temperature.
For electrical equipment, conductors must be needed in operation, but each wire has its own maximum current load range. If the current load is abnormal and exceeds the original bearing capacity of the wire, the wire temperature will be instantly raised, and then the wire will be burned down. The reason why this situation may be related to the lack of lubricating oil after long-term operation of the equipment, at the same time, it may also be that the operating space of the equipment is too small to emit heat in time, and this situation will also occur. In addition, there is no timely cleaning of dust and debris for equipment
Arc and spark
Arc and spark
, can also lead to excessive temperature, which threatens the safety of electrical equipment.
(3) Arc and spark.
In the operation of electrical equipment, it is easy to cause arc and spark due to the damage of conductor insulation layer. Once this happens, it will directly threaten the overall safety of the power plant, especially the electric spark is easy to cause electric misfire, which is extremely difficult to deal with.
(4) Harmonic fault.
In the operation of electronic equipment, it is inevitable to generate harmonics, which have a great impact on electronic equipment and will lead to misoperation, which is easy to threaten the safe operation of electrical equipment and the current operation, and is not conducive to the improvement of power grid quality [5].
(1) Solving countermeasure of short circuit fault of insulation layer
In order to prevent short circuit in the insulation layer, it is necessary to do a good job in equipment and line layout to prevent damage of equipment in use. At the same time, anti-corrosion and moisture-proof design, protect the insulation layer, avoid direct contact with the outside world. In order to avoid the fire caused by the sudden stop of the equipment in use, dual power sources can be used, and the two power sources can be switched freely. Once one of the power sources stops working, the other power source can take over its work in time.
Dual power supply
Dual power supply
This can also provide a certain amount of time for emergency repair personnel to successfully complete the task of emergency repair. At the same time, to avoid short circuit caused by grounding, can be added for electrical equipment metal shell, in this way can also effectively prevent unnecessary danger caused by high temperature.
(2) the solution of wire heating
To reduce the adverse effect brought by the conductor temperature, you select the wire in combination with the practical situation of electrical equipment, and calculate the good conductor maximum load, load control wires, applying protection device which at the same time, the real-time monitoring of running status of electric equipment, with the application of protection device, once the electrical equipment fails, the device will automatically alarm, Relevant staff can also carry out rush repair work according to the prompts. The relevant staff of the enterprise should also maintain the electrical equipment regularly, clean up the debris and dust on the equipment according to the maintenance plan, give the electrical equipment enough operating space, and ensure that the heat can be sent out in time. In addition, the relevant staff should also do a good job in temperature detection and record, check whether the electrical equipment in use is abnormal high, if such a situation occurs, it is necessary to take immediate measures to cool it, to prevent unnecessary damage caused by excessive temperature.
(3) Arc and spark solutions
Because electrical equipment is easy to produce arc and spark in operation, so, should be easy to produce arc and spark equipment away from dangerous sites, and do a good job of emergency measures, equipped with appropriate protective equipment. Cables that are not easy to ignite can be applied, and not applied
Have a burning wire, and do a good job of daily inspection, this can also prevent the occurrence of insulation damage, once found abnormal situation, should be dealt with immediately.
(4) Harmonic solutions
Because electrical equipment is easy to be affected by harmonics in use, and harmonics can not be eliminated automatically, it is necessary to change the structure of current converter and apply certain control strategies to eliminate harmonics. At the same time, it can also be used to suppress harmonic generation, such as the application of filters in order to prevent the electrical equipment from being interfered.

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