Commonly used power cable technology forty asked! worth collecting!
Article Source：Jocol Group
1, commonly used wires, cables by the use of what types of points?
A: According to the use can be divided into bare wires, insulated wires, heat-resistant wires, shielded wires, power cables, control ...
1, commonly used wires, cables by the use of what types of points?
A: According to the use can be divided into bare wires, insulated wires, heat-resistant wires, shielded wires, power cables, control cables, communication cables, RF cables.
2, what kind of insulated wire?
A: The existing insulation wire has the following: PVC insulated wire, PVC insulated cord, nitrile PVC insulation insulated cord, rubber insulated wire, agricultural underground buried aluminum core plastic insulated wire, rubber insulated cotton yarn Textile cord, PVC insulated nylon sheathed wires, PVC insulated cables for power and lighting.
3, cable bridge for what kind of occasions?
A: The cable bridge is suitable for general industrial and mining enterprises indoor and outdoor overhead laying power cables, control cables, can also be used for telecommunications, radio and television departments in the indoor and outdoor erection.
4, cable accessories which?
A: The commonly used electrical accessories are cable terminal box, cable junction box, connecting pipe and terminal blocks, steel plate trough, cable bridge and so on.
5, what is the cable middle connector?
A: connect the cable with the cable conductor, insulation shield and protective layer, so that the cable connection device, known as the cable intermediate connector.
6, what is the main electrical wiring?
A: The main electrical wiring is the power plant, substation in the main electrical equipment and bus connections, including the main bus and auxiliary power system according to certain functional requirements of the connection.
7, in the choice of power cable cross-section, which should comply with the provisions?
A: The choice of power cables should follow the following principles:
(1) the rated voltage of the cable is greater than or equal to the rated voltage of the power supply system at the installation point;
(2) the cable continually allows the current to be equal to or greater than the maximum continuous current of the supply load;
(3) core cross-section to meet the stability of the power supply system when the short-circuit requirements;
(4) according to the length of the cable to determine whether the voltage drop to meet the requirements;
(5) The minimum short-circuit current at the end of the line should be such that the protective device is reliable.
8, cross-linked polyethylene cable and oil-paper cable What are the advantages?
A: (1) easy to install, because it allows the minimum bending radius is small and light weight;
(2) not subject to line drop restrictions;
(3) thermal performance is good, allowing high working temperature, transmission capacity;
(4) cable accessories are simple, are dry structure;
(5) operation and maintenance is simple, no oil spill;
(6) lower prices;
(7) high reliability, low failure rate;
(8) manufacturing process less, simple process, significant economic benefits.
9, fixed AC single-core cable clip What are the requirements? Why?
A: The fixture should have no iron pieces to form a closed magnetic circuit, because when the cable core through the current, in its surrounding magnetic lines, magnetic lines of force and the size of the current through the core is proportional to the use of iron and other magnetic materials, according to Electromagnetic induction can be seen in the iron will produce eddy current to make the cable heat, or even burn the cable. So you can not use iron parts for single-core AC cable fixture.
10, the following characteristics of the biggest features and advantages of heat-shrinkable cable head accessories?
A: The biggest feature of heat shrink attachment is to replace the traditional stress cone with a stress tube, which not only simplifies the construction process, but also reduces the size of the terminal of the joint, easy installation, saving time,
Can be superior to metal. Heat shrinkable cable accessories set perfusion and dry bag as a whole, the advantages of these two accessories.
11, what should the inspection work before cable laying?
A: (1) bracket should be complete, paint complete.
(2) cable model, voltage, specifications meet the design.
(3) cable insulation is good, when the oil and paper cable seal in doubt, should be judged by moisture; buried cable and small cable should be tested by the DC voltage test failure; oil-filled cable oil samples should be qualified.
(4) oil-filled cable oil pressure should not be less than 1.47MPa.
12, the oil and paper insulation power cable seal in doubt, how to use a simple way to check the cable insulation paper is damp?
A: The cable insulation paper lit or put about 150 ℃ in the cable oil inspection, no "hissing" sound or white foam appears, indicating no moisture.
13, cable signs should be marked what content? Write any requirements?
A: The sign should be marked with the cable design number, cable type, specification and starting point. The cables used in parallel should have the serial number. Requires writing clear, easy to fall off.
14, the location of the buried cable should be set in the location?
A: at both ends of the cable, cable straight line 50 ~ 100m cable connector a few cables to change the direction of the corner.
15, the production of cable connector with yellow wax ribbon, black glass paint, E-glass ribbon, etc., before the construction of how to deal with drainage?
A: (1) constant temperature drying method: the insulation tape into a diameter of 25 ~ 30mm small volume, into
110 ~ 120 ℃ constant temperature drying oven bake 4 ~ 5h, cooling dry out, into the dry sealed tube.
(2) oil-immersed drainage method: the insulation with a small volume into the temperature of 120 ~ 130 ℃ in the cable oil, from the bottom of the pot to maintain a distance of 30mm, after a certain period of time after the oil no longer produce bubbles, In a bucket with a cable oil, the oil level should exceed all the loaded objects and seal them.
16, the role of cable jacket is what?
A: protect the inner sheath from mechanical damage and chemical corrosion, enhance the mechanical strength.
17, outdoor cable trench should meet the requirements?
A: The upper part of the cable trench should be slightly higher than the ground, stamped with concrete made of the cover, the cable should be flat on the bracket, a good drain.
What is the role of the inner sheath of the cable?
A; so that the insulation will not be in contact with water, air or other objects to prevent insulation moisture and insulation from mechanical damage.
19, the use of steel clamp should pay attention to what?
A: Before use, be sure to check the insulation handle insulation is intact, the use of wire clamp can not be used to cut more than the specifications of the metal wire, and prohibit the use of wire clamp instead of hammer beat the tool to avoid damage.
20, what is the insulation strength?
A: Insulation material in the electric field, when the electric field strength increases to a certain limit will be breakdown, this lead to the breakdown of the electric field strength is called the insulation strength.
What are the advantages of cross-linked heat shrinkable cable accessories?
A: This is a new material, it is compared with other types of accessories with excellent electrical performance
The other is small, small size, easy installation, supporting materials, etc., also has a weather resistance, anti-pollution, fire self-extinguishing and other capabilities.
22, the cable conductor connection point of the mechanical strength of what?
A: The mechanical strength of the connection point is generally lower than the tensile strength of the cable conductor itself. For fixed power cables, the tensile strength of the connection point is not less than 60% of the tensile strength of the conductor itself.
23, the power cable insulation material should have what the main performance?
A should have the following main performance:
(1) high breakdown strength;
(2) low dielectric loss;
(3) a very high insulation resistance;
(4) excellent resistance to discharge performance;
(5) has a certain degree of flexibility and mechanical strength;
(6) long-term stability of insulation properties.
24, mechanical laying cable, the traction strength of what provisions?
A: For the copper cable, when the traction head, the traction strength is allowed to 70N / cm; for aluminum core cable, when the traction head, the traction strength is allowed to 40N / cm; if the use of wire mesh traction, lead Set the cable to allow the strength of 10N / cm; lead jacket cable 40N / cm.
25, what is the provisions of the cable protection tube?
A: (1) cable need to wear protective tube laying, the pipe diameter should not be less than the cable diameter
1.5 times, concrete pipe, clay pipe, asbestos, cement pipe diameter should not be less than 100mm;
(2) the bending radius of the cable tube should be consistent with the provisions of the penetration of the cable bend radius;
(3) Each pipe shall not exceed a maximum of three elbows and not more than two at right angles.
26, how to measure the outer diameter of the cable jacket?
A: In the circumference of the sheath evenly distributed at five points, measuring the outer diameter of the jacket and its average, the average diameter of both outer diameter of the jacket.
27, different cross-section of the copper cable how to connect?
A: different cross-section of the copper cable connection, can be used to open the weak back copper pipe to tin solder connection can also be used pure copper rods according to different cross-section requirements connected to the copper pipe to crimp connection.
28, a brief description of 10KV cross-linked cable heat shrink production of indoor terminal process?
(1) Preparation phase: Check whether the cable accessories are complete, the model is matched, check and confirm the cable with or without moisture, check the cable.
(2) cut off the excess cable, according to the scene to determine the length of the cable.
(3) stripping the sheath.
(4) welding ground wire, the ground wire welded to the steel belt.
(5) filled with three fork and wrapped sealant.
(6) to install three-core branch jacket, the jacket into the roots, starting from the central contraction, first to the roots, and then to the Ministry.
(7) stripping copper and outer semiconducting layer, stripping three core branching sleeve 20mm above the copper belt, is strictly prohibited damage to the main insulation, clean the semi-conductive layer.
(8) to install the stress pipe, the nozzle end part of the support after the heat shrink.
(9) Install the terminal block.
(10) Install the insulation tube.
(11) Install the sealing tube.
(12) nuclear phase after the installation of color tube.
29, indoor, outdoor prefabricated terminal installation steps which?
A: (1) the cable in place according to the location, fixed, clean the surface, with reference to the instructions to remove the outer jacket, if any special needs, the outer jacket peel length can be adjusted, respectively, by the copper, 2 sets of ground.
(2) by the outer jacket mouth to measure the size of the need to cut off the excess cable, into the heat shrink three fingers to the third fork root by the middle of the heating shrinkage, from the spike up the mouth to measure the size (35kv 350 ~ 380mm ). Remove the excess copper (keep 20mm), and then retain the semiconductor pre-set position, crimp outlet terminal seal.
30, under what circumstances, the scene of the installation of the motor should be core inspection?
A: When the motor has one of the following circumstances, should be carried out core inspection:
(1) the date of manufacture exceeds the manufacturer's warranty period;
(2) by visual inspection or electrical test, the quality is suspicious;
(3) open motor when the end of the inspection is suspicious;
(4) When there is an abnormal situation during trial operation.
31, generators manual synchronization should have what conditions?
A: The three conditions of the juxtaposition of the generator are the voltage, frequency, and phase of the generator and the voltage, frequency and phase of the operating system are less than the specified value.
32, bus device construction, what should be checked?
A: The following checks should be made:
(1) metal parts of the processing, preparation, welding screw should be consistent with the provisions;
(2) the Department of bolts, washers, cotter and other parts should be complete and reliable;
(3) bus preparation and installation should be consistent with the provisions of the phase and the ground to meet the electrical requirements;
(4) porcelain pieces, iron parts and glued joints should be complete, oil-filled casing should be no oil, oil level is normal;
(5) paint complete, the color is correct, well grounded.
33, in the 35kv and below the power cable connector, to improve the distribution of the sheath of the electric field there are several ways (please list five), and briefly its method.
A: (1) bulging bells: in the lead pack cut off the edge of the lead bag pry, into a trumpet-like, its edge should be smooth, rounded, symmetrical.
(2) reserved package insulation: in the lead incision to the cable core between the separation point leaving a section of the package insulation paper.
(3) Cut off the semiconductive paper: Cut the semiconductive paper below the bell.
(4) wrap the stress cone: with insulating tape and conductive metal material into a cone, artificially expand the shield to improve the electric field distribution.
(5) equipotential method: For dry-type or cross-linked polyethylene cable head, in the core of the insulation on the surface of a section of metal band, and connected together.
(6) installation of stress control tube: for 35kv and hair under the heat shrink tube cable head, first from the core copper shield end of the direction of the semiconductor to the core insulation profile around the two-layer semiconductor belt, and then the corresponding specifications of stress Tube, set at the end of the copper shield, heat shrinkage forming.
34, cable bracket processing should meet the requirements?
A: (1) steel should be straight, no obvious distortion, cutting error should be within the range of 5mm, incision should be no curling, burr;
(2) the bracket should be welded firmly, no visible beak deformation, the vertical distance between the vertical and design deviation
Should not be greater than 5mm;
(3) metal stent must be anti-corrosion treatment, located in the hot and humid, salt, fog and chemical corrosion area, should be designed for special anti-corrosion treatment.
35, list your familiar cable rack.
A: Tailored E-frame, assembly E-frame, bridge cable rack, cable tray, hook-type bracket, a single cable bracket.
36, laying the cable should meet the requirements?
A: The following requirements should be met:
(1) safe operation, as far as possible to avoid a variety of external damage, improve the cable line power supply reliability;
(2) economic aspects, from the investment in the most considerable aspects;
(3) construction, the cable line path must be easy to turn the workers and after the operation of the maintenance.
37, the production of cable terminal or intermediate connector of the insulation material which?
A: There are insulation, insulation, insulation, insulation gloves, insulation resin.
38, outlined the general operation of the cable head procedures.
A: (1) preparation before preparation: including ○ 1 read the installation instructions; ○ 2 to see the scene; ○ 3 preparation; ○ 4 cable test tide; ○ 5 pre-production test.
(2) joint production process: including ○ 1 cut off the excess cable; ○ 2 cable protection layer stripping; ○ 3 conductor connection; ○ 4 wrapped around insulation (or shrink pipe); ○ 5 installation connector shell; ○ 6 filling insulation Agent, and the like.
(3) after the production of electrical testing.
39, cable protection tube processing should meet the requirements?
A: (1) the mouth should be no hair assassination and sharp corners, the mouth should be made horn.
(2) After the bending of the cable tube, there should be no cracks and significant concave phenomenon, the degree of bending should not be greater than the tube diameter of 10%; cable tube bending radius should not be less than the minimum allowable bending radius of the cable The
(3) metal pipe should be coated in the appearance of anti-corrosion paint or leaching table, galvanized pipe zinc layer peeling should also be coated with anti-corrosion paint.
40, the cable arrangement to meet the requirements?
A: (1) power cables and control cables should not be configured on the same shelf.
(2) high and low voltage cables, strong and weak electric control cable should be layered according to the order configuration, the general situation should be from top to bottom, but with more than 35kv high voltage cable into the cabinet, to meet the bending radius, Configuration.
41, cable trench laying cable method is what?
A: The method of laying cables in cable trenches with direct burial power