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Choose the appropriate cable laying method in the photovoltaic power generation system

Choose the appropriate cable laying method in the photovoltaic power generation system

solar dc cable

Reasonable planning and correct selection of the laying method of photovoltaic cables is one of the important aspects of cable design.

When laying cables, consider comprehensively the engineering conditions, environmental conditions, cable specifications, models, and quantities, and select the appropriate laying method according to the requirements of reliable operation, easy maintenance, and technical and economical principles.

The laying of DC cables in photovoltaic power generation projects mainly includes direct burial sand laying, laying through pipes, laying in trenches, laying in cable trenches, laying in tunnels, etc. The laying of AC cables is not much different from the laying methods of general power systems.

DC cables are mostly used between PV modules, between strings and DC combiner boxes, and between combiner boxes and inverters. They have a small cross-sectional area and a large number. Usually, the cables are bundled along the module bracket or passed through pipes. Direct burial for laying, generally consider when laying:

(1) Connecting cables between components and connecting cables between strings and combiner boxes, using component brackets as channel support and fixation for cable laying as much as possible, can reduce the effect of environmental factors to a certain extent.

(2) The force of the cable laying should be uniform and appropriate, and should not be too tight. Generally, the temperature difference between day and night is large in photovoltaic places, and the cable breakage caused by thermal expansion and cold contraction should be avoided.

(3) For the cable leads of photovoltaic materials on the surface of the building, the overall appearance of the building should be considered, and the laying position should avoid laying cables on the sharp edges of walls and brackets, so as to avoid short circuits caused by cutting and abrasion damage to the insulating layer, or cut off by shearing force The wire causes an open circuit. At the same time, problems such as direct lightning strikes on cable lines should be considered.

(4) Reasonably plan cable laying paths, reduce crossovers, and combine laying as much as possible to reduce the amount of earthwork excavation and cable consumption during project construction.

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How to classy of cables and wires,and applications of cable and wires

How to classy of cables and wires,and applications of cable and wires

  1. What are the types of commonly used wires and cables according to their uses? Answer: According to the use, it can be divided into bare wires, insulated wires, heat-resistant wires, shielded wires, power cables, control cables, communication cables, radio frequency cables, etc.
  2. What kinds of insulated wires are there? Answer: There are the following types of insulated wires: PVC insulated wire, PVC insulated flexible wire, nitrile-polyvinyl chloride mixture insulated flexible wire, rubber insulated wire, agricultural underground buried aluminum core plastic insulated wire, rubber insulated cotton yarn Textile cords, PVC insulated nylon sheathed wires, PVC insulated cords for electricity and lighting, etc.
  3. What occasions is the cable tray suitable for? Answer: The cable tray is suitable for indoor and outdoor overhead laying of power cables and control cables in general industrial and mining enterprises, and can also be used for indoor and outdoor erection in telecommunications, radio and television and other departments.
  4. What are the cable accessories? Answer: Commonly used electrical accessories include cable terminal junction boxes, cable intermediate junction boxes, connecting pipes and terminals, steel wiring troughs, cable trays, etc.
  5. What is the cable intermediate joint? Answer: The device that connects the cable with the conductor, insulating shielding layer and protective layer of the cable to connect the cable line is called the cable intermediate joint.

 

Wire and cable applications

  1. Power system

The wire and cable products used in the power system mainly include overhead bare wires, bus bars (bus bars), power cables (plastic cables, oil-paper power cables (basically replaced by plastic power cables), rubber sheathed cables, overhead insulated cables), branch cables (replacing part of the busbar), magnet wire and electrical equipment wire and cable for power equipment, etc.

 

  1. Information transmission system

The wires and cables used in the information transmission system mainly include local telephone cables, TV cables, electronic cables, radio frequency cables, optical fiber cables, data cables, electromagnetic wires, power communication or other composite cables.

 

  1. Mechanical equipment, instrumentation system

Except for overhead bare wires, almost all other products are used in this part, but mainly power cables, magnet wires, data cables, instrumentation cables, etc.

 

 

Wire and cable products are mainly divided into five categories

  1. Bare wires and bare conductor products

The main features of this type of products are: pure conductor metal, without insulation and sheath layers, such as steel-cored aluminum stranded wires, copper-aluminum busbars, electric locomotive wires, etc.; the processing technology is mainly pressure processing, such as smelting, calendering, drawing The products are mainly used in suburban, rural areas, user main lines, switch cabinets, etc.

  1. Power cable

The main features of this type of product are: extruding (winding) an insulating layer on the outside of the conductor, such as overhead insulated cables, or twisting several cores (corresponding to the phase wire, neutral wire and ground wire of the power system), such as overhead insulated cables with more than two cores , or add a jacket layer, such as plastic/rubber sheathed wire and cable. The main process technologies are drawing, stranding, insulation extrusion (wrapping), cabling, armoring, sheath extrusion, etc. There are certain differences in the combination of different processes of various products.

The products are mainly used in the transmission of strong electric energy in the power generation, distribution, transmission, transformation and power supply lines, with large current (tens of amps to several thousand amps) and high voltages (220V to 500kV and above).

 

  1. Wire and cable for electrical equipment

The main features of this type of products are: a wide range of varieties and specifications, a wide range of applications, the use of voltages of 1kV and below, and new products are constantly derived in the face of special occasions, such as fire-resistant cables, flame-retardant cables, low-smoke halogen-free / low Smoke and low halogen cables, termite-proof, mouse-proof cables, oil-resistant/cold-resistant/temperature-resistant/wear-resistant cables, medical/agricultural/mining cables, thin-walled wires, etc.

 

  1. Communication cables and optical fibers (brief introduction)

With the rapid development of the communication industry in the past two decades, products have also developed at an astonishing speed. From the simple telephone and telegraph cables in the past to thousands of pairs of voice cables, coaxial cables, optical cables, data cables, and even combined communication cables.

 

The structure size of such products is usually small and uniform, and the manufacturing precision is high.

  1. Magnet wire (winding wire

Mainly used for various motors, instruments and meters

Derivatives/New Products of Wire and Cable

Derivatives/new products of wires and cables are mainly due to the requirements of different application occasions, application requirements, convenience of equipment and reduction of equipment costs, etc., and adopt new materials, special materials, or change product structure, or improve process requirements, or different. A variety of products are combined.

 

Use different materials such as flame retardant cables, low smoke zero halogen/low smoke low halogen cables, termite-proof, mouse-proof cables, oil-resistant/cold-resistant/temperature-resistant cables, etc.

Change the product structure such as: fire-resistant cable, etc.;

Improve process requirements such as: medical cables, etc.;

Combination products such as: OPGW, etc.;

Easy to install and reduce equipment costs such as: prefabricated branch cables, etc.

 

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