What is a cable

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1、 Definition of cable

Cable is a wire product used to transmit electrical energy information and achieve electromagnetic energy conversion. "There are both conductors and insulating layers, and sometimes a tight inner protective layer that prevents moisture intrusion, or an outer protective layer with high mechanical strength. Products with complex structures and large cross-sectional areas are called cables.".

2、 Classification of cables

Cables include power cables, control cables, compensation cables, shielded cables, high-temperature cables, computer cables, signal cables, coaxial cables, fire-resistant cables, marine cables, mining cables, aluminum alloy cables, and so on. They are all composed of single or multiple strands of wire and insulating layer, used to connect circuits, electrical appliances, etc.

According to the system of photovoltaic power stations, cables can be divided into DC cables and AC cables, which are classified as follows according to different purposes and use environments:

1. DC cable

(1) A series cable between components.

(2) Parallel cables between strings and between strings and DC distribution boxes (combiner boxes).

(3) Cable from DC distribution box to inverter.

The above cables are DC cables, which are frequently laid outdoors and require moisture resistance, exposure to sunlight, cold resistance, heat resistance, and UV resistance. In some special environments, it is also necessary to prevent acid and alkali and other chemicals.

2. AC cable

(1) Connecting cable from inverter to step-up transformer.

(2) Connecting cable from step-up transformer to power distribution device.

(3) The connecting cable from the power distribution device to the power grid or users.

This part of cable is AC load cable, which is widely laid in indoor environment, and can be selected according to general power cable selection requirements.

3、 Cable type

1. Composition and sequence

The model composition and sequence of wires and cables are as follows: [1: Category, Purpose], [2: Conductor], [3: Insulation], [4: Inner Sheath], [5: Structural Features], [6: Outer Sheath or Derivative], [7: Usage Features]

Items 1-5 and 7 are represented by pinyin letters, and polymer materials are represented by the first letter of the English name. Each item can have 1-2 letters; Item 6 contains 1-3 numbers.

2. Common Codes

Usage code - not marked as power cable, K - (control cable), P - (signal cable);

Conductor material code - not marked as copper (also can be marked as CU), L - (aluminum);

Internal protective layer codes - Q - (lead wrapped), L - (aluminum wrapped), H - (rubber sheathed), V - (PVC sheathed), and the internal sheath is generally not marked;

Outer sheath code - V - (polyvinyl chloride), Y - (polyethylene power cable);

Derivative codes - D - (non drip), P - (dry insulation);

Special product codes - TH - (wet tropical zone), TA - (dry tropical zone), ZR - (flame retardant), NH - (fire resistant), WDZ - (low smoke zero halogen, enterprise standard).

3. Ellipsis principle

Omission principle in model: Copper is the main conductor material used in wire and cable products, so the copper core code T is omitted, except for bare wires and bare conductor products. "Bare wires and bare conductor products, power cables, and electromagnetic cables do not indicate major category codes, and wires and cables for electrical equipment and communication cables are not listed, but minor category or series codes are listed.".

Item 7 is a mark for various special occasions or additional special requirements, marked with a pinyin letter after the "-". Sometimes, in order to highlight the item, this item is written to the top. For example, ZR - (flame retardant), NH - (fire resistant), WDZ - (low smoke zero halogen, enterprise standard), TH - (for humid and hot areas), FY - (anti termite, enterprise standard), etc.

4. Main content

1) SYV: Solid polyethylene insulated RF coaxial cable, coaxial cable, radio frequency signal transmission in wireless communication, broadcasting, monitoring system engineering, and related electronic equipment (including integrated coaxial cable)

2) SYWV (Y): Physically foamed polyethylene insulated cable TV system cable, video (RF) coaxial cable (SYV, SYWV, SYFV) suitable for closed circuit monitoring and cable TV engineering

SYWV (Y), SYKV cable TV, broadband network dedicated cable structure: (coaxial cable) single oxygen-free round copper wire+physical foam polyethylene (insulation)+(tin wire+aluminum)+polyvinyl chloride (polyethylene)

3) Signal control cables (RVV sheathed wire, RVVP shielded wire) are suitable for building intercom, anti-theft alarm, fire protection, automatic meter reading, and other projects

RVVP: Copper core PVC insulated shielded PVC sheathed flexible cable, voltage 250V/300V, 2-24 core Purpose: instrument, instrument, intercom, monitoring, control installation

4) RG: Physically Foamed Polyethylene Insulated Access Network Cable for Transmission of Data Analog Signals in Coaxial Fiber Hybrid Networks (HFC)

5) KVVP: PVC sheathed braided shielded cable, used for signal transmission, control, and measurement of electrical appliances, instruments, and power distribution devices

6) RVV (227IEC52/53): PVC insulated flexible cable, use: household appliances, small electric tools, instruments, and power lighting

7) AVVR: PVC sheathed flexible cable for installation

8) SBVV: HYA data communication cables (indoor and outdoor) are used for connection of telephone communication and radio equipment as well as junction box wiring of telephone distribution network

9) RV, RVP: PVC insulated cable

10) RVS, RVB: Suitable for connecting cables for household appliances, small electric tools, instruments, meters, and power lighting

11) BV, BVR: PVC insulated cable, Purpose: Suitable for fixed wiring of electrical instruments and power lighting

12) RIB: Speaker connection cable (fever cable)

13) KVV: PVC insulated control cable, use: electrical appliances, instruments, power distribution devices, signal transmission, control, measurement

14) SFTP: Twisted pair for transmission of telephone, data, and information networks

15) UL2464: Computer Connection Cable

16) VGA: display cable

17) SDFAVP, SDFAVVP, SYFPY: coaxial cable, dedicated for elevators

18) JVPV, JVPVP, JVVP: Copper core PVC insulated and sheathed copper wire, woven electronic computer control cable

4、 Main uses of cables

Cables are mainly used for power supply; Power transmission and distribution; Winding resistance of motors, electrical appliances, and electrical instruments to achieve electromagnetic energy conversion; Measuring electrical and physical parameters; Transmission of signals, information, and control; For common antenna TV or cable TV systems; Used as a feed line for transmitting and receiving antennas of radio stations or as a connection line for various radio frequency communication and testing equipment.

5、 Main performance of the cable

1. Electrical performance

Conductivity - Most products require good electrical conductivity, while individual products require a certain resistance range.

Electrical insulation performance - insulation resistance, dielectric coefficient, dielectric loss, electrical resistance characteristics, etc.

Transmission characteristics - refer to high-frequency transmission characteristics, anti-interference characteristics, etc.

2. Aging performance

It refers to the ability of a product and its constituent materials to maintain their original performance under the action of mechanical stress, electrical stress, thermal stress, and various other external factors, or under the action of external climatic conditions.

3. Thermal performance

It refers to the temperature resistance grade of the product, the working temperature, the heating and heat dissipation characteristics of the power transmission cable, the current carrying capacity, short circuit and overload capacity, the thermal deformability and thermal shock resistance of the synthetic material, the thermal expansion of the material, and the dripping performance of the impregnation or coating material.

4. Corrosion and climate resistance

It refers to resistance to electrochemical corrosion, biological and bacterial corrosion, chemical (oil, acid, alkali, chemical solvents, etc.) corrosion, salt spray resistance, light resistance, cold resistance, mold resistance, and moisture resistance.

5. Mechanical properties

It refers to tensile strength, elongation, flexibility, elasticity, softness, vibration resistance, wear resistance, and mechanical impact resistance.

6. Other performance

This includes the characteristics of some materials (such as the hardness and creep of metal materials, and the compatibility of polymer materials) as well as some special use characteristics of the product (such as non flame retardance, atomic radiation resistance, insect bite resistance, delayed transmission, and energy damping).