Is used to transmit power or signal current, signal voltage covered with insulation layer, protective layer, shielding layer, etc. According to the voltage can be divided into high voltage cable and low voltage cable. Compared with low-voltage overhead lines and low-voltage overhead insulated lines, although the cost is higher and the installation and maintenance is more difficult, the low-voltage cable line has been widely used in the low-voltage distribution system because it has the characteristics of reliable operation, no pole, no ground occupation, no visual obstruction, and little external influence.
Structure
It is composed of three parts: wire core, insulation layer and protective layer. The wire core is used to conduct current and is generally twisted by multiple strands of copper wire or multiple strands of aluminum wire. Low voltage cable has single core, double core, three core, four core and so on. Two-core cables are used for single-phase lines, three-core and four-core cables are used for three-phase three-wire lines and three-phase four-wire lines, respectively, and single-core cables can be applied to single-phase or three-phase lines as needed. Commonly used low-voltage cable core cross-sectional area of 10,16, 25, 35, 50, 70, 95, 120,150, 185, 240 mm and so on.
Speculiarity
Low-voltage cable has the characteristics of reliable operation, no pole, no ground occupation, no visual obstruction, little influence from the outside world, etc., and has been widely used in low-voltage distribution system.
NO.1, Jiangnan Cable has advanced production technology and equipment. From the manufacturing of conductors to the processing of insulation, shielding and sheathing, every step is precise and strict to ensure the high quality of medium voltage cables.
NO.2, the quality control is extremely strict. The company has established a perfect quality inspection system, from the selection of raw materials to the finished products leaving the factory, checking at every level. Each medium-voltage cable has to go through a number of strict tests to ensure that the products meet or even exceed the national standards.
NO.3, Jiangnan Cable has invested heavily in research and development. According to the market demand and customers' special requirements, we can develop medium voltage cables with different characteristics, such as better environmental resistance and better current carrying capacity. Moreover, the rich product line can meet the different needs of various complex projects and provide customers with one-stop cable solutions.
Our Cases
what we finished
| Customized | Cable Specifications | Insulation Material | Shield Construction | Sheath Material | Armor Structure | Special Performance | Length | ||||||||
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1. Low-voltage cable: suitable for fixed laying in AC 50Hz, rated voltage 3kv and below on the transmission and distribution lines for electricity transmission.
2. Medium and low voltage cables: (generally 35KV and below) : PVC insulated cables, polyethylene insulated cables, cross-linked polyethylene insulated cables, etc.
3. High-voltage cable: (generally 110KV and above) : polyethylene cable and cross-linked polyethylene insulated cable.
4. Ultra-high voltage cable: (275 ~ 800KV)
Advantage
Low voltage power cable itself has the characteristics of trustworthiness, secrecy, etc., suitable for laying in a variety of places; Moreover, it is not easy to be affected by external weather factors and has strong performance, which reduces the cost of engineering construction and maintenance of electric power installation projects.
5. Uhv cable: (1000KV and above).
A layer or layers of metal or non-metal material covering the outer part of a cable. The protective layer is used to protect the insulation layer from external damage and water intrusion during transportation, laying and use.
(1) Paper insulated cable protective layer. The paper insulated cable protective layer is divided into two parts: inner protective layer and outer protective layer. The inner protective layer is directly extruded on the insulation layer, which in addition to protecting the insulation from moisture, also has the effect of preventing the outflow of insulation oil, and has a certain mechanical strength. The inner cover has three kinds of lead, aluminum and polyvinyl chloride. The outer protective layer protects the inner protective layer to increase the cable's ability to withstand mechanical external forces and corrosion resistance. The outer protective layer includes an inner liner layer, a metal armor layer and an outer coating layer. The inner liner layer protects the metal sheath from being damaged by the metal armor layer, and can add anti-corrosion measures; Metal armor layer can withstand mechanical external force; The outer coating protects the armored metal from external corrosion.
(2) Plastic cable protective layer. PVC sheathing is usually used over plastic insulation.
(3) Protective layer of rubber cable. The protective layer of rubber cable is divided into inner protective layer and outer protective layer. The inner cover has three kinds: polyvinyl chloride sheath, neoprene rubber sheath (non-combustible rubber) and lead sheath; The outer sheath is divided into three kinds: steel tape armor, rubber sheath and plastic sheath.
Sort
Graded by voltage
According to the voltage level, it can be divided into medium and low voltage power cables (35 kV and below), high voltage cables (110 kV and above), ultra-high voltage cables (275 ~ 800 kV) and ultra-high voltage cables (1000 kV and above). In addition, it can also be divided into AC cables and DC cables according to the current system.
Divided by insulation material
1. Oil-impregnated paper insulated power cable Power cable insulated with oil-impregnated paper. It has the longest application history. It is safe and reliable, long service life, low price. The main disadvantage is that the laying is limited by the drop. Since the development of non-dripping paper-impregnated insulation, the problem of drop limitation has been solved, so that oil-impregnated paper-insulated cables can continue to be widely used.
2. Plastic insulated power cable The insulation layer is extruded plastic power cable. Commonly used plastics are polyvinyl chloride, polyethylene, crosslinked polyethylene. The plastic cable has the advantages of simple structure, convenient manufacturing and processing, light weight, convenient laying and installation, and is not limited by laying drop. Therefore, it is widely used as a medium and low voltage cable, and has the trend of replacing viscous impregnated oil paper cables. The disadvantage is that there is a dendritic breakdown phenomenon, which limits its use at higher voltages.
3. The insulating layer of rubber insulated power cable is rubber plus various adjuvants, extruded on the conductive wire core after full mixing, and vulcanized by heating. It is soft and elastic, suitable for frequent movement and small bending radius of laying.
Commonly used as insulation materials are natural rubber - styrene butadiene rubber mixture, ethylene-polypropylene rubber, butyl rubber and so on.
An insulating material in a cable that has a specific function to withstand voltage. The insulation layer is divided into two types: core insulation and band insulation: the insulation coated on the online core is called core insulation; The insulation of the insulated wire core of a multi-core cable is called tape insulation. With insulation and protective layer separated to form a reliable ground insulation. The insulation layer is usually made by dipping paper, plastic, rubber, etc.
(1) Paper insulation cable is a cable made of impregnated cable paper as an insulating layer, collectively known as paper insulated cable. According to the situation of paper impregnation, it can be divided into: ① oil-impregnated paper insulated cable; ② Dry insulated cable; ③ non-dripping cable.
(2) The insulation layer is made of thermoplastic extruded cross-linked cables, collectively known as plastic cables, which are widely used. Plastic cables can be divided into polyvinyl chloride cables, polyethylene cables and cross-linked polyethylene cables. Cables with natural styrene butadiene rubber, butyl rubber and ethylene propylene rubber as insulating layers are called rubber cables. Low-voltage cables with a voltage class of 1kV can use paper insulated cables and plastic cables, and more plastic cables are used. Low voltage cables with voltage class of 0.5 kV are mostly rubber cables.
Low-Voltage Cable Use
Low-voltage cable is used for transmission and distribution of electric energy cable, often used in Chengpei underground power grid, power station leading lines, industrial and mining enterprises internal power supply and underwater transmission lines across the river and sea.
1. Aluminum core cables should be used in general environments and places, but copper core cables should be used in places with intense vibration and special buildings and special requirements; 2. Buried cables are generally armored cables with outer protective layer. In places where there is no possibility of mechanical damage, plastic sheathed cables and lead (aluminum) covered cables with outer sheaths can also be used;
3. In the soil with chemical corrosion or stray current corrosion, buried cables should not be used as far as possible. If it must be laid in the ground, anti-corrosion cables should be used;
4. Cables laid in tubes or tubes are generally plastic sheathed cables, and armored cables can also be used;
5. The cables laid in the cable trench or cable tunnel should not be flammable or flammable outer protective layer. armored cables, plastic sheathed cables and lead (aluminum) covered cables are generally used;
6. When the cable is laid in a place with a large height difference, plastic insulated cables, non-dripping cables and dry insulated cables should be used.
Line
Low voltage line with cable. The cable is composed of a core, an insulating layer and a protective layer. There are many types of cables, and low-voltage cable lines mainly use low-voltage power cables.
The commonly used laying methods of low-voltage cable lines are: ① directly buried; ② Laid in the cable trench; ③ Laying along the wall; ④ Laid in the cable tunnel, etc. The type of low-voltage power cable is mainly selected according to the environmental conditions and laying methods. Compared with low-voltage overhead lines and low-voltage overhead insulated lines, although the cost is higher and the installation and maintenance is more difficult, the low-voltage cable line has been widely used in the low-voltage distribution system because it has the characteristics of reliable operation, no pole, no ground occupation, no visual obstruction, and little external influence. Low-voltage cable lines are mainly used in places that have high requirements on power supply reliability (see Power supply quality), corrosive gases, inflammable, explosive, and so on, where it is not appropriate to erect low-voltage overhead lines or low-voltage overhead insulated lines.
YQ: Light rubber sheathed cable;
YZ: medium rubber sheathed cable;
YC: Heavy rubber sheathed cable;
VDZAN-YJY23: low voltage halogen-free armored cable;
ND-YJY: Cross-linked polyethylene insulated halogen-free low-smoke flame-retardant polyolefin sheathed power cable;
YV: Cross-linked polyethylene insulated polyvinyl chloride sheathed power cable;
V: PVC insulation PVC sheathed copper core.
Power cables in the general environment, you can choose aluminum core cables, in places with special requirements, choose copper core cables, buried laying, to choose armored cables, no mechanical damage places, you can choose plastic sheathed cables, when the buried laying soil is corrosive, to choose anti-corrosion cables.
"The technical standards of low-voltage power cables include conditions of use, performance parameters, technical requirements, testing, packaging, transportation, storage, etc. Suitable for PE, PVC, crosslinked PE insulated low voltage wire and cable with AC discharge voltage 11 and below. The normative reference documents include the use conditions, performance parameters, technical requirements, testing, packaging, transportation, storage, etc. of IkV and below wires and cables. The latest version applies to this regulation.
Common low voltage cable
1. Copper core conductor power cable: at present, the domestic low-voltage power cables are composed of each core wire, and the anti-interference ability of the cable of this structure is poor, the performance of lightning resistance is poor, the three-phase impedance of the cable is unbalanced and the zero-sequence impedance is large, and it is difficult to make the line protection electrical appliances operate reliably. The copper, aluminum polyvinyl chloride copper core conductor power cable with rated voltage of 1kv and below developed by Jiangsu Baoseng Cable factory solves the above problems.
2. Crosslinked polyethylene insulated power cable: Referred to as XLPE cable, it is the use of chemical or physical methods to make the cable insulation material polyethylene plastic molecules from linear structure into a three-dimensional network structure, that is, the original thermoplastic polyethylene into thermosetting crosslinked polyethylene plastic, thereby greatly improving the heat resistance and service life of the cable, still maintain its excellent electrical performance.
3. Polyvinyl chloride insulated polyvinyl chloride sheathed power cable: polyvinyl chloride insulated polyvinyl chloride sheathed power cable long-term operating temperature does not exceed 70 ° C, the maximum temperature of the cable conductor does not exceed 160 ° C. The longest duration of short circuit shall not exceed 5s, and the minimum construction laying temperature shall not be lower than 0℃.
Low voltage power cables have been used for a long time and also need maintenance. Otherwise, if the leakage of electrical energy is caused, a big accident may occur. In fact, the daily maintenance of this cable product is also very simple, because all our products are made under a specific model. When we're testing, all of us need to do is follow the same model. At the police academy, pay attention to check the insulation layer on the outer layer of the cable of the product. If there is damage or oxidation, it should also be dealt with in time to avoid major accidents. If necessary, check the connector of the power cable according to the low-voltage power cable model. If the connector is loose, reinforce it in time.
Low voltage power cables can withstand the impact of some mechanical external forces to a large extent, because it has very good soft and bending characteristics, so even if it is frequently moved and twisted during use, its quality will not be affected. Because of the special place where he works, and because of some environmental factors, we have high requirements for her overall softness and bending performance. When we install low-voltage power cables, we first need to pay attention not to let it be scratched by some sharp substances. Because once there is a scratch, it may shorten his overall service life.
The first type of failure: the entire cable is burned or individual phases are burned, such failures cause serious damage to the cable at the fault point.
The second type of fault: all phases of the cable are short-circuited, and similarly, such failures cause serious damage to the cable at the fault point.
The third type of fault: there is only one phase of the cable short circuit, and the fault point damage is light but obvious.
The fourth type of fault: the cable internal short circuit, the appearance can not see traces, such faults are generally caused by the quality of the cable.
For enterprises, units and some small and medium-sized cities, county-level power supply bureaus, the solution of low-voltage cable faults is their most concerned. At the same time, the total amount of low-voltage cables is much greater than the number of high-voltage cables, but there is no fault tester on the market for low-voltage cable fault characteristics and development, the so-called low-voltage cable fault tester is still based on the "flash method", nothing more than the "high-voltage impact" equipment power reduction.
The following is the solution to the low voltage cable fault
Step 1: Measure the distance with a rangefinder. In fact, we must first determine whether the cable fault is high or low resistance or ground, and use different test methods according to this condition. If it is a ground fault, the distance is measured directly by the low-voltage pulse method of the rangefinder; If it is a high resistance fault, the method of high voltage impact discharge should be used to measure the distance, and many auxiliary equipment should be used to measure the distance by the method of high voltage impact discharge: Such as high-voltage pulse capacitors, discharge balls, current limiting resistors, inductors and signal sampler, etc., the operation is troublesome and unsafe, with a certain risk, and the more cumbersome is to analyze the sampling waveform, which requires relatively high knowledge of the tester.
Step 2: Find the path (this step can be skipped if the path is clear). In the search for the path, to add a signal to the cable (path signal generator), and then use the receiver to receive this signal, along the path of the signal to go again, to determine the path of the cable. However, the range of this path is roughly between 1-2 meters, which is not particularly accurate.
Step 3: Accurate positioning based on the measured distance. It is based on the sound generated by the spark discharge, when the loudest place is heard from the headset of the fixed-point instrument, that is, the location of the fault point is found. However, because it is to listen to the sound, so, affected by the environmental noise, it takes quite a long time to find, sometimes until the evening. When it comes to cross-linked cables, it takes more time, because the cross-linked cables are generally internal discharge, the sound is very small, almost inaudible, and finally only the measurement.
Therefore, this method can solve most of the power cable faults with oil impinged paper as insulation material, for the cable faults with crosslinked materials and polyethylene materials as insulation materials in recent years, the test effect is not ideal, because the sound generated by the spark discharge is often very small (there is no damage to the cable skin, but the internal discharge of the cable), in this case, We'll have to do it some other way.
Although there are such shortcomings, the cable fault tester designed by the principle of "flash method" has solved many cable faults for enterprises in a long period of time. With the rapid development of all walks of life, the use of cables is more and more extensive, and the types of cables are also increasing, so that the constant occurrence of cable failures is inevitable. Industries for the cable used in the grade, the use of the environment, the way of wiring and distribution, insulation requirements are different, the cable fault characteristics of different cables are also very different, the reason is that there are many factors that make the cable failure, but now people because of the habit of the past, always want to solve all the cable failure in one way, Therefore, the cable fault tester designed on the principle of "flash method" is still dominant in the market.
There are many differences between the faults of high-voltage cables and low-voltage cables. The faults of high-voltage cables are mainly operation faults, and most of them are high-resistance faults, and high-resistance faults are divided into two types: leakage and flicker; The low-voltage cable failure is only open, short and open three cases (of course, high-voltage cables also include these three cases).
