What does it mean that the cable conductor allows the operating temperature to be 90 degrees for a l

Cable conductors are prone to quality problems in long-term high temperature environments, and this kind of cable can work below 90 degrees Celsius for a long time.

It can work for a long time at 90 degrees.

The cable material is divided into two parts: one is the conductor and the other is the insulator.

The function of a conductor is to turn on the current, so it generates heat, and the higher the current, the more it heats up (the heat is proportional to the square of the current). The insulator itself does not generate heat, but it is wrapped around the conductor, and the heat emitted by the conductor will be transferred to the insulator 100%, causing the temperature of the insulator to rise.

The conductor is made of metal, which is relatively not afraid of high temperatures, and one or two pairs of copper and aluminum will not have any effect. However, the insulator is made of organic matter, and it is relatively afraid of high temperatures, and the temperature of one or two will make the insulator unbearable.

Therefore, in order to ensure that the insulator of the cable will not be damaged by high temperatures, it is necessary to limit the heat generation of the conductor, that is, to limit the temperature of the conductor. The "long-term allowable working temperature of the cable conductor is 90 degrees" means that the working temperature of the cable conductor can be maintained at 90 degrees for a long time without causing additional damage to the insulating material of the cable (normal losses are always present). Otherwise, the life of the cable should be infinite!

But this 90 degrees is not absolute either. It is also permissible to exceed 90 degrees for a short period of time (not too much), and of course the life of the cable will be shortened a little bit as a result. Conversely, if the operating temperature is lower than 90 degrees for a long time, the service life of the cable will be extended accordingly.

A cable load temperature of 30-50 is normal.

The allowable temperature value of different types of cables is also different, such as the long-term temperature resistance of XLPE insulated cable is 90, and the long-term temperature resistance of PVC insulated cable is only 70.

Cable (electric cable; Power cable): Usually consists of several wires or groups of wires. 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 insulation, which are used to connect electrical circuits, electrical appliances, etc.

Wire and cable products used to transmit electrical (magnetic) energy, information and realize electromagnetic energy conversion. Wire and cable in a broad sense is also referred to as a cable, and a cable in a narrow sense refers to an insulated cable, which can be defined as: a collection composed of the following parts; One or more insulated cores, as well as their respective cladding, total and outer sheaths, and cables may also have additional uninsulated conductors.

The structural elements of wire and cable products can be generally divided into four main structural components: wire fiber cluster, insulation, shielding and sheath, as well as filling elements and bearing elements. According to the use requirements and application of the product, some products have a simple structure. The properties of the wire itself are the internal factors that affect the current carrying capacity of the cable, and the current carrying capacity of the cable can be increased by increasing the core area, using high conductive materials, using insulating materials with good thermal conductivity with high temperature resistance, and reducing contact resistance.

1.Increase the core area and increase the current carrying capacity of the cable.

The core area (conductor cross-sectional area) is positively correlated with the current carrying capacity, which is usually 5 8 a m for copper wire and 3 5 a m for aluminum wire.

2.The use of highly conductive materials to increase the current carrying capacity of the cable.

If copper wire is used to replace aluminum wire, the current carrying capacity can be increased by 30% under the same specification. Silver wire is even used in some demanding occasions.

3.The insulating material with good high temperature resistance and good thermal conductivity is used to improve the current carrying capacity of the cherry tree cable.

Although the temperature resistance of the insulating material can reach more than 100 meters, the allowable operating temperature is usually reduced in consideration of the actual laying conditions and safety, which is different in each country.

The manufacturing of wires and cables is completely different from the way most electromechanical products are produced. Mechanical and electrical products are usually assembled into parts from another part, and multiple parts are then assembled into a single product, and the product is measured in units or pieces.

Wires and cables are measured in terms of length. All wires and cables are made from conductor processing, and insulation, shielding, cable-forming, and sheath are added layer by layer to the periphery of the conductor to make wire and cable products. The more complex the product structure, the more layers there are. <>

A cable consists of two parts: a conductor and an insulator.

The function of the conductor is to turn on the current, so it will generate heat, and the higher the current, the more it will heat up.

The insulator itself does not generate heat, but it is wrapped around the conductor, and the heat emitted by the conductor is transferred to the insulator, which increases the temperature of the insulator.

The conductor is made of metal, which is relatively not afraid of high temperatures, and the general temperature will not have any effect on copper and aluminum. However, the insulator is made of organic matter, and it is relatively afraid of high temperatures, and the temperature exceeds 100 degrees Celsius, and the insulator will not be able to stand it, and it will melt if it reaches the melting point.

Therefore, in order to ensure that the insulator of the cable will not be damaged by high temperature, it is necessary to limit the heat generation of the conductor, that is, to limit the temperature of the conductor.

The maximum allowable temperature is the maximum temperature that the cable can withstand without causing damage!

In principle, it is not allowed to exceed the minimum operating temperature of the insulating cover and protective sheath, because there are many options for wire and cable specifications and materials used for the insulation and protective layer, so in practice this temperature is not fixed and depends on the maximum carrying current of the cable.

1. AC rated voltage of cold-resistant cable: U0 U;

2. Maximum working temperature: 105 ;

3. Minimum ambient temperature: fixed laying-40;

4. The cable installation and laying temperature should not be less than -25;

5. Allowable bending radius of cable: the minimum cable is 12 times of the outer diameter of the cable.

The main features of heat-resistant and high-temperature wires and cables.

1. Heat-resistant and high-temperature wires and cables are generally determined by two needs: the first is that the ambient temperature of wires and cables is high, and the cable can transmit signals or electrical energy normally at high temperatures for a long time; The other is the power transmission cable, which is mainly used to increase the interception capacity as the main purpose.

2. Cables working in high temperature environments. Ordinary cables are prone to insulation aging and scorching at high temperatures, and the use of cables loses performance and cannot be used due to damage. The high-temperature cable can work normally and stably at the rated high temperature, the signal or power transmission performance is not affected, and the cable can also ensure that the cable has a long service life.

This type of functional cable is the most common and most common type of high-temperature cable, and the use characteristics are also the most easy to understand.

3. The high-temperature cable with increased load is mainly to reduce the outer diameter and weight of the cable under the premise of ensuring current carrying and develop towards lightweight. Generally speaking, the higher the operating temperature of the cable, the greater the current carrying capacity of the cable of the same cross-section.

The insulation of the wire used in the case of overload will age quickly, and if the heat emitted by the core makes the temperature of the insulation layer exceed 250, the wire will catch fire, so the selection of the wire should consider the electrical current, and then determine it.

When the ambient temperature is 25 degrees and the maximum working temperature of the wire is 65 degrees, the load current of the copper core cable of 120 square millimeters is generally between 380A.

Summary. According to the relevant standards of our country, the surface temperature of cable operation should not exceed 90% of the rated temperature of the cable. Normally, a 110kv cable is rated at 70 °C, then its operating surface temperature should not exceed 63.

If the surface temperature of the cable is too high, it may cause damage to the cable or other safety accidents. Therefore, during the use of cables, real-time monitoring and detection are required, and corresponding measures are taken for adjustment and maintenance.

According to the relevant standards of our country, the surface temperature of cable operation should not exceed 90% of the rated temperature of the cable. Normally, the rated temperature of 110kv cable is 70, then its operating surface temperature should not exceed 63 good round. If the surface temperature of the cable is too high, it may cause damage to the cable or other safety accidents.

Therefore, in the process of using cables, it is necessary to carry out real-time monitoring and detection, and take corresponding measures to adjust and maintain.

I'm sorry I don't understand, but can you elaborate on that?

The operating surface temperature of 110kV cable is affected by a variety of factors, such as current load, ambient temperature, cable laying square balance, etc. Under normal circumstances, the temperature barrier on the surface of the 110kV cable should be within the safe range.

Cable is an important part of power transmission, and its temperature is an important factor affecting the safe operation of the power system. According to the relevant regulations, the working temperature of ordinary cables is generally limited to below 70, and the maximum is not more than 90 in special occasions. So, why limit the temperature of the cable?

First of all, the material and manufacturing process of the electric front round cable determine its maximum operating temperature. Excessive temperatures can lead to aging of cable materials and deterioration of insulation properties, which can reduce the safety of the power system. In addition, high temperatures not only affect the service life of the cable, but also cause damage to the components around it.

Therefore, the maximum temperature of the cable is limited to ensure the safe operation of the power system and prevent major accidents.

Second, limiting cable temperatures also improves the efficiency of the power system. When the cable is energized, a certain resistance will be generated, causing the loss of electrical energy. If the cable exceeds the maximum permissible temperature, the resistance increases and the power loss increases.

This will not only cause a waste of energy, but also lead to a large overall load of the power system, affecting the power capacity.

Finally, it is noted that the temperature of the cable depends not only on itself, but also on the surrounding environment. In some special occasions, such as high-temperature environments, closed places, etc., the working temperature of the cable will be more strictly limited. Therefore, when designing and using cables, the surrounding environment must be fully considered to ensure the safety of cable operation and the long-term stable operation of the power system.

In principle, it is not allowed to exceed the minimum service temperature of the insulating cover and protective sheath, due to the specifications of the wire and cable.

There are many options for the materials used for the insulation and protective layers, so in practice this temperature is not fixed and depends on the maximum carrying current of the cable.

For example, EPDM.

The cladding is at least 70 degrees, 90 degrees, polyvinyl chloride.

The general cladding is 65 degrees, the general rubber cladding is also 65 degrees, and the RVV copper core PVC insulation layer with sheath is 105 degrees.

In addition, the insulation and protective layer of existing cables are mostly made of organic polymers, so if the surface temperature reaches 250 degrees, a little longer will cause the polymer to age, denature, or even break the chain, coke or cause an open flame.