Will the temperature of the high voltage cable rise when it is working normally?

Overhead high-voltage lines generally do not use high-voltage cables, and overhead high-voltage lines are generally erected with steel-core aluminum stranded three-phase three-wire systems. If the investment in high-voltage cables is very high, high-voltage cables are generally used in places where poles cannot be erected in the city, and high-voltage cables are used to communicate with underground special cables. Upstairs it was wrong to say that the high-voltage cable was exposed to air 360 degrees.

The temperature rise of the high-voltage cable is related to the load and temperature of the cable through it, and the temperature rise of the cable through the same load in summer and winter is different, and it is definitely much higher in summer. Excessive temperature rise will accelerate the insulation aging of the cable. Generally, according to the rated ampacity of the cable, it is no problem to pass the load.

The high-voltage overhead lines in the southern region will also freeze in winter, so the overhead high-voltage line block distance should have a certain degree of relaxation to prevent thermal expansion and contraction in hot and cold weather.

will be elevated. Because cables also have resistance.

There is current, there is resistance.

Then the work will be done, that is to say, there is Joule heating, which is also what you said will heat up.

How much can the temperature rise?

Theoretically, if its Joule heating is always there, then it will always heat up.

But that's not the reality.

It is also affected by the ambient temperature, and how high the temperature can rise depends on the environment.

Therefore, it is also uncertain whether the Southern Power Grid will freeze.

It depends on the environment and climate.

Temperature resistance, generally refers to the cable running current through, resulting in a temperature rise, the same can also be tested, temperature resistance test is generally rarely carried out, but one thing to be sure is that the cable in the air 360 degrees contact with air, all the heat generated can be dissipated in a short time!

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 analysis is as follows. 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.

electric 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.

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Extended Information: Wire and cable products used to transmit electrical (magnetic) energy, information and realize electromagnetic energy conversion. Wires and cables in a broad sense are also referred to as cables, and cables in a narrow sense refer to insulated cables, which can be defined as:

A collection consisting 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, insulation, shielding and sheath, as well as filler elements and bearing elements. According to the requirements of the product and the application, some products have extremely simple structures.

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 high temperature resistance and good thermal conductivity is used to improve the current carrying capacity of the cable.

Although the temperature resistance of the chain insulating material can reach 100 or more, it usually reduces the allowable use temperature in consideration of the actual laying conditions and safety, which is different in various countries.

110kV cable single-phase temperature is high what is going on, the wire has a certain resistance, as long as there is a current flowing, it will produce heat, heating is normal, the temperature of the general cable is 65 degrees when working normally, but if the cable is not normal heating phenomenon, it is necessary to find out the cause and eliminate the fault in time, otherwise it will lead to the insulation thermal breakdown of the cable, resulting in the phenomenon of interphase short circuit tripping of the cable, which may lead to a disaster, so we should pay attention to the cause of its heating and solve, The main reasons for cable heating are as follows: 1. The resistance of the cable conductor does not meet the requirements, resulting in the heating phenomenon of the cable during operation. 2. Improper cable selection, resulting in the conductor cross-section of the cable used is too small, and the overload phenomenon occurs during operation.

3. The cable is arranged too densely when installed, the ventilation and heat dissipation effect is not good, or the cable is too close to other heat sources, which affects the normal heat dissipation of the cable, and may also cause the cable to heat up during operation. 4. The joint manufacturing technology is not good, and the crimping is not tight, resulting in excessive contact resistance at the joint, which will also cause the cable to heat up. 5. The interphase insulation performance of the cable is not good, resulting in small insulation resistance, and heating will also occur during operation.

6. The local sheath of the armored cable is damaged, which causes slow destruction of the insulation performance after water ingress, resulting in the gradual reduction of insulation resistance, and also causes heating in the operation of the cable. Hope it helps.

Summary. The high single-phase temperature of the 110kV cable can be due to damage to the cable or damage to the insulation, which causes excessive current to flow on the cable, causing a fault.

The high single-phase temperature of the 110kV cable can be due to damage to the cable or damage to the insulation, which causes excessive current to flow on the cable, causing a fault.

If the single-phase temperature of the 110kV cable is high, measures should be taken to solve it as soon as possible. First, a shell grounding test should be performed to determine the exact cause of the problem. If it is necessary to repair the socks and replace the cable, you should try to use a qualified cable and consider reducing the load current to avoid the occurrence of similar faults.

Is this the case with a low ground resistance?

Yes, if the ground resistance value is low, it will cause the residual and single-phase temperature of the 110kV cable to rise, this is due to the low resistance value may cause the current to leak out of the ground wire, which will lead to the increase of the cable heat such as destroying the slag cover effect.

Single-phase grounding is also to look at.

Yes, it is necessary to check if there is a single disadvantage dust front grounding cause. It is important to check whether the grounding resistance is low, and whether the grounding system is loose or disconnected.

The maximum temperature of the outer sheath of the cable should not exceed a few degrees, which will cause the internal insulation to deteriorate.

The maximum surface temperature of the 110kV cable sheath can not exceed 80, if it exceeds this closed sheath, it may cause the insulation aging and deterioration inside the cable, and affect the normal use of the cable.

How many degrees can the surface temperature of the cable differ from the internal temperature of the cable, and is there a reference value?

The difference between the internal temperature and the surface temperature of different types of cables is different, but typically, the difference ranges from 20 to 40.