After the high voltage cable head is done, how to judge whether the semiconductor layer has been pee

Now there are more and more people making cable glands, ** is getting cheaper and cheaper, and the level is getting worse and worse. Let's talk about the discharge part in the picture first, which is the place where the UP main circle is drawn. It was found that the discharge parts were all at the tip of the semi-conductive layer.

These tips are expressly forbidden in cable gland manufacturing techniques. The reason for the discharge is that the technical level of the production workers is not good, and the transition between the semi-conductive layer and the main insulation is not made in accordance with the requirements of the cable joint accessory manual. The semi-conductive layer here should be a straight line, not like a dog gnawing on it, with a tip.

At the same time, sandpaper of more than 600 should be used to polish the transition part of the semi-conductive layer to the main insulation.

After the high-voltage cable head is ready, do you want to judge whether there is a wave in the semiconductor layer? Resistance can be measured with a multimeter or a shake meter to detect whether the insulation layer is peeled off from half to the bottom layer.

Now that you have done a good job, you should be able to judge whether there is a wave in the semiconductor residue, as long as you follow the operation, it is no problem.

After the high-voltage cable head is ready, you can disassemble the wire head to detect if the semiconductor is broadcast.

The semiconductor layer is now completely exposed if this cable is opened, and now if this cable is opened, it will be completely exposed.

First, the structure and function of the cable.

1) The cable is mainly divided into three parts: conductive layer, insulation layer, and protective layer (semiconductor layer, shielding layer and outer sheath).

Conductive layer: conducts electricity and transmits energy.

Insulation layer: The conductive layer is isolated from the outside world, and the conductive layer operates safely and reliably.

Protective layer: The protective insulation layer is not damaged by the outside world, and the insulation performance is good.

The main insulation layer of high-voltage cables: PVC and XLPE PVE.

PVC: used for medium voltage cables of 6kV and below.

XLPE PVE: used for 6KV and high-voltage cables.

High-voltage cable head, how to judge whether the semiconductor layer has after it is done, can be measured and detected by some measuring instruments.

You can just do a measurement of the resistance.

This can be judged because it can be seen above.

How to judge semiconductors after the high-voltage cable head is ready? I don't know if I ever broadcast this.

The high-voltage cable head has been judged to be that well, is there that wave? It can be judged directly.

First, the semiconductor is lightly cut with a paper cutter along the direction of the cable, so that the semiconductor is divided into three parts, and it can be easier to heat it with a spray gun fire and peel off one part of the other.

In addition, the outer semi-conductive layer stripper is suitable for the outer semi-conductive layer stripping of XLPE high-voltage cables, and it is not easy to damage the insulation if it is not "using an electrician knife to cut the semiconductor layer longitudinally into several strips and cut them one by one". The outer semi-conductive layer peeler is easy to buy in China.

Summary. Because the cable conductor is generally made of multiple wires stranded and compacted, it is inevitable that there will be local gaps, burrs and other surface non-smooth phenomena between the conductor surface and the insulation layer when squeezing the insulation, resulting in the concentration of electric field, causing local air gap discharge and tree discharge, and then leading to the decline of the electrical resistance of the cable. A conductor shield (semi-conductive material) is squeezed between the surface of the conductor and the insulation, which can be in close contact with the insulation.

At the same time, due to the equipotential of the semi-conductive layer and the conductor, the generation of partial discharge can be effectively avoided. The 10kV cable head will destroy the original magnetic field distribution during production, and peeling off the semiconductor layer is to make the magnetic field lines evenly distributed along the direction of the electric field during the production, and will not produce partial discharge to destroy the cable insulation.

What will be the problem if the 10kv cable head does not strip off the semi-conductive layer, and how to solve it.

Because the cable conductor is generally made of multiple wires stranded and compacted, it is inevitable that there will be local gaps, burrs and other surface non-smooth phenomena between the conductor surface and the insulation layer when squeezing the insulation, resulting in the concentration of electric field, causing local air gap discharge and tree discharge, and then leading to the decline of the electrical resistance of the cable. A conductor shield (semi-conductive material) is squeezed between the surface of the conductor and the insulation, which can be in close contact with the insulation. At the same time, due to the equipotential of the semi-conductive layer and the conductor, the generation of partial discharge can be effectively avoided.

The 10kV cable head will destroy the original magnetic cooker field distribution during production, and stripping off the semiconductor layer is to make the magnetic field line field evenly distributed along the direction of the electric field during the production, and will not produce partial discharge to destroy the cable insulation.

The failure rate of Xunyu is as high as 73% due to the uneven peeling of the semi-conductive layer, which shows that it is a common phenomenon to cause the uneven peeling of the semi-conductive layer in on-site construction. Usually the uneven peeling of the semi-conductive layer in the construction refers to the outer semi-conductive layer, and the dissection of the faulty phase cable joint finds that the semi-conductive layer is made of various common defects.

If the semi-conductive layer is stripped for a long time (i.e., the retained semi-conductive layer is short), the semi-conductive layer of the stress cone can not be overlapped with it, and the main insulation without shielding will produce an induced potential, forming an electric field stress between the semi-conductive layers at both ends, and it is very easy to produce insulation damage after long-term operation, and cause equipment burning accidents; If the stripping of the semi-conductive layer is short (that is, the retained semi-conductive layer is longer), it will cause the main insulation distance to become shorter, and the capacity is easy to creepage during operation, and in serious cases, it will cause insulation breakdown. Therefore, the installation must be carried out in strict accordance with the provisions of the internal structure of the cable accessories.

Dear, hello, I am glad to answer for you, the high-voltage cable head production semiconductor layer does not go to what should be the response to it is to connect the high-voltage cable connector must strip off the semiconductor layer clean and tidy, and to get along with the semiconductor layer and the insulation layer to cut the semiconductor into a 45-degree cone, and then polish it with clean fine sandpaper, and then clean it with anhydrous alcohol or acetone, if you don't do this, when there is atmospheric overvoltage or operating overvoltage on the line, it will inevitably break down here. If you don't remove it, you may have poor contact or can't be electrified, and there will be a certain danger in it, so be cautious! Please take the stop off, just in case.

The outer semi-conductive layer stripper is suitable for the outer semi-conductive layer of XLPE high-voltage cables, but it is easy to injure the insulation as the upstairs said "using an electrician knife to cut the semiconductor layer longitudinally into several strips and cutting them one by one". The outer semi-conductive layer peeler is easy to buy in China.