High Voltage Cable Jelly
Application of high voltage cable jelly 。。
Compatibility of high voltage cable jelly
Manufacturability of high voltage cable jelly
Telstra announces "Always On" service for submarine cable
At the 2017 Pacific Telecommunication Conference, Telstra announces the launch of the "Always On" service for the next few months for Asia's busiest submarine cable routes - Hong Kong, China to Singapore, and Japan to China, Hong Kong. Commercial.
It is reported that this service will use the advantage of Australia Telecom’s extensive and diverse coverage of the submarine cable network in the Asia Pacific region to ensure the stability of the network connection even in the event of cable breaks or damage caused by natural disasters.
Currently, the Asian market now has nearly 50% of the Internet users worldwide, activating tens of millions of new Internet devices each year. In 2016 alone, the data consumption in the Asian market grew by 70%. At the core of all this is a huge network of submarine cables that carry 99% of the international data traffic and keep all devices connected to the Internet.
Ellie Sweeney, executive director of global sales at Australia Telecom, said: "The ability of network connectivity is critical to the modern economy. Consumers and businesses want to be able to connect to the network anytime, anywhere. However, international connections are often challenged, especially by ships, earthquakes and typhoons. Caused by cable breakage."
Sweeney said, "The damage to the submarine cable may take several days to repair, even in an extreme case, it will take several weeks. With the launch of Australian Telecom's Always On service guarantee, users will be involved in the accident. Within a few hours it was assigned to a safe path to restore network connectivity, and we expect that this process will be completed in a matter of minutes in the future."
About high voltage cable
High-voltage cable is a type of power cable and refers to a power cable used to transmit between 1 kv and 1000 kv, and is mostly used for power transmission and distribution.
Components of the high-voltage cable from the inside to the outside include: conductor, insulation, inner sheath, filler (armored), and external insulation. Of course, armored high-voltage cables are mainly used for ground-buried, which can resist the high-strength compression on the ground and prevent other external damage.
This product is suitable for AC rated voltage 35KV and below for transmission and distribution can be used for fixed installation circuit, the cable conductor of the long-term maximum operating temperature of 90 degrees, short circuit (maximum time does not exceed 5S), cable conductor maximum temperature does not exceed 250 degrees.
1.8kV and below are low voltage cables; 3.6KV~35KV are medium voltage cables; 35KV~110KV are high voltage cables; 110~220KV are UHV cables;
UHV cable is a kind of power cable that appears along with the continuous development of cable technology. UHV cable is generally used as a middle hinge zone in large-scale transmission systems and belongs to a high-voltage high-voltage cable, mainly used for long-distance power. transmission.
cause of issue
The cable is the bridge between the power supply equipment and the electrical equipment, and plays the role of transmitting electrical energy. Because of its wide application, faults often occur. The following briefly analyzes the causes of the common problems of high-voltage cables. The classification according to the causes of faults can be roughly divided into the following categories: manufacturer's manufacturing reasons, construction quality reasons, design unit design reasons, and external force destruction Four categories.
Manufacturer makes reason
According to the different parts, the manufacturer's manufacturing reasons are divided into three categories: cable body reason, cable joint reason, and cable grounding system reason.
Cause of cable body manufacturing
The common problems in the cable production process are insulation eccentricity, uneven insulation shield thickness, impurities in the insulation, protrusions inside and outside the shield, uneven degree of cross-linking, moisture in the cable, poor sealing of the cable metal sheath, etc. Severe failures may occur during or shortly after the completion of the test, most of which are in the form of defects in the cable system, causing serious risks to the long-term safe operation of the cable.
Cable connector manufacturing reasons
High-voltage cable joints have previously been of the wrap-around type, die-cast type, molded type, etc., and require a large amount of work for on-site production, and due to the limitations of on-site conditions and manufacturing processes, there is inevitably an air gap between insulating tape layers. With impurities, it is prone to problems. The types commonly used in China are assembly and prefabrication.
The cable joints are divided into cable end connectors and cable intermediate joints. No matter what the joint type is, the cable joint failure usually occurs at the fracture of the cable insulation shield because it is the site where the electrical stress is concentrated and the cause of the cable joint failure due to manufacturing reasons is stress. Cone body manufacturing defects, insulation filler problems, oil leaks and other reasons.
Cable grounding system
The cable grounding system includes the cable grounding box, the cable grounding protection box (with protective layer protector), the cable cross-interconnect box, and the protection layer protector. The general problem that is easy to occur is mainly because the poor sealing of the box body leads to multi-point grounding, causing the metal sheath induction current to be too large. In addition, the selection of protective layer protector parameters is unreasonable or the quality of the zinc oxide crystal is unstable, and the protective layer protector is easily damaged.
Reason for construction quality
There are many cases of high-voltage cable system failure due to construction quality. The main reasons are the following: First, the site conditions are relatively poor, the environment and process requirements are very high when the cables and connectors are manufactured in the factory, and the construction site temperature, humidity, dust Not well controlled. Secondly, during the cable construction, it is inevitable that tiny scratches will be left on the insulating surface. The sand particles on the semi-conductive particles and the abrasive cloth may also be embedded in the insulation. In addition, the insulation will be inhaled due to the insulation exposed to the air during the joint construction process. Moisture, these all leave hidden dangers for long-term safe operation. Third, the installation did not strictly follow the process of construction or process regulations did not take into account the possible problems. The fourth is that the DC voltage withstand test results in the formation of a back-EMF in the joint resulting in insulation failure. The fifth is due to poor sealing. The middle joint must adopt the sealed structure of metal copper shell plus PE or PVC insulation coating to ensure the solidity of the seal during construction on site, which effectively ensures the sealing and waterproof performance of the joint.
Cable breakdown caused by thermal expansion of the cable causes breakdown. When the cross-linking cable load is high, the temperature of the core is increased, the cable is heated to expand, and the cable is turned on the bracket elevation at the turning point in the tunnel. The long-term heavy-duty operation of the cable has a large amount of peristaltic force, which causes the bracket facade to crush the outer jacket of the cable. , Metal sheathing, intrusion into the cable insulation leads to cable breakdown.