Development of Submarine Cables

In 1988, a transoceanic submarine optical cable (TAT-8) system was installed between the United States, Britain and France, with a total length of 6,700 kilometers.This optical cable contains 3 pairs of optical fibers, each pair has a transmission rate of 280Mb/s, and the relay station distance is 67 kilometers. This is the first communication submarine cable across the Atlantic Ocean, marking the arrival of the era of submarine cable. In 1989, the submarine optical cable (13,200 kilometers in length) across the Pacific was also successfully constructed. Since then, submarine optical cables have replaced concentric cables in the field of intercontinental submarine cables across the ocean, and submarine cables have no longer been laid between oceans.
Optical fiber has large transmission capacity and long distance between relay stations, which is suitable for long-distance communication under the sea. Optical fibers used in submarine optical cables have higher requirements than optical fibers used in terrestrial optical cables; they require low loss, high strength, long manufacturing length, and long relay distances of optical cables, generally above 50 kilometers.

The transmission performance of optical fibers is required Will not change within 25 years. In terms of the structure of the submarine optical cable: it is required to withstand strong pressure and tension, especially for deep-sea optical cables (optical cables laid on the seabed at a depth of more than 1,000 meters). In addition to the weight of the optical cable itself, sea waves must be added to the laying and maintenance operations. The dynamic stress added to the optical cable, under such a large load condition, the strain of the optical cable must be limited to 0.7-0.8%; the structure of the submarine optical cable requires strong and light materials, but light metal aluminum cannot be used because aluminum and sea water will Hydrogen is generated in response to electrochemistry, and hydrogen molecules diffuse into the glass material of the optical fiber, which increases the loss of the optical fiber. Therefore, the submarine optical cable must not only prevent hydrogen from being generated inside, but also prevent hydrogen from penetrating into the optical cable from the outside. For this reason, in the early 1990s, a carbon- or titanium-coated optical fiber was developed to prevent hydrogen penetration and chemical corrosion. The optical fiber connector is also required to be high-strength, requiring the connection to maintain the strength of the original optical fiber and the surface of the original optical fiber from damage.

According to the above requirements and characteristics, the basic structure of the submarine optical cable is to spirally wrap the optical fiber after one or two coating treatments around the center and around the reinforcing member (made of steel wire). The structure of several typical deep-sea optical cables: deep-sea optical cables, the optical fiber is arranged in a spiral U-shaped grooved plastic skeleton, and the groove is filled with grease or elastic plastic to form the core. The core is wrapped with high-strength steel stay wire. During the wrapping process, all the gaps should be filled with waterproof material. Then a layer of copper tape is wrapped around the steel wire and the seam is welded to make the steel wire and the copper tube form a resistance A combination of compression and tension, this copper tube is also a conductor that carries a remote current. A layer of polyethylene sheath should be added on the outside of the steel wire and copper pipe. Such a tight multi-core cable structure is to protect the optical fiber, prevent breakage and prevent the intrusion of seawater, and also to withstand huge tension and pressure during laying, recovery and repair.

Even with such tight protection, in the late 1980s, there were instances where the polyethylene insulators of deep-sea optical cables were bitten by sharks causing power failures. The remote power supply of the submarine cable system is very important, and the repeaters along the submarine cable rely on the remote power supply of the landing station. The digital repeater used in the submarine optical cable has many functions, and the power consumption is several times larger than that of the analog repeater of the submarine cable. The power supply requires high reliability and cannot be interrupted. Therefore, in areas where sharks are infested, two layers of steel tape and a layer of polyethylene outer sheath should be added to the outside of the submarine optical cable.

In the 1990s, submarine optical cables and satellite communications have become the main means of contemporary intercontinental communications. From 1989 to the end of 1998, my country has successively participated in the construction and investment of 18 international submarine optical cables. The first international submarine cable system to land in China was the China-Japan (C-J) submarine cable system built in December 1993. In February 1996, the China-Korea submarine optical cable was completed and opened, and landed in Qingdao, China and Taian, South Korea, with a total length of 549 kilometers; in November 1997, China’s participation in the construction of the ball submarine optical cable system (FLAG) was completed and put into operation. The intercontinental optical cable systems landed in China were landed in 12 countries and regions including the United Kingdom, Egypt, India, Thailand, and Japan. The total length is more than 27,000 kilometers, of which the Chinese section is 622 kilometers. The Asia-Europe submarine optical cable system jointly initiated by the company is under construction. The system connects Asia, Europe and Oceania. The system has landed in 33 countries and regions. The total length is 38,000 kilometers. It is the longest submarine optical cable in the world. 8-wavelength wavelength division multiplexing technology, the design capacity of the backbone route is as high as 40Gb/s, landed in China’s Shanghai and Shantou, completed and opened at the end of 1999.

The volume of intercontinental communications undertaken by submarine optical cables has increased year by year, and has exceeded that of satellite communications, becoming the main force of modern intercontinental communications.

What are the differences between YJV3+2 and YJV4+1 cables?

The YJV power cable  is composed of one or several soft wires, and the outer covering is covered with a light soft sheath; the cable is composed of one or several insulated wires, and the outside is covered with a tough outer layer made of metal or rubber.

As we all know, there are single-core cable and multi-core distinctions in wire and cable. Single-core cable means that there is only one conductor in an insulating layer, and multi-core means that there are multiple conductors in an insulating layer. Then there will be doubts from users who don’t know. 3+2 cores and 4+1 cores are both 5 cores. What is the difference between them? YJV3+2 and YJV4+1 cables are wires and cables.  In fact, these two kinds of wires and cables have their own characteristics.

The 3+2 and 4+1 on the YJV power cable indicate the number of cores of a cable. There are 2 or 3, 3+2, 4+1, and 5 wires that are insulated from each other in a cable, respectively Called 2-core or 3-core, 3+2 core, 4+1 core, 5 core wire.

What is the difference between YJV3+2 cable and YJV4+1 cable in the model name?

1.YJV 3+2 core

3 of the 3+2 cable is the three phase wires (L1, L2, L3 phase wires, the diameter of these three wires is large), the diameter of the wires is the same, 2 is the neutral wire and the PE wire, and one wire is used to connect the neutral wire (N in The diameter of this wire is smaller than L1, L2, L3), and one wire is used to connect to the grounding wire (PE grounding protection wire, this diameter is also smaller than L1, L2, L3).

2.YJV 4+1 core

The 4 of the 4+1 cable means that the diameter of the three phase wires is the same as the diameter of the neutral wire, 1 means that the PE ground wire has a single diameter; 4+1 means that a cable consists of 4 wires, one of which is used to connect to the live wire (L1 phase wire). ), one wire is used to connect to the neutral wire (N neutral wire), and one wire is used to connect to the ground wire (PE grounding protection wire).

The above is about the structure difference between YJV3+2 cable and YJV4+1 cable, and the difference in naming. We all know that cables are named based on models, and different models of cables are different in nature, and each model of cable has its own characteristics.

Cable raw material copper, trend analysis in July

Analysis of the main products of cable raw materials (copper): According to the monitoring data of the cable network, the domestic spot copper price continued to fall sharply in July, and the overall copper price fell during the month. The average spot copper price in the beginning of the month was 42585. RMB/ton, the average spot copper price at the end of the month was 39,030 yuan/ton, and the price dropped by 3555 yuan/ton, a decrease of about 8.35%.

Macroscopically, abroad, the minutes of the Federal Reserve’s June meeting announced recently confirmed the recovery of the US economy. The Federal Reserve’s interest rate hike in September may intensify. This topic may still be the focus of the market in August. However, the US GDP in the second quarter fell short of expectations. It was not easy to realize the interest rate hike in September. What is more certain is that the strength of the US dollar will not change, which may trigger a new round of upsurge of funds leaving the commodity market, which will also put pressure on copper prices. On the domestic front, the current Chinese economy is still operating at a low level. Although the Chinese government continues to introduce loose monetary policy in the second half of the year, it has limited room for short-term boost to the real economy. Therefore, the copper market may still be under pressure in the first half of August. When the off-peak season alternates, copper prices may rebound.

Market: Since the second quarter, the downstream operating rate has gradually increased, and through the arrival of the peak season of copper pipes and other industries, the overall market turnover has improved, but year by year, this year’s peak season is not busy. Affected by the weakening of consumption in the off-season in July and the weakness of China’s economy, spot copper prices have dropped sharply, but merchants’ adjustments have remained stable and no selling has been seen. After the copper price hit a new low, suppliers are reluctant to sell. When copper supply has shrunk, consumption has shrunk, and the overall economy is severely severe, copper prices are unable to rebound, and the subsequent continued decline may break through.

Inventory: LME and Shanghai copper inventories continued to show a slight growth trend this month. The latest statistical data shows that LME copper stocks reported 345,475 tons, which is a bit higher than before; while in the past week, Shanghai copper stocks on the Shanghai Futures Exchange increased slightly to 103,117 tons. Inventory has been in a downward channel for several months, but it increased slightly in July. The growth in July may be related to the recent cross-market arbitrage. Due to the continued profitability of imports, the positive arbitrage of buying LME copper and selling Shanghai copper has the opportunity. This may attract some traders to ship the goods to the warehouse, but the overall amount of change is not large. . At present, the overall supply pressure of copper is not great, and the difficulty of copper price upwards still comes from the shrinkage of the demand side.cable cu

Outlook forecast: July economic indicators have been significantly eased compared to the previous month, but the market focus has remained on the economic side. The recent US data has been weak and unfavorable, but the dollar is still strong, putting pressure on basic metals such as copper, plus China Copper consumption has always been in a weak position, which has greatly reduced global copper consumption. Therefore, copper prices have been unable to rebound and have fallen frequently. In the short term, there is still room for rebound in copper prices, but in the long run, US interest rate hikes have reached the long-term strength of the US dollar index, coupled with the copper market demand has not yet recovered significantly, copper prices will weaken again later.

One of the largest submarine optical cable projects in the world

China Mobile International Corp, Facebook, MTN GlobalConnect, Orange, STC, Egypt Telecom, Vodafone and WIOCC have announced a partnership to build 2Africa, the most comprehensive undersea fiber optic cable serving the African continent and the Middle East, and will also connect through East Africa and other undersea cables to expand connectivity with Asia.Wires and cables

The developer has awarded Alcatel Subsea Network the contract to build the cable to greatly enhance connectivity throughout Africa and the Middle East.

2Africa is 37,000 km long and will connect Europe (east via Egypt), the Middle East (via Saudi Arabia) and 21 landing sites in 16 African countries, according to the report. 2Africa will provide much-needed Internet capacity and reliability across much of Africa, complement the rapidly growing capacity demand in the Middle East, and support further growth in 5G and fixed broadband access.

In countries where the 2Africa cable will land, service providers will have access to operator neutral data center or open access cable landing station capacity on a fair and impartial basis. This will support the development of a healthy Internet ecosystem by greatly enhancing the accessibility of businesses and consumers.Wires and cables

2Africa Cable will implement a new technology, ASN SDM1, which will enable the deployment of up to 16 pairs of optical fibres instead of the eight pairs supported by earlier technologies, resulting in greater and more cost-effective capacity. The cable will adopt optical switching technology to achieve flexible bandwidth management. The cable burial depth is also 50% higher than in older systems, and cabling will avoid known locations of seabed interference, all of which helps ensure the highest level of availability.

The system is scheduled to enter service in April 2023 and will deliver more than the total capacity of all submarine cables serving Africa today, with key components designed to have a capacity of up to 180Tbps. Once completed, it will be one of the largest undersea cable projects in the world.Wires and cables