Fault and Maintenance of Submarine Cable

About Submarine Cable

Progress has been reported on a project to build a 1.4 GW high-voltage submarine cable linking Germany and the United Kingdom. The European Investment Bank has agreed to provide 400 million euros in funding for the 2.8 billion euro project.

This is a 2.8 billion euro high-voltage DC line. DC submarine power wire is a major underwater power transmission line. It has 725 km long, has a capacity of 1.4 GW, and has a DC voltage of 525 KV. And will be connected to Germany and the United Kingdom.

The submarine high voltage power cable is a high voltage wire of 110 KV or more. The entire manufacturing process of high-voltage wires is the same as that of general power cables. But there are special requirements for the mechanical strength and corrosion resistance of the lines, and the lines are required to be as long as possible.

Compared to communication cables, undersea wires tend to have a larger diameter as well as higher strength, however, the situation is also still serious for its exposure to hazards.

ZMS electric cable company editor takes you to understand the submarine power cable damage factors mainly include the following.

Common Faults

1 Subsea Cable Anchors and Fishing Gear Damage

With the development of the port industry and the development of the coastline, marine navigation has increased year by year. Including repair, mooring, and construction of ships. The submarine power cable fishing and anchoring caused by external damage accidents also increased. It’s becoming one of the main factors endangering the safe operation of the electric line.

Anchor and fishing gear hook, and smash will make the cable seriously damaged, modern large trawler winches and bollards will produce a lot of tension, and can destroy almost all hooked submarine power wires.

2 Submarine Cable Free Suspension Damage

Large round rock fields, exposed rocks on the seafloor, submarine canyons, and steep slopes are topographic features that can easily cause the free suspension of submarine power cables.

When the wire is suspended or overhung on steep slopes and another terrain, it is susceptible to sway from side to side under the influence of currents and surges. Under the continuous action of alternating displacement, it leads to damage and wear of the cable in the stress concentration area, which in turn leads to insulation damage and breakdown.

The free suspension of submarine cables by the impact of the water will produce a vortex, and the vibration caused by the vortex vibration is called a vortex. Vortex vibration will lead to fatigue cracking of the lead sheath so that the cable into the water is caused by accidents.

3 Submarine Cable Corrosion Damage

The metal armor of the submarine power cable is in the marine environment. And it is subject to electrochemical and electrochemical corrosion in cooperation with mechanical and biological effects. And the corrosion mechanism is complicated under the wave wash.

The electric corrosion of armor will cause the failure of the submarine electric cable. And the sand and wave scouring of the submarine will wear the anti-corrosion layer of cord armor, which also greatly accelerates the corrosion rate of armor material and poses a great threat to the line operating life.

4 Submarine Cable or Other Damage Factors

In addition to the above-mentioned damage factors of submarine electric lines. Including tension and bending damage to the cord in construction and salvage, electrical damage to the cable after water penetration, insulation aging, and joint failure.

Preventive Maintenance

Through the analysis of the above damage, the main factors affecting the safety of submarine power cables. Such as geological terrain and ship operations, are to improve the safety of submarine power cables from the design, construction, and monitoring.

1 Submarine Cable Design Protection

The design protection of submarine power lines mainly includes two aspects of subsea line routing and cable selection.

After a detailed geological survey, choose the route to avoid as far as possible. Such as navigation channels, anchoring areas, submarine bedrock areas, submarine canyons, steep slopes, water rapids, and another unfavorable underwater environments. Avoid and minimize damage to submarine cables from anchoring, free suspension, and quicksand scouring.

For unfavorable terrain that cannot be avoided, consider choosing a cable with higher protection capability. For example, a double-layer reverse-stranded armor form has greater resistance to external damage than a single armor structure. Its outer layer with short pitch can improve both impact resistance and flexibility. Which makes the cable better match the undulating terrain of the seabed and reduces the probability of free hanging.

2 Submarine Cable Construction Protection

The construction of submarine power cables often takes deep burial laying and covering device protection.

The purpose of deep burial laying is to bury the submarine power cable at a depth where the drop anchor and fishing gear will not basically touch. This is to achieve the purpose of protecting the cable.

The burial depth is mainly based on the softness of the geology, the tonnage of navigable vessels, and the ability of burial tools to determine. When the geological conditions are not suitable for high-pressure water gun flushing burial, mechanical slotting, blasting, cutting and other means can be considered.

In extremely unfavorable conditions, such as bedrock areas extending for a long time, the line and other pipeline crossings, etc. It is necessary to use a more appropriate cover device protection method.

3 Submarine Cable Monitoring Protection

The monitoring and protection of submarine cables focus on the monitoring of certain parameters and the protection of the area where the wires are located.

Submarine power cables can be monitored in real-time by optical composite submarine cable fiber optic temperature and stress. Then timely grasp of submarine power cables in the installation and operation of the force.

The routing area protection can grasp the dynamic information of vessels in real time with the ship monitoring system specially designed for fishing vessels. Monitor the navigation of vessels close to the cable routing, and issue alerts to vessels suspected of mooring. And effectively combined with port surveillance and other systems for monitoring. Such as video, radar, etc.

4 Other Protective Measures

After the construction of the submarine power cable project, it should be declared to the maritime department for the record. The cable routing area should be marked, and the announcement information should be issued to warn the passing ships. And reduce the probability of cable destruction.

Submarine power cable landing points on both sides of the coast should be set up. Including no anchor warning signs or various types of signage. Its warning signs must be eye-catching and has stable and reliable night lighting. Sea and air patrol of cable routing is also an effective way to protect the cable.

The channel, anchor area, breeding area, and other areas prone to ship anchoring and fishing gear damage zone. Easy to cause wear and tear in the bad geological area and other areas for key monitoring. The ship is back to avoid the platform, new and expanded marine engineering construction, regular sand suction, and desalting operations time. And the main fishing period and other dangerous times are prone to submarine power cable destruction accident management.

Strengthen propaganda, post propaganda slogans at piers, and stations. And operating vessels along the route of submarine power cables, and making regular propaganda and announcements in the media, etc.

XLPE Insulated DC High-Voltage Submarine Cable is a premium product from the ZMS cable supplier. These DC submarine wires are used for power transmission to offshore islands, oil platforms, or across rivers and lakes.

ZMS cheap cables are designed based on major national or international standards such as VDE, IEC, ICEA, or according to customer designs and standards.

This paper analyzes several aspects. That causes damage to submarine electric wires and proposes measures to protect them from design routing. And cable selection, construction protection, and monitoring. ZMS cables products insist on safety first and professionalism most important to protect customer rights and provide the best quality service.

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