Submarine cables, also known as undersea cables, are used for transmitting power or communication signals across seas. Semiconductive products play a crucial role in submarine cables, which is specifically reflected in the following aspects:

Electric field homogenization

– Application location: Conductor shielding layer and insulation shielding layer of submarine cables. In submarine cables, conductors transmit high voltage electricity. The unevenness of the conductor surface can cause an uneven distribution of the electric field, and the interface where the outer side of the insulation layer contacts the metal sheath is also prone to electric field concentration.
– Working principle: The semiconductive shielding material is extruded onto the surface of the conductor to form a conductor shielding layer, which can eliminate microscopic defects on the surface of the conductor and make the electric field distribution between the conductor and the insulating layer more uniform. The insulating shielding layer is located on the outside of the insulating layer and can evenly distribute the electric field on the outer surface of the insulating layer. The electrical conductivity of semiconductive materials lies between that of conductors and insulating materials, which enables the charge to be distributed more evenly, reduces the local electric field intensity, and prevents the insulating layer from accelerating aging or being punctured due to excessively high local electric fields. For instance, when submarine cables transmit high voltages, the semiconductive shielding layer can effectively prevent the electric field from being overly concentrated in certain parts of the insulation layer, ensuring the long-term stable operation of the submarine cables.

Electrical connection and grounding

– Application location: The joint parts of submarine cables and the connection parts between the metal armor layer and the grounding system.
– Working principle: At the joints of submarine cables, semiconductive tapes or semiconductive filling materials can be used to improve the electrical connection between different components and ensure the consistency of electrical performance. Semiconductive materials can reduce the contact resistance at the joints, make the current distribution more uniform and reduce heat generation. In addition, the metal armor layer of the submarine cable needs to be reliably grounded. Semiconductive products can assist in achieving a better grounding effect, conducting the induced current, static electricity, etc. generated during the operation of the submarine cable into the ground. For instance, connecting the metal armor layer to the grounding electrode through semiconductive tape can enhance the reliability of grounding, ensure the safe operation of submarine cables, and at the same time reduce the potential impact on Marine life and the environment.

Moisture-proof and anti-corrosion

– Application location: Internal gaps of submarine cables and the surface of insulation layers.
– Working principle: Some semiconductive materials have certain water absorption and chemical stability. Filling semiconductive filling paste inside the submarine cable can absorb the small amount of moisture that may seep in, preventing moisture from corroding the insulation layer and conductors. Meanwhile, the semiconductive shielding layer tightly wraps around the surface of the conductor and insulation layer, which can to a certain extent prevent the erosion of the internal structure of the cable by salt, microorganisms and other substances in seawater, thus prolonging the service life of the submarine cable. For instance, in deep-sea environments, semiconductive filling paste can effectively slow down the damage caused by moisture to the core components of submarine cables, ensuring their normal operation.

Fault detection and location

– Application location: Through the insulation shielding layer and other parts of submarine cables.
– Working principle: When an insulation fault occurs in a submarine cable, the semiconductive insulation shielding layer can serve as a channel for the fault current. By detecting the current distribution and variation in the semiconductive layer, the fault point can be located more accurately. Due to the conductivity of semiconductive materials, fault currents will generate specific signal characteristics in the semiconductive layer. By using relevant detection equipment, these characteristics can be captured to quickly determine the fault location, facilitating timely maintenance and reducing the impact of submarine cable faults on power transmission or communication services.