Medium-voltage (MV) power cables form the spine of electric power distribution systems in the contemporary world. They are where transmission and distribution converge for industrial, commercial, and utility purposes. They cover voltages between 1 kV and 35 kV and act as the linking wire between the low-voltage (LV) and high-voltage (HV) systems to transmit power reliably and effectively.

This article has details on the nature, structure, application, and benefit of medium-voltage power cable as explained by the High Voltage Cable Manufacturers the way they did for the high-voltage cables. We will give the selection process, installation process, and maintenance practice to be efficient and reliable in the long run.

Learning Medium Voltage Power Cables

Medium-voltage power cables are transmission voltage power cables ranging from 1 kV to 35 kV. They have vast applications, like in utility systems, industrial parks, commercial complexes, renewable energy generation facilities, and underground power supply networks.

Role of MV Cables

Significance of MV cables, as explained by High Voltage Cable Suppliers, is that they are able to deliver electrical power at maximum efficiency with the least loss but in a safe and compact form. They are manufactured with some coverings for protection, shielding, and insulation to make them insensitive to the surroundings and mode of operation.

Structure of Medium Voltage Power Cable

MV power cables are made of multiple layers to achieve better electrical, thermal, and mechanical properties. These are:

1. Conductor

The conductor is the majority of the cable with electricity within. It's likely copper or aluminium, stranded or solid construction. Copper conductors are superior conductors and are more flexible than aluminium conductors, which are lighter and cheaper.

2. Conductor shielding

A semiconductor coating is applied over the conductor to offer uniform electric field distribution and stress concentration removal. The coating stops insulation breakdown and overall cable performance enhancement.

3. Insulation

Cross-linked polyethylene (XLPE), ethylene propylene rubber (EPR), or paper insulation material is used as a high-quality insulation material for MV cables. XLPE has the widest usage due to the best electrical, thermal, and also mechanical properties.

4. Shielding of insulation

It is a semiconductor cover screen for smooth transition from metal to insulation. It is applied in the regulation of electric fields and is safe.

5. Metallic Shield

Metal tape shield or copper wire shield of tape type is used to wrap over insulation for grounding prevention and electromagnetic interference (EMI) reduction. It also insulates cables from electrical faults.

6. Inner Sheath (Bedding)

Inner sheath provides a cover layer between the metal or copper tape shield and the metal or copper wire shield and the electric and outer protection layers, and the water protection and mechanical strength.

7. Armor (Optional)

There are a few MV cables that also have an additional mechanical protection in the shape of a mechanical protection layer in the shape of an armoured layer of steel wire (SWA) or aluminium wire (AWA). Armoured cables are normally used for underground and direct burial applications.

 8. Outer Sheath

The outer sheath provides complete protection from the external environment, chemicals, water, and mechanical stress. It is typically made of polyvinyl chloride (PVC), polyethylene (PE), or low-smoke zero-halogen (LSZH) material.

Medium Voltage Power Cables Types

MV cables vary in construction, insulation, and application area. Some of them are:

●       XLPE Insulated MV Cables: Technologically superior cable with good heat resistance and most commonly used for underground and overhead installation.

●       EPR Insulated MV Cables: Where maximum flexibility and application at extreme temperatures up to the utmost are required.

●       Armoured MV Cables: For mechanical stresses and direct burial installation.

●       Aerial Bundled Cables (ABC): Overhead distribution for greater safety and reliability.

●       Paper-Insulated MV Cables: Obsolete cables in legacy systems, replaced by polymer-insulated cables.

Applications of Medium Voltage Power Cables

MV power cables find applications in every type of industry and sector, like:

1. Power Distribution Systems

They form distribution utility networks and provide power to residential, commercial, and industrial complexes.

2. Industrial Plants

MV cables find application in intra-power distribution within industrial manufacturing plants, refineries, and processing plants.

3. Renewable Energy Projects

Solar farms, wind farms, and hydroelectric power plants employ MV cables to transport electricity from generation to substations.

4. Underwater and Buried Cables

MV cables are especially suited for underground supply of cities and laying of submarine cables for application off-shore.

5. Railways and Metro Systems

MV cables power the traction and signalling gear of electric railways and metro rails.

6. Oil & Gas Industry

Offshore oil platforms, drilling vessels, and petrochemical refineries use MV cables for the safe and efficient supply of power.

Medium Voltage Power Cable Selection Criteria

The correct selection of the MV cable depends on many factors, including:

●       Voltage Rating: For the requirement of voltage support in systems.

●       Conductor Material: Copper for conductivity, aluminium for the cost factor.

●       Insulation Material: XLPE for maximum efficiency; EPR for flexibility.

●       Environmental Factors: For water resistance, chemical resistance, and resistance to temperature changes.

●       Installation Procedures: Overhead, underground, or direct burial requirements.

●       Standards Acceptance: IEC, IEEE, and UL acceptance of international standards.

Installation Procedures

MV cables are securely fixed so that they have a longer lifespan. The key installation procedures are:

●       Cable routing: Avoid sharp bends and tensioning.

●       Joining and Termination: Apply good quality accessories to avoid electrical faulting.

●       Earthling and Shielding. Apply proper earthing to avoid EMI and electrical faults.

●       Environmental Protection: Apply protection sheaths and hostile environment conduits.

●       Testing and Commissioning: Apply insulation resistance test and voltage withstand test before energization.

Practices of Safety and Maintenance

Maintenance practices are necessary to prolong the life of MV cables and prevent failure. Best recommended practices are:

●       Periodic Inspection: Inspect for physical degradation, corrosion, and abrasion of insulation.

●       Thermal Imaging: Identify heat spots and potential faults with the use of infrared cameras.

●       Partial Discharge Testing: Identify faults in insulation before they fail.

●       Optimum Load Management: Don't overload and avoid overheating and failure.

Benefits of Medium Voltage Power Cables

MV cables also have some advantages, which are listed below:

●       Higher Efficiency: Less transmission loss compared to low-voltage wires.

●       Better Safety: Secure shielding and insulation provide safe handling.

●       Longer Lifespan: Durable materials ensure longer service life.

●       Flexibility: Easy to use in most applications and environments.

●       Fewer Electromagnetic Interferences (EMIs): Shielding minimizes signal interference in sensitive areas.

Conclusion

MV power cables are a valued commodity to ensure effective and efficient supply of power to most regions of a building. Their cutting-edge production, diverse usage, and safety complacency make them a realm for clever electrical networks. Choosing, fixing, and servicing of MV cables with absolute precaution ensures high performance, security, and extensive longevity. Identification of the most critical aspects of MV cables enables policymakers and engineers to make more informed decisions in trying to offer maximum efficiency and reliability in power supply.

Also Read: How to Choose the Right Cables for the Mining Industry?