Type YRUHKGXSekFoyn 3.6/6 kV Mining Power cables
Mining steel wire armored individual shield, copper core power cable,
XLPE insulation, PVC sheath, with seal
With longitudinal seal, flame retardant PVC shell
Type YRUHKGXSekFoyn cables are specially designed for mining applications.
They are built to withstand the harsh conditions of underground installations, particularly in mining environments where risks from methane or coal dust explosions exist.
These cables are intended for low voltage networks (rated up to 1 kV) in mining sites and are suitable for both non-methane and methane areas, provided that the explosion risk classifications (classes A or B) are met.
Construction and Materials
1. Conductors and Their Screening
Conductor Composition:
The cable features copper conductors that are multi-stranded and round. These are compacted to Class 2 as per EN 60228 standards.
In some designs, working conductors are twisted around an additional copper core (either as a wire or stranded element) to enhance mechanical stability.
Individual Conductor Screening:
Each working conductor is individually shielded. This is achieved either by applying conductive tapes or by using a polyethylene-based conductive layer combined with a copper tape.
This individual screening helps to minimize electrical interference and improves the cable’s overall performance.
2. Insulation and Internal Layers
Insulation Material:
The insulation is made of cross-linked polyethylene (XLPE) – specifically, type DIX 3 as defined by PN-HD 620 S1:2002.
The natural (uncolored) appearance of the insulation is maintained.
Internal Sheath:
A PVC inner sheath (type DMV 31 according to PN-HD 620 S1:2002) is applied over the insulation.
To protect the insulation and add mechanical integrity, the cable is filled with a compound based on unvulcanized rubber or a specialized polwinit (tire) compound.
3. Sealing and Shielding
Radial Sealing:
A radial seal is provided by an Al/PVC tape, which ensures the cable’s resistance to water ingress.
Overall (General) Screening:
An overall shield in the form of a copper tape wrap is applied over the insulated and internally sheathed core.
Additionally, a separating PVC layer (of the same type as the internal sheath) is included between the overall screen and the outer armor.
4. Armor and External Protection
Armor:
The cable is armored with round steel wires. This steel wire armor provides essential mechanical protection against physical impacts, which is critical in the harsh conditions of underground mining operations.
Longitudinal Sealing:
Along the length of the cable, a water-activated, swelling tape is applied. This longitudinal seal helps to maintain the cable’s integrity when exposed to moisture or water.
External Sheath:
The final layer is an external PVC sheath made of a flame retardant (polwinit-based) compound, ensuring that the cable resists flame propagation.
The sheath is typically colored red for easy identification.
Technical Specifications
Temperature Ratings and Electrical Tests
Operating Temperature:
Maximum conductor operating temperature is +90°C, while under fault conditions, the conductor can reach up to +250°C.
Ambient Conditions:
The cable is rated for a minimum ambient temperature of -30°C when permanently installed. During installation (without preheating), it can withstand temperatures as low as -50°C.
Bending Radius:
The minimum bending radius is specified as 12 times the cable’s external diameter (12 x D).
Test Voltage:
An 11 kV AC test (50 Hz for 5 minutes) is used to verify the cable’s insulation integrity.
Flame Propagation:
The cable meets flame propagation resistance standards per IEC 60332-1-2 and IEC 60332-3-24C.
Mechanical Strength:
The maximum tensile force is calculated as 50 times the sum of the cross-sectional areas of the working conductors (in mm²).
Cable Variants and Dimensions
Conductor Sizes:
Cables are available with three copper conductors in various cross-sectional areas (e.g., 25, 35, 50, 70, 95, 120, 150, and 185 mm²).
Layer Thicknesses and Overall Dimensions:
Detailed tables (provided in the original documentation) list the nominal thicknesses for the insulation, internal sheath, and armor, along with the approximate overall cable diameter and weight per kilometer.
Electrical Characteristics:
Parameters such as the maximum conductor resistance at 20°C, current-carrying capacities, unit inductance (mH/km), and unit inductive reactance (Ω/km) are specified for each cable size.
Installation Considerations and Derating Factors
Current-Carrying Capacity Adjustments:
Parallel Cable Laying:
When cables are installed in parallel (e.g., stacked on supports), their current-carrying capacity must be derated using specified correction factors. For example:
1 cable: correction factor = 1.00
2 cables: correction factor = 0.93
3 cables: correction factor = 0.90
6 cables: correction factor = 0.87
9 cables: correction factor = 0.86
Ambient Temperature Adjustments:
For environments with ambient temperatures above 25°C, additional correction factors (Kt) are applied. For instance:
At 30°C: Kt = 0.96
At 35°C: Kt = 0.92
At 40°C: Kt = 0.88
At 45°C: Kt = 0.83
At 50°C: Kt = 0.78
At 55°C: Kt = 0.73
These adjustments ensure that the cable operates safely and within its rated performance under varying installation conditions.
Application and Certification
Applications:
The cables are primarily used in underground electrical networks within mining installations.
They are suited for areas where the risk of explosion due to methane or coal dust exists (hazard zones “a”, “b”, and “c”), and they are designed to perform reliably even on inclined surfaces (exceeding 45°), such as shafts and mining galleries.
Certifications:
The cables comply with the standard ZN-TF 203:2006.
Additional certifications include EMAG, WUG, and RoHS81, attesting to their performance, safety, and environmental compliance.
Summary
Type YRUHKGXSekFoyn 3.6/6 kV Mining Power cables offer a robust and comprehensive solution for demanding underground mining applications. With copper conductors that are individually and overall shielded, XLPE insulation, multiple protective layers (including PVC inner and outer sheaths, water-resistant seals, and steel wire armor), these cables provide high mechanical strength, excellent electrical performance, and enhanced fire safety. Their design accommodates a wide range of operating temperatures and installation conditions while meeting strict international standards and certifications.
This detailed construction and specification ensure that the cables are well suited for the challenging and hazardous environments encountered in modern mining operations.
Frequently Asked Questions (FAQ)
Q: What is the rated voltage of the cable?
A: The cable is designed for a rated voltage of 3.6/6 kV, making it ideal for low-voltage power distribution in mining installations.
Q: What type of conductor is used in this cable?
A: It uses multi-stranded, round copper conductors compacted to Class 2 per EN 60228, ensuring both flexibility and excellent conductivity.
Q: How are individual conductors shielded?
A: Each working conductor is individually shielded using conductive tapes or a polyethylene-based conductive layer combined with copper tape, which minimizes interference and enhances performance.
Q: What insulation material is used in the cable?
A: The cable employs cross-linked polyethylene (XLPE) insulation, specifically type DIX 3 as per PN-HD 620 S1:2002, offering excellent electrical properties and thermal resistance.
Q: What is the purpose of the PVC inner sheath?
A: The inner PVC sheath (type DMV 31) protects the insulation layer, ensuring mechanical stability and additional environmental protection.
Q: How is water ingress prevented?
A: The cable features both radial and longitudinal sealing. A radial seal is achieved with an Al/PVC tape, while a water-activated, swelling tape provides longitudinal sealing to protect against moisture.
Q: How is overall electromagnetic interference minimized?
A: Overall screening is provided by a copper tape wrap that surrounds the insulated and internally sheathed conductors, reducing electromagnetic interference.
Q: What type of armor is used for mechanical protection?
A: The cable is armored with round steel wires, which offer robust mechanical protection in the demanding conditions of underground mining.
Q: What is the function of the flame-retardant PVC outer sheath?
A: The outer sheath, made from a flame-retardant PVC (polwinit-based), is designed to prevent the spread of flames, enhancing safety in hazardous mining environments.
Q: In which environments is this cable primarily used?
A: It is intended for underground mining applications, especially in areas prone to methane or coal dust explosions, where enhanced safety and durability are critical.
Q: What certifications does the cable hold?
A: The cable complies with the ZN-TF 203:2006 standard and carries certifications such as EMAG, WUG, and RoHS81, ensuring it meets stringent quality and environmental standards.
Q: What are the operating temperature limits of the cable?
A: The cable can continuously operate at a maximum conductor temperature of +90°C and can handle short-circuit conditions with temperatures reaching up to +250°C.
Q: What are the minimum ambient temperature requirements for installation?
A: For permanently installed cables, the minimum ambient temperature is -30°C, while for installations without preheating, it can go as low as -50°C.
Q: How is the minimum bending radius specified?
A: The minimum bending radius is defined as 12 times the cable’s external diameter (12 x D), ensuring safe installation without damaging the cable.
Q: What electrical test is performed on the cable?
A: An 11 kV AC test at 50 Hz for 5 minutes is conducted to verify the integrity of the insulation system.
Q: How does the cable handle current-carrying capacity in different installations?
A: Its current-carrying capacity is affected by installation conditions. When installed in parallel or on supports, derating factors must be applied to ensure safe operation.
Q: What are the correction factors for cables installed in parallel?
A: For instance, when two cables are installed together, a correction factor of 0.93 is applied; for three cables it is 0.90, six cables 0.87, and nine cables 0.86.
Q: How do ambient temperatures above 25°C affect the cable?
A: Higher ambient temperatures require additional correction factors (Kt) that reduce the current-carrying capacity. For example, at 30°C, Kt is 0.96, at 35°C it is 0.92, and so on.
Q: Can this cable be used in both methane and non-methane mining areas?
A: Yes, the cable is engineered for both methane and non-methane zones, provided it meets the explosion risk classifications (classes A, B, or C) as required.
Q: What are the typical colors of the cable layers?
A: The insulation is naturally uncolored, while the outer sheath is typically red, aiding in quick visual identification.
Q: How does the cable’s design ensure high mechanical strength?
A: The combination of robust steel wire armor, a secure PVC outer sheath, and proper sealing techniques ensures that the cable withstands mechanical stresses in harsh mining environments.
Q: What conductor sizes are available for this cable?
A: The cable is available in various sizes, with conductor cross-sectional areas of 25, 35, 50, 70, 95, 120, 150, and 185 mm² to suit different load requirements.
Q: What are the cable’s typical electrical characteristics?
A: Detailed tables in the documentation specify parameters such as maximum resistance at 20°C, unit inductance (mH/km), and unit inductive reactance (Ω/km), which vary with conductor size.
Q: How is flame retardancy ensured in the cable design?
A: The cable meets IEC flame retardancy standards (IEC 60332-1-2 and IEC 60332-3-24C) through the use of flame-retardant materials in the outer sheath.
Q: What maintenance is recommended for these cables in the field?
A: Regular inspections should be conducted to check for physical damage, signs of moisture ingress, and the condition of both the armor and sheath, ensuring long-term reliability.
Q: How are the cables packaged for shipment?
A: Typically, cables are packaged in 500 or 1000-meter drums, but custom lengths and packaging options are available to meet specific project requirements.
Q: What is the purpose of the internal separating PVC layer?
A: This layer acts as a barrier between the overall screen and the outer armor, providing extra insulation and enhancing the cable’s protection.
Q: How does the cable perform under short-circuit conditions?
A: It is designed to handle short-circuit conditions effectively, with the conductor temperature able to reach up to +250°C for brief periods without permanent damage.
Q: What physical conditions can the cable withstand on mining sites?
A: The cable is built to endure rugged underground environments, including inclined surfaces, high mechanical stresses, and exposure to harsh environmental conditions.
Q: How is electromagnetic interference (EMI) minimized in this cable?
A: EMI is minimized through both individual and overall screening, ensuring that the cable maintains signal integrity even in electrically noisy mining environments.
Q: Are there any special considerations for installing these cables in mining shafts?
A: Yes, proper derating factors must be applied based on the number of cables installed together and the ambient temperature, and the installation must account for the minimum bending radius to avoid damage.
Q: How does the cable contribute to overall mine safety?
A: With its flame retardant design, robust mechanical protection, and effective sealing against moisture, the cable significantly enhances safety by reducing the risk of electrical faults and fire hazards in explosive environments.
Q: What testing protocols ensure the cable’s quality before installation?
A: Besides the 11 kV AC high-voltage test, the cable undergoes mechanical strength tests and checks for proper sealing, insulation, and adherence to international standards.
Q: Can the cable be used for both power distribution and control circuits in mines?
A: While primarily designed for power distribution, the cable’s construction and screening features can also support low-level control and signal circuits where appropriate.
Q: How does the cable design mitigate risks associated with mining explosions?
A: The use of flame-retardant materials, robust screening, and high-quality insulation reduces the likelihood of ignition and flame spread, thus enhancing safety in areas with explosive atmospheres.
Type YRUHKGXSekFoyn 3.6/6 kV Mining Power Cable
Type YRUHKGXSekFoyn 3.6/6 kV Mining Power Cable is a robust, high-performance solution designed for harsh underground mining environments. Featuring multi-stranded copper conductors, advanced XLPE insulation, and a flame-retardant PVC outer sheath, this cable ensures excellent electrical performance and safety. Its innovative design includes individual and overall conductor shielding, dual sealing against water ingress, and durable steel wire armor for superior mechanical protection. Ideal for low-voltage power distribution in mining operations—especially in areas with methane or coal dust hazards—this cable meets stringent international standards and certifications such as ZN-TF 203:2006, EMAG, and RoHS81. Upgrade your mine’s electrical infrastructure with this reliable, efficient, and safety-compliant mining cable.
6/30/20219 min read