Introduction: The Composite Cable Revolution

RHEYFIRM®(RTS) (N)TSCGEWTOEUS OFE is a breakthrough composite reeling cable engineered by Anhui Feichun Special Cable Co., Ltd. to meet the DIN VDE 0250-813 German industrial standard. It is the engineering world’s answer to a seemingly impossible challenge: simultaneously carrying massive amounts of high-voltage power (up to 30 kV) and zero-latency, high-bandwidth fiber optic data streams, while being relentlessly spooled onto a motorized drum under extreme mechanical tension and bending stress.

This cable powers the world’s largest Ship-to-Shore (STS) cranes at automated port terminals, massive bucket-wheel excavators processing millions of tons of ore annually, and heavy-duty stacker-reclaimers in mining and material handling operations. It is a genuine engineering marvel combining contradictory material science requirements: controlling powerful electromagnetic fields while simultaneously protecting fragile glass fiber optics from crushing forces and bending micro-fractures.

What makes RHEYFIRM(RTS) extraordinary is not just its technical performance, but its economics. While European manufacturers (Nexans, Prysmian, TF Kable) command premium pricing and delivery lead times exceeding 24 weeks, global port and mining chief engineers are increasingly discovering that Feichun delivers identical engineering quality at factory-direct pricing with production lead times as short as 4-8 weeks.

Technical Anatomy and DIN VDE 0250-813 Compliance

Combining Medium Voltage and fiber optic data (OFE) into a single continuously flexing jacket requires engineering precision at every layer. The DIN VDE 0250-813 standard specifies extraordinary requirements for composite MV cables, and RHEYFIRM(RTS) exceeds them systematically across all electrical, mechanical, and reliability parameters.

Why Triple-Extrusion EPR Matters for Fiber Protection

The inner semi-conductive layer prevents electric field concentration at conductor surface. The EPR rubber core (Class GI, chemically cross-linked) maintains dielectric strength under continuous flexing. The outer semi-conductive layer smooths the electric field transition to the outer sheath. Together, they guarantee zero corona discharge—the primary enemy of fiber optic transmission, which would melt glass fibers or corrupt signal integrity through induced currents.

Individual tinned copper wire screening around each phase core (not shared screen) means each phase’s electromagnetic field is completely contained independently. This eliminates crosstalk and ensures that if one phase experiences transient overvoltage, the other phases and the sensitive fiber optics remain unaffected.

Engineering Strategy: Fiber Protection Inside a High-Voltage Powerhouse

The sheer physical crushing force of a motorized drum wrapping a heavy MV composite cable—sometimes with 10+ metric tons of tension—can easily flatten soft internal cores. If the optical fiber tubes are crushed, macro-bending signal loss is immediate and catastrophic. Furthermore, if the MV phase cores lack perfect triple-extrusion construction and semi-conductive field control, electromagnetic interference (EMI) or partial discharge (corona) will corrupt data streams or actually melt the optical tubes.

Interstitial Armoring: Geometry as a Shield

Feichun engineers the cable cross-section so that the three massive MV phase cores form a triangular bundle. The fragile optical fiber tubes rest deep within the structural “valleys”—the geometric interstices—between these phase cores. This placement achieves multiple engineering goals simultaneously: the heavy copper bearings structures crush-resistant properties; the tight geometry prevents the optical tubes from shifting during bending; and the electromagnetic field of each phase core is automatically shielded by the copper mass itself.

This is not accidental placement. Every millimeter of internal geometry is CAD-designed and verified through finite element analysis (FEA) stress modeling. The goal is absolute assurance that the fragile glass fibers experience zero macro-bending stress during normal operation.

Torsion Lockdown: Preventing Corkscrew Fracture

As the cable is continuously spooled in and out of the motorized reel, the twisting motion inherent in helical winding tries to corkscrew the entire cable structure. If left unchecked, this twisting would snap glass fibers or degrade their mechanical properties through micro-stress accumulation.

Feichun’s integrated high-tensile anti-torsion braid (synthetic textile mesh vulcanized directly between inner and outer rubber sheaths) locks the entire cable structure in place. The cable can bend freely around the motorized reel circumference, but it will never rotate axially. This ensures both the copper conductors and the glass fibers enjoy extended operational lifecycle—often 10+ years of continuous daily operation under extreme conditions.

Manufacturing Perfection: Triple-Extrusion CCV and Quality Assurance

Catenary Continuous Vulcanization (CCV) Lines

To guarantee zero air voids in the triple-extrusion EPR insulation system (which would create micro-cavities where corona discharge could initiate), Feichun manufactures the phase cores using Catenary Continuous Vulcanization (CCV) lines. This advanced technique extrudes the inner semi-conductive layer, EPR rubber core, and outer semi-conductive layer simultaneously, not sequentially.

Simultaneous extrusion means: perfect molecular adhesion between layers (no delamination risk); zero air void formation (voids are where electrical failure begins); and absolute field containment. Every batch undergoes 100% partial discharge testing at 1.5 × rated voltage per IEC 60270 protocols. Cables with any detectable corona (> 5 pC) are rejected before leaving the factory.

Fiber Optic Integration Quality Checks

Unlike cables where fiber optics are an afterthought, RHEYFIRM(RTS) integrates the fiber tubes as integral structural elements during core assembly. Quality checkpoints include:

Mechanical Stress Testing: Sample cables are wound onto motorized reels and cycled 10,000+ times at operating tension to simulate 5+ years of field use. Fiber signal attenuation is measured at 1310 nm, 1550 nm, and 1625 nm wavelengths. Maximum acceptable attenuation: 0.3 dB/km after full mechanical cycling (vastly exceeds standards).

Bend Loss Validation: Individual fiber optic samples are subjected to IEC 60794 bend radius tests, confirming operation at minimum 15 × OD installation radius and 12–14 × OD operational drum radii without permanent signal degradation.

Thermal Cycling: Complete cable assemblies are thermal-cycled −25°C to +80°C (100+ cycles) while under slight tension. Fiber signal continuity and electrical insulation resistance are verified after each cycle cluster to catch any delamination or sheath degradation.

Real-World Performance: Port Automation and Mining Operations

Ship-to-Shore (STS) Cranes: The Primary Application

Modern STS cranes lift 30–65 metric ton containers at speeds up to 270 containers per hour. The main power cable (often 95–150 mm² conductor cross-section, 18/30 kV rated) delivers continuous power while simultaneous fiber optics carry real-time position sensing, load cell data, and emergency control signals. The cable bundles coil and uncoil 100+ times per shift with no signal loss or power anomalies.

RHEYFIRM(RTS) excels here because: electrical field containment (triple-extrusion EPR) prevents corona from corrupting sensor data; interstitial fiber armoring protects glass from crushing forces; and anti-torsion braid prevents axial rotation that would otherwise degrade both electrical and optical performance over time.

Bucket-Wheel Excavators: Extreme Duty Environments

Bucket-wheel excavators are among the largest moving machines on Earth, processing up to 200,000 metric tons of material per day. The bucket-wheel drive motor draws enormous stall currents during dig operations. The same cable simultaneously transmits conveyor belt speed feedback and bucket-fill condition data via fiber optics.

Feichun has deployed RHEYFIRM(RTS) 18/30 kV variants on bucket-wheel systems across Australia, Indonesia, and South America. Field data shows zero cable-related shutdowns over 5+ year operating periods—a remarkable achievement given the mechanical stress (20+ metric ton rope tension), temperature cycling (50°C+ diurnal swings in desert operations), and continuous duty cycle.

Stacker-Reclaimers: Material Handling Precision

Modern stacker-reclaimers require precise load sensing to optimize throughput. RHEYFIRM(RTS) cables enable real-time feedback of conveyor loads, boom positioning, and system stress states—all while delivering reliable power to heavy motors. The integrated fiber optics eliminate the need for separate sensor cable bundles, reducing overall system weight and complexity.

Premium Alternative to Nexans, Prysmian, and European Suppliers

Cost Economics: Import Substitution Without Compromise

Procurement teams at global ports and mining operations have historically sourced RHEYFIRM(RTS) equivalents from Nexans (France), Prysmian PROTOMONT (Italy), TF Kable (Germany), Draka (Netherlands), or Lapp (Germany). Lead times routinely exceed 24 weeks. Price premiums for European sourcing can reach 40–60% above cost of equivalent DIN VDE-compliant cables manufactured in Asia.

Feichun delivers identical engineering quality—same triple-extrusion processes, same DIN VDE 0250-813 compliance, same CCV manufacturing methodology—at factory-direct pricing. Lead times: 4–8 weeks for standard configurations, 8–12 weeks for custom voltage ratings or conductor sizes. Price advantage: 35–50% below European equivalents when comparing equivalent specifications.

Quality Parity Verification

Global infrastructure engineers often ask: “Is Chinese cable really equivalent?” The answer is substantive engineering rigor, not national origin. Feichun’s quality metrics include:

• DIN VDE 0250-813 Compliance: All RHEYFIRM(RTS) cables undergo certified testing per German standards, not Chinese national standards.
• Third-Party Verification: Feichun retains independent German and Italian testing laboratories to verify partial discharge, insulation strength, and mechanical properties on every production batch.
• CCV Manufacturing: Feichun’s CCV lines are German-designed and German-built (Haake Technologies), ensuring process control equivalent to Nexans or Prysmian.
• Traceability Documentation: Each cable is laser-marked with batch code, manufacturing date, and voltage rating. Complete test documentation is linked to production batches in digital archive.

Technical FAQ: Solving Complex Installation Challenges

How do I ensure fiber optics remain functional during high-tension motorized drum operation?

RHEYFIRM(RTS) cables are engineered for motorized drum operation up to 20 metric tons of tension. The key is proper drum design and cable management. First, ensure the drum has sufficient diameter to maintain bending radius ≥ 12 × cable OD (this is typically met by standard STS crane and bucket-wheel excavator drums, which are 1.2–2.5 meters in diameter). Second, use cable routing guides to prevent pinching or kinking as the cable feeds onto the drum. Third, verify that tension control maintains smooth, consistent load without shock loading. Under these conditions, fiber optics experience zero degradation—we have field data from installations with 5+ years of continuous operation (8,000+ operational hours annually) showing zero signal attenuation above baseline.

Can RHEYFIRM(RTS) operate in high-EMI industrial environments without data corruption?

Yes, with proper system design. The individual tinned copper wire screen around each phase core provides excellent EMI shielding. However, the critical factor is grounding: the screen must be grounded at both the power source and load terminals to prevent high-frequency current coupling. Feichun’s application engineers can specify grounding practices and, if necessary, compatible ferrite filters or shielded connectors at terminations. In ports with large numbers of VFD-driven equipment, we recommend screen grounding at 20–50 meter intervals along longer runs to prevent shield resonance effects. With proper grounding, fiber optic signal integrity is unaffected even in environments with 500+ V/meter transient electric fields.

What is the maximum allowable bending radius for RHEYFIRM(RTS) during dynamic operation?

Installation (static) minimum: 15 × cable OD. Motorized drum operation (dynamic): 12–14 × OD is standard. A typical RHEYFIRM(RTS) cable with 50 mm² conductor has OD approximately 25–28 mm, meaning minimum drum radius should be 300–392 mm during installation, and 300–392 mm during operation. This is well within standard STS crane and bucket-wheel excavator drum specifications. Feichun can provide detailed bending radius specifications for custom conductor sizes upon request.

How do I verify fiber optic continuity and attenuation after installation?

Use an Optical Time Domain Reflectometer (OTDR) at 1310 nm and 1550 nm wavelengths to measure end-to-end attenuation and verify splice integrity if the cable is spliced on-site. Baseline attenuation for RHEYFIRM(RTS) fibers is typically 0.25–0.35 dB/km depending on fiber type (single-mode vs. multi-mode). After installation and after any future maintenance work, attenuation should not increase by more than 0.1 dB/km (equivalent to < 1 meter of macro-bending loss). Feichun provides OTDR baseline test reports as part of shipment documentation—your installation team can verify against these baseline values.

What happens if one phase of the MV cable experiences partial discharge or corona?

RHEYFIRM(RTS) cables undergo 100% partial discharge testing at 1.5 × rated voltage before shipment. If partial discharge is detected, the cable is rejected and destroyed (never shipped). In service, if PD should occur due to mechanical damage, moisture ingress, or installation error, the individual copper wire screen around the affected phase would contain the discharge locally. The other phases’ screens and the fiber optic tubes are protected by geometric isolation. However, detection of corona in service indicates a fault that must be investigated immediately—likely causes include water intrusion, mechanical damage, or improper termination. Contact Feichun’s technical support immediately if corona is suspected in service.

Is RHEYFIRM(RTS) suitable for offshore applications?

Yes. Feichun offers RHEYFIRM(RTS) variants with enhanced outer sheath formulations for marine environments, including elevated UV protection and accelerated salt-spray corrosion resistance (ASTM B117 testing). Offshore crane installations require additional certifications (DNV, ABS, Lloyd’s Register compatibility verification), which Feichun’s technical team can arrange. Lead times for certified marine-grade RHEYFIRM(RTS) are typically 10–14 weeks. Cost premium: 10–15% above standard industrial variants.