Steel Tape Armoured Medium Voltage Cable Ultra-High Current 15kV Direct Burial

The YJV22 8.7/15kV 3×300 is a medium-voltage power cable featuring a large cross-section, three-core design, and high current-carrying capacity, specifically engineered for 15kV three-phase high-capacity power distribution networks. This cable utilizes three 300mm² Class 2 compacted, high-purity copper conductors and incorporates a comprehensive dual-layer (inner and outer) semi-conductive shielding system, a thickened partial-discharge-resistant XLPE main insulation layer, a copper tape metallic shield, an inner bedding layer, double-layer contra-helically wound galvanized steel tape armor, and a weather-resistant, anti-aging PVC outer sheath.

Unlike common 3×95 and 3×185 medium-voltage cable specifications, this 3×300 cable is engineered to deliver maximum continuous current-carrying capacity for 15kV distribution systems. It is particularly well-suited for primary feeders handling peak system loads, centralized collection trunk lines for large-scale renewable energy plants, and medium-voltage backbone circuits within massive industrial parks and core municipal grid infrastructures. Featuring an integrated dual-shielding structure and undergoing 100% factory-level partial discharge testing, the cable meets the rigorous grid-connection standards required for 15kV power systems. Its built-in double steel tape armor eliminates the need for oversized, heavy-duty protective conduits in direct-burial installations; this effectively manages the project's total lifecycle costs while ensuring long-term dielectric stability and superior mechanical durability. Currently, this specification has become a preferred standardized solution for ultra-high current applications, widely adopted by power design institutes, national grid operators, and global EPC contractors across the design, feasibility study, and procurement phases of major medium-voltage infrastructure projects.

• YJ: Cross-linked polyethylene (XLPE) insulation formulated specifically for the 8.7/15kV medium-voltage class; features exceptionally high dielectric strength and demonstrates superior resistance to electrical treeing, water treeing, and partial discharge inception under sustained high electric field stress.
• V: PVC inner bedding/separation sheath; serves to prevent mechanical abrasion and electrochemical corrosion between the steel tape armor and the internal insulated core assembly.
• 22: Double-layer overlapping galvanized steel tape armor with an outer PVC protective sheath; forms a robust mechanical barrier designed for deep-burial environments, capable of withstanding deep soil pressure, impacts from heavy excavation machinery, punctures by sharp rocks, and rodent damage.
• 8.7/15kV: Rated insulation voltage U₀/U = 8.7/15kV, with a maximum system operating voltage Uₘ = 17.5kV; formally designed and validated for continuous operation within 15kV three-phase medium-voltage distribution networks.
• 3×300: Three high-purity electrolytic copper conductors (Class 2 compacted stranded), each with a cross-sectional area of ​​300mm²; arranged in a symmetrical three-core balanced configuration to enable high-current, three-phase power transmission.

• GB/T 12706.1–4:2020 – National standard for extruded insulation power cables with rated voltages from 0.6/1 kV to 26/35 kV
• IEC 60502-2 – International standard for medium-voltage extruded insulation power cables (maximum system voltage Um up to 36 kV)
• IEC 60228 – Standard for the construction of Class 2 compacted stranded copper conductors
• GB/T 19666 – Flame-retardant grade specifications; ZA/ZB/ZC flame-retardant modified versions are available for customization for these extra-large cross-section specifications
• Mandatory medium-voltage factory test requirements: Partial discharge ≤10 pC at a test voltage of 1.73U₀, fully compliant with grid access inspection and acceptance rules
• Comprehensive certification system: ISO9001 Quality Management System certification, CCC mandatory certification, CE certification, CB certification, full-item type test reports, partial discharge test records, raw material incoming inspection documents, and third-party independent test certificates; fully meets requirements for international tendering, technical reviews, and project completion acceptance audits

The three 300mm² phase conductors are manufactured using a precision compacting and stranding process that optimizes conductor roundness and compactness. This significantly reduces DC resistance, heat generation, and active power loss during long-distance, heavy-load medium-voltage power transmission. The copper material exhibits minimal creep deformation under decades of terminal crimping stress, ensuring stable contact resistance throughout more than 30 years of continuous grid operation and completely eliminating the long-term overheating risks often associated with medium-voltage aluminum conductors. The conductor surface is uniform and smooth, ensuring a precise fit and stable, reliable crimping performance with specialized heavy-duty 15kV cable terminals and complete termination accessory sets.

An extruded, uniform semi-conductive layer adheres tightly to the outer surface of the conductor, smoothing out the non-uniform electric field distribution around the conductor. This eliminates localized high-field concentration points and suppresses the onset of partial discharge—an essential structural component for ensuring the 8.7/15kV medium-voltage cable meets required dielectric performance standards.

The insulation thickness is precisely engineered and calculated to withstand the full electric field stress associated with the 8.7/15kV voltage rating. The extrusion line is equipped with a real-time online monitoring system for insulation thickness and eccentricity, and every finished cable undergoes 100% offline partial discharge testing to completely eliminate internal air gaps, microscopic impurities, and latent insulation defects. Utilizing premium-grade medium-voltage XLPE material effectively inhibits electrical tree propagation, water tree aging, and insulation breakdown caused by long-term deep burial in moist, acidic, or alkaline corrosive soils, ensuring stable dielectric performance under conditions of cyclical peak load fluctuations and transient lightning surges.

The outer semi-conductive layer and the inner shielding layer work in tandem to ensure uniform electric field distribution. The helically wrapped copper tape metallic shield conducts induced currents and fault short-circuit currents, meeting grounding design requirements for medium-voltage shielding systems; it effectively suppresses outward electromagnetic interference radiation and fully complies with grid system grounding standards.

Fills the voids between the three large-cross-section cores, maintaining a uniform, circular geometry for the large-diameter cable; alleviates internal compression, shear, and friction during pulling, bending, and installation, preventing scratches to the insulation surface; and retards moisture ingress in environments such as semi-enclosed cable trenches or deep underground burials.

Forms a continuous, intact physical barrier between the steel tape armor and the insulated core assembly, preventing abrasion or damage to the sheath during routing and bending operations; additionally, when installed in chemically active or contaminated soil, it inhibits electrochemical corrosion reactions between the galvanized steel tape and the internal metal or polymer components.

Utilizing a structure of double-layer, counter-helically wound overlapping steel tapes, this cable withstands extreme lateral soil pressure, meeting the requirements for deep-buried installation of extra-large cross-section medium-voltage trunk cables. This structure effectively resists intense lateral soil compression, accidental large-scale excavation impacts, sharp rock punctures, and rodent damage. This design allows the high-current main feeder cable (rated 8.7/15kV, 3×300 specification) to be buried directly without the need for additional large-diameter heavy-duty protective conduits.

The outer sheath provides comprehensive external protection against soil chemical corrosion, UV degradation, ozone aging, and long-term moisture ingress. Suitable for overhead, cable trench, and tunnel installations, as well as complex underground operating conditions, the cable maintains its structural integrity throughout its entire design service life.

U₀/U: 8.7/15kV (AC 50Hz); maximum system operating voltage Um = 17.5kV; specifically designed for installation as main feeders in 15kV three-phase medium-voltage distribution networks

Conductor configuration: 3 cores × 300mm² (Class 2 compacted stranded high-purity electrolytic copper); features a symmetrical three-core balanced structure, suitable for high-current power transmission

Maximum permissible continuous operating temperature of conductor: 90°C

Maximum withstand temperature during short-circuit (duration ≤ 5 seconds): 250°C

Minimum permissible ambient temperature for installation: 0°C (standard version); low-temperature custom version supports installation in harsh environments down to -20°C

Rated design service life under standard installation and normal operating conditions: ≥30 years

The minimum bending radius requirement for this 3-core YJV22 8.7/15kV 3×300 cable is ≥15 times the cable's outer diameter.

Structural Limitation Note: While the armor layer can withstand radial pressure and impact loads, it cannot sustain significant axial tensile force; for this type of heavy-duty, high-current medium-voltage main feeder cable, long-span overhead suspension or installation methods involving high vertical drops and significant tension are not recommended.

Its continuous current-carrying capacity meets the design requirements for high-capacity 15kV primary main feeder transmission; the low-resistance copper conductor effectively limits voltage drop and active power loss on medium-to-long-distance substation feeder trunk lines, preventing excessive voltage deviation that could otherwise compromise the stable operation of downstream high-capacity distribution equipment and transformer banks.

• Dual full-shielding system combined with 100% partial discharge testing, ensuring qualification for 15kV grid connection
• Pre-matched 3×300mm² extra-large cross-section, eliminating tedious, repetitive load calculations
• The use of an integrated double-steel-tape armored structure enables direct-burial installation for medium-voltage backbone lines, thereby reducing costs.
• The use of copper conductors eliminates the risk of joint overheating during the long-term operation of critical medium-voltage backbone lines.
• Flexible flame-retardant ratings compliant with international fire safety standards for public infrastructure

• A mature, mass-produced specification that avoids the price premiums often associated with custom manufacturing
• Direct-burial installation reduces the overall cost of civil engineering works.
• Low long-term O&M costs offset the initial investment in copper materials.
• Strategic stock reserves of mainstream medium-voltage specifications shorten order delivery times.
• The use of standardized, matching heavy-duty medium-voltage accessories reduces the management costs associated with decentralized procurement.

• 15kV primary feeder cables connecting large-scale distribution substation switchgear to outdoor box-type transformers, pole-mounted transformers, and downstream high-capacity 15kV distribution node clusters.
• Direct-buried medium-voltage backbone cables for the renovation of existing urban 15kV core power grids, overhead-to-underground line conversion projects, and regional grid capacity expansion and upgrade initiatives.
• Direct-buried trunk cables interconnecting large-capacity box-type transformer clusters and centralized medium-voltage main switch rooms within the power collection systems of large-scale ground-mounted PV plants and onshore wind farms.
• Medium-voltage primary distribution trunk cabling within centralized high-voltage power supply layouts for heavy metallurgical plants, large mining enterprises, chemical industrial parks, and mega-scale industrial complexes.
• Medium-voltage power lines installed along urban arterial road tunnels, underground utility tunnels, and bridge corridors; suitable for environments exposed to significant risks of mechanical impact, crushing, and damage from large-scale excavation activities.
• Grid-interconnecting backbone cables suitable for centralized power supply hubs in industrial parks, auxiliary medium-voltage distribution backbone systems for large-scale data centers, and emergency backup medium-voltage grid layouts for tertiary hospitals.
• Medium-distance, direct-buried 15kV backbone and branch distribution lines suitable for large-scale suburban electrification upgrades and rural grid backbone extension projects.

Project Requirements: Replace aging 15kV overhead backbone lines with underground armored cables across 18 central commercial districts and high-density residential areas. The project required a massive volume of cable and necessitated deep direct-burial installation. Products had to pass comprehensive partial discharge testing and grid-connection acceptance standards set by the local power supply bureau, ensuring the long-term, stable, safe, and continuous operation of the public grid's backbone lines.

Solution Implemented: Bulk supply of YJV22 8.7/15kV 3×300 three-core medium-voltage armored cables, with a total supplied length of 32.1 kilometers.

Project Outcome: The adoption of a heavy-duty steel-tape armored structure eliminated the need for large-diameter conduits, reducing overall civil engineering costs by 30%. The dual-layer, fully shielded design passed the medium-voltage type tests and partial discharge tests mandated by the power utility. Following delivery, the system has operated stably without faults; consequently, the local power utility designated this specific cable model as the standard for ultra-high-current, direct-buried main feeder lines in future urban overhead-to-underground conversion projects.

Project Requirements: Installation of direct-buried interconnecting main cables linking the on-site array of high-capacity box-type substations to the centralized medium-voltage main switchgear room. The installation environment consisted of farmland, presenting risks such as soil compression, rodent activity, and accidental excavation by heavy agricultural machinery. Strict compliance with grid-connection technical specifications and project budget constraints was also required.

Solution Implemented: YJV22 8.7/15kV 3×300 three-core cables, with a total supply length of 19.8 km; cable cross-sections were matched to the grouping configurations of the box-type substation generation units.

Project Outcome: The dual-layer shielding structure effectively controlled partial discharge levels amidst the load fluctuations characteristic of PV power generation. The direct-buried design streamlined the installation process for these large-cross-section cables, enabling early grid connection. Over four years of continuous operational monitoring, no insulation breakdowns or joint overheating failures occurred, and the system consistently met all routine inspection and performance assessment requirements set by the grid company.

Project Requirements: Laying new medium-voltage backbone lines—routed through dedicated cable trenches along the plant perimeter and sections of deep direct-burial—to supply power to transformers serving high-capacity stamping, welding, and forging production lines. The system required extremely low transmission losses and sufficient overload margin to accommodate the phased expansion of production lines in the future.

Solution Implemented: YJV22 8.7/15kV 3×300 three-core medium-voltage armored cable; total supply length: 11.7 km.

Project Outcomes: Low-resistance copper conductors effectively reduced energy consumption and voltage drop during full-load operation; the use of extra-large gauge cables provided ample overload margin, accommodating subsequent phased equipment expansions; the armored structure effectively prevented accidental cable damage during plant road reconstruction and utility upgrades, while ensuring the project consistently passed internal occupational safety audits and annual third-party power system inspections.

Before selecting the YJV22 8.7/15kV 3×300 cable, calculations for peak load current-carrying capacity and checks for long-distance voltage drop, short-circuit thermal stability, and partial discharge design reviews must be completed, taking into account actual transmission distances and system fault level parameters. Our technical team offers free, customized selection reports and technical comparison data to help avoid safety risks associated with insufficient current-carrying capacity or wasted investment due to over-specification.

Installation requires the use of compatible, large-size 8.7/15kV-rated cold-shrink or heat-shrink termination accessories. Procedures such as stripping the semi-conductive layer, trimming the insulation, positioning stress control tubes, and restoring the shielding layer must strictly adhere to standardized operating protocols to eliminate electric field distortion and potential sites for partial discharge initiation at the cable termination. The use of low-voltage terminations as substitutes is strictly prohibited.

Throughout the laying process, the requirement that the bending radius must be no less than 15 times the cable's outer diameter must be strictly observed. Forced sharp bends or violent bending maneuvers are strictly prohibited to prevent the internal insulation layer from wrinkling or developing air gaps, which could trigger potential partial discharge defects and compromise the long-term operational reliability of the medium-voltage cable. For cables with exceptionally large diameters, anti-abrasion liners and chamfered protective devices must be installed at conduit openings to prevent the outer sheath from sustaining scratches or abrasions during the cable-pulling operation.

Independent and reliable grounding must be implemented at both the starting and terminating ends of the steel-tape armor layer and the copper-tape metal shielding layer, in accordance with local electrical codes. This measure serves to suppress induced circulating currents and the accumulation of induced voltage within the metal layers, thereby eliminating potential electrical safety hazards associated with the long-term operation of deeply buried medium-voltage cables.

This YJV22 8.7/15kV 3×300 cable is suitable for fixed installation via direct burial, or within cable trenches and tunnels. It is not suitable for long-distance overhead suspension installations or for vertical installations involving significant elevation differences that would subject the cable to immense axial tensile stress. For applications requiring long-term submersion in water, the YJV32 steel-wire armored cable should be selected as an alternative.

Cable drums must be stored on flat, solid ground within a dry, well-ventilated warehouse, avoiding prolonged exposure to rain or direct sunlight. During loading, unloading, and long-distance transport, precautions must be taken to prevent severe impacts, crushing, or tipping of the drums; such incidents could cause cracking of the outer sheath or damage to the internal insulation structure, thereby compromising the cable's insulation performance.

All products are manufactured in strict accordance with GB/T 12706 and relevant IEC international standards. We provide a complimentary, complete documentation package—including factory qualification certificates, full type test reports, partial discharge test records, third-party inspection reports, and editable technical data sheets—fully satisfying the requirements for document review, submission approval, and grid project acceptance in global tenders for this 8.7/15kV 3×300 specification.

We utilize certified 99.97% high-purity electrolytic copper rods and partial-discharge-resistant grade XLPE (cross-linked polyethylene) specifically designed for the production of large-cross-section medium-voltage cables. Key manufacturing processes—such as conductor stranding, extrusion of inner shielding and main insulation, copper tape shielding, armoring, and sheathing—are equipped with real-time online monitoring systems for dimensions and concentricity. This ensures stable conductor DC resistance, uniform insulation thickness, and consistent partial discharge performance across production batches, thereby minimizing the risk of rejection during incoming inspections for large-volume tender orders.

Based on technical drawings and specific project needs, we offer tailored services for YJV22 8.7/15kV 3×300 cables, including flame-retardant modifications (ZA/ZB/ZC ratings), low-smoke zero-halogen (LSZH) outer sheath upgrades, cut-to-length services, and custom packaging options (such as large wooden/steel reels or export-grade packaging).

We operate our own manufacturing facilities, eliminating intermediary markups. We support small-batch sample orders to meet pre-project qualification testing needs and prioritize production for large-volume orders. We maintain ample finished-goods inventory for standard YJV22 8.7/15kV 3×300 specifications, ensuring rapid dispatch to meet urgent delivery requirements for medium-voltage projects.

Our team of expert cable design engineers provides free services, including load calculations, ampacity verification, full-lifecycle cost comparisons (copper vs. aluminum), installation route optimization, remote or on-site technical guidance, and systematic after-sales quality tracking. These services are backed by a formal, long-term product warranty, fully alleviating technical and quality-related concerns for procurement and engineering teams.

We possess mature export packaging solutions, comprehensive capabilities for handling customs documentation, and efficient, coordinated global logistics channels. We have a proven track record of reliable supply for projects across Southeast Asia, Central Asia, Africa, the Middle East, and Latin America, covering substation main feeders, municipal grid backbone upgrades, and large-scale renewable energy infrastructure. We are also well-versed in local inspection, acceptance, and compliance filing regulations across various overseas markets for these standard, high-current medium-voltage primary feeder specifications.