8.7/15kV WDZ-YJY23 Double Steel Tape Armored LSZH Medium Voltage Power Cable for Substation, Tunnel & Direct Burial Power Transmission
Tóm tắt sản phẩm
Mô tả sản phẩm
- WDZ: Low-smoke, zero-halogen (LSZH), flame-retardant type; flame-retardant grades (WDZA, WDZB, or WDZC) can be customized based on fire safety design requirements.
- YJ: Cross-linked polyethylene (XLPE) primary insulation, offering excellent resistance to medium-voltage electrical stress.
- Y: Low-smoke, zero-halogen polyolefin inner bedding/inner sheath.
- 23: Double-layer overlapping galvanized steel tape armor + LSZH outer sheath; designed for heavy-duty mechanical protection in underground, tunnel, and harsh installation environments.
- Rated Voltage: 8.7/15kV medium-voltage class (Um=17.5kV); widely used in urban primary distribution networks, substation interconnectors, and large-scale industrial power supply systems.
The 8.7/15kV WDZ-YJY23 is a professional medium-voltage, flame-retardant, armored power cable developed for transmission and distribution lines that require both high mechanical protection and strict adherence to fire safety standards. Unlike unarmored medium-voltage WDZ-YJY cables—which are vulnerable to soil compression, excavation damage, and rodent gnawing when buried underground—this product features a double-layer steel tape armor structure that effectively withstands external impact, crushing, and puncture forces. At the same time, it retains LSZH flame-retardant properties, meeting fire safety code requirements for enclosed public transport facilities, underground utility tunnels, and densely populated public infrastructure.
In the event of a fire, WDZ-YJY23 cables emit only sparse, transparent smoke and release no corrosive halogen-acid gases; this ensures clear visibility along evacuation routes, inhibits flame propagation along the medium-voltage cable lines, and prevents widespread grid trip-outs caused by cable combustion. This medium-voltage cable is frequently selected by power design institutes, municipal power contractors, substation developers, renewable energy EPC firms, and electrical wholesalers for installations involving direct burial, cable trenches, tunnels, utility tunnels, and semi-exposed cable trays. The product complies with mandatory national standards for medium-voltage cables and full-scope IEC testing specifications; comprehensive technical documentation is available to meet requirements for grid tenders, project filings, fire safety inspections, grid-connection approvals, and final project acceptance.
- GB/T 12706.2-2020 Power cables with extruded insulation for rated voltages from 6 kV to 30 kV
- GB 31247 Classification for burning behavior of low-smoke, halogen-free cables
- GB/T 19666 Classification and test methods for flame-retardant power cables
- IEC 60502-2 Power cables with extruded insulation for rated voltages from 6 kV to 30 kV (medium voltage)
- IEC 60332-3 Vertical flame spread test for bunched multi-core cables
- IEC 60754 Test for halogen content and corrosive gas emissions
- IEC 61034 Measurement of smoke density under burning conditions
- IEC 60228 Standards for conductor dimensions and resistance
We offer customization options including flame-retardant grade adjustments (Class A/B/C), non-standard conductor cross-sections, fixed-length cutting, and special sheath color coding. We also facilitate third-party certification applications (such as CE, CCC, and KEMA) for overseas medium-voltage tender projects.
- Compacted Stranded Oxygen-Free Copper Conductor
A Class 2 circular compacted conductor made of high-purity annealed copper, compliant with IEC 60228 standards. It features low DC resistance at 20°C, stable long-term conductivity, and excellent oxidation resistance, effectively minimizing transmission losses in long-distance medium-voltage backbone lines. Conductor cross-sections range from 16mm² to 800mm², meeting diverse design requirements for medium-voltage loads and short-circuit withstand capabilities.
- Extruded Semi-Conductive Conductor Shield
A semi-conductive shield layer applied via a precision extrusion process. This layer eliminates air gaps between the conductor and the XLPE insulation, ensuring uniform electric field distribution and suppressing partial discharge—critical factors in guaranteeing the long-term insulation stability and aging resistance of the medium-voltage cable.
- Thick-walled XLPE Medium-Voltage Insulation Layer
The cross-linked polyethylene (XLPE) insulation layer is manufactured using a precision extrusion process and features an in-line, closed-loop control system for monitoring eccentricity and thickness. This layer offers excellent thermal aging resistance, high dielectric strength, ozone resistance, and the ability to suppress partial discharge; it maintains stable insulation performance over a 25-year design service life, even under conditions of prolonged thermal cycling and continuous operation at rated load.
- Extruded Semi-conductive Insulation Shield
The external semi-conductive shield, matched to the insulation structure, forms a complete internal electric field shielding system. This layer effectively limits surface electric field concentration and ensures compliance with strict partial discharge testing requirements during factory acceptance testing for 8.7/15kV medium-voltage cables.
- Copper Tape Metallic Shield
Utilizing an overlapping copper tape wrap configuration, this shielding structure suppresses electromagnetic interference generated during medium-voltage operation and provides a short-circuit grounding path (in accordance with power system grounding design standards). Additionally, it shields against external electromagnetic interference, thereby protecting adjacent communication and control cables.
- Halogen-free fillers and binding tapes
Eco-friendly, halogen-free filler materials fill the interstices between insulated cores, ensuring the cable maintains a round profile and enhancing overall crush resistance; they also prevent core twisting or displacement during high-tension pulling or bending operations. The overall binding tape stabilizes the internal core structure and minimizes internal friction and wear.
- Low-Smoke Zero-Halogen (LSZH) bedding layer
An extruded LSZH polyolefin bedding layer serves as a buffer and separation layer between the cores and the steel tape armor. It prevents the sharp edges of the steel tape from damaging the internal shielding and insulation structures during bending or under compressive stress, while also enhancing overall moisture resistance.
- Double-layer galvanized steel tape armor
This mechanical armor layer, formed by two overlapping wraps of galvanized steel tape, effectively withstands soil pressure, impacts from excavation, rodent gnawing, and punctures from sharp rocks. It enables direct-burial installation without the need for heavy-duty protective conduits, thereby simplifying the installation plan for medium-voltage cables and reducing the scope of civil engineering work.
- LSZH (Low-Smoke Zero-Halogen) Flame-Retardant Outer Sheath
Features an LSZH flame-retardant polyolefin outer sheath offering superior resistance to soil acidity/alkalinity, groundwater penetration, and microbial/mold attack. It exhibits excellent weatherability and UV resistance, making it suitable for sections exposed to the elements, such as bridge installations. During combustion, it emits no toxic halogen gases and produces low smoke density, fully complying with fire safety and environmental assessment requirements for critical public infrastructure.
| Indicator | Value |
|---|---|
| Rated Operating Voltage | Standard 8.7/15 kV (Um=17.5 kV); medium-voltage specifications such as 6/10 kV and 12/20 kV can be customized based on project requirements. |
| Maximum Long-Term Continuous Conductor Operating Temperature | 90°C |
| Maximum Short-Circuit Withstand Temperature (Duration ≤ 5 seconds) | 250°C |
| Minimum Ambient Installation Temperature | Not lower than 0°C; pre-heating is required for installation in temperatures below freezing to prevent brittle cracking of the outer sheath. |
| Minimum Permissible Bending Radius for Finished Armored Cable | Multi-core cable ≥ 15 times the outer diameter; single-core cable ≥ 20 times the outer diameter. |
| Indicator | Value |
|---|---|
| Selectable flame-retardant grades | WDZA, WDZB, and WDZC, catering to various fire safety design requirements. |
| Combustion smoke light transmittance | ≥60%, meeting low-smoke, eco-friendly performance standards. |
| Halogen emission test results | Halogen-free; no corrosive acidic gases are produced during combustion. |
| Total heat release and smoke generation metrics | Comply with Class B1 standards for building fire-resistant materials. |
Available in mainstream single-core and three-core configurations for medium-voltage systems, fully compatible with three-phase medium-voltage incoming, outgoing, and distribution designs for urban power grids, substations, and industrial power supply projects.
Includes: factory acceptance test reports (by batch), raw material certificates of conformity, medium-voltage partial discharge test reports, flame retardancy test reports, smoke density and halogen content test reports, and product certificates of conformity. We can assist in obtaining CCC mandatory certification, CE certification, KEMA type-test certification, and other third-party test reports to meet requirements for grid connection approval, domestic government project tenders, and qualification reviews for overseas project customs clearance.
- Advantage 1: Integration of Three Key Performance Features—Medium-Voltage Insulation + Armored Mechanical Protection + Low-Smoke Zero-Halogen (LSZH) Fire Safety
Compared to unarmored medium-voltage WDZ-YJY cables, the integrated double steel tape armor structure effectively mitigates risks associated with direct burial—such as crushing, accidental excavation damage, and rodent attacks—thereby supporting direct burial installation and eliminating the cost of additional protective conduit. Furthermore, the LSZH flame-retardant design complies with mandatory fire safety regulations for enclosed underground public spaces, achieving a perfect blend of medium-voltage insulation reliability, robust mechanical protection, and fire safety/environmental performance within a single-cable solution.
- Advantage 2: Lower overall investment for medium-voltage direct-burial projects
For large-scale medium-voltage underground installation projects, the use of WDZ-YJY23 cable eliminates the need to purchase rigid conduits and saves on costs associated with trenching, conduit installation, and backfilling materials. Although the price per unit of this cable is slightly higher than that of unarmored medium-voltage cable, the combined cost of materials, labor, and civil works is significantly lower; this shortens construction schedules and effectively controls capital expenditure for urban grid upgrades and substation expansion projects.
- Advantage 3: Superior underground corrosion resistance and long-term operational stability
This cable features a dual-layer (inner and outer) Low-Smoke Zero-Halogen (LSZH) sheath structure that withstands soil acidity and alkalinity, groundwater infiltration, damp or waterlogged foundations, and corrosive environments such as riverbank installations, effectively inhibiting the formation of "water trees" within the medium-voltage insulation layer. Its design ensures a stable service life exceeding 25 years under continuous direct-burial operation, thereby reducing the frequency and cost of major overhauls, fault-related replacements, and routine maintenance for grid operators and project owners.
- Advantage 4: Stable circuit integrity and controllable partial discharge during fire emergencies
When exposed to open flames, this medium-voltage cable inhibits flame propagation along the line, ensuring a continuous power supply for emergency power sources, fire linkage control systems, and backup transformer input circuits. In contrast, traditional PVC-sheathed YJY23 medium-voltage cables release large amounts of toxic smoke and corrosive halogen gases during combustion; these emissions not only hinder evacuation and corrode equipment but also risk causing insulation breakdown and system trips, thereby failing to meet the mandatory fire safety design requirements for public transportation and key public buildings.
- Advantage 5: Fully aligned with requirements for grid tenders, grid connection, and project acceptance
The WDZ-YJY23 cable is a recommended model specified in design standards for medium-voltage electrical systems in urban power grids, metro networks, underground utility tunnels, and key municipal projects. Comprehensive certification documentation can be compiled and customized to meet the specific requirements of tender applications, project filings, fire safety inspections, and grid connection approvals, thereby eliminating obstacles related to qualification non-compliance during the tendering, grid connection, and project acceptance phases.
- Urban Grid Upgrades and Substation Interconnection Projects
Medium-voltage (MV) main incoming and outgoing lines for urban distribution substations; ring-network interconnection cables for urban grid renovations; direct-buried MV distribution trunk lines for residential grid upgrades; and long-distance underground cable routes requiring mechanical protection against crushing.
- Urban Underground Utility Tunnels and Public Infrastructure Projects
MV distribution trunk lines within urban utility tunnels; MV interconnection cables between underground building complexes; and long-distance direct-buried distribution lines for municipal centralized energy stations; meeting requirements for low-smoke, eco-friendly design and damage-resistant installation within enclosed, confined spaces.
- Rail Transit, Highway Tunnel, and Underground Transport Hub Projects
MV circuits for metro traction and auxiliary power supply; dedicated MV power supply circuits for tunnel ventilation, pumping stations, and monitoring systems; and main incoming cables for underground transport hubs; featuring low-smoke, zero-halogen (LSZH) properties that comply with strict fire safety, evacuation, and design standards for enclosed underground transport environments.
- Power Transformation Systems for Large-Scale Public Buildings and Super-High-Rise Complexes
Incoming feeder lines for substations serving hospital groups, airport terminals, large sports venues, and exhibition centers; underground medium-voltage supply mains for super-high-rise commercial complexes; and dedicated medium-voltage lines for fire-safety backup power in densely populated public areas subject to strict fire safety regulations.
- New Energy Collection and Transmission Projects for Ground-Mounted PV and Wind Farms
Medium-voltage collection mains for large-scale ground-mounted photovoltaic power plants; long-distance tie lines connecting onshore wind farms to step-up substations; and underground medium-voltage distribution cabling for energy storage stations—designed to withstand complex outdoor terrain, installation in backfilled agricultural land, and mildly corrosive soil environments.
- Power Supply Systems for Industrial Parks, Chemical Zones, and Heavy Industry
Main medium-voltage distribution networks for industrial clusters; dedicated power supply cables for heavy-duty motors in factory workshops; and underground medium-voltage lines for auxiliary power systems in chemical plants—featuring corrosion-resistant sheathing and flame-retardant construction to suit mildly corrosive soil and production environments in industrial sites.
A municipal power engineering general contractor selected a large volume of 8.7/15kV WDZ-YJY23 3*300mm² three-core cables to serve as the medium-voltage (MV) incoming main lines for an urban underground utility tunnel expansion and upgrade project. The original design specified unarmored WDZ-YJY cables housed in heavy-duty protective conduits; however, this approach resulted in a total material and construction budget that exceeded government approval limits. Following a comprehensive review—including MV load calculations, partial discharge performance verification, and a cost-benefit analysis—the client switched to a direct-burial installation method using WDZ-YJY23 cables, thereby reducing total material and labor costs by 29%. Our technical team provided a complete set of MV test reports and certification documents required for government tender evaluation and grid utility filing. We coordinated phased deliveries to align with the civil construction schedule and provided on-site technical guidance covering critical aspects such as cable pulling tension control, adherence to bending radius specifications, and standardized MV cable termination procedures. Upon completion, the project successfully passed the joint acceptance inspection conducted by municipal authorities, fire safety departments, and the power grid utility.
An EPC contractor for a rail transit project undertook the construction of medium-voltage power infrastructure for a new subway extension line. To comply with mandatory subway fire safety design standards, the project required direct-burial medium-voltage main cables capable of withstanding external construction damage and featuring low-smoke, zero-halogen, flame-retardant properties; the design institute specified the 8.7/15kV WDZ-YJY23 model as the sole approved product. We arranged for the production and submission of samples for third-party testing, successfully passing evaluations for medium-voltage partial discharge and fire resistance; compiled a comprehensive certification dossier for filing and review by rail transit authorities; optimized the Bill of Materials (BOM) to minimize excess inventory and material waste; and scheduled off-peak logistics to ensure compliance with urban traffic restrictions. After two years of stable operation on the power grid, periodic partial discharge and thermal imaging inspections confirmed normal insulation conditions with no instances of terminal overheating, and all operational metrics fully met the requirements for the long-term operation of the subway power system.
A renewable energy procurement company purchased a large volume of 8.7/15kV three-core WDZ-YJY23 cables for the medium-voltage direct-buried collection lines of a gigawatt (GW)-scale ground-mounted photovoltaic (PV) power plant. Given the project's vast footprint—spanning extensive agricultural terrain—the cables required high crush resistance to withstand backfilling operations, as well as aging resistance and fire safety compliance for outdoor use. The cables featured an integrated armored design that eliminated the need for protective conduits, thereby significantly shortening the on-site installation schedule and reducing the project's overall investment cost. We provided customized cable reel labeling to facilitate on-site phase identification and management, utilized seaworthy wooden reel packaging for inter-regional transport, conducted spot checks for partial discharge and fire performance to ensure consistent product quality, and signed a long-term framework supply agreement covering medium-voltage cabling for the project's subsequent expansion phases.
- Regulations for Low-Temperature Cable Laying
Cable pulling, bending, and laying operations are strictly prohibited when the ambient temperature is below 0°C. If winter installation is unavoidable, the cable reels must undergo a staged preheating process to prevent the outer sheath from becoming brittle and cracking, or the internal insulation layer from sustaining damage due to forced bending or tensile stress.
- Strict Adherence to Minimum Bending Radius
During operations such as conduit pulling, navigating turns in cable trenches, vertical shaft installations, and laying on cable trays, the bending radius of medium-voltage cables must not fall below the specified minimum. Excessive bending can compress the internal medium-voltage shielding layers and insulation structure, deform the steel tape armor, and create internal air gaps; this can trigger partial discharge and create a long-term risk of insulation breakdown during medium-voltage operation.
- Standardization Specifications for Medium-Voltage Cable Termination
When fabricating cable terminations, compatible, specialized 8.7/15kV medium-voltage cold-shrink or heat-shrink termination kits must be used. Strict adherence to procedures is required for all termination components, including the stripping of the semi-conductive layer, shielding treatment, insulation restoration, and sealing. Improper termination fabrication can lead to localized electric field concentration, partial discharge, and overheating during long-term medium-voltage load operation; these issues accelerate insulation aging and can trigger line faults.
- Specifications for Direct-Burial Installation of Medium-Voltage Cables
For the direct-burial installation of medium-voltage cables, a bedding layer of graded fine sand must be laid both beneath and above the cable. Warning bricks and signage must be installed along the cable route in accordance with electrical standards. Safe clearance distances from water supply, gas, and telecommunications pipelines must be maintained to prevent accidental damage from future external excavation work. The burial depth must be at least 700mm in standard sections, while the depth should be appropriately increased in areas where the cable crosses roadways.
- Protection Measures and Joint Sealing for Humid Environments
When installing cables in damp cable manholes, enclosed underground utility tunnels, or underground cable trenches, compatible waterproof cable glands and fully sealed straight-through joint accessories must be installed at cable entry/exit points and joints. This prevents groundwater from seeping into the medium-voltage cable cores, thereby avoiding the formation of "water trees" and the degradation of insulation performance caused by long-term moisture exposure.
- Cable Tray Layout Classification and Fire Separation Requirements
When WDZ-YJY23 medium-voltage cables are installed in the same tray or channel as non-flame-retardant medium-voltage cables, separation barriers and fire stops must be installed in accordance with electrical design standards. These measures serve to inhibit the rate of flame spread and prevent fire from propagating between cables in the event of combustion.
- Storage Specifications for Medium-Voltage Cables in Warehouses and Construction Sites
Finished cable reels should be stored in dry, well-ventilated indoor warehouses and kept out of direct sunlight and rain to delay sheath aging and embrittlement. Reels must be placed securely in a horizontal position to prevent armor deformation caused by vertical compression; stacking heavy objects directly onto the cable reels is strictly prohibited.
- Customization Services for Medium-Voltage Specifications Fully Compliant with Project Drawings
We manufacture 8.7/15kV WDZ-YJY23 medium-voltage cables in a wide range of cross-sections and single-core or three-core configurations. Based on your project drawings, we offer services such as cut-to-length delivery, custom sheath colors, phase sequence printing on cable drums, and tailored export packaging solutions. Should design adjustments be made to underground medium-voltage lines, our expert technical team provides free support for cable model substitution verification, short-circuit withstand capability checks, and ampacity calculations.
- Rigorous Quality Control Across the Entire Medium-Voltage Production Process
We utilize only certified high-purity copper rods, qualified medium-voltage grade XLPE insulation, verified LSZH (Low-Smoke Zero-Halogen) sheath materials, and galvanized steel tape. Every production batch undergoes DC resistance testing, insulation resistance checks, finished-product partial discharge (PD) testing, and spot checks for flame retardancy and smoke emission performance prior to shipment. This ensures consistent and reliable electrical safety performance for large-scale grid projects and bulk engineering orders.
- One-Stop Documentation Services for Medium-Voltage Equipment (Tendering & Grid Acceptance)
We consolidate essential documents—such as factory test reports, raw material certificates, medium-voltage partial discharge test reports, fire safety compliance documents, and product certificates—into a comprehensive technical dossier. We offer customized documentation services tailored to specific requirements, including grid tendering, project filing, fire safety acceptance, grid-connection approval, and overseas customs clearance. This significantly reduces the time and manpower procurement and engineering teams would otherwise spend on document sorting and qualification verification.
- Flexible Order Volumes and Global Logistics Solutions
We accommodate a wide range of order models, from small-batch trial production for preliminary medium-voltage performance verification to medium-scale stock production and large-volume bulk supply for major power infrastructure projects. For domestic power projects, we provide door-to-door delivery; for overseas orders, we offer sea-worthy wooden reel packaging, container loading arrangements, and coordination of the full suite of export customs documentation.
- Professional After-Sales Support Team for Medium-Voltage Electrical Technology
Our team of senior medium-voltage electrical engineers offers a range of complimentary services, including current-carrying capacity verification, optimization of medium-voltage cable selection, consultation on direct-burial installation schemes, review of Bills of Quantities (BOQ), and technical liaison with design institutes and grid authorities. We provide rapid response for on-site wiring, installation of medium-voltage accessories, and troubleshooting during the construction phase, ensuring the timely resolution of technical issues and the smooth progress of the project—from construction through to grid connection.
- Stable Pricing Strategy for Long-Term Framework Partnerships
For power engineering contractors, electrical distributors, and clients with ongoing, high-volume procurement needs for medium-voltage products, we offer pricing based on long-term framework agreements, tiered volume discounts, and copper price-locking schemes. These measures effectively stabilize procurement budgets for medium-voltage projects, helping clients mitigate the risks associated with copper price fluctuations in long-cycle grid construction projects.
