26/35kV WDZ-YJY23 Double Steel Tape Armored LSZH Medium-High Voltage Power Cable for Urban Grid, Tunnel Direct Burial & New Energy Substation Transmission
পণ্যের সারসংক্ষেপ
পণ্যের বিবরণ
Detailed model specifications designed for medium-to-high voltage design engineers, cost estimators, grid procurement specialists, and EPC project managers, enabling quick identification of structural classifications and electrical applications:
The 26/35kV WDZ-YJY23 is a high-specification, medium-to-high voltage, flame-retardant, armored power cable designed for 35kV fixed power transmission trunk lines. It is engineered to meet the demands of rigorous operating environments that require both robust mechanical protection and compliance with stringent fire safety standards. Unlike unarmored 26/35kV WDZ-YJY cables—which are vulnerable to soil compression, excavation damage, rodent gnawing, and punctures from sharp rocks during underground installation—this product features a double steel-tape armor structure that effectively withstands external impact, crushing, and puncture forces. At the same time, it retains low-smoke, zero-halogen, and flame-retardant properties, ensuring compliance with strict fire safety regulations for locations such as enclosed underground utility tunnels, subway tunnels, densely populated public infrastructure, and petrochemical industrial parks.
In the event of a fire, the WDZ-YJY23 cable emits only a small amount of transparent smoke and releases no corrosive halogen-acid gases; this ensures clear visibility along evacuation routes, inhibits flame propagation along the 35kV cable line, and effectively prevents widespread grid tripping incidents caused by cable combustion or insulation breakdown. This 35kV cable is widely selected by electric power design institutes, municipal power EPC contractors, substation developers, renewable energy investors, and professional electrical wholesalers for use in major projects involving direct burial, cable trenches, tunnels, utility tunnels, and semi-exposed cable trays. The product fully complies with the mandatory national inspection standard GB/T 12706.3-2020 for medium- and high-voltage cables as well as IEC international testing specifications; comprehensive technical documentation is available to meet requirements for grid tenders, project filing, fire safety acceptance, grid-connection approval, and final project acceptance.
- GB/T 12706.3-2020 Power cables with extruded insulation for rated voltages of 35 kV (Um = 40.5 kV)
- GB 31247 Specification 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 (extended to cover the 35 kV class)
- IEC 60332-3 Test for vertical flame spread of vertically-mounted bunched wires or cables
- IEC 60754 Test on halogen content and corrosive gas emission
- IEC 61034 Measurement of smoke density under burning conditions
- IEC 60228 Standard for conductor dimensions and DC resistance
We offer adjustable flame-retardant performance (Classes A, B, and C), custom non-standard cross-sections, cut-to-length services, and special sheath color coding. Additionally, we provide support for third-party certification applications (such as CCC, CE, and KEMA type-test certifications) required for overseas 35kV tenders.
A Class 2 circular compacted conductor made of high-purity annealed copper, compliant with IEC 60228 standards. It features extremely low DC resistance at 20°C, stable long-term conductivity, and excellent oxidation resistance, effectively minimizing line losses during transmission over long-distance 35kV trunk lines. Conductor cross-sections range from 50mm² to 800mm², meeting diverse 35kV load requirements as well as design standards for short-circuit withstand and current-carrying capacity.
The use of a uniformly extruded semi-conductive shield eliminates air gaps between the conductor and the XLPE insulation layer, homogenizes the high electric field distribution, and suppresses partial discharge; this is crucial for ensuring the long-term insulation stability and resistance to water-tree aging of 35kV cables.
The cross-linked polyethylene (XLPE) insulation layer is manufactured using a precision extrusion process equipped with an online closed-loop control system for eccentricity and thickness. It features excellent thermal aging resistance, extremely high dielectric strength, ozone resistance, and partial discharge suppression capabilities, maintaining stable insulation performance over a 30-year design service life—even under prolonged temperature cycling and continuous operation at rated load.
The outer semi-conductive shield, matched to the insulation structure, forms a complete internal electric field shielding system; it effectively limits surface electric field concentration and meets the stringent testing requirements for ultra-low partial discharge levels during factory acceptance testing of the finished 26/35kV cable.
Utilizing an overlapping copper tape shielding structure, this layer suppresses electromagnetic interference generated during 35kV high-voltage operation and provides a reliable short-circuit grounding path. It complies with power system grounding design standards and shields adjacent communication and control cables from external electromagnetic interference.
Environmentally friendly, halogen-free filler material fills the gaps between insulated cores, enhancing cable roundness and overall crush resistance while preventing core twisting or displacement caused by severe tension or bending during installation. The overall wrapping tape stabilizes the internal core structure and minimizes internal friction and wear.
An extruded LSZH polyolefin inner bedding layer serves as a buffer and isolation barrier between the cores and the steel tape armor. It prevents the sharp edges of the steel armor from damaging the internal shielding and insulation structures under bending or compressive stress, while also enhancing overall moisture resistance.
Mechanical armor consisting of two layers of overlapping galvanized steel tape effectively withstands soil pressure, impacts from excavation, rodent gnawing, and punctures by sharp rocks. It supports direct-burial installation without the need for heavy-duty protective conduits, thereby simplifying the 35kV direct-burial installation plan and significantly reducing the volume of civil engineering work.
Featuring a low-smoke, zero-halogen (LSZH), flame-retardant polyolefin outer sheath, the cable offers exceptional resistance to soil acidity/alkalinity, groundwater penetration, and microbial or fungal attack, as well as superior weather and UV resistance (suitable for sections with partial exposure, such as bridge installations). It emits no toxic halogen gases and produces low smoke density during combustion, fully complying with fire safety and environmental assessment standards for critical public infrastructure and hazardous industrial zones.
| Indicator | Description |
|---|---|
| Key Electrical and Thermal Performance Indicators | |
| Rated operating voltage | Standard 26/35kV (Um=40.5kV); customizable specifications (e.g., 21/35kV, 18/30kV) available upon request |
| Maximum continuous operating temperature of conductor | 90°C |
| Maximum short-circuit temperature (duration ≤ 5 seconds) | 250°C |
| Minimum ambient installation temperature | ≥0°C; pre-heating required for installation below 0°C to prevent outer sheath embrittlement and cracking |
| Minimum permissible bending radius for finished armored cable | Multi-core ≥ 15 * cable outer diameter; Single-core ≥ 20 * cable outer diameter |
| Fire Safety Performance Indicators | |
| Optional flame-retardant grades | WDZA / WDZB / WDZC (meeting various fire safety design requirements) |
| Smoke light transmittance | ≥60% (compliant with low-smoke environmental standards) |
| Halogen emission test results | Halogen-free; no corrosive acidic gases produced during combustion |
| Total heat release and smoke generation metrics | Compliant with Class B1 standards for building fire-resistant materials |
We offer standard single-core and three-core configurations suitable for 35kV medium-to-high voltage systems, fully compatible with 35kV three-phase incoming/outgoing line and ring-main distribution designs for urban power grids, substations, and large-scale industrial power supply projects.
Includes factory inspection reports, raw material certificates of conformity, partial discharge test reports for finished 35kV cables, flame-retardant performance test reports, smoke density and halogen content test reports, and product certificates of conformity. Additionally, we can facilitate CCC mandatory certification, CE certification, KEMA type-test certificates, and other third-party test documentation to meet requirements for grid entry approval, domestic government project tenders, and qualification reviews for overseas project customs clearance.
-
Advantage 1: Integration of Three Major Performance Features—High-Grade 35kV Insulation, Armored Mechanical Protection, and Low-Smoke Zero-Halogen (LSZH) Fire Safety
Compared to unarmored 26/35kV WDZ-YJY cables, this cable features an integrated double-steel-tape armor structure that effectively mitigates risks associated with direct-burial installation—such as crushing, accidental excavation damage, and rodent interference—thereby supporting direct burial and eliminating the cost of additional protective conduit. Furthermore, its LSZH flame-retardant design complies with mandatory fire safety regulations for enclosed underground public spaces. By combining high-reliability 35kV insulation, robust mechanical protection, and eco-friendly fire safety, it serves as an ideal choice for 35kV backbone projects where fire risk is a critical concern.
-
Advantage 2: Suitable for large-scale 35kV direct-burial projects with lower overall investment
For direct-burial projects such as municipal grid upgrades and substation expansions, the use of WDZ-YJY23 cable eliminates the need to purchase rigid conduits and saves on costs associated with trench excavation, fitting installation, and backfilling materials. Although the unit price of the cable is slightly higher than that of non-armored 35kV cable, the total cost—encompassing materials, labor, and civil engineering—is significantly reduced; this shortens construction schedules and effectively controls capital expenditure for long-term power infrastructure projects.
-
Advantage 3: Superior underground corrosion resistance and long-term operational stability at 35kV
The cable features a dual-layer (inner and outer) Low-Smoke Zero-Halogen (LSZH) sheath structure that effectively withstands soil acidity/alkalinity, groundwater infiltration, damp or waterlogged foundations, and the corrosive conditions of riverbank direct-burial environments. It also effectively inhibits "water treeing" degradation within the thickened 35kV insulation layer. Its design ensures a stable service life exceeding 30 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 during fire emergencies and extremely low partial discharge
When exposed to open flames, this 35kV medium-to-high voltage cable effectively inhibits flame propagation along the line, ensuring a continuous power supply for emergency power systems, fire linkage control systems, and backup transformer input circuits. In contrast, traditional PVC-armored YJY23-type 35kV cables release large amounts of toxic smoke and corrosive halogen gases during combustion; these emissions not only hinder personnel evacuation and corrode equipment but also risk causing insulation breakdown and circuit tripping at 35kV, thereby failing to meet mandatory fire safety design requirements for public transportation and key public buildings.
-
Advantage 5: Fully aligned with grid tendering, grid connection, and project acceptance requirements
The WDZ-YJY23 26/35kV cable is a recommended model specified in medium-to-high voltage electrical design standards for sectors such as urban power grids, metro systems, underground utility tunnels, petrochemical parks, and key municipal projects. Comprehensive certification documentation can be compiled and customized to meet the specific needs of tender applications, project filings, fire safety inspections, and grid connection approvals, thereby eliminating potential obstacles to tendering, grid integration, and final project acceptance caused by non-compliant qualifications.
-
Urban Power Grid Upgrades and 35kV Substation Interconnection Projects
Main supply and feeder lines for urban 35kV distribution substations; ring-network interconnection cables for urban grid renovations; 35kV direct-buried distribution mains for residential grid upgrades; and long-distance underground cable routes requiring mechanical protection against crushing.
-
Urban Utility Tunnels and Public Tunnel Projects
35kV distribution trunk lines within urban utility tunnels; medium-to-high voltage interconnection cables between large underground 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
35kV circuits for metro traction and auxiliary power supply; dedicated 35kV power supply circuits for tunnel ventilation, pumping stations, and monitoring systems; and main incoming cables for underground transport hubs; featuring low-smoke, halogen-free properties that comply with strict fire safety, evacuation, and design standards for enclosed underground transport environments.
-
Central Substation Systems for Large-Scale Public Buildings and Super-High-Rise Complexes
Suitable for central substation incoming lines serving hospital groups, airport terminals, large stadiums, and exhibition centers; 35kV underground power supply trunk lines for super-high-rise commercial complexes; and dedicated 35kV lines for fire-safety backup power in densely populated public venues subject to strict fire safety regulations.
-
New Energy Collection and Transmission Projects for Ground-Mounted PV and Onshore Wind Farms
Suitable for 35kV collection trunk cables in gigawatt (GW)-scale ground-mounted PV power plants; long-distance tie lines connecting onshore wind farms to step-up substations; and buried 35kV distribution lines for energy storage stations. Product designs are adapted for complex outdoor terrain, installation in backfilled farmland soil, and mildly corrosive soil environments.
-
Power Supply Systems for Industrial Parks, Petrochemical Bases, and Heavy Industry
Suitable for primary 35kV distribution networks in industrial clusters; dedicated power supply cables for heavy-duty motors in factory workshops; and buried 35kV lines for auxiliary power systems in chemical plants. Featuring corrosion-resistant sheathing and flame-retardant construction, these products are designed to withstand mildly corrosive industrial soil and meet stringent fire safety requirements in production environments.
-
Case Study 1: 35kV Main Feeder Upgrade for the Phase V Urban Utility Tunnel Project
During an urban underground utility tunnel expansion and upgrade project, a municipal power engineering general contractor selected a large volume of 26/35kV WDZ-YJY23 3*400mm² three-core cables for the 35kV main feeder lines. The original design specified unarmored 35kV WDZ-YJY cables paired with heavy-duty protective conduits; this approach resulted in a total budget for materials and installation that exceeded government-approved limits. Following 35kV load calculations, partial discharge performance verification, and a cost-benefit analysis, the client switched to a direct-burial installation method using WDZ-YJY23 cables, reducing total material and labor costs by 31%. Our technical team provided a comprehensive set of 35kV test reports and certification documents required for government tender reviews and grid authority filings. 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, bending radius specifications, and standardized 35kV cable termination procedures. Upon completion, the project successfully passed the joint acceptance inspection conducted by municipal, fire safety, and power grid authorities.
-
Case Study 2: 35kV Substation and Transmission Line Project for an Intercity Metro Extension
An EPC contractor for a rail transit project undertook the construction of the 35kV power infrastructure for an intercity metro extension line. Project specifications required the main 35kV cables to be resistant to external construction-related damage while also possessing low-smoke, zero-halogen (LSZH) and flame-retardant properties to comply with mandatory metro fire safety design standards. The design firm designated the 26/35kV WDZ-YJY23 cable model as the sole product to be used. We arranged for the delivery of pre-production samples for third-party testing of 35kV partial discharge and combustion performance; compiled a comprehensive set of certification documents for filing and review by rail transit authorities; optimized the Bill of Materials (BOM) to minimize excess inventory and construction waste; and scheduled off-peak transportation to comply with urban traffic restrictions. After three years of stable operation on the power grid, periodic partial discharge and thermal imaging inspections revealed no insulation anomalies or terminal overheating issues, and all operational metrics fully met the long-term requirements for the metro power system.
-
Case Study 3: 35kV Collection Line Project for a Large-Scale Onshore Wind Farm
A renewable energy procurement company purchased a large volume of three-core 26/35kV WDZ-YJY23 cables for the 35kV underground collection lines connecting the turbine array of a 500MW onshore wind farm. Situated in a vast hilly region, the project required cables capable of withstanding the crushing forces associated with soil backfilling, while also meeting outdoor durability and fire safety standards. The cables featured an integrated armor design, eliminating the need for protective conduits; this significantly shortened the on-site installation schedule and reduced the project's overall investment cost. We provided customized phase-sequence markings on the cable reels to facilitate on-site phase identification and management, utilized export-grade wooden reels suitable for maritime transport to meet cross-regional logistics needs, and conducted batch-based sampling tests for partial discharge and fire performance to ensure consistent quality across the entire order. Additionally, we signed a long-term framework supply agreement covering the 35kV line works for the project's subsequent expansion phases.
-
Regulations for Low-Temperature Cable Installation
Cable pulling, bending, and laying operations are strictly prohibited when the ambient temperature is below 0°C. If winter construction 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 installation, and cable tray routing, the bending radius of 35kV medium-to-high voltage cables must not fall below the specified minimum. Excessive bending compresses the internal 35kV shielding layers and insulation structure, causing deformation of the steel tape armor and the formation of internal air gaps; this creates a risk of partial discharge and long-term insulation breakdown during high-voltage operation.
-
Standardized Specifications for 35kV Terminal Connections
When fabricating cable terminals, compatible, professional-grade 26/35kV medium-to-high voltage cold-shrink or heat-shrink termination kits must be used. Strict adherence to procedures—including semi-conductive layer stripping, shielding treatment, insulation restoration, and sealing—is required for all terminal components. Improper fabrication can lead to localized electric field concentration, partial discharge, and overheating during long-term, load-bearing operation at the 35kV voltage level, thereby accelerating insulation aging and causing line failures.
-
Specifications for 35kV Direct-Burial Installation
For the direct-burial installation of 35kV cables, a bedding layer of graded fine sand must be laid both beneath and above the cable itself. Warning bricks and signage must be installed along the cable route in accordance with electrical standards. Safe clearance distances must be maintained from water supply, gas, and telecommunications pipelines to prevent accidental damage during future external excavation work. The burial depth must be no less than 1,000 mm for standard sections, while sections crossing roadways require a depth exceeding 1,200 mm.
-
Installation and Joint Sealing/Protection Measures for Humid Environments
For installations in damp cable manholes, enclosed underground utility tunnels, and underground trenches, compatible waterproof cable sealing 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 35kV 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-Resistant Separation Requirements
When WDZ-YJY23 type 35kV medium/high-voltage cables are laid in the same cable tray alongside non-flame-retardant standard medium/high-voltage cables, separating partitions and fire barriers 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 during a combustion event.
-
Storage Specifications for 35kV Cables (Warehouse and Site)
Finished cable reels should be stored in dry, well-ventilated indoor warehouses and protected from prolonged exposure to 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 surface of the cable reels is strictly prohibited.
-
Customized services fully compliant with 35kV medium-high voltage specifications and design drawings
We manufacture 26/35kV WDZ-YJY23 medium-high voltage cables in a wide range of cross-sectional sizes and single-core/three-core configurations. We also offer services tailored to specific 35kV project requirements, including cut-to-length delivery, custom sheath colors, phase sequence marking on cable drums, and specialized export packaging for sea freight. Should designers modify 35kV direct-burial installation plans, our expert technical team provides complimentary support for cable model substitution verification, short-circuit withstand capability checks, and ampacity calculations.
-
Strict end-to-end quality control covering raw materials and batch production for 35kV products
We utilize only certified high-purity copper rods, qualified medium-high voltage grade XLPE insulation, inspected LSZH (Low Smoke Zero Halogen) sheath materials, and galvanized steel tape. Before leaving the factory, 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. This ensures consistent and reliable electrical safety for 35kV cables used in large-scale grid projects and bulk engineering orders.
-
One-Stop Documentation Services for 35kV Projects: Tendering and Grid Acceptance
We consolidate key materials—such as factory test reports, raw material certificates, 35kV partial discharge test reports, fire safety compliance documents, and product certificates—into a complete, standardized documentation package. Our tailored services meet the specific requirements of grid tenders, project filings, fire safety inspections, grid-connection approvals, and overseas customs clearance, thereby significantly reducing the time and manpower procurement and engineering teams spend on document organization and qualification verification.
-
Flexible Order Volumes and Global Logistics Solutions
We cater to diverse needs, ranging from small-batch trial orders for initial 35kV performance verification and medium-scale stock production to high-volume supplies for major power infrastructure projects. For domestic power projects, we offer door-to-door delivery; for export orders, we provide sea-worthy wooden reel packaging, container loading arrangements, and coordination of the full suite of export customs clearance documentation.
-
Dedicated After-Sales Technical Support Team for Medium- and High-Voltage Electrical Systems
Our senior electrical engineers specializing in medium- and high-voltage systems provide a range of complimentary services, including ampacity verification, optimization of 35kV cable selection, consultation on direct-burial installation plans, preparation of bills of quantities, and technical coordination with design institutes and power grid authorities. We offer rapid response for on-site wiring, 35kV cable jointing, and troubleshooting during the construction phase, ensuring the timely resolution of technical issues and keeping the overall construction and grid-connection schedules for 35kV projects on track.
-
Stable Pricing Strategies for Long-Term Framework Partnerships
For power engineering contractors, electrical distributors, and clients with ongoing, high-volume procurement needs for 35kV products, we offer long-term framework agreement pricing, tiered volume discounts, and copper price-locking schemes. These measures effectively stabilize procurement budgets for 35kV projects and mitigate the risks associated with copper price fluctuations inherent in long-cycle power grid construction projects.
