kezhiding
kezhiding
Explore our core engineered transformers designed for maximum reliability, fire safety, and environmental protection.
Understanding the transition from oil-immersed systems to cast resin dry-type technology across high-density industrial and commercial sectors.
The global electrical power infrastructure is undergoing a massive transformation driven by decarbonization, electrification of transport, expansion of AI-driven data infrastructure, and rapid industrialization in emerging markets. At the center of this transition is the 35kV medium-voltage dry-type transformer. Historically, medium-voltage distribution systems relied heavily on mineral oil-immersed transformers due to their low initial capital costs and thermal transfer capacity. However, modern commercial, industrial, and municipal infrastructure projects increasingly demand solutions that eliminate fire risks, prevent environmental soil contamination, minimize maintenance overhead, and operate safely in confined or densely populated environments.
China has established itself as the world’s foremost powerhouse in 35kV dry-type transformer manufacturing, standardizing advanced vacuum casting technologies, utilizing high-grade cold-rolled grain-oriented (CRGO) silicon steel, and perfecting epoxy resin formulation. Modern 35kV cast resin dry-type transformers (such as the SCB10, SCB11, SCB13, and SCB14 standard series) engineered by premier Chinese exporters are certified to withstand demanding environmental classes (E2/E3), climatic stress levels (C2/C3), and strict fire behavior standards (F1). These systems provide unprecedented insulation integrity, operational resilience, and energy efficiency, fulfilling international standards such as IEC 60076, IEEE C57.12.01, and EN 60076-11.
An in-depth structural analysis of 35kV epoxy resin cast dry-type power distribution units.
The 35kV cast resin dry-type transformer operates at a critical voltage junction in modern electrical grids, stepping down primary utility distribution (33kV, 34.5kV, or 35kV) directly to industrial utilization voltages (such as 10kV, 6.6kV, 3.3kV, 690V, or 400V). Unlike lower voltage transformers (e.g., 10kV or 11kV), the 35kV rating requires significantly higher Basic Impulse Level (BIL) insulation withstand capability—typically reaching 170kV or 200kV peak lightning impulse withstand voltage.
| Technical Parameter | Standard Specification (SCB11 / SCB13 Series) | High-Efficiency Custom Variant (SCB14 / Amorphous) |
|---|---|---|
| Rated Primary Voltage | 33 kV / 34.5 kV / 35 kV (±2x2.5% Off-Load or On-Load Tap Changing) | 35 kV (Custom multi-tap configurations available) |
| Secondary Voltage | 0.4 kV, 3.3 kV, 6.6 kV, 10.5 kV, 11 kV (3-Phase 4-Wire / 3-Wire) | Tailored secondary outputs for industrial equipment |
| Insulation Class | Class F (155°C rise limit) or Class H (180°C rise limit) | Class H Nomex-reinforced resin system |
| Basic Impulse Level (BIL) | 170 kV Peak Lightning Impulse / 70 kV Power Frequency | 200 kV Peak Lightning Impulse / 85 kV Power Frequency |
| Partial Discharge Level | ≤ 10 pC (Pico-Coulombs) under 1.3 Um testing | ≤ 5 pC (Ensures decades of micro-crack-free operation) |
| Vector Group | Dyn11, Yyn0, Dyn1, or Custom phase-shifted arrangements | Dyn11 / Phase-shifting dual secondary for 12-pulse rectifiers |
| Enclosure Protection | IP00 (Indoor open), IP20 (Indoor ventilated), IP23 (Outdoor protected) | IP31 / IP54 (Heavy industrial or corrosive environments) |
High-voltage coils are wound on automated precision machines and encapsulated in filler-reinforced epoxy resin inside vacuum casting chambers, completely preventing moisture ingress and bubble formation.
Cores are built using high-permeability, low-loss cold-rolled grain-oriented (CRGO) silicon steel sheets cut at a 45-degree mitered angle with step-lap joints, drastically lowering no-load losses and noise levels.
Embedded PT100 temperature sensors inside the 3-phase low-voltage windings continuously transmit real-time thermal telemetry to automated forced-air (AF) cooling fans and SCADA controls.
Why international EPC contractors, utility companies, and OEM integrators source 35kV dry-type transformers from premier Chinese manufacturers.
China possesses the world's most complete raw material industrial chain for transformer production—ranging from premium domestic CRGO steel mills (BaoSteel, WISCO) to refined electrolytic copper, specialized epoxy resins, and automated insulating core accessories. This eliminates supply chain bottlenecks and guarantees competitive unit economics.
While Western transformer OEMs frequently quote delivery times ranging from 52 to 80 weeks due to capacity constraints, leading Chinese factories complete engineering design, custom coil winding, vacuum casting, routine factory acceptance testing (FAT), and international shipping staging within 6 to 12 weeks.
Top-tier Chinese manufacturers operate state-of-the-art high-voltage testing halls equipped with impulse voltage generators, partial discharge screening rooms, power frequency withstand voltage test sets, and double-frequency induction voltage test equipment, ensuring 100% FAT compliance prior to export packing.
Custom-engineered 35kV dry-type power equipment driving modern infrastructure globally.
High-density server facilities demand clean, uninterruptible power with minimum fire risk. 35kV dry-type transformers step down incoming high voltage directly inside multi-story facility substations, reducing low-voltage cable run losses and eliminating the need for oil catch basins or fire containment walls.
Renewable energy substations utilize 35kV dry-type step-up transformers integrated inside compact outdoor kiosks or containerized power stations, converting inverter voltage (e.g., 690V or 800V) directly to the 35kV collection grid with superior harmonic resistance.
Confined spaces such as subways, highway tunnels, and deep shaft mines demand flame-retardant, self-extinguishing transformers. Our 35kV units, alongside custom tunnel voltage boosters, provide stabilized voltage output under heavy dynamic motor starting loads.
Densely populated high-rise buildings utilize 35kV cast resin units in basement or roof-level substations. Zero risk of oil explosion and minimal ambient noise (<58 dB) make them ideal for luxury commercial real estate and medical centers.
Industrial processing plants exposed to heavy dust, corrosive vapors, or severe vibration rely on IP31/IP54 enclosed 35kV dry-type transformers with reinforced insulation to maintain uninterrupted operation under severe industrial duty cycles.
Metro electrical traction substations utilize specialized 35kV dry-type rectifier transformers (12-pulse or 24-pulse configuration) to supply steady DC power to transit grids while effectively neutralizing system harmonics.
How IoT sensing, eco-friendly materials, and ultra-low loss technology are redefining the 35kV voltage transformer sector.
As power grids transform into digital, decentralized smart energy networks, the humble distribution transformer is undergoing a technological revolution. Leading manufacturers in China are pioneering three major vectors of innovation in the 35kV dry-type domain:
Shenzhen Kezhiding Electronic Co., Ltd., located in Jinbolong Industrial Zone, Shenzhen, is a high-tech enterprise under Kaohsiung Ding Sheng Group in Taiwan. With years of experience in the power equipment field, it offers a full-chain service system covering R&D, production, after-sales, and sales, and is a top-notch power solution provider.
The company focuses on R&D and production of power equipment. Its diverse product range includes various types of voltage regulators, transformers, non-standard voltage regulators, voltage-transformer integrated machines, high-power UPS, tunnel boosters, etc. It provides both customized and standardized products, meeting different power needs in high-tech industries and engineering projects such as CNC machines, medical equipment, and tunnel construction.
Adhering to the principle of "people-oriented, quality-first", the company strictly follows a quality management system throughout the whole process from product design to after-sales service. This ensures product quality and production efficiency, winning wide trust from customers.
Currently, its products cover the domestic market and are exported to Southeast Asia, India, Africa, the Middle East and other regions. With excellent quality and perfect service, the company has established a good brand image in the global power equipment market, providing efficient and reliable power supply services for customers worldwide.
Four foundational pillars that make us the premier technical partner for power equipment globally.
As a physical factory, we engage in brand-new production without middlemen taking a cut. We have a professional production line. From stamping and welding, insulation and winding to assembly, whether it’s large components like oil tanks and transformer oil or small parts like screws and wires, every material is brand-new.
We focus on the R & D and production of voltage regulators and transformers. Our products are applied in various industries and have provided solutions and equipment for numerous enterprises, winning the trust of a large number of users.
Our experienced team offers consulting services and tailor-made solutions. We carefully manage your requirements to effectively reduce the cost for our customers. The products we manufacture can be customized according to the specific needs of your mechanical equipment.
Backed by a professional engineer team, we provide strong technical support. We track the shipment in real-time and offer 24-hour telephone service for an immediate response.
Complete power management systems for demanding global industrial applications.
Expert answers addressing 35kV dry-type transformer selection, maintenance, custom voltage regulation, and shipping standards.
35kV dry-type transformers utilize epoxy resin vacuum casting instead of combustible transformer oil. This makes them inherently fireproof (F1 fire class), self-extinguishing, and non-polluting. They eliminate the risk of oil leaks, ground soil contamination, and gas explosion, allowing them to be safely installed indoors, inside high-density commercial basements, or within environmentally protected water catchment zones without expensive concrete catch basins.
Partial discharge (PD) degrades insulation over time. Shenzhen Kezhiding utilizes advanced multi-stage vacuum casting chambers and degassing processes. Epoxy resin with quartz powder fillers is poured into coils under absolute vacuum. This ensures micro-bubble-free encapsulation, guaranteeing PD levels strictly controlled below 5pC to 10pC at 1.3 times rated operating voltage, dramatically extending equipment service life past 30 years.
Yes. As a physical source factory, Shenzhen Kezhiding specializes in non-standard custom engineering. We regularly manufacture 35kV transformers with custom step-down outputs (such as 35kV to 6.6kV, 35kV to 3.3kV, or dual-output 35kV to 400V/230V), custom tap changer steps (e.g., ±2x2.5% or ±5%), custom phase displacement for 12/24 pulse rectifiers, and specialized frequency ratings (50Hz / 60Hz).
Our standard 35kV cast resin transformers operate reliably from -25°C to +40°C. For extreme climates, specialized Class H insulation permits higher thermal rises. Enclosures range from IP00 (open core and coil for installation inside existing switchgear rooms), IP20 (indoor dust-protected ventilated steel housing), to IP23/IP31 (outdoor rain-proof or drop-proof louvers equipped with insect screening and anti-condensation space heaters).
Thanks to our integrated supply chain in Jinbolong Industrial Zone, Shenzhen, standard 35kV dry-type units are produced, pressure tested, and ready for sea transport within 3 to 5 weeks. Fully customized non-standard engineering orders typically ship within 6 to 8 weeks, significantly faster than the 12-to-18-month lead times currently common among European or North American manufacturers.
Each unit features a digital thermal protection controller connected to three PT100 platinum RTD sensors embedded inside the phase windings. The control unit displays real-time coil temperatures, automatically starts/stops low-noise forced-air (AF) cooling fans to increase transformer capacity by up to 30-50% during peak surge demands, and triggers remote SCADA alarms or trip contacts if over-temperature thresholds are reached.
All Shenzhen Kezhiding 35kV transformers are designed and factory tested in full compliance with international electrical standards, including IEC 60076-11 (Dry-type power transformers), IEEE C57.12.01, EN 60076, and ISO 9001 quality management guidelines. Routine test reports—including winding resistance, voltage ratio, phase displacement, short-circuit impedance, no-load loss, separate-source AC withstand voltage, and induced overvoltage testing—are provided with every shipment.
We provide 24-hour technical hotline support, remote video commissioning assistance led by experienced senior engineers, and full technical documentation packages including CAD dimensional drawings, schematic diagrams, and installation manuals. In addition, real-time tracking is provided throughout shipment to ensure hassle-free delivery to your job site or port of destination.
