• Product advantages
• Product parameters
• Ordering instructions

Product advantages

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Why Choose Our 6.6kV Three-phase Epoxy Cast Dry Distribution Transformer？

Leading Technology

• High pressure copper tape winding – Flame retardant formula, vacuum pouring

• Low pressure copper foil winding – Thermosetting epoxy prepreg cloth insulation

• High quality iron core – 45° full oblique joint step laminated structure
 

The Iron Core

• Made of cold rolled grain oriented silicon steel sheet with mineral oxide insulation

• Precision cutting and stacking minimizes loss, no-load current, and noise

• Class F or Class H core paint prevents corrosion and rust
 

Low Voltage Winding

• High quality copper foil with thermosetting epoxy prepreg cloth insulation

• Excellent insulation resistance and radial stress resistance against short circuit

• Tinned copper bar outgoing terminal

• Oven heated to 140°C for 4 hours – excellent industrial gas corrosion resistance
 

High Voltage Winding

• Insulated copper wire with Hengfengyou Electric patented technology

• Small volume: linear voltage gradient from top to bottom

• Large capacity: tape winding technology

• Extremely low electric field between adjacent conductors

• Reliable structure during operation and transportation
 

Key Advantages

• Copper tape + copper foil winding, flame retardant vacuum casting

• 45° full oblique joint core – low loss, low noise

• Thermosetting epoxy insulation – Class F/H available

• Strong short circuit withstand and industrial gas corrosion resistance

• OEM customized solutions available

 

Company Advantages – Built for Global Buyers

• Certifications |CB, CCC, KEMA, SASO, and more |
• Quality System | SQA management – guaranteed consistency |
• Fast Response | Quick quote + electrical design support |
• Delivery | Short lead time, worldwide shipping |
• After-Sales | Complete service system |
• Customization | OEM/ODM – factory visit welcome |


6.6kV Three-phase Epoxy Cast Dry Distribution Transformer Case

6.6kV Three-phase Epoxy Cast Dry Distribution Transformer FAQ

1. Product Definition & Applicable Standards

Q1: What is a 6.6kV epoxy resin cast dry-type transformer? What scenarios is it specially designed for?
A1: The 6.6kV epoxy resin cast dry-type transformer is a fireproof, pollution-free, fully enclosed indoor power distribution transformer, completely different from traditional oil-immersed transformers. It adopts vacuum epoxy resin casting insulation without insulating oil, featuring flame retardant, explosion-proof, moisture-proof and maintenance-free performance. It is mainly used for urban commercial buildings, industrial workshops, data centers, subway transportation, hospital power distribution, underground pipe galleries and indoor high-safety power supply scenarios. It focuses on high safety and environmental-friendly power supply instead of outdoor overhead distribution, being the core preferred equipment for indoor medium-voltage power distribution systems with strict fire protection requirements.
Q2: What international standards do 6.6kV dry-type transformers comply with? Are they adapted to global industrial and building power specifications?
A2: Our 6.6kV epoxy cast dry-type transformers are fully designed and tested per IEC 60076-11 dry-type transformer special standard, IEC 60076 general standard and CE European safety directives, fully matching 6.6kV medium-voltage power distribution specifications for industrial plants and civil buildings worldwide. Meanwhile, it supports compliance with GB, EN, GOST, ANSI/IEEE, AS/NZS and SASO regional standards. Unlike oil-immersed transformers suitable for outdoor overhead and conventional industrial scenarios, dry-type transformers strictly meet indoor fire safety, low pollution and low noise operation standards, with higher safety grade and wider civil engineering adaptability.
Q3: Can you provide complete certification documents for 6.6kV dry-type transformers? Are engineering filing and safety certification documents available?
A3: We provide full sets of official certification documents for 6.6kV epoxy dry-type transformers, including IEC dry-type exclusive type test reports, CE safety certification, flame retardant grade certification, factory FAT test reports and full quality qualification certificates. For overseas industrial construction, municipal engineering and commercial building power supply projects, we can provide customized multi-language official documents, supporting local safety inspection, project filing, customs clearance and grid access acceptance, fully meeting international indoor electrical equipment safety access standards.

2. Core Structural & Technical Differentiations

Q4: What is the core structural feature of 6.6kV epoxy dry-type transformer? How is it different from traditional oil-immersed transformers?
A4: The biggest advantage of the 6.6kV dry-type transformer is its vacuum epoxy resin integral casting structure. The high-voltage and low-voltage windings are integrally cast with high-purity epoxy resin in a vacuum environment, forming a fully sealed insulation body. It completely eliminates oil leakage, fire and explosion risks existing in oil-immersed transformers. The whole machine adopts rigid integrated frame structure, with strong mechanical strength, anti-short-circuit impact and anti-vibration capability. The internal structure has no oil circuit and no wearing oil parts, realizing truly maintenance-free operation, which is the core structural difference from all oil-filled distribution transformers.
Q5: What voltage levels and capacity ranges are available for 6.6kV dry-type transformer series?
A5: 6.6kV epoxy cast dry-type transformers are dedicated for indoor medium-voltage industrial and civil power distribution, with 6.6kV high voltage and 0.4kV low voltage as the standard voltage class. The conventional capacity ranges from 50kVA to 2500kVA, covering medium and large-capacity stable power demand for factories, buildings and public facilities. Different from outdoor small and medium-capacity oil-immersed transformers focusing on decentralized distribution, dry-type products focus on centralized, continuous and stable power supply for indoor key loads, with stronger overload resistance and higher operation stability.
Q6: What winding and core technologies are adopted for 6.6kV dry-type transformers? What are the energy efficiency and safety advantages?
A6: The 6.6kV dry-type series adopts high-grade oriented CRGO silicon steel sheet laminated core and high-purity oxygen-free copper integral cast winding (aluminum winding optional). The vacuum casting process eliminates internal air gaps, effectively reducing partial discharge and magnetic leakage loss. The product complies with international high energy efficiency standards, with extremely low no-load and load loss. The epoxy resin material features self-extinguishing, flame retardant and non-combustible properties, which will not burn, splash or spread open fire in case of overload or short circuit fault. The integral casting structure also prevents winding deformation and dust accumulation, ensuring long-term safe and efficient operation indoors.
Q7: What are the environmental adaptability advantages of 6.6kV epoxy dry-type transformers for indoor and harsh industrial scenarios?
A7: Targeting indoor closed and harsh industrial operation environments, 6.6kV dry-type transformers adopt exclusive environmental optimization design. The fully cast sealed structure effectively isolates dust, moisture, corrosive gas and metal particles, adapting to long-term operation in humid, dusty and chemical industrial workshops. The whole machine has no liquid insulation medium, no volatilization and no pollution, meeting indoor environmental protection requirements. It supports normal operation in ambient temperature of -20℃ to +45℃, equipped with intelligent temperature control fan system and over-temperature protection device. It has excellent anti-corrosion, anti-moisture and anti-pollution performance, suitable for buildings, workshops and underground indoor confined spaces.
Q8: What is the noise level and operation life of 6.6kV dry-type transformers?
A8: Benefiting from optimized core mute lamination process and integral casting shock absorption structure, the standard operating noise of 6.6kV dry-type transformers is ≤50dB, lower than traditional oil-immersed transformers, meeting strict indoor building and urban environmental protection noise standards. The design service life reaches 25 years, and the stable operation life can be extended to 30 years with regular dust cleaning and temperature inspection. The high-stability epoxy insulation material does not age, deteriorate or deform easily, adapting to long-term unattended stable operation of indoor power distribution systems.

3. Customization & Installation Adaptability

Q9: What customized services are supported for 6.6kV epoxy dry-type transformers?
A9: We support exclusive customized optimization for 6.6kV international standard dry-type transformers, including 50Hz/60Hz frequency conversion adaptation, special voltage ratio and impedance adjustment, high anti-harmonic design for inverter loads, enhanced anti-corrosion formula for chemical workshops, low-temperature resistant casting formula for high-altitude cold areas, and multi-language customized nameplate and logo. Core accessories such as intelligent temperature controllers, cooling fans, high-voltage insulators and protection sensors can be upgraded to international famous brands. All customized parameters are recorded in formal technical agreements to fully match project indoor power distribution design standards.
Q10: What are the installation advantages of 6.6kV dry-type transformer? Is special fire-proof foundation required?
A10: The biggest installation advantage of 6.6kV dry-type transformer is simple indoor floor-mounted installation without fire-proof isolation pool. Different from oil-immersed transformers that require fire-proof foundation and oil storage facilities, dry-type products can be directly installed in indoor power distribution rooms, basements and underground pipe galleries, saving civil engineering investment and occupied space. The whole machine is compact and modular, supporting integral hoisting and rapid positioning installation, with no fire safety hidden dangers, greatly simplifying indoor power distribution room construction standards.
Q11: Can you provide installation dimension drawings and indoor matching parameters?
A11: Official quotations and technical documents are attached with complete 6.6kV dry-type exclusive installation drawings, overall dimension parameters, foundation hole position drawings, hoisting data and ventilation space matching parameters. We provide professional indoor power distribution room layout and ventilation design guidance according to international electrical installation specifications, ensuring perfect matching with customer's civil engineering and electrical design. For special space-limited projects, we can customize compact reduced-size structure to achieve zero installation adaptation error.

4. Production, Testing & Delivery

Q12: What is the production cycle of 6.6kV dry-type transformer series? How to guarantee delivery for indoor engineering projects?
A12: The production cycle of standard 6.6kV epoxy cast dry-type transformers is 15–22 working days. For customized anti-harmonic, low-temperature resistant and enhanced safety models, the cycle is 22–35 working days. We adopt exclusive dry-type transformer vacuum casting production lines with standardized process flow and stable production capacity. For large-scale factory renovation and building power supply projects, we implement priority production scheduling and phased batch delivery to ensure engineering construction progress.
Q13: What professional tests will 6.6kV dry-type transformers undergo before delivery? Is third-party witnessing acceptable?
A13: All 6.6kV dry-type transformers pass 100% full-item professional testing before delivery, including vacuum casting quality inspection, partial discharge test, lightning impulse test, power frequency withstand voltage test, temperature rise limit test, short-circuit resistance test and fan linkage test, aiming at indoor safety operation characteristics. We fully support SGS, BV, TUV and other third-party on-site FAT witnessing and batch sampling inspection, and can provide exclusive dry-type transformer test reports to meet international indoor engineering acceptance standards.
Q14: What export packaging is adopted for 6.6kV dry-type transformers to adapt to long-distance transportation?
A14: 6.6kV dry-type transformers adopt reinforced fumigation wooden box export packaging, with multi-layer anti-rust, moisture-proof, shockproof and dust-proof professional protection. Since there is no insulating oil, the whole machine can be shipped in fixed integral packaging without oil drainage and nitrogen filling. Equipped with fixed damping brackets and transportation impact recorders, it effectively prevents casting body cracking and structural vibration damage during long-distance transportation. All packaging boxes pass IPPC fumigation treatment, fully meeting global import quarantine and long-distance sea and land transportation requirements.

5. Quotation, Customs & Logistics

Q15: What is the quotation validity of 6.6kV dry-type transformers? Is the price stable?
A15: The standard quotation validity of 6.6kV dry-type transformer series is 15 days with fixed price, not affected by short-term raw material price fluctuations. For large-scale industrial supporting and municipal building batch projects, the quotation validity can be extended to 120 days. Expired quotations can be reissued free of charge according to the latest project requirements and international dry-type transformer safety standards.
Q16: What payment terms are supported for 6.6kV dry-type overseas projects?
A16: We support flexible international payment methods suitable for industrial and civil engineering projects, including TT telegraphic transfer and irrevocable sight L/C. For long-term cooperative EPC projects and municipal key power supply projects, the advance payment ratio and commercial terms can be flexibly negotiated. All business terms are standardized in formal foreign trade contracts to ensure safe, compliant and transparent transactions for both parties.
Q17: Can you provide preferential customs clearance documents for 6.6kV dry-type transformers?
A17: We provide complete customs clearance documents including CO certificate of origin, FORM A, FORM E and other preferential tariff certificates, which can help overseas customers apply for tariff reduction and exemption, simplify engineering equipment customs clearance procedures, and effectively reduce project import costs. All documents comply with international medium-voltage electrical equipment import filing and safety supervision standards.
Q18: What logistics solutions are available for 6.6kV dry-type transformers?
A18: 6.6kV dry-type transformers have no liquid leakage risk and no special transportation restrictions, supporting diversified safe logistics solutions, including sea freight, China-Europe railway, cross-border truck transportation and bulk consolidated shipment. For large-capacity models, we provide professional fixed and shockproof transportation schemes to avoid casting body damage. We recommend the most cost-effective and safe logistics scheme according to project location and delivery cycle.

6. After-sales Service & Quality Guarantee

Q19: What is the warranty policy for 6.6kV dry-type transformers?
A19: The standard warranty period of 6.6kV epoxy cast dry-type transformers is 1 year. For industrial key projects and municipal public building power supply projects, the warranty period can be extended to 2–3 years. The warranty covers all manufacturing defects, casting process defects and original accessory quality faults. Faults caused by unauthorized disassembly, improper operation, severe overloading, man-made impact damage and natural disasters are excluded from the warranty scope.
Q20: Do you provide lifelong spare parts supply and technical support?
A20: We provide lifelong supply of exclusive original spare parts for 6.6kV dry-type transformers, including intelligent temperature controllers, cooling fans, temperature sensors, insulators and protection devices, with 100% model matching. We provide 24/7 global online technical support, quickly solving on-site installation, commissioning, temperature abnormality and daily operation faults. For overseas large-scale engineering projects, we can arrange professional engineers for on-site guidance and SAT acceptance services.
Q21: What quality control system is adopted for 6.6kV dry-type products?
A21: Our factory strictly implements ISO9001 full-process quality management system, and formulates exclusive inspection standards for epoxy cast dry-type transformers aiming at casting compactness, partial discharge index, flame retardant performance and temperature resistance. Every 6.6kV dry-type transformer passes strict vacuum casting inspection, partial discharge detection and full-load aging test before delivery. We fully support third-party factory audits and sampling inspections to ensure stable and reliable quality of exported dry-type equipment.

Product parameters

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额定容量Capacity	额定电压及分接范围Rated voltage&Off-load tapping				联结组标号 Vector  GroupSymbol		空载损耗 NO-load loss（W）	负载损耗 Load loss（W） F级绝缘	空载电流 NO-load current（%）	短路阻抗Short circuit impedance(%)
	高压 H.V(kv)	高压分接范围  High pressure   Tap range（%）		低压 L.V(kv)
30	11 10.5 10 6.6 6.3 6	±5% ±2.5%		0.4 0.69	Dyn11 Yyn0		150	710	2	4
50							215	1000	2	4
80							295	1380	1.5	4
100							320	1570	1.5	4
125							375	1850	1.3	4
160							430	2130	1.3	4
200		±5% ±2x2.5%					495	2530	1.1	4
250							575	2760	1.1	4
315							705	3470	1	4
400							785	3990	1	4
500							930	4880	1	4
630							1070	5880	0.85	4
630							1040	5960	0.85	6
800							1215	6960	0.85	6
1000							1415	8130	0.85	6
1250							1670	9100	0.85	6
1600							1960	11700	0.85	6
2000							2440	14400	0.7	6
2500							2880	17100	0.7	6

 

Ordering instructions

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- Main parameters of transformer (voltage, capacity, loss and other main parameters)
- Transformer operating environment (altitude, temperature, humidity, location, etc.)
- Other customization requirements (coupling groups, colors, oil pillows, etc.)
- The minimum order quantity is 1 sets, worldwide delivery within 7 days
- Normal delivery period of 30 days, worldwide fast delivery