• Product advantages
• Product parameters
• Ordering instructions

Product advantages

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Why Choose Our 11kV 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 |


11kV Three-phase Epoxy Cast Dry Distribution Transformer Case



11kV Three-phase Epoxy Cast Dry Distribution Transformer FAQ
1. Standard & Certification Compliance

Q1: What international standards do your 11kV three-phase dry-type transformers comply with? Can they meet global grid connection requirements?
A1: Our 11kV three-phase dry-type transformers are designed, type-tested and mass-produced in strict accordance with the IEC 60076 series standards specifically for dry-type transformers, which adopts a professional standard system different from oil-immersed transformers. According to project and local grid requirements, we can also fully adapt to GB, EN, GOST, ANSI/IEEE, AS/NZS, INMETRO, SABS, KEBS, SASO and other regional standards. Clients only need to provide the project country and grid owner technical specifications, and we will conduct a full standard compliance assessment and issue complete official certification documents.
Q2: Can you provide dry-type transformer type test reports and third-party witnessed test documents? Is factory witness testing available?
A2: We provide full CNAS-accredited type test reports for dry-type transformers. The test items cover core dry-type performance, including temperature rise limit test, no-load & load loss measurement, impedance characteristic test, lightning impulse withstand test, short-circuit withstand test, and partial discharge test. For key grid projects and large EPC projects, Factory Witnessed Test (WTT) is available by advance appointment, allowing full-process monitoring and production verification by owners, EPC contractors and third-party institutions.
Q3: Can you provide full English technical documents? Do you support multi-language manual customization?
A3: The standard delivery package includes complete English technical documents, such as dry-type transformer English nameplate, general arrangement drawing, wiring diagram, official FAT report, operation and maintenance manual, spare parts list and factory test certificates. Custom manuals and compliance documents in Spanish, Portuguese, Arabic, French and Russian are available on request, fully adapting to overseas bidding, grid acceptance and on-site operation.

2. Core Technical Performance

Q4: What winding materials are optional for 11kV three-phase dry-type transformers? Can material quality guarantees be specified in the contract?
A4: We offer two mainstream winding options: oxygen-free pure copper winding and high-strength aluminum alloy winding, which can be selected according to project budget, load characteristics and service life requirements. The winding material can be clearly defined in the technical agreement and formal contract, supported by material test certificates, batch traceability reports and production records. Equipped with a dedicated 11kV high-voltage dry-type insulation system, the transformer eliminates oil-leakage risks, features superior insulation stability and operational safety, and supports long-term maintenance-free operation.
Q5: Are electrical parameters customizable? How do you handle non-compliant test results?
A5: All key electrical parameters support one-to-one non-standard customization, including no-load loss, load loss, short-circuit impedance, tap range, temperature rise limit and partial discharge value, fully matching client datasheets and strict grid technical requirements. Every unit undergoes a complete set of dry-type exclusive factory tests. All non-compliant transformers are prohibited from delivery. We provide free rework and retesting, and offer free replacement for unrepairable units to ensure 100% qualified delivery.
Q6: Can 11kV dry-type transformers operate in high-altitude, coastal salt-spray, humid and seismic areas?
A6: We provide customized upgrade solutions for harsh working conditions to adapt to indoor and outdoor operation. High-altitude versions adopt enhanced insulation to prevent low-voltage discharge and insulation breakdown. Coastal anti-corrosion versions apply C5M heavy-duty anti-corrosion coating to resist salt spray and oxidation. Humid-area models adopt fully sealed moisture-proof structure and anti-condensation insulation treatment. Seismic-area versions are reinforced with optimized mechanical structure and shock-resistant components. All modifications are designed according to actual site conditions.
Q7: Are the transformers suitable for solar and wind farm grid-tie? What is the harmonic resistance performance?
A7: Our harmonic-resistant 11kV dry-type transformers are specially developed for renewable energy grid-tie projects. Optimized core lamination and winding structure effectively suppress harmonic heating, voltage distortion and current fluctuation. The design perfectly adapts to the intermittent and fluctuating nonlinear loads of PV and wind power systems, ensuring stable long-term grid-connected operation and meeting grid harmonic control standards.
Q8: What is the standard noise level? Is low-noise version available for residential areas?
A8: Under standard IEC test conditions, the standard operating noise is ≤58dB. For residential communities, municipal facilities, commercial zones and campuses with strict noise requirements, an ultra-low-noise version (≤50dB) is optional. By adopting damping components, optimized silent core structure and improved winding arrangement, vibration and noise are fundamentally reduced. Official noise test certificates can be provided for project acceptance.
Q9: Can the transformer withstand lightning impulse and sudden short-circuit faults?
A9: The transformer adopts standard 11kV high-voltage lightning impulse insulation design to resist lightning and switching overvoltage and avoid insulation breakdown. The reinforced anti-short-circuit structure optimizes internal stress distribution and winding fixation, greatly improving the capability to withstand sudden short-circuit faults. It fully complies with global grid safety operation standards, and third-party lightning impulse and short-circuit test reports are available upon request.
Q10: What is the design service life? Does the insulation system follow the 6℃ aging rule?
A10: The standard design service life is 20 years. Compared with oil-immersed transformers, dry-type transformers feature higher insulation stability and slower aging rate, achieving an actual service life of 25–30 years with proper maintenance. Adopting high-grade dry-type composite insulation, the product strictly follows the 6℃ insulation aging principle with sufficient temperature margin, slowing down insulation degradation and ensuring long-term stable operation.
Q11: Are you a genuine manufacturer of 11kV dry-type transformers? What are your production capabilities?
A11: We are a professional dry-type transformer manufacturer based in Qingdao, China, with decades of experience in R&D, production and global export of 10–35kV dry-type power transformers. All core components including iron cores, windings and insulation parts are self-produced with no outsourcing of key processes. Our products are widely applied in global grid projects, industrial plants, renewable energy farms, municipal infrastructure and EPC projects. Factory audits are warmly welcomed.

3. Customization, Dimension & Transportation

Q12: Do you support non-standard customization for 11kV three-phase dry-type transformers?
A12: Full-range non-standard customization is supported, covering electrical parameters, tap changer range, overall dimensions, mounting type, IP protection grade upgrade, special environmental adaptation, and temperature control & cooling system configuration. We can also install international brand thermostats, cooling fans, insulators and terminal blocks as required. All customized requirements will be recorded in the official technical agreement to guarantee consistent delivery.
Q13: Can you provide exact weight and dimension drawings? Are the transformers suitable for cross-border shipment?
A13: Exact net weight, shipping weight, overall dimension and installation dimension drawings will be provided together with the formal quotation. For large-capacity oversized units, we assess oversize transportation risks in advance and provide professional hoisting, fixing and cross-border transportation solutions to ensure safe and deformation-free delivery.
Q14: What is the export packaging standard for 11kV dry-type transformers? Is it suitable for long ocean transit?
A14: Different from oil-immersed transformers, dry-type units have no oil leakage risk and feature safer and simpler packaging. Medium and small-capacity transformers adopt integral curing protection plus customized IPPC fumigated wooden cases. For long ocean shipping, extra moisture-proof film, shockproof foam and steel belt fixation are applied, equipped with impact recorders to monitor vibration, tilt and collision data, fully adapting to sea, railway and cross-border road transportation.

4. Production & FAT Acceptance

Q15: What is the production lead time? How to guarantee on-time delivery?
A15: The standard lead time is 15–20 working days for conventional models. Customized units or transformers for harsh environments require 25–40 working days. The exact delivery schedule is confirmed in the contract. We regularly update production, quality inspection and stocking progress, and adopt standardized production management and risk control mechanisms to ensure on-time delivery as contracted.
Q16: Can clients or third-party organizations witness factory FAT tests?
A16: On-site client inspection and FAT witnessing are fully supported. We also accept on-site supervision, sampling and acceptance by internationally authoritative third-party institutions such as SGS and BV. We arrange test schedules in advance and provide complete production records, material certificates and test plans for transparent and verifiable acceptance.
Q17: Are core components traceable? Are key production processes outsourced?
A17: All core components including iron cores, windings, insulation materials, temperature control systems and cooling fans have unique batch traceability codes and complete qualification certificates. Key processes such as core stacking, winding, insulation casting, curing drying and overall debugging are 100% self-produced without outsourcing, ensuring stable and consistent product quality.

5. Quotation, Payment & Customs Clearance

Q18: How long is the quotation valid? Will raw material price fluctuations affect the quotation?
A18: Standard quotations are fixed and valid for 15 days, unaffected by fluctuations in copper, aluminum and silicon steel prices. For large-scale and long-term cooperative projects, the validity period can be extended up to 180 days. Expired quotations will be renewed according to current raw material and production costs.
Q19: What payment terms are accepted? Is L/C acceptable?
A19: We accept TT (Telegraphic Transfer) and irrevocable sight L/C. Advance payment ratio and commercial terms can be negotiated flexibly according to project scale and order volume. All business terms are clearly specified in the formal sales contract to protect both parties’ interests.
Q20: Can you provide certificates of origin for preferential tariff clearance?
A20: We provide CO, FORM E, FORM A and other official customs documents, assisting overseas customers in tariff reduction, customs clearance and project filing to avoid clearance delays and extra tariff costs.

6. Packaging, Logistics & Insurance

Q21: What is the export packaging standard? Is it suitable for ocean freight?
A21: All export products adopt international standard packaging with comprehensive anti-rust, moisture-proof and shockproof treatment, adapting to high humidity, salt spray and bumpy ocean transportation environments. All wooden cases have IPPC fumigation marks, meeting global quarantine standards for direct customs clearance without secondary treatment.
Q22: What logistics options are available?
A22: We provide diversified logistics solutions: ocean freight for global general delivery, bulk carrier for oversized equipment, China-Europe railway for Eurasian inland projects, and cross-border truck transport for neighboring countries. We select the most efficient and cost-effective solution based on project location, equipment size and delivery schedule.
Q23: What is the cargo damage claim procedure?
A23: All export cargoes are fully insured covering sea, railway and road transportation risks. In case of cargo damage upon arrival, clients shall collect on-site evidence and submit an insurance application within 48 hours. We provide full supporting documents for loss assessment and claim settlement. The final result is subject to the insurance policy and third-party evaluation.

7. SAT & Commissioning Service

Q24: Do you provide overseas on-site installation and commissioning services?
A24: We provide global on-site technical services, including professional dry-type transformer installation guidance, on-site commissioning, testing and SAT acceptance with independent quotation. 24/7 free remote technical support is always available to solve installation, operation and grid connection problems in real time.

8. Warranty & After-sales Service

Q25: What is the warranty period and coverage?
A25: The standard warranty period is 1 year. For grid, EPC and key new energy projects, the warranty can be extended to 2–5 years. The warranty covers manufacturing defects and original accessory faults caused by factory production problems. Damage caused by improper operation, overload, external impact, unauthorized modification and natural aging is excluded.
Q26: Do you supply spare parts after warranty expiration?
A26: We provide lifetime original spare parts supply service for core wearing components such as temperature controllers, cooling fans, insulators and terminal blocks, ensuring long-term stable equipment operation throughout the product lifecycle.
Q27: What is the technical support response time? How do you handle critical failures?
A27: 24/7 online technical support is available for troubleshooting, with immediate response for routine problems. On-site service can be arranged within 7–15 working days upon negotiation. For critical faults such as equipment shutdown and grid connection failure, we activate an emergency response mechanism to minimize project losses.
Q28: What is your factory quality control system?
A28: We implement a full-process ISO quality management system, including incoming material inspection, in-process patrol inspection, semi-finished product verification and full-item finished product testing. Every 11kV dry-type transformer undergoes 100% full testing before delivery. Third-party inspection and factory audits by BV, SGS and other authoritative organizations are fully supported.

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