• Product advantages
• Product parameters
• Ordering instructions

Product advantages

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6.6kV Three-phase Power Distribution Transformer Overview

This 6.6kV three-phase distribution transformer is a high-efficiency, low-loss power distribution equipment specially developed and customized for medium-voltage power grid systems and industrial power supply systems with 6.6kV voltage level. Adopting high-quality oriented silicon steel sheets and high-purity anaerobic copper windings as core raw materials, the transformer boasts excellent structural stability and electrical performance. It features low operating noise, extremely low no-load and load loss, as well as outstanding overload resistance and operational reliability.
The product supports two mainstream structural types: oil-immersed and dry-type, with a complete capacity range covering 50kVA to 25000kVA. Voltage ratios, dimensional parameters and technical specifications can be fully customized according to customer demands, perfectly adapting to diverse application scenarios including industrial factory power supply, urban and rural power grid distribution, commercial complex power supply and residential community power distribution projects.

6.6kV Three-phase Power Distribution Transformer Certification & Compliance Standards

International Standards: Fully compliant with IEC 60076 international power transformer core standards
Overseas Market Certifications: Equipped with CE, CB, EAC, KEMA and other authoritative overseas certifications, supporting smooth access to global mainstream markets

6.6kV Three-phase Power Distribution Transformer Exported Countries & Regions

The typical exported countries and regions include Vietnam, Indonesia, Laos, Pakistan, Uzbekistan, Kazakhstan, Kyrgyzstan, Mongolia and many other countries. We have accumulated rich experience in overseas project customization, delivery, installation and after-sales service, capable of providing one-stop professional power distribution equipment solutions for global customers.


6.6kV Three-phase Power Distribution Transformer Case


6.6kV Three-phase Power Distribution Transformer FAQ
1. Standard & Grid Certification

Q1: Which international standards govern your 6.6kV oil-immersed transformers? Can they comply with overseas industrial grid codes?
A1: Our 6.6kV oil-immersed distribution transformers are fully designed, type-tested and certified per IEC 60076 series and IEC 60076-11 liquid-immersed transformer safety standards, specially tailored for 6.6kV medium-voltage industrial grid systems. Besides universal international standards, we support full compliance with regional mandatory standards including GB, EN 60076, GOST 11920, ANSI C57, AS/NZS 60076, INMETRO, SABS and SASO. Unlike conventional 6kV low-voltage distribution equipment, 6.6kV transformers are applied to formal industrial medium-voltage grids with strict grid access rules. We can provide standard matching reports, grid conformity certificates and third-party authentication documents according to the grid specifications of the project country to meet official grid connection filing requirements.
Q2: Are official type test reports and third-party witnessed test certificates available? Is factory witness testing mandatory for grid projects?
A2: We provide full set of CNAS accredited official type test reports exclusive for 6.6kV voltage level, covering medium-voltage professional test items: partial discharge detection, power frequency withstand, lightning impulse, short-circuit dynamic stability, load loss and temperature rise limit test. For overseas medium-voltage grid renovation, mining power distribution and large industrial park projects that require mandatory witnessing, we support exclusiveFactory Witnessed Test (WTT). On-site supervision and testing by SGS, BV, TUV and other international third-party institutions are fully acceptable, with independent witnessed test reports issued for project approval and grid filing.
Q3: Can you provide standardized English technical documents? Are multi-language official certificates available for customs and grid filing?
A3: The standard delivery package includes complete English formal documents: voltage-level exclusive nameplate, general arrangement drawing, installation dimension drawing, internal wiring diagram, full FAT test report, official operation and maintenance manual, spare parts schedule and factory qualification certificate. For cross-border engineering projects, we support customized formal documents in Spanish, Portuguese, Arabic, French and Russian. All documents conform to local engineering filing and customs inspection standards, supporting one-stop project acceptance.

2. Core Technical Performance & Industrial Adaptability

Q4: What winding options are available for 6.6kV transformers? Can material performance be guaranteed in formal contracts?
A4: We offer two industrial-grade winding configurations: high-purity oxygen-free copper winding and high-strength aluminum alloy winding, customized based on project load rate, running years and grid stability requirements. All winding material parameters, chemical composition and mechanical performance indicators can be clearly defined in technical agreements and formal contracts, with original material factory test reports and full production process traceability records attached. Different from ordinary 6kV transformers, 6.6kV products adopt medium-voltage reinforced insulation and anti-vibration winding fixing process, which effectively resists voltage fluctuation and frequent impact load of industrial medium-voltage grids, avoiding winding displacement and partial discharge failure.
Q5: Can medium-voltage electrical parameters be customized? How to manage defective finished products?
A5: All professional medium-voltage parameters of 6.6kV transformers support personalized customization, including medium-voltage no-load loss, industrial-grade load loss, precise short-circuit impedance, multi-stage tap adjustment range and medium-voltage temperature rise protection threshold. All customized parameters strictly match customer’s medium-voltage grid design datasheet. Each transformer will pass 100% full-item medium-voltage professional factory testing before delivery. Any non-compliant equipment will be completely blocked from delivery, with free full-process rework, parameter debugging or equipment replacement, bearing all costs and ensuring zero defective products put into industrial grid operation.
Q6: Can 6.6kV transformers adapt to extreme industrial environments such as high altitude, coastal corrosion, heavy humidity, strong vibration and dust mines?
A6: We provide targeted extreme environment upgrade solutions for 6.6kV medium-voltage industrial scenarios. For high-altitude areas above 1000m, we upgrade medium-voltage insulation grade and increase air gap distance to prevent high-altitude low-pressure insulation breakdown. For coastal industrial zones, we adopt C5M marine-grade anti-corrosion coating to resist severe salt spray and chemical corrosion. For humid and rainy areas, full welding sealed oil tank and moisture-proof isolation structure are adopted. For mining and seismic industrial zones, integral mechanical reinforcement and anti-shock structure are optimized. For heavy dust industrial sites, fully enclosed dust-proof and anti-pollution design is configured. All upgrades are customized according to actual site environmental parameters.
Q7: Is the 6.6kV transformer applicable for medium-voltage grid connection of photovoltaic, wind power and industrial energy storage projects? What is its harmonic suppression capability?
A7: Our 6.6kV anti-harmonic medium-voltage transformers are specially developed for medium-voltage grid-connected scenarios of distributed photovoltaics, wind farms and industrial energy storage stations. Adopting low-loss high-permeability core and asymmetric winding structural design, it can effectively suppress high-order harmonic interference generated by inverter equipment, solve harmonic overheating and medium-voltage voltage distortion problems caused by fluctuating new energy loads. It is fully adapted to unstable power output of new energy stations and frequent switching of industrial loads, ensuring stable grid-connected operation of medium-voltage systems.
Q8: What is the standard noise level of 6.6kV equipment? Can ultra-low noise design be used for suburban industrial and residential adjacent areas?
A8: Under IEC standard test conditions, the standard operating noise of 6.6kV oil-immersed transformers is ≤56dB. For projects adjacent to residential areas, suburban industrial parks and municipal supporting facilities, we provide customized ultra-low noise version (≤45dB). Through multi-layer vibration damping system, core gap optimization and silent oil tank structural design, the operating noise is greatly reduced, meeting international environmental noise protection standards. Special noise test qualification certificates can be provided for project environmental assessment.
Q9: Does the 6.6kV transformer have medium-voltage lightning protection and short-circuit fault resistance capability?
A9: The equipment adopts professional 6.6kV medium-voltage lightning impulse insulation design, which can withstand standard lightning overvoltage and system switching overvoltage, suitable for outdoor medium-voltage industrial grid operation. The integral reinforced anti-short-circuit structure improves the equipment's ability to withstand sudden short-circuit faults of medium-voltage grids, effectively coping with industrial grid overload impact and fault surge. It fully meets international medium-voltage power grid operation standards, and professional short-circuit withstand test reports can be provided upon request.
Q10: What is the design service life of 6.6kV medium-voltage transformers? How is the insulation aging controlled?
A10: The industrial-grade design service life of 6.6kV transformers is 20 years. Benefiting from redundant medium-voltage insulation design and high-quality anti-aging oil-paper composite insulation system, the service life can reach 28–32 years under standardized daily maintenance. The equipment strictly follows the international 6℃ insulation aging rule, with sufficient temperature safety margin reserved, which effectively delays insulation aging and ensures long-term stable operation of medium-voltage equipment under continuous full-load operation.
Q11: Are you a professional manufacturer dedicated to 6.6kV medium-voltage transformers?
A11: We are a professional medium and high voltage transformer manufacturer based in Qingdao, China, with decades of R&D and manufacturing experience in 6.6kV medium-voltage industrial transformers. We have independent medium-voltage professional production lines and medium-voltage test benches. All core processes such as winding winding, insulation assembly, vacuum oil injection and medium-voltage pressure test are independently completed in the factory without outsourcing. Our products are widely exported to global industrial parks, mining enterprises and medium-voltage grid EPC projects, and factory audits and on-site inspections are warmly welcomed.

3. Non-standard Customization, Dimension & Cross-border Transportation

Q12: What non-standard customization services are supported for 6.6kV transformers?
A12: We support full-scene non-standard customization for 6.6kV medium-voltage industrial equipment, covering medium-voltage electrical parameter adjustment, on-load/off-load tap changer customization, special installation size optimization, vertical/horizontal mounting adaptation and extreme environment special upgrade. All medium-voltage core accessories (medium-voltage bushings, intelligent temperature controllers, pressure relief valves, etc.) can be equipped with customer-specified international famous brands. All customized contents are recorded in detailed technical agreements to ensure full compliance with project medium-voltage design requirements.
Q13: Can you provide accurate dimension and weight data? Is the equipment suitable for international cross-border transportation?
A13: Official quotations are attached with accurate net/gross weight, overall dimension, installation size, hoisting size and center of gravity parameters of 6.6kV transformers. Most 6.6kV medium-capacity equipment has no over-limit transportation risks. For large-capacity models, we will pre-evaluate cross-border transportation risks, provide professional hoisting schemes and cross-border logistics optimization solutions to ensure safe delivery of medium-voltage equipment.
Q14: What professional export packaging is adopted for 6.6kV transformers for long-distance overseas transportation?
A14: Standard medium and small-capacity 6.6kV transformers adopt full oil-sealed delivery for fast on-site commissioning. For transoceanic long-distance transportation and multi-transshipment projects, we adopt professional oil-drained and nitrogen-filled sealed protection, equipped with high-precision transportation impact recorders to monitor the whole transportation process. All export wooden packages have IPPC fumigation marks, with multi-layer anti-rust, moisture-proof and shockproof protection, meeting international long-distance shipping standards.

4. Production Schedule & FAT Inspection Management

Q15: What is the production cycle of 6.6kV transformers? What measures are taken to guarantee on-time delivery?
A15: The production cycle of standard 6.6kV oil-immersed transformers is 15–22 working days; for non-standard customized models and extreme environment adaptive equipment, the production cycle is 22–38 working days. The exact delivery time is locked in the formal contract. We implement phased production progress updates, arrange special personnel to track production and quality inspection progress, and restrict delivery risks through contractual clauses to ensure on-time delivery and project commissioning.
Q16: Is third-party and customer on-site FAT witnessing acceptable for 6.6kV equipment?
A16: We fully support on-site FAT witnessing and acceptance by customers and international third-party authoritative institutions including SGS, BV and TUV. We can flexibly adjust the test schedule according to customer needs, fully open the production workshop and medium-voltage test links, and provide complete production records, material certificates and medium-voltage test data to ensure transparent and traceable acceptance process.
Q17: Are core components traceable? Are key medium-voltage process outsourced?
A17: All core components of 6.6kV medium-voltage transformers have independent batch numbers, full-process traceability records and official qualification certificates. The core medium-voltage processes related to equipment safety and performance are all self-produced and self-inspected in the factory without any outsourcing, fundamentally ensuring the stability and consistency of medium-voltage equipment quality.

5. Quotation, Payment Terms & Customs Clearance Service

Q18: What is the validity period of the quotation? Will raw material price fluctuations affect the quoted price?
A18: The standard quotation for 6.6kV medium-voltage transformers is valid for 15 days with fixed price, free from raw material price fluctuations. For large-scale industrial medium-voltage grid projects and long-term cooperative orders, we can extend the quotation validity to 120–180 days. Expired quotations can be reissued free of charge according to the latest project requirements.
Q19: What payment methods are supported? Can we adopt L/C payment for medium-voltage engineering projects?
A19: We support flexible international payment methods, including TT telegraphic transfer and irrevocable sight L/C, which is applicable to large overseas EPC engineering projects. The advance payment ratio and commercial terms can be negotiated according to project scale and cooperation cycle, and all terms are clearly specified in formal foreign trade contracts to ensure standardized and compliant transactions.
Q20: Can you provide official customs documents to assist customers in tariff preference and customs clearance?
A20: We provide complete customs clearance documents such as CO certificate of origin, FORM A, FORM E and other preferential tariff certificates, which can help overseas customers successfully apply for tariff reduction and exemption, simplify customs clearance procedures and reduce import engineering costs.

6. Export Packaging, Logistics & Cargo Insurance

Q21: Does the export packaging meet international marine transportation standards?
A21: All 6.6kV medium-voltage transformers adopt exclusive foreign trade export packaging, with multi-layer anti-corrosion, moisture-proof, shockproof and anti-compression protection. The packaging wooden cases pass IPPC fumigation treatment, meeting global import quarantine and long-distance ocean transportation standards, without any customs clearance obstacles.
Q22: What diversified logistics solutions are available for overseas medium-voltage projects?
A22: We provide customized logistics solutions for different regional projects: ocean freight for global conventional projects, China-Europe railway for inland Eurasian industrial zones, cross-border truck transportation for neighboring countries, and bulk carrier transportation for large-capacity equipment. We select the most safe and cost-effective logistics scheme according to equipment parameters and project location.
Q23: What is the cargo damage insurance claim process? Will you provide full support?
A23: All exported 6.6kV equipment is covered by full-process cargo transportation insurance. After the goods arrive, customers only need to collect on-site evidence and submit an insurance application within 48 hours. We provide full set of transportation documents, factory certificates and test reports to assist third-party loss assessment and insurance claim settlement, minimizing customer economic losses.

7. On-site Installation, Commissioning & SAT Service

Q24: Do you provide overseas on-site installation guidance, commissioning and SAT acceptance services for medium-voltage equipment?
A24: We provide global one-stop technical services for 6.6kV medium-voltage transformers, including on-site installation guidance, medium-voltage power-on commissioning, system debugging, fault detection and SAT project acceptance, with independent customized service quotations. Meanwhile, we provide 24/7 free online remote technical support to solve equipment operation and commissioning problems at any time.

8. Warranty Policy & After-sales Support

Q25: What is the official warranty period and coverage of 6.6kV medium-voltage transformers?
A25: The standard warranty period is 1 year. For medium-voltage grid projects, mining industrial projects and large EPC projects, the warranty period can be extended to 3–5 years. The warranty covers all equipment manufacturing defects and original accessory quality faults. Equipment failures caused by man-made improper operation, overload operation, external force damage and unauthorized modification are not included in the warranty scope.
Q26: Can you supply original factory spare parts permanently after the warranty expires?
A26: We provide lifelong supply of original matching spare parts for 6.6kV medium-voltage transformers, including insulating accessories, sealing parts, control components and protective parts. All spare parts are completely matched with the original equipment to ensure long-term stable and safe operation of medium-voltage equipment.
Q27: What is the response speed of after-sales technical support? How to deal with medium-voltage equipment emergency faults?
A27: We provide 24/7 online real-time technical support, with immediate response to conventional operation and maintenance problems. On-site after-sales service can be arranged within 7–15 working days upon customer negotiation. For emergency faults such as medium-voltage equipment tripping and shutdown, we activate the emergency response mechanism to prioritize fault disposal and reduce project production downtime losses.
Q28: What quality control system is adopted for 6.6kV medium-voltage transformers?
A28: Our factory strictly implements ISO9001 full-process quality management system and exclusive medium-voltage equipment inspection standards. Every 6.6kV transformer passes professional medium-voltage full-item test and aging test before delivery. We fully support third-party institutions such as SGS, BV and TUV to conduct factory audits, sampling inspections and factory supervision to ensure 100% qualified delivery of equipment.

Product parameters

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  - Output voltage: 0.4kV 0.415 kv 0.420kv 0.430kv 0.440kv
  - Capacity: 30-2500 kva
  - Frequency: 50/60 HZ
  - Remark: voltage, capacity, frequency, connection group and loss can be customized according to customer requirements

S11     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）	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 kva	11 10.5 10 6.3 6	±5% ±2x2.5%		0.4 0.415 0.420 0.430 0.440	Dyn11 Yyn0		100	630/600	1.5	4
50 kva							130	910/870	1.3	4
63 kva							150	1090/1040	1.2	4
80 kva							180	1310/1250	1.2	4
100 kva							200	1580/1500	1.1	4
125 kva							240	1890/1800	1.1	4
160 kva							280	2310/2200	1	4
200 kva							340	2730/2600	1	4
250 kva							400	3200/3050	0.9	4
300 kva							480	3830/3650	0.9	4
400 kva							570	4520/4300	0.8	4
500 kva							680	5410/5150	0.8	4
630 kva							810	6200	0.6	4.5
800 kva							980	7500	0.6	4.5
1000 kva							1150	10300	0.6	4.5
1250 kva							1360	12000	0.5	4.5
1600 kva							1640	14500	0.5	4.5
2000 kva							1940	18300	0.4	5
2500 kva							2290	21200	0.4	5

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 (tap switch, color, oil pillow, etc.)
- The minimum order quantity is 1 sets, worldwide delivery within 7 days
- Normal delivery period of 30 days, worldwide fast delivery