• Product advantages
• Product parameters
• Ordering instructions

Product advantages

---

Key Advantages of our 11kV Three-Phase Oil-Immersed Power Distribution Transformer

• Leading-Edge Winding Technology: Engineered with advanced high-voltage copper tape winding and low-voltage copper foil winding, this 11kV three-phase oil-immersed power distribution transformer delivers unmatched lightning impulse resistance and features premium Class-A insulation materials.

• Superior Mechanical Strength: Designed with low magnetic leakage and exceptional short-circuit withstand capability, our 11kV three-phase oil-immersed power distribution transformer ensures ultimate grid stability.

• Advanced Step-Lap Core Structure: Utilizing a 45° full-oblique joint step-laminated core structure, this 11kV three-phase oil-immersed power distribution transformer significantly lowers operational noise and no-load losses.

Precision-Engineered Tank & Enclosure

• State-of-the-Art CNC Fabrication: The tank of the 11kV three-phase oil-immersed power distribution transformer is processed using top-tier Mitsubishi laser cutting machines and advanced CNC punching and bending equipment to guarantee flawless dimensional accuracy.

• Robot Automatic Welding & Zero-Leakage: Featuring ABB robotic automatic welding and high-precision laser detection, the enclosure eliminates any risk of oil leakage, boasting an extraordinary quality qualification rate of 99.99998%.

• 50-Year Ultra-Durable Coating: Treated with premium electrostatic powder spraying, the anti-corrosion coating system offers exceptional hardness ($\ge 0.4$) and salt spray resistance within 100h, promising up to 50 years of paint durability.

• Fully Sealed & Maintenance-Free: The fully sealed structure protects the cooling medium from aging, offering a maintenance-free service life exceeding 30 years for the 11kV three-phase oil-immersed power distribution transformer.

High-Efficiency Iron Core & Coils

• Premium Silicon Steel Core: The iron core of our 11kV three-phase oil-immersed power distribution transformer is built from high-quality, cold-rolled grain-oriented (CRGO) silicon steel sheets with mineral oxide insulation (sourced from industry giants like Baosteel and Wisco). By controlling precision cutting and stacking, we minimize no-load current and acoustic noise.

• Patented Winding Innovation: While the low-voltage coils utilize high-grade copper foil for excellent insulation resistance, the high-voltage windings leverage Hengfengshuai Electric’s patented technology using insulated copper wire, providing supreme resistance to radial stresses caused by short circuits.

• Structural Reinforcement: The entire core and coil assembly is specially reinforced to withstand rigorous vibrations during transportation and normal grid operations.

Top-Tier Raw Materials & Components

To ensure the premium quality of each 11kV three-phase oil-immersed power distribution transformer, we only source from world-class suppliers:

• Core Sheets: Baosteel & Wisco high-permeability CRGO silicon steel.

• Conductors: Premium-grade Chinese anaerobic (oxygen-free) copper.

• Insulating Oil: CNPC (PetroChina Kunlun Petroleum) High-Quality 25# Transformer Oil.

Technical Configurations & Safety Standard

• Tinned Copper Connections: Equipped with high-conductivity tinned copper bars for low-voltage outgoing terminals, and robust ring tinned bolts for high-voltage outlet terminals.

• Flexible Tap Changer Options: Standard configuration features a 5-step or 7-step Off-Circuit Tap Changer (NLTC), with On-Load Tap Changer (OLTC) available for customization.

• Advanced Gas Relay Protection: For units rated above 630 kVA, high-sensitivity gas relays are installed as standard to ensure real-time safety monitoring for the 33kV three-phase oil-immersed power distribution transformer.

Why Choose Hengfengshuai 11kV Three-Phase Oil-Immersed Power Distribution Transformer?

As the core power hub for modern green grids and low-carbon industrial projects, choosing Hengfengshuai means choosing a higher grid return on investment (ROI) and significantly reduced operational risks.

Thanks to Hengfengyou Electric's proprietary "Ultra-Low Loss Energy-Saving Power Transformer" patented technology, every Hengfengshuai 11kV three-phase oil-immersed power distribution transformer achieves a 5% saving in raw materials. Compared to standard market alternatives, its comprehensive operational losses are reduced by 10% to 20%.

Whether for urban grid upgrades, large industrial parks, renewable energy plants like wind and solar, or long-distance international transport projects, the Hengfengshuai 11kV three-phase oil-immersed power distribution transformer is your ultimate eco-friendly, energy-saving, and cost-effective turnkey high-voltage power solution.


11kV Three-Phase Oil-Immersed Power Distribution Transformer Case


11kV Three-Phase Oil-Immersed Power Distribution Transformer FAQ

1. Standard & Certification

Q1: What international standards do your 11kV transformers comply with? Can they meet local grid connection requirements?
A1: Our 11kV transformers are designed and tested in accordance with IEC 60076 series standards. We can also adapt designs to GB, EN, GOST, ANSI/IEEE, AS/NZS, INMETRO, SABS, KEBS and SASO. Submit your project country and grid owner specifications, we will carry out standard compliance assessment and provide relevant certification documents.
Q2: Can you provide type test reports and third-party witnessed test reports? Is witnessed factory test available?
A2: Full CNAS-accredited type test reports are available, covering temperature rise, loss measurement, impedance, lightning impulse and short-circuit tests. Factory Witnessed Test (WTT) can be scheduled in advance for grid and major EPC projects.
Q3: Can you supply English technical documentation? Do you support multi-language manuals?
A3: Standard package includes English nameplate, general arrangement drawing, wiring diagram, FAT report, operation & maintenance manual and spare parts list. Spanish, Portuguese, Arabic, French and Russian manuals can be customized on request.

2. Technical Performance

Q4: Copper or aluminium windings? Can you issue material guarantee in contract?
A4: Anaerobic copper or aluminium windings are optional per project demand. Winding material can be clearly defined in technical agreement and contract, supported by material test certificates and production traceability records. The 11kV HV insulation system ensures stable long-term running.
Q5: Can all electrical parameters be customized? How to handle non-conforming test results?
A5: Key parameters including no-load loss, load loss, short-circuit impedance, tap range and temperature rise can be customized to client datasheet. Every unit passes full factory testing. Non-compliant transformers will not be shipped and will be reworked or replaced free of charge.
Q6: Can 11kV transformers operate in high altitude, coastal salt spray, humid or seismic zones?
A6: Special environmental design is available. We provide insulation upgrade for high altitude, C5M anti-corrosion coating for coastal salt mist, sealed moisture-proof structure and mechanical reinforcement for seismic areas. All design modifications are based on your site conditions.
Q7: Are these transformers suitable for solar and wind farm grid-tie? What about harmonic resistance?
A7: Harmonic-resistant 11kV transformers are offered for renewable energy projects. Optimized core and winding design suppress harmonic heating and voltage distortion to handle intermittent and fluctuating PV & wind loads.
Q8: What is the standard noise level? Can low-noise version be supplied for residential districts?
A8: Standard noise ≤58dB under IEC test conditions. Low-noise design (≤50dB) is optional for residential, municipal and commercial areas, adopting vibration damping and silent structural optimization. Noise test certificates can be provided.
Q9: Can the transformer resist lightning impulse and sudden short-circuit faults?
A9: 11kV transformers adopt standard lightning impulse insulation design to withstand lightning and switching overvoltage. Reinforced anti-short-circuit construction improves fault withstand capability to meet global grid operation requirements. Short-circuit test reports available upon request.
Q10: What is the design service life? Does insulation follow the 6℃ ageing rule?
A10: Design service life is 20 years. With proper maintenance, service life can reach 25–30 years. Oil-paper insulation strictly follows 6℃ ageing principle, and sufficient temperature margin slows down insulation degradation.
Q11: Are you a genuine 11kV transformer manufacturer?
A11: We are a professional transformer manufacturer located in Qingdao, China, with decades of production and export experience. Core processes are completed in-house. We supply power transformers to global grid, industrial and EPC customers. Factory audit is welcome.

3. Customization, Dimension & Transportation

Q12: Can you make non-standard 11kV transformers?
A12: Full non-standard customization is supported, including electrical parameters, tap changer range, overall dimensions, mounting type and special environmental adaptation. Key accessories can be fitted with customer-specified international brands. All custom requirements will be documented in technical agreement.
Q13: Can you provide weight and dimension drawings? Is the transformer suitable for cross-border shipment?
A13: Exact weight and dimension data will be delivered together with formal quotation. For large capacity units, we assess oversize risk in advance and provide hoisting & cross-border transport solution for safe delivery.
Q14: What transport packing mode for 11kV transformers?
A14: Medium & small capacity transformers can be shipped fully oil-sealed for quick site commissioning. For long ocean transit, oil drained + nitrogen-filled protection with impact recorder can be adopted to protect windings and insulation.

4. Production & FAT Acceptance

Q15: What is production lead time? How to guarantee on-time delivery?
A15: Standard lead time 15–25 working days; customized or harsh-environment units need 25–40 working days. Exact schedule confirmed in contract. We update production progress regularly and manage delivery risk with contractual commitment.
Q16: Can client or third party witness factory FAT?
A16: Client on-site inspection and FAT witnessing by third parties such as SGS, BV are accepted. We arrange schedule and provide full production and test records for transparent inspection.
Q17: Are core components traceable? Are key processes outsourced?
A17: All core components have batch traceability and full certificates. Critical manufacturing processes are self-produced without outsourcing to secure consistent quality.

5. Quotation, Payment & Customs Clearance

Q18: How long quotation remains valid? Will price change with raw material cost?
A18: Standard quotation validity is 15 days with fixed price. Validity can be extended up to 180 days for large projects. Quotation will be reissued after expiry.
Q19: What payment terms do you accept? Is L/C acceptable?
A19: TT and irrevocable sight L/C are acceptable. Advance payment ratio and commercial terms can be negotiated based on project scale, all terms written in formal contract.
Q20: Can you issue certificate of origin for preferential tariff?
A20: We provide CO, FORM E, FORM A and other customs documents to help customers apply for tariff reduction and smooth customs clearance.

6. Packaging, Logistics & Insurance

Q21: What export packing standard? Suitable for sea freight?
A21: Export package adopts anti-rust, moisture-proof and shockproof treatment for long ocean voyage. Wooden cases carry IPPC fumigation mark to meet international quarantine rules.
Q22: What logistics options are available?
A22: Multiple logistics plans: sea freight for global delivery, bulk carrier for oversize equipment, China-Europe railway for Eurasian inland projects, truck transport for neighbouring countries.
Q23: What is cargo damage claim procedure?
A23: Cargo will be fully insured. Client needs to collect site evidence and submit insurance application within 48 hours after arrival. We provide full document support for claim settlement, subject to insurance policy and third-party assessment.

7. SAT & Commissioning Service

Q24: Do you offer overseas on-site installation and commissioning?
A24: We offer global on-site technical service including installation guidance, commissioning, testing and SAT acceptance with separate quotation. Free 24/7 remote technical support is always available.

8. Warranty & After-sales Service

Q25: What is warranty period and coverage?
A25: Standard warranty is 1 year, extendable to 2–5 years for grid and EPC projects. Warranty covers manufacturing defects and original accessory faults, excluding improper operation, overload, external damage and unauthorized modification.
Q26: Can you supply spare parts after warranty expires?
A26: Lifetime supply of original spare parts for core wearing components, guaranteeing long-term stable equipment operation.
Q27: What is response time for technical support?
A27: 24/7 online technical support for troubleshooting. On-site service can be arranged within 7–15 working days upon negotiation. Emergency response will be activated for critical failures to reduce project loss.
Q28: How do you manage factory quality control?
A28: We implement ISO full-process quality control system. Every 11kV transformer passes full test items before delivery. Third-party inspection and factory audit by BV, SGS and other organizations are supported.

Product parameters

---

 - Input voltage: 11kV
  - Output voltage: 0.4kV 0.415 kv 0.420kv 0.430kv 0.440kv
  - Capacity: 25-2500 kva（Up to 10MVA）
  - Frequency: 50/60 HZ
  - Remark: voltage, capacity, frequency, connection group and loss can be customized according to customer requirements

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
60 kva							150	1090/1040	1.2	4
75 kva							180	1310/1250	1.2	4
100 kva							200	1580/1500	1.1	4
125 kva							240	1890/1800	1.1	4
150 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
600 kva							810	6200	0.6	4.5
750 kva							980	7500	0.6	4.5
1000 kva							1150	10300	0.6	4.5
1250 kva							1360	12000	0.5	4.5
1500 kva							1640	14500	0.5	4.5
2000 kva							1940	18300	0.4	5
2500 kva							2290	21200	0.4	5

Ordering instructions

---

 - 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