• Product advantages
• Product parameters
• Ordering instructions

Product advantages

---

Key Advantages of our 20kV 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 20kV 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 20kV 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 20kV 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 20kV 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 20kV three-phase oil-immersed power distribution transformer.

High-Efficiency Iron Core & Coils

• Premium Silicon Steel Core: The iron core of our 20kV 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). Precision cutting and stacking processes drastically cut no-load current and operational acoustic noise, enabling energy-saving performance that can meet the European 2015/2014/548/EC ecodesign Tier 2 energy efficiency regulations.

• 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 20kV 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 20kV three-phase oil-immersed power distribution transformer.

Why Choose Hengfengshuai 20kV 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 20kV 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 20kV three-phase oil-immersed power distribution transformer is your ultimate eco-friendly, energy-saving, and cost-effective turnkey high-voltage power solution.


20kV Three-Phase Oil-Immersed Power Distribution Transformer Case




20kV Three-Phase Oil-Immersed Power Distribution Transformer FAQ

1. Standards & Certification

Q1: What international standards do your 20kV oil-immersed transformers comply with? Can they meet local grid standards for 20kV power systems?
A1: All our 20kV oil-immersed transformers are fully designed, tested and manufactured in strict accordance with IEC 60076 series international core standards for medium-voltage power transformers. We support customized compliance with regional 20kV grid standards covering EN (European), GOST (Russia & CIS), ANSI/IEEE (North America), AS/NZS (Australia & New Zealand), INMETRO (Brazil), SABS (South Africa), KEBS (Kenya) and SASO (Saudi Arabia). We will complete professional standard compliance evaluation and provide full valid certification documents according to the project country and owner’s 20kV grid specifications before order confirmation.
Q2: Can you provide type test reports and third-party witnessed test reports for 20kV transformers? Is WTT available for 20kV projects?
A2: Complete official type test reports certified by authoritative CNAS, UL and KEMA laboratories are available for all standard 20kV oil-immersed transformer models. For high-standard 20kV main grid and key overseas EPC projects, factory witnessed tests (WTT) covering 20kV-level temperature rise, sudden short-circuit, lightning impulse and dielectric strength tests can be arranged in advance to meet grid acceptance requirements.
Q3: Are all technical documents of 20kV oil-immersed transformers provided in English? Can you offer multi-language technical files?
A3: Standard delivery includes a full set of English technical document packages for 20kV oil-immersed transformers, including nameplate data drawings, general assembly drawings, FAT factory test reports, operation & maintenance manuals and spare parts lists. French, Spanish, Portuguese, Arabic and Russian versions of 20kV transformer technical documents can be customized on request for different regional projects.

2. Technical Performance & Customization

Q4: Do your 20kV oil-immersed transformers adopt copper or aluminum windings? Can you provide written material commitment?
A4: Both pure copper winding and aluminum winding solutions are optional for all 20kV oil-immersed transformers. The winding material specification can be clearly defined in the technical agreement and formal contract. We can provide supporting material inspection certificates to guarantee the consistency of transformer winding materials.
Q5: Can 20kV transformer loss, impedance, temperature rise and insulation parameters fully follow our technical datasheet? How to handle unqualified test data?
A5: All core electrical parameters of 20kV oil-immersed transformers, including no-load loss, load loss, short-circuit impedance, temperature rise and insulation level, can be fully customized according to clients’ 20kV grid technical specifications. All products undergo strict pre-delivery testing and verification. Any 20kV oil-immersed transformer that fails FAT parameter testing will be prohibited from delivery to ensure 100% compliance with contract technical indicators.
Q6: Can your 20kV oil-immersed transformers adapt to harsh working conditions such as high altitude, high temperature, salt spray and seismic areas?
A6: We provide professional harsh environment customized design for 20kV oil-immersed transformers, including high-altitude temperature rise compensation design, tropical high-temperature heat dissipation optimization, coastal high-grade salt spray anti-corrosion treatment (up to C5M grade) and seismic reinforcement structure. We will tailor the exclusive 20kV transformer solution according to the project’s actual ambient temperature, altitude, salt spray grade and seismic intensity.
Q7: Are your 20kV oil-immersed transformers suitable for photovoltaic and wind power harmonic load? Do you have anti-harmonic optimization design?
A7: We specially customize anti-harmonic 20kV oil-immersed transformers for new energy grid-connected projects. By optimizing internal magnetic flux structure and increasing temperature rise margin, the transformers can stably adapt to complex harmonic working conditions of 20kV photovoltaic and wind power grid-connected systems, effectively avoiding overheating and abnormal loss caused by harmonic interference.
Q8: What is the noise level of your 20kV oil-immersed transformers? Can it meet residential and municipal low-noise acceptance standards?
A8: The noise test of all 20kV oil-immersed transformers strictly complies with IEC international standards. For municipal and residential supporting 20kV power projects, we can carry out professional low-noise optimized design. Official noise test curves and reports can be provided to meet local project acceptance standards.
Q9: Can the lightning impulse and short-circuit resistance of 20kV oil-immersed transformers meet international grid operation requirements?
A9: All 20kV oil-immersed transformers are designed with standard lightning impulse withstand level matching 20kV medium-voltage grid standards. Products for main grid projects are equipped with enhanced sudden short-circuit resistance design, and complete short-circuit type test reports can be provided for project review and acceptance.
Q10: What is the design service life of 20kV oil-immersed transformers? Does it follow the 6℃ insulation aging rule?
A10: The standard design service life of 20kV oil-immersed transformers is 20 years for distribution type and 30 years for main power type. Under standardized operation and stable load conditions, the actual service life can reach 25-30 years (distribution) and 35-50 years (main transformer). All our 20kV oil-immersed transformers strictly follow the oil-paper insulation 6℃ aging law.

3. Customization, Dimension & Transportation

Q11: Do you support non-standard customization for 20kV oil-immersed transformers? Can we specify dimensions, tapping positions and accessory brands?
A11: Full non-standard customization is available for all 20kV oil-immersed transformers. We can adjust external dimensions, tapping range, voltage matching and functional configurations according to project requirements. Core accessories such as on-load tap changers, high-voltage bushings, temperature controllers, gas relays and pressure relief valves can be configured with client-specified brands for 20kV project customization.
Q12: Can you provide accurate weight and dimension data of 20kV transformers? Can the equipment adapt to international transportation and on-site hoisting?
A12: Detailed net weight, gross weight and overall dimension data of20kV oil-immersed transformers will be provided together with the official quotation. For large-capacity 20kV main transformers, we will evaluate hoisting load, road limit and container adaptability in advance, and provide professional over-limit transportation solutions for global 20kV power projects.
Q13: What is your standard oil filling and protection method for shipped 20kV oil-immersed transformers?
A13: Small and medium-capacity 20kV oil-immersed distribution transformers adopt full oil filling for conventional transportation. For large-capacity 20kV main transformers and long-distance ocean transportation, we adopt oil-discharged nitrogen-filled protection technology to avoid winding damage caused by transportation vibration and impact. Impact recorders are equipped to monitor the whole transportation process of 20kV transformer equipment.

4. Production & FAT Acceptance

Q14: What is the production lead time for 20kV oil-immersed transformers? Can you guarantee on-time delivery?
A14: The production cycle of 20kV oil-immersed transformers is determined according to product capacity, voltage level and customization complexity, and clearly specified in the formal contract. We will actively issue early warnings for potential delivery risks and undertake corresponding liabilities in strict accordance with contract terms for all 20kV transformer orders.
Q15: Can clients or third-party institutions conduct factory supervision and FAT witnessed tests for 20kV transformers?
A15: We fully support customer and third-party (SGS/BV) factory supervision and FAT test witnessing for all 20kV oil-immersed transformers. We will coordinate production schedules and test procedures in advance to fully meet the inspection and acceptance requirements of global 20kV power projects.
Q16: Are core production processes of 20kV transformers self-produced? Are raw materials traceable?
A16: The core components (iron core, winding, fuel tank) of 20kV oil-immersed transformers are independently produced and strictly controlled in our factory. No outsourcing for core production processes. All key raw materials of each 20kV transformer are traceable with complete batch inspection documents to ensure stable product quality.

5. Business & Payment Terms

Q17: How long is the quotation validity for 20kV oil-immersed transformers? Will prices be adjusted due to raw material fluctuations?
A17: The standard quotation for 20kV oil-immersed transformers is valid for 15 days with fixed prices within the validity period. For bulk 20kV transformer project orders, the quotation validity can be extended to 90 days (maximum 180 days) through negotiation.
Q18: What payment terms do you accept for 20kV transformer orders? Is L/C payment supported?
A18: We support flexible international payment terms for 20kV oil-immersed transformer orders, including TT telegraphic transfer and irrevocable sight L/C. The advance payment ratio can be flexibly negotiated according to project scale and contract amount.
Q19: Can you provide certificate of origin for 20kV transformers to help clients enjoy tariff preferences?
A19: We can provide CO certificate of origin, FORM E and other free trade agreement certification documents for exported 20kV oil-immersed transformers, helping global clients obtain corresponding tariff reduction and exemption benefits.

6. Packaging, Logistics & Insurance

Q20: What is the export packaging standard for 20kV oil-immersed transformers? Does it meet international port quarantine requirements?
A20: All exported 20kV oil-immersed transformers adopt professional anti-rust, moisture-proof and shock-proof export packaging. Wooden packages are equipped with standard IPPC fumigation marks, fully complying with international port quarantine and long-distance ocean transportation standards.
Q21: What logistics solutions are available for overseas 20kV transformer projects?
A21: We provide diversified global logistics solutions for 20kV oil-immersed transformers, including sea freight, bulk carrier, China-Europe railway and truck transportation. Sea freight is applicable to most international projects; bulk carrier is for oversized and overweight 20kV large-capacity transformers; railway and truck transportation serve Central Asia and inland European 20kV power projects.
Q22: What is the cargo damage claim process for 20kV transformers during transportation?
A22: Clients shall collect on-site evidence and file an insurance claim within 48 hours after the arrival of20kV oil-immersed transformer equipment. We will provide complete shipping documents to assist insurance assessment and claim settlement. The final liability determination is subject to the insurance policy, shipping remarks and official public assessment report.

7. On-site Service & SAT Acceptance

Q23: Can you provide overseas on-site installation, commissioning and SAT acceptance services for 20kV transformers?
A23: We provide global one-stop technical services for 20kV oil-immersed transformer projects, including on-site installation guidance, equipment commissioning and SAT on-site acceptance. Service fees, travel expenses and response cycles can be quoted separately. Free remote online technical support is available for all 20kV transformer users worldwide.

8. Warranty, After-sales & Quality Control

Q24: What is the warranty period for 20kV oil-immersed transformers? What does the warranty cover?
A24: The standard warranty period for all20kV oil-immersed transformers is 1 year, which can be upgraded to 2-5 years according to project requirements. The warranty takes effect 7 working days after the client’s equipment receipt and acceptance. The warranty covers manufacturing quality defects of 20kV transformers, excluding on-site improper operation, overload operation and external force damage.
Q25: Can you supply original factory spare parts for 20kV transformers after the warranty period?
A25: We promise lifelong supply of original factory spare parts for all sold 20kV oil-immersed transformers. We can provide spare parts quotation and delivery cycle at any time to ensure long-term stable operation of 20kV power equipment.
Q26: What is your after-sales technical response speed for 20kV transformer faults?
A26: We provide 24-hour global online technical support for all 20kV oil-immersed transformer users. For on-site emergency maintenance demands, we will arrange professional engineers to arrive at the site within 7-15 working days after receiving the client’s written notice (negotiable according to regional conditions). Emergency response procedures will be activated for critical faults threatening equipment and personal safety.
Q27: How do you control the quality of 20kV oil-immersed transformers?
A27: We implement strict ISO full quality management system and SQA supplier quality control for all 20kV oil-immersed transformer production processes. All production and testing procedures follow standardized specifications. Our factory has passed on-site audits and inspections by authoritative third-party institutions such as BV and SGS for many times, ensuring stable and reliable quality of every 20kV transformer.

9. Factory Strength Advantage

Q28: Are you a professional manufacturer of 20kV oil-immersed transformers?
A28: Yes. We are a professional factory focusing on R&D, design and production of 20kV oil-immersed power transformers with nearly 30 years of manufacturing experience. Located in Qingdao, China, our factory has mature 20kV transformer production technology, a professional senior engineering team and complete production and testing equipment. Global clients are warmly welcome to visit our factory and audit 20kV transformer production lines.

Product parameters

---

 - Input voltage: 20kV 22kv

   - Output voltage: 0.4/0.415kv
   - Capacity: 50kva-5000 kva

   - Frequency: 50/60hz
   - Remark: voltage, capacity, frequency, connection group and loss can be customized according to customer requirements

 

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