I. Introduction: Transformer manufacturing industry – the “main battlefield” of winding wires
Transformer is the core equipment of the power system, undertaking key functions such as voltage conversion, power distribution, signal transmission, and impedance matching. From distribution transformers to UHV transformers, from power transformers to special transformers, each type of transformer is inseparable from high-performance winding wires (enameled wires, paper-covered wires, glass fiber-coated wires, etc.) as core electromagnetic components.
The transformer manufacturing industry is the largest downstream application market in the winding wire industry. The global annual consumption of various winding wires exceeds 2 million tons, covering a variety of materials such as copper, aluminum, paper, paint film, glass fiber, and insulating oil. This article will systematically review the application, selection, process and future trends of various winding wires in transformer manufacturing.
1.1 Core requirements for winding wires in transformer manufacturing
| Performance | Requirements | Reasons |
|---|---|---|
| Electrical Insulation | High BDV, flame retardant | Withstands high electric fields |
| High temperature resistance | 105-260°C | Continuous operating temperature |
| Oil Resistant | Excellent | Oil immersed environment |
| Mechanical Strength | High | Winding Tension, Short Circuit Current |
| Thermal Conductivity | Good | High power heat dissipation |
| Life | > 30 years | Long life requirements |
| Cost | Moderate | Mass production |
1.2 4 major types of transformer winding wires
| Type | Temperature level | Breakdown voltage | Applicable voltage | Main applications |
|---|---|---|---|---|
| Enameled wire | 130-220°C | 5-12 kV | < 15 kV | Universal transformer windings |
| Glass fiber covered wire | 155-260°C | 5-15 kV | < 15 kV | Dry type transformer windings |
| Paper covered wire | 105-220°C | 6-30 kV | 15-500 kV | Oil-immersed transformer winding |
| Mica/Ceramic Covered Wire | 260-1000°C | 12-30 kV | High Voltage/UHV | Special Transformer |
1.3 The core value of transformer winding wire
- ✅Determines transformer performance: Directly affects efficiency, temperature rise, and lifespan
- ✅ Determine the transformer volume: The tank full rate affects the structural design
- ✅ Determine the cost of the transformer: Winding wire accounts for 25-40% of the total cost
- ✅ Determining transformer safety: Insulation reliability is the primary requirement
II. Core types and manufacturing characteristics of transformers
2.1 8 major types of transformers
| Type | Capacity range | Voltage range | Frequency | Main applications |
|---|---|---|---|---|
| Distribution transformers | 50-2,500 kVA | < 35 kV | 50/60 Hz | Distribution networks |
| Power transformers | 2.5-1,000 MVA | 35-500 kV | 50/60 Hz | Transmission grids |
| Dry-type transformer | 50-25,000 kVA | < 35 kV | 50/60 Hz | Indoor, subway |
| Oil-immersed transformers | 50-1,000 MVA | < 500 kV | 50/60 Hz | Outdoor, substations |
| Rectifier transformers | 100-50,000 kVA | < 110 kV | 50/60 Hz | Electrolysis, electroplating |
| Electric Furnace Transformers | 1-100 MVA | < 110 kV | 50/60 Hz | Electric Arc Furnaces |
| Traction transformer | 5-100 MVA | 25 kV | 50/60 Hz | Railway, subway |
| Test transformers | 50-3,000 kVA | < 1,000 kV | 50 Hz | High voltage testing |
2.2 Key processes in transformer manufacturing
Transformer manufacturing involves 8 core processes:
- Iron core manufacturing: cutting, stacking and fastening of silicon steel sheets
- Winding manufacturing: winding, pressing, baking, dipping
- Insulation parts processing: cardboard, laminated parts, insulation cylinders
- Body assembly: winding set, insulation assembly
- Drying treatment: vacuum drying, oil immersion
- General assembly: fuel tank, casing, oil conservator
- Oil/gas injection: transformer oil, SF6 gas
- Experimental testing: routine testing, type testing, special testing
2.3 Core process of winding manufacturing
Winding manufacturing is the core link of transformers and involves 6 key processes:
| Process | Key Points |
|---|---|
| Winding | Tension control, neat arrangement, tightness |
| Compression | Constant voltage compression to avoid damage to the insulation |
| Welding | Copper strip welding, silver soldering, electron beam welding |
| Drying | Vacuum drying, temperature control |
| Impregnation | Impregnating paint penetration, drying and curing |
| Detection | Number of turns, DC resistance, insulation resistance |
III. Application of enameled wire in transformers
3.1 Core advantages of enameled wire
Enameled wire is widely used in transformers. Its core advantages are:
– High tank full rate: 75-80% (paper covered wire 60-70%)
– Automated production: suitable for large batches
– Low Cost: The cost of paint film is much lower than that of wrapping paper
– Complete specifications: Can produce 0.05-5.0 mm
– Temperature Rating: F/H/R/C Level Full Coverage
3.2 Application of enameled wire in various transformers
| Transformer type | Enameled wire selection | Temperature grade | Reasons |
|---|---|---|---|
| Distribution Transformer (Small) | PEW Grade 1-2 | Grade F | Low cost and sufficient |
| General transformer | PEI Grade 2 | Grade H | Excellent overall performance |
| Dry-type transformer | PEI / PAI Grade 2-3 | H/R grade | Flame retardant, temperature resistant |
| High Frequency Transformer | PEI Grade 2 + Litz | Grade H | High Frequency Performance |
| Switching power supply transformer | PEI / PAI Grade 1-2 | Grade H | High frequency, miniaturization |
| Rectifier transformer | PEI Grade 2-3 | Grade H | Anti-harmonic |
| Traction Transformer | PAI Grade 3 | Grade R | Vibration Resistant, Temperature Resistant |
3.3 Key parameters for enameled wire selection
Key Parameters:
– Conductor specifications: diameter / cross-sectional area
– Paint film type: PE / PEI / PAI / PI
– Paint film grade: Grade 1 / 2 / 3 / 4
– Temperature Class: F/H/R/C Class
– Breakdown voltage: 5-15 kV
– Chemical resistance: oil and refrigerant resistant
3.4 Limitations of enameled wire in transformers
- ❌ Breakdown voltage is limited by paint film thickness (< 15 kV)
- ❌ BDV decreases by 10-30% in oil immersion environment
- ❌ High-temperature scenes require advanced paint films such as PAI/PI (high cost)
- ❌ The paint film cannot be repaired after damage
IV. Application of paper covered wire in transformers
4.1 Core advantages of paper covered wire
Paper-covered wire is the core material of high-voltage transformers. Its core advantages are:
– High breakdown voltage: multiple layers of paper stacked (10-30 kV)
– OIL COMPATIBLE: perfect combination with transformer oil
– Oil Immersion Buff: BDV increased by 3-5×
– Repairable: Local damage can be repaired
– Long Life: > 30 years
4.2 Application of paper covered wire in various types of transformers
| Transformer type | Paper covered wire selection | Number of paper layers | Temperature grade |
|---|---|---|---|
| 35 kV oil-immersed transformer | Cable paper 4-6 layers | 4-6 | Class A (105°C) |
| 110 kV oil-immersed transformer | Cable paper 8-10 layers | 8-10 | Class A (105°C) |
| 220 kV oil-immersed transformer | High performance cable paper 10-12 layers | 10-12 | Class A (105°C) |
| 500 kV UHV transformer | Nomex + cable paper 12-15 layers | 12-15 | Class A/E (105-120°C) |
| Dry-type transformer (small) | Mylar composite paper 2-4 layers | 2-4 | Class E/B (120-130°C) |
| Dry-type transformers (high temperature) | Nomex 410 4-6 layers | 4-6 | Class H (180°C) |
| Oil-immersed reactor | Cable paper 6-8 layers | 6-8 | Class A (105°C) |
| Sleeving | Cable paper 10-15 ply | 10-15 | Class A (105°C) |
4.3 Oil-paper insulation combination for oil-immersed transformer
The insulation of oil-immersed transformers is composite insulation of oil + paper, which is the “golden combination” of transformers.
| Insulating materials | Dry dielectric strength | Oil immersion dielectric strength | Oil immersion gain |
|---|---|---|---|
| Transformer oil | – | 10-15 kV/mm | – |
| Cable paper | 10-15 kV/mm | 30-50 kV/mm | 3-5× |
| Nomex 410 | 18-25 kV/mm | 30-45 kV/mm | 1.5-2× |
| PET film | 100-150 kV/mm | 80-130 kV/mm | 0.8× |
| PI film | 150-200 kV/mm | 130-180 kV/mm | 0.9× |
4.4 Typical design of 35 kV oil-immersed transformer windings
5,000 kVA 35 kV Oil-immersed Distribution Transformer:
– High voltage winding (35 kV): 6-layer cable paper covering, copper wire
– Low voltage winding (400 V): Enameled wire Class H Grade 2, copper wire
– Voltage regulating winding: 4 layers of cable paper covering
– Phase insulation: cardboard + corrugated cardboard
– Insulation class: Class A (105°C)
– Oil immersion medium: 25# transformer oil
– Design life: 30 years
4.5 Typical design of 110 kV oil-immersed transformer windings
50 MVA 110 kV oil-immersed power transformer:
– High voltage winding (110 kV): 8-10 layers of cable paper + electrostatic screen
– Medium voltage winding (35 kV): 6 layers of cable paper covering
– Low voltage winding (10 kV): 4 layers of cable paper covering
– Voltage regulating winding: 4-6 layers of cable paper
– Insulation class: Class A (105°C)
– Oil immersion medium: 25# transformer oil
– Design life: 40 years
V. Application of glass fiber covered wires in dry-type transformers
5.1 Core characteristics of dry-type transformers
Dry-type transformers compared with oil-immersed transformers:
– ✅ Oil-free, fire-proof and explosion-proof
– ✅Easy to install and maintain
– ✅ Suitable for indoor, subway and airport use
– ❌ Difference in heat dissipation (air vs oil)
– ❌ Small capacity (generally < 25,000 kVA)
5.2 Advantages of glass fiber covered wires in dry-type transformers
- ✅ Flame retardant (naturally flame retardant)
- ✅ High temperature resistance (H grade from 180°C)
- ✅ High mechanical strength
- ✅ Resistant to short circuit current
- ✅ Long lifespan (> 25 years)
5.3 Glass fiber covered wire selection
| Dry-type transformer | Recommended wire | Temperature grade |
|---|---|---|
| < 500 kVA Small | Enameled Wire Class F/H | Class F/H |
| 500-2,500 kVA Medium | Single/Double Glass Fiber Clad Class H | Class H |
| 2,500-10,000 kVA Large | Double Glass Fiber Clad Class H | Class H |
| 10,000-25,000 kVA Extra Large | Triple Glass Fiber Clad Rated R | Rated R |
| SCB Dry Type Transformer | Double-layer fiberglass + resin casting | Class H |
5.4 SCB Dry Type Transformer
SCB (epoxy resin cast dry-type transformer) is the mainstream of dry-type transformers:
– Winding: Double layer fiberglass covered wire
– Pouring: Epoxy resin vacuum casting
– Flame retardant grade: F1 grade (non-self-igniting)
– Temperature resistance: Class H (180°C)
-Application: subway, airport, high-rise building
5.5 Comparison between dry-type transformer and oil-immersed transformer
| Dimension | Dry-type transformer | Oil-immersed transformer |
|---|---|---|
| Insulating medium | Air + solid insulation | Transformer oil + paper |
| Flame retardancy | Excellent | Poor (oil is flammable) |
| Heat dissipation | Poor | Excellent |
| Capacity | Small | Large |
| Noise | Large | Small |
| Installation location | Indoor | Outdoor/stand-alone |
| Maintenance | Simple | Complex |
| Lifespan | 25-30 years | 30-40 years |
| Cost | High | Medium |
VI. Application in special transformers
6.1 Rectifier transformer
Rectifier transformers are used for DC power supply in electrolysis, electroplating, traction, etc.:
– Primary side: AC power grid
– Secondary side: polyphase output with phase shift
– Followed by rectifier (thyristor/diode)
– Serious harmonics, requiring special designWinding selection:
– Primary winding: Enameled wire Grade H Grade 2-3
– Secondary winding: Enameled wire Grade H Grade 2-3
– Phase-shifting winding: Enameled wire Grade H Grade 2
6.2 Electric furnace transformer
Electric furnace transformers are used for electric arc furnace steelmaking:
– Large capacity (1-100 MVA)
– Low secondary voltage (tens to hundreds of volts)
– The secondary side current is extremely large (tens of thousands of amperes)
– Frequent short circuits and large inrush current
Winding selection:
– Primary winding: paper covered wire 4-6 layers
– Secondary winding: copper foil + glass fiber coating
– Mechanical strength against impact is key
6.3 Traction transformer
Traction transformers are used in railways, subways, and urban rail transit:
– Input: Grid voltage (25 kV catenary)
– Output: Traction motor voltage
– Strong vibration and strong impact
– High temperature and high humidity environment
Winding selection:
– Primary winding: enameled wire + glass fiber H/R grade
– Secondary winding: Enameled wire Grade H Grade 2-3
– Vibration resistance is the primary requirement
6.4 Test transformer
Test transformer for high voltage testing:
– Extremely high voltages (tens of kV – 1,000 kV)
– Power frequency/impact
– short-time work
– BDV is extremely demanding
Winding selection:
– Primary winding: 2-4 layers of paper covered wire
– High voltage winding: paper covered wire 10-20 layers + oil immersed- Electrostatic screen: paper covered wire + aluminum foil
6.5 Isolation transformer
Isolation transformers are used for safe isolation:
– Complete isolation once or twice
– Shield
– Medical, industrial, IT applicationsWinding selection:
– Primary winding: Enameled wire Class H
– Secondary winding: Enameled wire Class H
– Shielding layer: copper foil + enameled wire
6.6 Mining transformer
Mining transformers are used in coal mines and metal mines:
– Extremely high safety requirements
– Explosion-proof, dust-proof, waterproof
– Mobile/Fixed
Winding selection:
– Primary winding: 2-4 layers of paper covered wire
– Secondary winding: 2-4 layers of paper covered wire
– Dry type transformer + Class H fiberglass covered wire(preferred)
VII. Key processes and quality control of transformer manufacturing
7.1 5 key processes in winding manufacturingProcess 1: Winding- Key equipment: vertical/horizontal winding machine
- Key parameters: tension, speed, arrangement
- Quality index: Turns accuracy ±0.1%Process 2: Pressing- Key equipment: hydraulic press
- Key parameters: pressure, pressing time
- Quality index: Winding height tolerance ±1 mmProcess 3: Welding- Key equipment: silver welding machine, copper welding machine, electron beam welding machine
- Key parameters: temperature, time
- Quality index: DC resistance deviation < 2%Process 4: Drying- Key equipment: vacuum drying tank
- Key parameters: temperature, vacuum degree, time
- Quality index: Moisture content < 0.5%Process 5: Dipping- Key equipment: Vacuum Pressure Impregnation Tank (VPI)
- Key parameters: vacuum, pressure, time
- Quality indicator: Insulation resistance > 1,000 MΩ
7.2 8 Key Tests for Quality Control
| Test items | Test methods | Qualification standards |
|---|---|---|
| DC resistance | Bridge method | Deviation < 2% |
| Insulation resistance | Megohmmeter | > 1,000 MΩ |
| Power frequency withstand voltage | Test transformer | 1 min withstand voltage |
| Induction withstand voltage | Double frequency induction | 1 min withstand voltage |
| Impact withstand voltage | Lightning impact | Full wave / cut wave |
| Partial Discharge | Partial Discharge Meter | < 100 pC |
| Temperature rise test | Short circuit method | Temperature rise < 65K |
| Noise Test | Sound Level Meter | < 65 dB |
7.3 Incoming material inspection of winding wires
| Inspection items | Methods | Standards |
|---|---|---|
| Appearance | Visual inspection | No damage or oxidation |
| Diameter | Micrometer | Tolerance ±0.01 mm |
| Paint film thickness | Micrometer | Meet Grade requirements |
| Breakdown voltage | Breakdown meter | Conforming to IEC 60851-5 |
| DC Resistors | Bridges | Meet Specifications |
| Flexibility | Bending test | Round rod diameter multiple |
| Adhesion | Twist test | No paint film peeling off |
VIII. Material innovation in improving transformer efficiency
8.1 4 major sources of transformer losses
| Loss type | Source | Proportion |
|---|---|---|
| Iron loss | Iron core (hysteresis loss + eddy current loss) | 60-70% |
| Copper Loss | Winding Resistance (I²R) | 25-35% |
| Stray losses | Loss caused by magnetic flux leakage | 3-5% |
| Dielectric loss | Loss of insulation material | 1-2% |
8.2 Five major innovation directions of winding wiresInnovation 1: High Temperature Superconducting (HTS) Wire- Zero resistance, zero copper loss
-Significantly improve efficiency
– Currently in the demonstration application stageInnovation 2: Transposed Conductors (CTC)- Reduce eddy current losses in large current windings
– For high current transformersInnovation 3: Low dielectric loss insulation- Nano-modified insulation
– Reduce dielectric loss by 30-50%Innovation 4: Low Resistance Copper (OFC)- 99.99% high purity copper
– Reduce copper loss by 5-10%Innovation 5: Flat Wire/Foil Winding- High current scene
– Reduce skin effect losses
8.3 Transformer efficiency grade (GB/T 19001)
| Level | Level 1 | Level 2 | Level 3 | Level 4 |
|---|---|---|---|---|
| Distribution transformer load loss | 100% | 90% | 80% | 70% |
| No-load loss | 100% | 90% | 80% | 70% |
| Short circuit impedance | Standard | Standard | Standard | Standard |
8.4 Material requirements for primary energy efficiency transformers
Material upgrades for Class 1 energy efficiency transformers:
– Core: High magnetic flux density silicon steel sheet (0.23 mm thick)
– Copper Wire: High Purity Oxygen Free Copper (OFC)
– Insulation paper: high performance low loss cable paper
– INSULATING OIL: Low loss transformer oil
IX. 4 typical application cases
9.1 Case 1: 35 kV oil-immersed distribution transformer
Application: 35 kV oil-immersed distribution transformer of a power company
Specifications:
– Capacity: 5,000 kVA
– Voltage: 35 kV / 10 kV
– Wiring group: Dyn11
– Insulation class: Class A (105°C)
Winding Design:
– High voltage winding: 6 layers of cable paper covering, round copper wire
– Low voltage winding: Enameled wire Grade H Grade 2, copper foil
– Voltage regulating winding: 4 layers of cable paper
Run results:
– 20 years in operation
– Well insulated
– Failure rate < 0.1%
– Efficiency > 99%
9.2 Case 2: 110 kV oil-immersed power transformer
Application: 110 kV oil-immersed power transformer in a substation
Specifications:
– Capacity: 50 MVA
– Voltage: 110 kV / 35 kV / 10 kV
– Three winding transformer
– Insulation class: Class A (105°C)
Winding Design:
– High voltage winding: 8-10 layers of cable paper covering
– Medium voltage winding: 6 layers of cable paper
– Low voltage winding: Cable paper 4 layers
– Electrostatic screen: paper covered wire + aluminum foil
Run results:
– 18 years in operation
– Insulation resistance > 10,000 MΩ
– Design life: 40 years
9.3 Case 3: SCB epoxy resin cast dry-type transformer
Application: SCB dry-type transformer in a subway station
Specifications:
– Capacity: 2,500 kVA
– Voltage: 10 kV / 0.4 kV
– Epoxy resin casting
– Flame retardant grade: F1
Winding Design:
– High voltage winding: Double-layer glass fiber covered wire Class H
– Low voltage winding: Double layer fiberglass covered wire Class H
– Copper foil + fiberglass
– Epoxy resin vacuum casting
Run results:
– 10 years in operation
– Flame retardant and reliable
– Suitable for subway environment
9.4 Case 4: 220 kV UHV transformer
Application: 220 kV transformer in a UHV substation
Specifications:
– Capacity: 180 MVA
– Voltage: 220 kV / 110 kV
– Insulation class: Class A (105°C)
Winding Design:
– High voltage winding: Nomex 410 + high performance cable paper 10-12 layers- Medium voltage winding: high performance cable paper 6-8 layers
– Low voltage winding: high performance cable paper 4-6 layers
– Voltage regulating winding: 4-6 layers of high-performance cable paper
– Static shielding: paper covered wire + aluminum foilRun results:
– 15 years in operation
– BDV > 500 kV
– Design life: 40 years
– Failure rate < 0.05%
X. Future Trend of Transformers
10.1 UHV transformer
- Voltage Level: 1,000 kV, 1,100 kV
- Capacity: 500-1,000 MVA
- Material Challenge: Ultra-high BDV, low loss
- Winding Selection: High Performance Cable Paper + Nomex Composite Insulation
10.2 Smart Transformer
- Sensor Integration: Temperature, Vibration, Partial Discharge
- Online Monitoring: Real-time health status
- Predictive Maintenance: AI failure prediction
- Digital Twin: Virtual Simulation
10.3 New energy transformer
- Photovoltaic transformer: low harmonics, high efficiency
- Wind power transformer: anti-vibration, low temperature resistance
- Energy Storage Transformer: Bidirectional power flow
- Hydrogen Energy Transformer: Corrosion Resistant
10.4 Energy-saving transformer
- Level 1 energy efficiency: GB 20052 standard
- Ultra-low loss: Amorphous alloy core
- High Temperature Superconducting: HTS wire
- Intelligent Cooling: Oil and water mixed cooling
10.5 Environmentally friendly transformer
- Vegetable Insulating Oil: Replaces mineral oil
- Natural ester insulating oil: soybean oil, rapeseed oil
- Recyclable Material: Bio-based insulating paper
- SF6 gas free: dry air replacement
XI. 20 Glossary of terms
| Chinese | English | Abbreviation | Definition |
|---|---|---|---|
| Transformer | Transformer | – | Electromagnetic equipment for voltage conversion |
| Distribution Transformer | Distribution Transformer | DT | Transformer at the end of the distribution network |
| Power Transformer | PT | Transformers in transmission networks | |
| Dry-Type Transformer | – | Air Insulated Transformer | |
| Oil-Immersed Transformer | – | Oil-Immersed Transformer | |
| Winding | Winding | – | Coils in transformers |
| Enameled Wire | PEW / PEW | Enameled copper/aluminum wire | |
| Paper Covered Wire | PCW / PWC | Paper Insulated Winding Wire | |
| Fiberglass Covered Wire | Fiberglass Covered Wire | FCW | Fiberglass Insulated Winding Wire |
| Breakdown Voltage | Breakdown Voltage | BDV | Critical voltage at which insulation is broken down |
| Partial Discharge | PD | Discharge caused by excessive local electric field intensity | |
| Vacuum Pressure Impregnation | VPI | Process of impregnating insulating paint | |
| Oil-Paper Insulation | Oil-Paper Insulation | – | Oil + paper composite insulation |
| Short-Circuit Impedance | Short-Circuit Impedance | – | Impedance of transformer during short circuit |
| No-load loss | No-Load Loss | – | Loss when the transformer is running without load |
| Load Loss | Load Loss | – | Loss when the transformer is under load |
| SCB transformer | – | SCB | Epoxy resin cast dry type transformer |
| Amorphous Alloy | Amorphous Alloy | – | Amorphous Metal Magnetic Materials |
| Vegetable Insulating Oil | Vegetable Insulating Oil | – | Plant-based environmentally friendly insulating oil |
| High-Temperature Superconducting | HTS | Zero-resistance superconducting materials |
XII. LP Winding Wire Company Introduction
LP Winding Wire is an international enterprise focusing on the research and development, production and sales of high-performance winding wires. Its main products cover multiple series such as ** enameled wires, paper-covered wires, glass fiber-coated wires, and composite insulated wires**.
Full range of products:
– Enameled wire series:
– Polyester (PE) enameled wire (130°C)
– Modified polyester enameled wire (155°C)
– Polyesterimide (PEI) enameled wire (180°C)
– PEI/PAI composite enameled wire (180°C)
– Polyamide-imide (PAI) enameled wire (200°C)
– Polyimide (PI) enameled wire (220-240°C)
– Paper covered wire series:
– Cable paper covered wire (105°C)
– Polyester film composite paper covered wire (130°C)
– Nomex 410 paper covered wire (180-220°C)
– Diamond Dispensing (DDP) Paper Covered Wire (130°C)
– Glass fiber covered wire series:
– Single layer fiberglass covered wire (Class F, 155°C)
– Double layer fiberglass covered wire (Class H, 180°C)
– Triple-layer fiberglass covered wire (R-rated, 200°C)
– Three layers + mica composite coated wire (Grade C, 220-260°C)
Special products for transformer industry:
– Special wires for distribution transformers
– Special wire for dry-type transformer
– Special wire for oil-immersed transformer
– Special wire for rectifier transformer
– Special wire for UHV transformer
Core Advantages:
– Full temperature class coverage (105°C – 260°C)
– Full voltage level coverage (220 V – 500 kV)
– Full transformer type coverage (distribution/power/dry/oil-immersed/special)
– Fully certified by UL, VDE, TÜV, CCC, and CSA
– Annual production capacity 50,000 tons
Contact Information:
– Official website: https://www.lpwindingwire.com
– Email: sales@lpwindingwire.com
XIII. Summary and Outlook
Transformer manufacturingis the largest downstream market in the winding wire industry. Enameled wire, paper-covered wire, and glass fiber-covered wire each have their own advantages, and together they support a full range of products fromdistribution transformers to UHV transformers.
Core selection principles:
1. Transformers below 35 kV: Mainly enameled wire/glass fiber covered wire
2. 35-110 kV oil-immersed transformer: paper covered wire (4-10 layers of cable paper)
3. 110-220 kV oil-immersed transformer: high-performance paper covered wire (8-12 layers)
4. 220-500 kV UHV transformer: high performance cable paper + Nomex composite
5. Dry type transformer: Glass fiber covered wire H/R grade
6. Special transformer: customized according to specific needs
Future Development Direction:
– UHV: 1,000 kV, 1,100 kV transformer
– Intelligent: Integrated sensors, AI predictive maintenance
– New Energy: Photovoltaic, wind power, energy storage transformers
– Energy Saving: Level 1 energy efficiency, amorphous alloy, HTS superconducting
– Eco-friendly: Plant-based insulating oil, recyclable materials, SF6-free
LP Winding Wire is willing to work together with global transformer manufacturers to provide a complete solution of enameled wire + paper covered wire + glass fiber covered wire, and contribute to global energy transformation and power development.
13.1 Selection decision tree
Determine transformer type
↓
Oil-immersed transformer?
├─ Yes → Voltage > 110 kV?
│ ├─ Yes → High performance paper covered wire (8-12 layers of cable paper)
│ └─ No → 35-110 kV?
│ ├─ Yes → Paper covered wire (cable paper 4-10 layers)
│ └─ No → Below 35 kV → Enameled wire Class H / Paper covered wire 4-6 layers
└─ No → Dry-type transformer → Glass fiber covered wire H/R grade
13.2 5 Suggestions for Action
- Clear the transformer type: Determine the categories of winding wire materials
- Clear the working voltage: Determine the insulation thickness and number of layers
- Determine the operating temperature: Determine the insulation level
- Clear the operating environment: Oil immersion? Dry? outdoor?
- Comprehensive consideration of economy and lifespan: Choose high-performance wires for high-end products
XIV. Transformer winding wire selection process
14.1 8-step selection process
1. Determine the transformer type → distribution/power/dry/oil-immersed/special
2. Determine capacity and voltage → Determine insulation level
3. Determine the operating temperature → Determine the paint film/paper grade
4. Determine the operating environment → Oil immersion? Dry? Chemical engineering? outdoor?
5. Determine economic expectations → select material range
6. Select the wire category → Enameled wire/Paper covered wire/Glass fiber
7. Determine specific specifications → Paint film grade/number of paper layers/number of fiberglass layers
8. Verification test → Partial discharge/withstand voltage/temperature rise