I. Introduction: Electrical equipment manufacturing – “Applying blue oceans” for paper wrapped wires
Electrical equipment manufacturing is the pillar industry of the national economy, covering transformers, motors, generators, high-voltage switches, transformers, reactors, capacitors, lightning arresters, cables, electrical control cabinets and dozens of other types of equipment. The core electromagnetic components of these devices – windings – generally rely on high-performance winding wires as the base material.
Paper Covered Wire (PCW) As a traditional main insulated winding wire, it has an irreplaceable core position in the electrical equipment manufacturing industry. From distribution transformers to 1,000 kV UHV transformers, from 1 kW motors to 1,000 MW generators, from low voltage transformers to 500 kV transformers, paper envelopes play a key role.
This paper will systematically sort out the applications of paper wrapped wires in 12 major electrical equipment manufacturing fields —— transformers, motors, generators, high-voltage switches, transformers, reactors, capacitors, lightning arresters, cables, electrical control cabinets, special electrical equipment, etc., and give selection guidelines, quality control, and future trends .
1.1 Why this review is important
- ✅ Wide range of applications : covers 12 categories of electrical equipment
- ✅ Large market : Global electrical equipment market > $3 trillion
- ✅ Large amount of paper wrapped cables : 70% + in transformers/reactors/transformers and other fields
- ✅ High technical requirements : Different devices have different paper wrapping requirements
1.2 Core Benefits of Enveloped Cables
| Strengths | Numeric | Applicable Equipment |
|---|---|---|
| Oil-immersed gain | 3-5 × BDV boost | Oil-immersed transformers, reactors |
| Breakdown voltage | 10-30 kV/mm | High voltage equipment |
| Cost | Low (cable paper 30-60RMB/kg) | Mass production |
| Life | 30-40 years | Long-life equipment |
| Repairable | Easy | Large Transformer |
| Biodegradation | Yes | Environmentally friendly equipment |
1.3 Overview of the 12 Application Areas
| Serial Number | Electrical Equipment | Paper Envelope Ratio | Key Performance |
|---|---|---|---|
| 1 | Oil-immersed transformer | 95% | Oil-immersed gain, lifetime |
| 1 | Oil-immersed reactor | 90% | Anti-vibration, BDV |
| 3 | High Voltage Transformer | 80% | High BDV, Stability |
| 4 | Large Motors | 60% | Short Circuit Resistance, Lifetime |
| 5 | Generator | 50% | High Strength, Heat Dissipation |
| 6 | High Voltage Sleeves | 70% | Oil Immersion Compatible, BDV |
| 7 | Oil Immersion Capacitor | 30% | Dielectric Loss |
| 8 | Traction Transformer | 40% | Anti-vibration |
| 9 | Wind Power Transformer | 30% | Weather Resistance |
| 10 | Test Transformer | 50% | Ultra High BDV |
| 11 | Electrical control cabinet | 20% | Insulation |
| 12 | Special Electrical Equipment | 60% | Customized |
II. Application of paper wrapping in transformer manufacturing
2.1 Oil-immersed distribution transformer
Paper cladding is the absolute main force in oil-immersed distribution transformers below 35 kV , accounting for 95% + of the winding insulation.
Specifications :
– Capacity: 50 kVA – 2,500 kVA
– Voltage: < 35 kV
– Insulation class: Class A (105°C)
Envelope design :
– High voltage winding: cable paper 2-6 layers
– Low-voltage windings: 2-4 layers of cable paper
– Regulating winding: 2-4 layers of cable paper
– Insulation medium: 25 # transformer oil
Running results :
– 25-40 years in operation
– Failure rate < 0.1%
– Design life: 30-40 years
2.2 Oil-immersed power transformers
35-220 kV oil-immersed power transformer : paper envelope layers 4-12
Specifications :
– Capacity: 2,500 kVA – 500 MVA
– Voltage: 35-220 kV
– Insulation class: Class A (105°C)
Envelope design :
– High voltage winding: cable paper 6-12 layers
– Medium voltage winding: cable paper 4-8 layers
– Low-voltage windings: 2-6 layers of cable paper
– Electrostatic screen: paper wrapped wire + aluminum foil
– Insulating medium: high-purity transformer oil
Use Cases :
– 110 kV/50 MVA oil-immersed power transformer
– 220 kV/180 MVA oil-immersed power transformer
– 15-25 years of operation
– Failure rate < 0.05%
2.3 Ultra High Voltage (UHV) Transformers
500 kV and above UHV Transformer : Paper Cable + Nomex Composite Solution
Specifications :
– Capacity: 500-1,500 MVA
– Voltage: 500-1,000 kV
– Insulation class: Class A (105°C)
Composite design :
– High voltage winding: cable paper 12-15 layers + Nomex 6-8 layers
– Medium voltage winding: 8-10 layers of cable paper
– Low-voltage windings: 4-6 layers of cable paper
– Electrostatic shielding: paper wrapped wire + aluminum foil
– Insulating medium: high-purity transformer oil
Use Cases :
– 500 kV/1,000 MVA UHV Transformer
– 1,000 kV/1,500 MVA UHV transformer
– BDV > 1,000 kV
– 10-15 years of operation
– Failure rate < 0.02%
2.4 Paper Cable Envelope Applications for Dry Type Transformers
Dry type transformer : paper wrapped wires need to be used with impregnation paint or epoxy resin
| Dry transformer | Paper wrapping | Impregnation process | Scenarios |
|---|---|---|---|
| Small Drying | Enameled + Paper Cable | Impregnated Paint | Indoor Power Distribution |
| SCB drying | Double glazing + resin | Vacuum casting | Subway, Airport |
| VPI Drying | Paper Envelope + Impregnation Paint | VPI Impregnation | Wind Power, Traction |
Core Description : Pure paper wrapped wire is rarely used in dry-type transformers and is mainly used in conjunction with the impregnation process.
2.5 Special transformers
| Transformer | Capacity | Voltage | Paper Cable Application |
|---|---|---|---|
| Rectifier Transformer | 0.1-50 MVA | < 110 kV | Layer 4-8 (Harmonic Scene) |
| Electric Furnace Transformer | 1-100 MVA | 6-110 kV | Layer 4-6 (Impact Resistance) |
| Traction Transformer | 5-100 MVA | 25 kV | Layer 4-6 (anti-vibration) |
| Test Transformer | 0.05 -3 MVA | < 1,000 kV | 10-20 floors (ultra-high BDV) |
| Isolation Transformer | 0.05 -100 kVA | < 1 kV | Layer 2-4 (Safety Isolation) |
| Mining Transformer | 0.05 -5 MVA | < 35 kV | Floor 2-6 (Explosion-proof) |
III. Application of paper wrapping wires in motors
3.1 Comparison of paper-enameled and enameled wires in motors
| Dimension | Enameled wire | Paper wrapped wire |
|---|---|---|
| Slot Fill Rate | 75-80% | 60-70% |
| Cooling | Excellent | Medium |
| Breakdown Voltage | 5-15 kV | 5-20 kV |
| Temperature resistance | 130-220°C | 105-180°C |
| Cost | Medium | Low |
| Applications | General Motors | Large Motors |
3.2 Large high-voltage motors
Applications : large fans, compressors, rolling mill motors
Specifications :
– Capacity: 500-50,000 kW
– Voltage: 3-15 kV
– Insulation class: Class B/F
Envelope design :
– Stator winding: cable paper 4-8 layers + enameled wire
– Rotor winding: cable paper 2-4 layers + enameled wire
– Tank insulation: cable paper + mica
– Impregnation: VPI Vacuum Pressure Impregnation
Typical Cases :
– 10 MW High Voltage Motor (Cement Industry)
– 25 MW synchronous motor (mill driven)
– 50 MW pumped storage motor
3.3 Medium motor
Applications : General industrial motors, traction motors, lifting motors
Specifications :
– Capacity: 100-1,000 kW
– Voltage: 380-6,000 V
– Insulation class: Class B/F
Application of paper wrapping :
– Groove insulation: cable paper 0.25 mm x 2 layers
– Phase insulation: 0.25 mm x 1 layer of cable paper
– Winding insulation: mainly enameled wire
– Impregnation: Impregnation paint
3.4 Small motors
Applications : appliance motors, small industrial motors
Description : Enameled wires are rarely used in small motors and are mainly dominated by enameled wires.
Special apps :
– Vintage motor repair (replace aged enameled wire)
– High temperature scenarios (when the enameled wire cannot meet)
3.5 Special motors
| Motor | Capacity | Envelope | Reason |
|---|---|---|---|
| Traction motor | 100-1,500 kW | 4-6 layers | Vibration and temperature resistant |
| Marine motors | 100-5,000 kW | 4-6 floors | Anti-vibration, moisture- and heat-resistant |
| Mining Motor | 50-1,000 kW | Floors 2-4 | Explosion-proof |
| Avionics | < 500 kW | Mainly PI | 220°C + Extreme Temperature |
IV. Application of paper wrapping in generators
4.1 Large hydroelectric generator
Applications : Hydropower plants, nuclear power plants
Specifications :
– Capacity: 100-1,000 MW
– Voltage: 10-30 kV
– Insulation class: Class B/F
Envelope design :
– Stator winding: cable paper 4-8 layers + enameled wire
– Tank insulation: cable paper + mica tape
– End insulation: cable paper + fiberglass
– Impregnation: VPI Vacuum Pressure Impregnation
Typical Cases :
– 700 MW hydroelectric generator at Three Gorges Hydropower Station
– 770 MW hydroelectric generator at Xiluodu Hydropower Station
– 20-30 years of operation
– Failure rate < 0.05%
4.2 Large steam turbine generator
Applications : Thermal power stations, gas-fired power stations
Specifications :
– Capacity: 100-1,200 MW
– Voltage: 15-27 kV
– Insulation class: Class B/F
Envelope design :
– Stator winding: cable paper 4-6 layers + enameled wire
– Rotor winding: enameled wire (high speed)
– Tank insulation: cable paper + mica
– Impregnation: VPI Vacuum Pressure Impregnation
4.3 Small and medium-sized generators
Applications : diesel generators, wind turbines, small hydropower
Specifications :
– Capacity: 10-50 MW
– Voltage: 400-10,500 V
– Insulation class: Class B/F
Application of paper wrapping :
– Groove insulation: cable paper
– Winding: mainly enameled wire
– End: cable paper + fiberglass
4.4 Wind turbines
Applications : onshore wind, offshore wind
Specifications :
– Capacity: 2-15 MW
– Voltage: 400-1,000 V
– Insulation class: H/C class
Application of paper wrapping :
– Tank insulation: Nomex-based
– Winding: enameled wire + paper wrapped wire
– End: Fiberglass
– Vibration resistant, weather resistant
Instructions : Paper wrapping applications in modern wind power are gradually being replaced by Nomex/PI.
V. Application of paper wrapping wires in transformers
5.1 Voltage transformer (PT)
Application : Power system measurement, protection
Specifications :
– Voltage: 0.4-500 kV
– Capacity: 50-500 VA
– Insulation class: A/E class
Envelope design :
– Primary winding: 4-15 layers of cable paper
– Secondary winding: enameled wire
– Insulating medium: transformer oil
– Iron core: silicon steel sheet
Key performance :
– High precision (level 0.2, level 0.5)
– High BDV
– Low dielectric loss
5.2 Current transformer (CT)
Application : Power system current measurement, protection
Specifications :
– Current: 5-5,000 A
– Voltage: 0.4-500 kV
– Insulation class: A/E class
Envelope design :
– Primary winding: copper busbar + cable paper
– Secondary winding: enameled wire
– Insulating medium: transformer oil or epoxy
Key performance :
– High precision (0.2S, 0.5s)
– High short circuit withstand current
– Low saturation
5.3 Sleeve transformer
Application : high-voltage transmission, substation
Application of paper wrapping :
– Multi-layer cable paper + oil immersion
– Electrostatic screen
– High insulation reliability
5.4 Electronic transformer
Applications : Smart Grid, Digital Substation
Instructions : Electronic transformers use Roche coils or optical sensing, reducing the use of paper wrapped wires.
VI. Application of paper wrapping wires in high-voltage switchgear
6.1 Oil-immersed high-voltage switch
Application : 35-220 kV high voltage switch
Application of paper wrapping :
– Current transformer: cable paper 4-8 layers
– Voltage transformer: cable paper 6-12 layers
– Operating coil: enameled wire
– Insulating medium: transformer oil
6.2 SF6 High Voltage Switch (GIS)
Application : 110-500 kV substation
Application of paper wrapping :
– Transformer: Cable paper 4-10 layers
– Operating mechanism: enameled wire
– Insulation medium: SF6 gas
6.3 Vacuum circuit breaker
Application : 10-35 kV power distribution
Application of paper wrapping :
– Operating coil: enameled wire
– Current transformer: cable paper 2-4 layers
6.4 Isolation switch, load switch
Application of paper wrapping :
– Operating coil: enameled wire
– Auxiliary transformer: Cable paper 2-4 layers
VII. Application of paper wrapping wires in reactors
7.1 Shunt reactor
Application : high-voltage transmission reactive power compensation
Specifications :
– Capacity: 10-200 Mvar
– Voltage: 35-1,000 kV
– Insulation class: Class A
Envelope design :
– Winding: 6-15 layers of cable paper
– Iron core: silicon steel sheet
– Insulating medium: transformer oil
Typical applications :
– Shunt reactor for 500 kV transmission
– 1,000 kV UHV shunt reactor
– 20-30 years of operation
7.2 Tandem reactors
Application : current limiting, filtering, reactive compensation
Specifications :
– Capacity: 100 kvar – 50 Mvar
– Voltage: 0.4-35 kV
Application of paper wrapping :
– Winding: 2-8 layers of cable paper
– Core: silicon steel sheet or amorphous alloy
7.3 Flat wave reactor
Application : Direct current transmission (HVDC)
Specifications :
– Capacity: 50-500 Mvar
– Voltage: ± 500-1,000 kV
Envelope design :
– Winding: 10-20 layers of cable paper
– Insulating medium: transformer oil
7.4 Filter reactor
Application : harmonic suppression, power electronics
Application of paper wrapping :
– Winding: 2-6 layers of cable paper
– Iron core: silicon steel sheet
– Impregnation: Impregnation paint
7.5 Current limiting reactor
Apply : Short Circuit Current Limit
Envelope design :
– High current: copper busbar + cable paper
– High insulation: 4-10 layers of cable paper
VIII. Application of paper wrapping in capacitors
8.1 Power Capacitors
Application : reactive compensation, harmonic filtering
Specifications :
– Capacity: 10-1,000 kvar
– Voltage: 0.4-35 kV
Application of paper wrapping :
– Early capacitors: paper-based
– Modern capacitors: PP film-based
– The paper wrapping is mainly in the inductive part
8.2 Pulse capacitors
Applications : Laser, Electromagnetic Emission, Medical
Application of paper wrapping :
– Inductance coil: cable paper
– Early media: paper media
8.3 Coupling capacitors
Application : High-voltage transmission line carrier communication
Application of paper wrapping :
– Early Media: Cable Paper
– Modern media: PP film + oil
IX. Application of paper wrapping wires in lightning arresters
9.1 Valve arrester
Applications : 35-220 kV power systems
Application of paper wrapping :
– Discharge gap: electrode + cable paper
– Valve disc: SiC or ZnO
– Insulation: cable paper + porcelain sleeve
9.2 Zinc Oxide Lightning Arrester
Application : 0.4-1,000 kV full voltage class
Application of paper wrapping :
– Early: Cable paper for gap insulation
– Modern: Mainly ZnO valve discs, reduced paper wrapped wires
9.3 Lightning arrester trends
- Composite jacket lightning arrester (silicone rubber)
- Smart Lightning Arrester (Online Monitoring)
- Reduced application of paper wrapping
X. Application of paper wrapping in cables
10.1 High-voltage power cables
Application : 110-500 kV transmission
Description : High voltage power cables are mainly cross-linked polyethylene (XLPE), and paper wrapped cables are mainly used in the early oil-impregnated paper insulated cables .
Oil-impregnated paper insulated cables :
– Conductor: Copper/Aluminum
– Insulation: multilayer cable paper
– Medium: Mineral oil
– Applications: Early high-voltage cables (largely obsolete)
10.2 Special cable
Applications : marine cables, mining cables, control cables
Application of paper wrapping :
– Early control cables: paper insulated
– Modern: PVC/XLPE-based
XI. Application of paper wrapping wires in electrical control cabinets
11.1 Low voltage control cabinet
Application : Power distribution cabinet, control cabinet, switch cabinet
Application of paper wrapping :
– Control transformer: cable paper 2-4 layers
– Transformer: Cable paper 2-4 layers
– Relay coil: enameled wire
11.2 Medium voltage switchgear
Application : 10-35 kV switchgear
Application of paper wrapping :
– Current transformer: cable paper 2-6 layers
– Voltage transformer: cable paper 4-8 layers
– Operating coil: enameled wire
11.3 Intelligent control cabinet
Applications : Smart Power Distribution, Automation
Description : The intelligent control cabinet is mainly electronic components, and the application of paper wrapping is reduced.
XII. Application of paper-coated wires in special electrical equipment
12.1 Traction substation equipment
Applications : electrified rail, urban rail
Application of paper wrapping :
– Traction transformer: cable paper 4-6 layers
– Auto-transformer: cable paper layers 4-6
– Transformer: Cable paper 2-6 layers
– Anti-vibration, high reliability
12.2 Wind Power Transformers
Applications : onshore wind, offshore wind
Application of paper wrapping :
– Wind Power Transformer: Cable Paper + Nomex Composite
– Box type transformer: cable paper 2-4 layers
– Corrosion resistant, weather resistant
12.3 Photovoltaic substation equipment
Applications : Solar power generation, grid-connected inversion
Application of paper wrapping :
– Step-up transformer: cable paper 2-6 layers
– Inverter: mainly enameled wire
– Low cost, reliable
12.4 Electrical equipment for energy storage
Application : Energy Storage Power Station, BMS
Application of paper wrapping :
– Energy storage transformer: cable paper 2-4 layers
– Filter reactor: 2-4 layers of cable paper
12.5 Hydrogen Power Transformers
Applications : hydrogen electrolysis, green hydrogen
Application of paper wrapping :
– Rectifier transformer: cable paper 4-8 layers
– Corrosion resistant, reliable
12.6 Nuclear Power Plant Electrical Equipment
Application : Class 1E equipment for nuclear power plants
Application of paper wrapping :
– Class 1E transformer: specially certified paper envelope
– Radiation resistant, life span 60 years
– Extremely reliable
XIII. Quality Control of Paper Covered Wire
13.1 Incoming Inspection
| Inspection Items | Inspection Methods | Acceptance Criteria |
|---|---|---|
| Thickness | Micrometer | 0.05-0.25 mm |
| Density | Densitometer | 0.7-1.0 g/cm ³ |
| Tensile strength | Tensile machine | > 8 kN/m (longitudinal) |
| Breakdown voltage | Breakdown instrument | > 10 kV/mm (dry state) |
| Moisture Content | Drying | < 8% |
| Ash | Scorching | < 1% |
| Appearance | Visual Inspection | No damage, no impurities |
13.2 Process control
| Process | Key Parameters | Detection Frequency |
|---|---|---|
| Conductor Incoming | Tensile Strength, Elongation, Diameter | Per Batch |
| Paper Covering | Tension, Tightness, Layers | Per Axis |
| Winding | Tension, Speed, Alignment | Per Axis |
| Pressing | Pressure, time | Per set |
| Vacuum Drying | Temperature, Vacuum, Time | Per Tank |
| Impregnation | Vacuum, Pressure | Per Tank |
| Oil Immersion | Vacuum, Pressure | Per Tank |
13.3 Factory Inspection
| Project | Methodology | Acceptance Criteria |
|---|---|---|
| DC Resistance | Bridge | Deviation < 2% |
| Insulation Resistance | Megohmmeter | > 1,000 MΩ |
| Power Frequency Withstand Voltage | Test Transformer | 1 min Withstand Voltage |
| Induction Voltage Resistance | Frequency Doubling Induction | 1 min Voltage Resistance |
| Partial Discharge | Local Discharge Instrument | < 100 pC |
| Temperature rise test | Short circuit method | Temperature rise < 65 K |
XIV. Future Development Direction of Paper Covered Wire
14.1 New paper insulation
Direction 1: High Density Cable Paper
– Density 1.0-1.2 g/cm ³
– 20-30% increase in BDV
– Oil-immersed transformer main direction
Direction 2: Modified cable paper
– Nano modified paper
– Flame retardant cable paper
– High strength cable paper
Direction 3: Composite Paper
– Cable Paper + pet Composite
– Cable Paper + Nomex Composite
– Cable Paper + PI Composite
14.2 New application areas
Area 1: New Energy
– Photovoltaic transformers
– Wind Power Transformer
– Energy storage transformer
– Hydrogen energy transformer
Area 2: Smart Grid
– Smart Transformer
– Electronic transformer
– Online monitoring
Domain 3: UHV
– 1,000 kV UHV
– ± 1,100 kV UHVDC
– Extreme cold/heat environment
Field 4: Rail transit
– High speed rail
– City Subway
– Magnetic levitation
14.3 Smart Manufacturing
Direction 1: Automatic winding
– Robot winding
– Precise tension control
– Visual inspection
Direction 2: Online Monitoring
– Temperature sensor
– Vibration sensor
– Partial discharge monitoring
Direction 3: Digital Twin
– Virtual simulation
– Lifetime prediction
– Optimized design
14.4 Eco-Friendly Insulation
Direction 1: Vegetable insulating oil
– Soybean oil
– Rapeseed oil
– Palm oil
Direction 2: Bio-based Paper
– Alternative wood pulp
– Sustainable raw materials
– Reduced carbon footprint
Direction 3: Degradable insulation
– Eco-friendly paper
– Degradable paint film
– Circular economy
XV. 20 Glossary of Terms
| Chinese | English | Abbreviations | Definitions |
|---|---|---|---|
| Paper Covered Wire | PCW | Cable Paper Covered Winding Wire | |
| Breakdown Voltage | Breakdown Voltage | BDV | Insulated Breakdown Critical Voltage |
| Oil-Immersed Insulation | – | Composite Insulation of Oil + Paper | |
| Partial Discharge | PD | Discharge caused by excessive local electric field | |
| Dielectric Constant | Dielectric Constant | ε | Ability of the dielectric to store electric fields |
| Dielectric Loss | tan δ | Dielectric Loss in AC Field | |
| Vacuum Pressure Impregnation | Vacuum Pressure Impregnation | VPI | Impregnation Insulating Paint Process |
| Dry Transformer | Dry-Type Transformer | – | Air/Solid Insulated Transformer |
| Oil Immersed Transformer | Oil-Immersed Transformer | – | Oil Insulated Transformer |
| Transformer | Instrument Transformer | PT/CT | Power System Measurement Transformer |
| Shunt Reactor | – | Reactive Compensation Reactor | |
| Series Reactor | – | Current Limiting/Filtering Reactor | |
| Flat-Wave Reactor | Smoothing Reactor | – | DC Transmission Reactor |
| Rectifier Transformer | Rectifier Transformer | – | Rectifier Transformer |
| Traction Transformer | – | Railway Traction Transformer | |
| Wind Power Transformer | – | Wind Power Transformer | |
| Photovoltaic Transformer | PV Transformer | – | Photovoltaic Power Generation Transformer |
| Lightning Arrester | Surge Arrester | – | Overvoltage Protection Equipment |
| Vacuum Circuit Breaker | Vacuum Circuit Breaker | VCB | Vacuum Circuit Breaker |
| High-Voltage Switchgear | – |
XVI. LP Winding Wire Company Introduction
LP Winding Wire is an international company specializing in the R&D, production and sales of high-performance winding wires. Its main products include enameled wires, paper wrapped wires, glass fiber wrapped wires, Nomex paper wrapped wires and other series.
Special products for the electrical equipment industry :
– For transformers :
– Paper wrapping for oil-immersed transformers (0.5-5.0 mm full specification)
– H-grade fiberglass/Nomex coated wire for dry transformers
– Nomex composite wire for SCB dry transformers
– Cable paper wrapping for rectifier transformer
– Anti-vibration coated wire for traction/wind power transformers
– For motors/generators :
– VPI impregnated paper wrapping for large motors
– High-strength cable paper wrapping for generators
– High BDV paper wrapping for high-voltage motors
– High density cable paper for groove insulation
– For transformers :
– Paper wrapping for 35-500 kV voltage transformers
– Paper wrapping for high-precision current transformers
– High BDV paper wrapping for sleeves
– For reactors :
– Paper wrapping for parallel reactors
– Paper wrapping for series reactors
– High BDV paper wrapping for flat wave reactors
– For high voltage switches :
– Paper wrapping for oil immersion switch transformer
– Paper wrapping for GIS transformers
– Enameled wire for operating coils
– Special for special electrical equipment :
– Grade 1E paper envelope for nuclear power
– Radiation resistant paper envelope
– Corrosion resistant paper wrapping
– Extreme temperature paper wrapping
Core strengths :
– Full temperature class coverage (A/C class)
– Full voltage level coverage (220 V – 1,000 kV)
– Coverage of all electrical equipment types (12 categories)
– UL, VDE, TÜV, CCC, CSA full certification
– Annual capacity of 50,000 tons
– DuPont Nomex Authorized Partner
Contact :
– Official Website : https://www.lpwindingwire.com
– Email : sales@lpwindingwire.com
XVII. Summary and outlook
As a traditional main insulated winding wire, paper wrapped wire has an irreplaceable core position in 12 categories of electrical equipment manufacturing . From distribution transformers to 1,000 kV UHVs, from small motors to 1,000 MW generators, from low-voltage transformers to 500 kV transformers, paper envelopes play a key role.
Key conclusions
| Areas of Application | Paper Envelope Dosage | Key Performance | Future Directions |
|---|---|---|---|
| Oil-immersed transformer | 95% | Oil-immersed gain, lifetime | Composite insulation |
| Oil-immersed reactor | 90% | Anti-vibration, BDV | Composite solution |
| High Voltage Transformer | 80% | High BDV, Stability | High Accuracy |
| Large motor | 60% | Short circuit resistance, lifetime | VPI process |
| Generator | 50% | High strength, heat dissipation | Composite insulation |
| Special electrical equipment | 60% | Customized | Radiation and corrosion resistance |
Future directions :
1. New paper insulation materials : high density, modified, composite
2. New application areas : new energy, smart grid, UHV, rail transit
3. Smart manufacturing : robotic winding, online monitoring, digital twins
4. Eco-friendly insulation : vegetable oil, bio-based paper, degradable materials
17.1 Selection Decision Tree
Determine the type of electrical equipment
↓
Oil immersion equipment?
├─ Is → the voltage > 110 kV?
│ ├─ Is → Envelope 8-12 Layers (Preferred)/Envelope + Nomex Composite
│ └─ No → 35-110 kV?
│ ├─ Is → Envelope Layer 4-10 (preferred)
│ └─ No → < 35 kV → Envelope Layer 2-6
└─ No → Dry Unit → Temperature > 180°C?
├─ Is → Nomex/Fiberglass (preferred)
└─ → No → 130-180°C enameled wire + impregnation
17.2 6 Tips for Action
- Specify equipment type : Oil-impregnated → paper wrapping; dry → Nomex/fiberglass
- Specify the operating voltage : 35-500 kV → paper wrapping; dry → Nomex
- Clarify operating temperature : > 180°C → Nomex; 130-180°C → FCW; < 130°C → enameled wire
- Clear budget : Adequate → Nomex/PI; sensitive → paper wrapped/enameled wire
- Define the operating environment : vibration/chemical/radiation → special insulation wires; conventional → paper wrapping wires
- Clear service life requirements : 30-40 years of → oil-impregnated paper wrapping; 20-30 years of → dry special
LP Winding Wire is willing to work with global electrical equipment manufacturers to provide a complete solution of paper wrapped wire + enameled wire + glass fiber coated wire + Nomex paper wrapped wire to contribute to the global energy transition and power development.