Professional Guide: Comprehensive Analysis of Oil-Immersed Transformer Model Parameters

Core Value and Application Advantages of Oil-Immersed Transformers

As essential equipment in modern power systems, oil-immersed transformers maintain an irreplaceable position in power transmission and distribution with their unique technical advantages. These transformers use mineral oil as insulation and cooling medium, offering the following distinctive features:

1. Exceptional Heat Dissipation: Transformer oil has 10 times greater heat capacity than air, effectively controlling winding temperature rise
2. Superior Insulation Properties: Breakdown voltage reaches 30-50kV/mm, far exceeding air medium
3. Cost-Effective Operation: Unit capacity cost is 20-30% lower than dry-type transformers
4. Extended Service Life: Can operate stably for 25-30 years with proper maintenance

In-Depth Analysis of Model Coding

Oil-immersed transformer model naming follows China National Standard GB/T 6451, with each letter and number carrying specific technical information:

Basic Structure Codes

• S: Three-phase transformer
• D: Single-phase transformer
• F: Amorphous alloy core
• Z: On-load tap changer type

Performance Parameter Identification

Example “S11-M-800/10”:

• S11: 11th generation three-phase oil-immersed transformer
• M: Fully sealed construction
• 800: Rated capacity 800kVA
• 10: High-voltage side rated voltage 10kV

Special Environment Codes

• TH: Tropical humid type
• TA: Tropical arid type
• W: Outdoor type
• G: Plateau type

Energy Efficiency Classes and Selection Recommendations

Current efficiency standards classify oil-immersed transformers into three levels:

Selection Recommendations:

1. Prioritize new models like S13, SH15
2. Consider amorphous alloy transformers for continuous load rates below 30%
3. Choose fully sealed type (M series) for humid/dusty environments
4. Select on-load tap changer type (Z series) for locations with significant voltage fluctuations

Key Maintenance Points

To ensure long-term reliable operation, focus on these maintenance items:

1. Oil Quality Management:
   • Annual dissolved gas analysis
   • Breakdown voltage should be ≥35kV/2.5mm
   • Control water content to ≤15ppm
2. Temperature Monitoring:
   • Normal operation top oil temperature ≤85℃
   • Winding hot spot temperature ≤98℃
   • Three-phase temperature difference should be ≤10K
3. Periodic Testing:
   • Quarterly insulation resistance measurements
   • Annual winding DC resistance tests
   • Short-circuit impedance testing every 3 years

Technology Development Trends

Current oil-immersed transformer technology is evolving in these directions:

1. Intelligent Upgrades:
   • Integrated online dissolved gas analysis
   • Intelligent temperature control systems
   • Remote condition diagnosis functions
2. Environmental Innovations:
   • Application of biodegradable vegetable insulating oil
   • Low-noise design (≤55dB)
   • Full life-cycle environmental management
3. Material Advancements:
   • Nano-modified insulating paper
   • New antioxidant additives
   • High thermal conductivity insulating oil

Professional Selection Service Recommendations

Customers should provide these key parameters when purchasing:

• Installation site characteristics (indoor/outdoor, altitude, ambient temperature)
• Load curve characteristics (continuous load, peak load)
• System voltage parameters (high-voltage side voltage, voltage regulation requirements)
• Special requirements (fireproof, moisture-proof, corrosion-resistant, etc.)

Quality oil-immersed transformer suppliers should provide:

• Complete type test reports
• Detailed installation guidance
• Professional maintenance training
• Comprehensive technical support system

Through scientific selection and standardized maintenance, oil-immersed transformers can achieve efficient, safe, and economical long-term operation, providing reliable protection for power systems. For more professional technical details, please consult transformer industry expert teams.