Distribution Transformer Types
03-07 2025 | By:
Types and Model Designations of Distribution Transformers
Distribution transformers are critical components in power systems, designed to step down voltage for end-users. Their model designations reflect technical specifications and structural features, standardized globally for clarity. Here’s an overview of key aspects:
1. Model Structure
Distribution transformer models are coded using letters and numbers to indicate characteristics :
Phase Configuration:
Single-phase: Marked as “D” (e.g., D10).
Three-phase: Marked as “S” (e.g., S11).
Cooling Method:
Oil-immersed: No letter (default) or “J” for forced oil circulation.
Dry-type: Marked as “G” (air-cooled) or “C” (resin-encapsulated).
Winding Material:
Copper windings are default (no code), while aluminum is marked as “L”.
Voltage Class:
Rated high-voltage side (e.g., 10kV or 35kV) follows the capacity value.
A typical model, like S11-M-630/10, deciphers as:
S: Three-phase
11: Design series (energy-efficient)
M: Sealed tank
630: Capacity (kVA)
10: High-voltage rating (kV)
2. Common Types and Applications
Oil-immersed Transformers:
Widely used for outdoor installations due to robust cooling (e.g., S9, S11). Ideal for rural grids and industrial zones .
Dry-type Transformers:
Fire-resistant and eco-friendly (e.g., SCB10). Suited for buildings, hospitals, and metro systems .
Amorphous Core Transformers:
Marked as “SH15”, reducing no-load losses by 70-80% compared to traditional models, perfect for low-load scenarios .
3. Technical Parameters
Key parameters include:
Capacity: Ranges from 50 kVA (small buildings) to 6300 kVA (urban substations).
Insulation Class: “F” (155°C) or “H” (180°C) for high-temperature resilience.
Impedance Voltage: Typically 4-6% to limit short-circuit currents .
4. Evolution and Standards
Modern standards prioritize energy efficiency. For example, S13 series reduces no-load loss by 25% over S11 . International codes like IEC 60076 align with Chinese GB standards for global compatibility.
ZTElecGroup’s Henan Zhongyuguang Power, founded in 1958 with over six decades of manufacturing expertise, has established itself as a pioneer in distribution transformer solutions. Here’s a comprehensive overview of their key technical specifications and industrial advantages:
1. Core Product Specifications
Voltage Class: Covers 10kV/20kV/35kV models, optimized for urban grids and industrial parks.
Capacity Range: 50kVA to 2500kVA units, supporting diverse applications from residential complexes to heavy industries.
Winding Material: Utilizes oxygen-free copper windings (OFW) with ≤0.003% oxygen content, ensuring 30% lower load losses compared to aluminum alternatives.
2. Technical Superiority
Connection Groups: Offers flexible Dyn11 and Yyn0 configurations, achieving <4% voltage imbalance in three-phase systems.
Efficiency Compliance: Meets GB20052-2020 Class II energy standards with no-load losses reduced by 15-20% through stepped core-lap technology.
3. Certifications & Adaptability
Holds ISO 9001, KEMA, and CQC certifications, with IP55 protection for harsh environments (-25°C to +40°C operation).
Specialized seismic designs pass 8-magnitude simulation tests, ideal for disaster-prone areas.
4. Procurement Value Proposition
Zhongyuguang’s 60-year R&D legacy ensures 99.2% operational reliability across 100,000+ installations. Their modular design allows 72-hour emergency delivery, while 10-year warranties and localized service networks minimize downtime.
For power utilities and EPC contractors seeking future-proof grid solutions, ZTElecGroup’s technical pedigree and proven field performance make them the strategic choice. Explore their full product portfolio at official channels.
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