What Are The Alphanumeric Codes In The Transformer Model?
In Shandong, a substation expansion project, engineers found two nominal same type of transformer actual parameter differences of up to 15% - the root cause of this oolong event, is actually a letter in the model code misunderstanding. Transformer model as the genetic code of power equipment, each character is hidden mystery.
I. Alphabetical sequence: structure code
The first letter reveals the core features:
- S: three-phase (Single-phase is D)
- C: epoxy resin casting (oil-immersed with J for tank)
- B: foil winding (omitted for cylindrical winding)
- Z: on-load voltage regulation (no symbol for unexcited voltage regulation)
Take SCB12-800/10 for example:
- SCB: three-phase epoxy cast foil winding
- 12: 12th generation design
- 800: rated capacity 800kVA
- 10: high voltage side voltage 10kV
Special suffix concealed function:
- N: indoor type (W for outdoor)
- F: Protective type (IP23)
- R: Rolled iron core structure
- H: fire-resistant type (temperature-resistant grade upgraded)
II. Numerical Matrix: Performance Coordinates
Accurate correspondence between capacity and voltage:
- Digits before slash: Rated capacity (kVA)
- Digits after slash: voltage level of high voltage side (kV)
- Implicit parameter between slashes: LV side voltage usually defaults to 0.4kV
Technical iteration in the design sequence number:
- S11: 11th generation oil-immersed (no-load loss reduced by 30% compared with S9)
- SCB14: amorphous alloy core (70% reduction in no-load current)
- SH15: three-dimensional rolled iron core (8dB noise reduction)
Environmental adaptability code:
- TH: hot and humid type (humidity ≤95%)
- TA: Dry heat type (altitude 2000m)
- G: High altitude type (4000m working condition)
III. Special Symbols: Function Key
Cooling Mode Code:
- AN: Natural air-cooled (no fan required)
- AF: Forced air-cooled (fan start-up temperature 65°C)
- ONAN: Oil-immersed self-cooling (oil temperature limit 95°C)
Insulation system marking:
- F: heat-resistant 155°C (Class B 130°C, Class H 180°C)
- C: Class C solid insulation (resistance to electrical tracerisation)
Energy efficiency class code words:
- 1 level: no-load loss ≤ 70% of standard value
- Class 2: ≤85% of standard value
- IE4: the highest level of international energy efficiency (efficiency ≥ 99%)
IV. Model Deciphering Practice
Case 1: S13-M-200/10
- S: three-phase
- 13: 13th generation design
- M: fully sealed structure
- 200: 200kVA
- 10: 10kV high voltage side
Case 2: SCBH15-1000/10-NX2
- SCBH: three-phase epoxy cast fireproof type
- 15: amorphous alloy core
- 1000: 1000kVA
- NX2: double noise reduction design (noise ≤ 45dB)
Case 3: DSSZ11-50000/220-TH
- D: Single-phase
- SSZ: three-winding on-load voltage regulation
- 11: 11th generation
- 50000: 50000kVA
- 220: 220kV
- TH: Specialised for hot and humid climates
The State Grid 2023 sampling found that the misinterpretation of the model number led to equipment selection errors accounted for 23%. When we see "SCB14-1250/10-AN/F" in the parameter table, this string of code is not only a product identification, but also a concentrated history of electrical engineering - from material technology to heat dissipation design, each character tells the story of technological evolution.