| Brand | ROCKWILL |
| Model NO. | Excitation Rectifier Dry-Type Transformers |
| Rated voltage | 22kV |
| Rated frequency | 50/60Hz |
| Rated capacity | 2500kVA |
| Series | DC(B) |
Model: DC(B)-315~2500.Main application fields: static excitation systems of hydropower plants, thermal power plants, and ultra-large capacity nuclear power plants.
Developed as a high-performance product to meet the demands of power plant static excitation systems. This product series adopts a single-phase structure design, supporting high-voltage isolated phase-segregated bus inlets, and shielding between high-voltage and low-voltage windings, suitable for the static excitation systems of hydropower plants, thermal power plants, and nuclear power plants.
| Feature | Description |
|---|---|
| Application | Static excitation systems for hydropower, thermal power & nuclear power plants |
| Core Material | High-quality cold-rolled grain-oriented silicon steel, 45° full mitered joint, resin-sealed surface |
| Winding | HV: epoxy resin vacuum cast; LV: copper foil; HV/LV shielding (Faraday cage) |
| Low Partial Discharge | ≤ 5 pC (at 1.1 Ur/√3 for 1 min) |
| High Overload Capacity | 150% rated current for 60 s; up to 200% short-time (Class H insulation) |
| Strong Short-circuit Withstand | Short-circuit impedance imbalance < 1%; high mechanical strength |
| Flame Retardant | Self-extinguishing epoxy resin, no fire/explosion risk |
| Low Noise | 3–5 dB below national standard; optimized magnetic flux density design |
| Harmonic Suppression | Faraday shielding layer between HV/LV to suppress harmonic overvoltage |
| Environmental Resistance | Moisture-proof, dust-proof, salt-fog resistant; suitable for harsh environments |
| Maintenance Free | No oil, no leakage, self-cleaning winding surface |
| Parameter | Specification |
|---|---|
| Model Series | DC(B), ZLSC, ZSC(B) |
| Phase | Single-phase (large units) / Three-phase |
| Rated Capacity | 315 – 2,500 kVA (excitation type); 20 – 5,000 kVA (rectifier type) |
| HV Voltage Level | 10 kV, 13.8 kV, 15.75 kV, 20 kV, 22 kV |
| LV Voltage | 0.4 kV, 0.66 kV, 0.69 kV (customizable) |
| Frequency | 50 Hz / 60 Hz |
| Tap Range | ±2×2.5% or ±5% (off-circuit tap changer) |
| Vector Group | Dyn11, Yyn0, Dd0, Yd11 (customizable) |
| Insulation Class | Class F (155 °C) / Class H (180 °C) |
| Cooling Mode | AN / AF |
| No-load Loss | ≤ 0.5% of rated capacity |
| Load Loss | ≤ 1.5% of rated capacity |
| No-load Current | 0.5 – 1.6% |
| Short-circuit Impedance | 4%, 6%, 8% (varies by capacity) |
| Impedance Imbalance | < 1% |
| Noise Level | ≤ 65 dB (capacity-dependent) |
| Lightning Impulse Withstand | 75 kV (10 kV class) |
| AC Withstand Voltage | 28 kV / 3 kV (HV/LV) |
| DC Bias Tolerance | ≤ 1.5% of rated current |
| Rectifier Pulse Number | 6-pulse (THDi ≈ 25%); 12/24-pulse (THDi < 7%) |
| Altitude | ≤ 1,000 m (derated above) |
| Ambient Temperature | –25 °C ~ +40 °C |
| Protection Class | IP00 / IP20 / IP23 |
| Winding Material | Copper (standard) / Aluminum (optional) |
| Rated Capacity (kVA) | No-load Loss (W) | Load Loss @ 120 °C (W) | No-load Current (%) | Impedance (%) |
|---|---|---|---|---|
| 315 | ~ 750 | ~ 3,500 | 1.2 | 4.0 |
| 500 | ~ 1,050 | ~ 5,100 | 1.0 | 4.0 |
| 630 | ~ 1,250 | ~ 6,200 | 0.9 | 6.0 |
| 800 | ~ 1,500 | ~ 7,500 | 0.8 | 6.0 |
| 1000 | ~ 1,750 | ~ 9,200 | 0.7 | 6.0 |
| 1250 | ~ 2,100 | ~ 11,000 | 0.7 | 6.0 |
| 1600 | ~ 2,500 | ~ 13,500 | 0.6 | 6.0 |
| 2000 | ~ 2,900 | ~ 16,200 | 0.6 | 8.0 |
| 2500 | ~ 3,400 | ~ 19,500 | 0.5 | 8.0 |
| Type | Standard | Purpose |
|---|---|---|
| International | IEC 60076 | Power transformers (general) |
| International | IEC 61378 | Transformers for industrial applications (rectifier/convertor) |
| China | GB 1094 series | Power transformers (general) |
| China | GB/T 10228 | Dry-type power transformer parameters |
| China | GB/T 18494 | Convertor transformers (specialized) |
| USA | IEEE C57.12 | Standard for transformers |
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