Excitation Rectifier Dry-Type Transformers

Attributes Description Documentation Resource Library

Key attributes

Brand	ROCKWILL
Model NO.	Excitation Rectifier Dry-Type Transformers
Rated voltage	22kV
Rated frequency	50/60Hz
Rated capacity	2500kVA
Series	DC(B)

Description

Product Overview

Model: DC(B)-315~2500.Main application fields: static excitation systems of hydropower plants, thermal power plants, and ultra-large capacity nuclear power plants.

Product superiority

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.

Performance Features

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

Technical Parameters

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)

Typical Capacity–Loss Reference (10 kV Class, F-Class)

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

Applicable Standards (Simplified)

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

Excitation Rectifier Dry-Type Transformers

Negotiable

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Model

DC(B)-315

Warranty by

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Whole-life care management services for equipment procurement, use, maintenance, and after-sales, ensuring safe operation of electrical equipment, continuous control, and worry-free electricity consumption.

The equipment supplier has passed platform qualification certification and technical evaluation, ensuring compliance, professionalism, and reliability from the source.