Electric Arc Furnace Special Transformer
Rated Power: 630kVA ~ 120000kVA
Rated Voltage: 6-110kV / 80-1200V
Rated Frequency: 50HZ, 60HZ
Phase: 3 phase
Tap range: Wide customized tap-changing range, 5-27 tap positions optional
Notes: The electric-arc furnace transformer is customizable in capacity, voltage combination, impedance voltage, vector group, tap-changer type, cooling/protection methods to meet diverse metallurgical and industrial smelting requirements.
Zhejiang Tianrun Electric Co., Ltd. is one of the leading manufacturers and suppliers of electric arc furnace special transformer in China. We are committed to providing high quality customized products with competitive price. We warmly welcome you to buy bulk advanced electric arc furnace special transformer from our factory. Also, quotation is available.
Product Overview
The electric-arc furnace transformer is a special oil-immersed transformer dedicated for metallurgical melting furnaces. It converts high-voltage grid power to low-voltage large-current output for arc smelting process. Designed for frequent impact-load, short-circuit surge and short-time overload working conditions. Adopts high-grade oriented silicon-steel core and high-mechanical-strength copper windings. Off-circuit tap-changer or OLTC optional for wide secondary-voltage adjustment. Complies with IEC 60076 & JB/T 9640 standards, widely applied for EAF steel-making, ladle refining and ferroalloy smelting projects.
Core Features
- Excellent short-circuit withstand capability, adapted to frequent impact-load of arc furnace.
- Low-loss oriented silicon-steel core, low noise and low no-load loss.
- Reinforced copper windings with high mechanical strength to resist short-circuit mechanical stress.
- Multiple cooling selections: ONAN / ONAF / OFWF.
- Wide secondary-voltage adjustment range, off-circuit tap-changer or OLTC optional.
- Complete protection configuration: buchholz relay, pressure-relief device, winding & oil temperature monitoring.
- Custom-designed short-circuit impedance for arc stabilization and fault-current limiting.
Product Structure
Core
High-grade cold-rolled oriented silicon-steel sheets, step-lap laminated structure, reinforced clamping for anti-vibration.
Windings
HV copper tape winding, LV copper foil winding; enhanced insulation and mechanical strength for short-circuit resistance.
Tank
Fully-sealed welded steel tank with anti-corrosion powder coating.
Tap-changer
Off-circuit tap-changer or OLTC for secondary voltage regulation.
Accessories
HV/LV bushings, buchholz relay, pressure-relief device, temperature sensors, oil drain & sampling valve.
Note
Overall dimension and accessory layout will be adjusted according to customer project requirements.
Specification
|
Item |
Description |
Reference Standard |
Remarks |
|
Phase |
3-phase |
IEC 60076-1, JB/T 9640-2014 |
Single-phase available upon request |
|
Rated Frequency |
50 Hz; 60 Hz optional |
IEC 60076-1 |
60Hz for overseas market |
|
Rated Capacity |
630 ~ 120000 kVA |
JB/T 9640-2014 |
Fully customized according to furnace demand |
|
Primary Voltage |
6kV / 10kV / 35kV / 66kV / 110kV |
IEC 60076-3 |
Matched to customer grid voltage |
|
Secondary Voltage |
80V-1200V wide adjustable |
JB/T 9640-2014 |
Secondary output with large-current up to tens of kA |
|
Regulation Mode |
Off-circuit tap-changer / OLTC |
IEC 60076-7 |
OLTC for continuous smelting; off-circuit for less-frequent adjustment |
|
Tap Positions |
5-27 taps optional |
JB/T 9640-2014 |
19 taps popular for EAF: first 5 taps constant-power, rest constant-current |
|
Cooling Mode |
ONAN / ONAF / OFWF |
IEC 60076-2 |
OFWF widely adopted for large-capacity furnace transformer |
|
Short-circuit Impedance |
6%-18% |
JB/T 9640-2014 |
Typical EAF value 6-8%; external series reactor optional |
|
No-load Loss |
Range depends on capacity & core grade |
IEC 60076-1, JB/T 9640-2014 |
Exact value confirmed by project design |
|
Load Loss |
Tested at minimum secondary voltage under constant-power condition |
IEC 60076-1, JB/T 9640-2014 |
Project-specific data |
|
No-load Current |
0.2%-3.0% |
JB/T 9640-2014 |
Larger capacity with smaller no-load current |
|
Vector Group |
Dd0, Yd11, Dyn11 etc. |
IEC 60076-1 |
Custom-designed for user power system |
|
Insulating Oil |
25# / 45# mineral transformer oil |
IEC 60296 |
25# for temperate zone; 45# for cold region |
|
Core Material |
Cold-rolled oriented silicon-steel sheet, 45° full-step-lap lamination |
JB/T 9640-2014 |
Reinforced clamping for anti-vibration |
|
Allowable Overload |
Short-time overload permitted for melting peak |
IEC 60076-7 |
Continuous full-overload operation forbidden |
|
Protection Devices |
Buchholz relay, pressure-relief valve, winding & oil temperature sensor, oil drain & sampling valve |
IEC 60076-5 |
Complete standard protection suite |
|
Tank Treatment |
Fully-sealed welded steel tank, electrostatic powder anti-corrosion coating |
Customer drawing standard |
Long service life, low maintenance |
|
Altitude Derating |
Derating required when altitude＞1000 m |
IEC 60076-1 |
Special design for high-altitude site |
Notes: All above-listed performance values are reference ranges. Exact figures shall be confirmed per customer's furnace-process technical specification.
Environment
- Altitude: ≤1000m; derating required for altitude ＞1000m
- Ambient temperature: -25℃ ~ +40℃
- Relative humidity: ≤90% at 25℃
- Installation: Indoor furnace substation. Keep away from explosive gas, corrosive vapour and heavy conductive dust.
- Anti-vibration reinforcement is available on request for heavy-vibration sites.
Application
- Metallurgy: EAF steel-making, ladle refining furnace, ferroalloy smelting.
- Chemical industry: calcium carbide, yellow phosphorus, silicon carbide production.
- Other industrial furnaces requiring low-voltage large-current power supply.
Proccess of Transformer
1-Wire‑wound winding of transfomer
2-Foil‑wound winding of transfomer
3-Vacuum casting of transformer
4-Epoxy resin casting of transfomer
5-Coil assembling over core
6-HV porcelain bushings of oil immersed transformer
7-Lead insulation taping and welding of transfomer
8-Vacuum oil filling of transformer
9-Tank sealing of transformer
Testing of Transformer
1-Measurement of winding resistance testing of transformer
2-Measurement of voltage ratio and check of phase displacement testing of transformer
3-Separate‑source AC withstand voltage testing of transformer
4-Measurement of no‑load loss and no‑load current of transformer
5-Measurement of short‑circuit impedance and load loss of transformer
6-No load loss and no load current testing of transformer
7-Temperature‑rise test of transformer
8-Partial‑discharge measurement of transformer
9-Winding ressitant and voltage ratio testing of transformer
FAQ
Q1: What makes electric-arc furnace transformer different from ordinary power transformer?
A: It is structurally reinforced for frequent impact-load, short-time overload and repeated short-circuit conditions, with custom impedance and wide secondary voltage range, which standard distribution transformers cannot satisfy.
Q2: Choose OLTC or off-circuit tap-changer?
A: OLTC allows tap-change under load for continuous melting, recommended for large-capacity furnaces. Off-circuit tap-changer requires power-off adjustment, for medium-small furnaces with infrequent parameter modification.
Q3: Can it run continuously under overload?
A: Short-time overload is permitted for melting peak, but long-term continuous over-rated operation is forbidden, which accelerates insulation ageing.
Q4: What data needed for custom offer?
A: Furnace type, capacity, primary voltage, secondary voltage range, cooling mode, tap-changer requirement, site altitude and ambient conditions.
Q5: Can transformer suppress arc-furnace-generated harmonics?
A: Transformer itself cannot filter harmonics. External harmonic filter shall be equipped if harmonic mitigation is required.
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